1. A frequency control method for a full-direct-current variable-frequency air-cooled module machine press is characterized by comprising the following steps of:

(1) after the press operates stably, judging the loading and unloading section based on the collected system outlet water temperature and the set target outlet water temperature;

(2) each loading and unloading interval is correspondingly provided with a corresponding frequency adjusting coefficient and a constant adjusting frequency of the variable frequency press; the frequency adjusting coefficients of different loading and unloading intervals are different from the constant adjusting frequency of the variable frequency press; in the same loading and unloading interval, when the loading and unloading interval is in different modes, the corresponding frequency adjusting coefficient and the constant adjusting frequency of the variable frequency press are different;

(3) calculating the frequency change value of the compressor according to the frequency regulation coefficient, the constant regulation frequency of the variable frequency compressor and the energy calculation period tau;

(4) accumulating the frequency change value;

(5) and judging the accumulated result, judging whether the energy distribution period is reached, meeting the conditions, and adjusting the frequency of the variable frequency compressor.

2. The frequency control method of the full-direct-current variable-frequency air-cooled module machine press according to claim 1, characterized by comprising the following steps:

dividing a system loading and unloading interval in a refrigeration mode into an emergency stop area, an unloading area, a slow unloading area, a holding area, a slow loading area and a loading area on the basis of a system water temperature loading deviation delta Tadd, a slow loading deviation delta TS-add, a system water temperature unloading deviation delta Tsub and a slow unloading deviation delta TS-sub, wherein each interval is provided with a corresponding refrigeration control strategy;

the division conditions of the loading and unloading intervals are as follows;

when the temperature T of the system outlet water_outSatisfy T_out≥T_C-set+ΔT_S-addWhen the condition is met, the system executes a control strategy of the loading area;

when the temperature T of the system outlet water_outSatisfy T_C-set+ΔT_add＜T_out＜T_C-set+ΔT_S-addWhen the condition is met, the system executes a control strategy of the slow loading area;

when the temperature T of the system outlet water_outSatisfy T_C-set-ΔT_S-sub≤T_out＜T_C-set-ΔT_subWhen the condition is met, the system executes an unloading area control strategy;

when the temperature T of the system outlet water_outSatisfy T_C-set-ΔT_sub≤T_out＜T_C-setWhen the condition is met, the system executes a control strategy of the slow unloading area;

when the temperature T of the system outlet water_outSatisfy T_C-set≤T_out＜T_C-set+ΔT_addIf the condition is met, the system executes a holding area control strategy;

when the temperature T of the system outlet water_outSatisfy T_out≤T_C-set-ΔT_S-subAnd when the condition is met, the system executes the emergency stop zone control strategy.

3. The frequency control method of the full-direct-current variable-frequency air-cooled module machine press according to claim 2, characterized in that:

in the cooling mode, the system executes the following loading area control strategy:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting a required frequency change value delta F ((n +1) · tau), accumulating output results, adjusting the frequency of the direct current variable frequency compressor when an energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the cooling mode, the system executes the control strategy of the slow loading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the cooling mode, the system implements a holding zone control strategy as follows:

keeping the current frequency state of the press, exiting the press frequency calculation control mode, and outputting a required frequency change value which is constantly delta F ((n + 1). tau) ═ 0, namely the frequency conversion press which is started maintains the current running frequency, and the compressor which is not started any more;

in the cooling mode, the system executes the control strategy of the slow unloading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value deltaF ((n + 1). tau), accumulating the output result,when the energy distribution period theta is reached, the frequency of the DC variable frequency compressor is adjusted, and when the energy distribution period theta is not reached, the current system outlet water temperature T is detected again_outAnd the ambient temperature T_o；

In the cooling mode, the system executes the unloading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor; judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting a required frequency change value delta F ((n +1) · tau), accumulating output results, adjusting the frequency of the direct current variable frequency compressor when an energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the cooling mode, the system executes the emergency stop zone control strategy as follows:

sequentially selecting the frequency conversion press with the longest running time every other press scram interval t according to the balance mode of the press for the opened press_JAnd stopping the machine.

4. The frequency control method of the full-direct-current variable-frequency air-cooled module machine press according to claim 3, characterized in that a required frequency change value calculation formula is as follows:

wherein:

tau is an energy calculation period when the normal energy regulation process is carried out, the system is controlled to sample the system outlet water temperature once every time tau, and the change value delta T of the system outlet water temperature at the current (n +1) th time is calculated_out(n + 1). tau) and adjusting the frequency delta f of the frequency down-conversion compressor in the cooling operation mode according to the variation value of the temperature of the system outlet water of the (n +1) th time_CCalculating the variation value delta F ((n +1) · tau) of the required frequency of the (n +1) th press;

T_out(n + 1). tau) is the system effluent temperature detected in the (n +1) th energy calculation cycle;

T_out(n.tau) is the system effluent temperature detected during the nth energy calculation cycle;

Δf_Cfrequency is regularly adjusted for the frequency conversion compressor in the refrigeration operation mode;

k_Cadjusting the coefficient for the refrigeration operation frequency;

the Δ f_CAnd k is_CCorresponding numerical values are set in different loading and unloading intervals.

5. The frequency control method of the full-direct-current variable-frequency air-cooled module machine press according to claim 1, characterized by further comprising the following steps of:

giving a starting command based on the system water outlet temperature T_outAnd the system ambient temperature T_OThe one-time startup is carried out, and the energy can be adjusted quickly according to the outlet water temperature T of the current system_outAnd the target outlet water temperature T is set by the user_C-setCalculating the difference value to quickly adjust the number of the variable frequency presses needing to be started when the machine is started;

in the process of starting up the frequency conversion press, the time interval t is adjusted according to the quick energy_KSequentially starting to the rated operation rotating speed N of refrigeration or heating_C-ratedAnd in turn maintaining a start-up settling time t_OAnd then entering a normal energy regulation process.

6. The frequency control method of the full-direct-current variable-frequency air-cooled module compressor according to claim 5, wherein the calculation formula for adjusting the number of variable-frequency compressors to be started when the compressor is started in a refrigeration mode is as follows:

M_ALLthe total number of frequency conversion presses which have no faults and are not forbidden in the system;

M_OPthe number of the frequency conversion presses needing to be started can be adjusted for starting the system quickly, the calculated result is rounded up according to the rounding, and if the number of the frequency conversion presses needing to be started exceeds the total number of the frequency conversion presses which have no faults and are not forbidden in the system, the frequency conversion presses needing to be started are calculated according to M_ALLThe frequency conversion press is started, and the selection mode of the frequency conversion press needing to be started in system control is as follows: sequencing according to the accumulated running time of the press, and sequentially selecting the frequency conversion press which has no fault, is not forbidden and has the shortest accumulated running time to be started.

7. The frequency control method of the full-direct-current variable-frequency air-cooled module machine press according to claim 5, characterized in that the calculation formula of the number of the variable-frequency press needing to be started can be adjusted by quickly starting the machine in the heating mode is as follows:

when the ambient temperature T_OThe conditions are satisfied: t is_OThe calculation formula of the number of the variable frequency presses needing to be started can be adjusted when the machine is started to be more than or equal to 0:

when the ambient temperature T_OThe conditions are satisfied: t is_OIf the voltage is less than 0, the calculation formula of the number of the frequency conversion presses needing to be started can be adjusted when the machine is started quickly as follows:

wherein M is_ALLThe total number of frequency conversion presses which have no faults and are not forbidden in the system;

M_OPthe number of the frequency conversion presses needing to be started can be adjusted for starting the system quickly, the calculated result is rounded up according to the rounding, and if the number of the frequency conversion presses needing to be started exceeds the total number of the frequency conversion presses which have no faults and are not forbidden in the system, the frequency conversion presses needing to be started are calculated according to M_ALLThe frequency conversion press is started, and the selection mode of the frequency conversion press needing to be started in system control is as follows: sorting according to the accumulated running time of the press, and sequentially selecting the press which is not in fault and is not forbiddenAnd starting the frequency conversion press with the shortest accumulated running time.

8. The frequency control method of the full-direct-current variable-frequency air-cooled module machine press according to claim 1, characterized by comprising the following steps: dividing a system loading and unloading interval in a heating mode into an emergency stop area, an unloading area, a slow unloading area, a holding area, a slow loading area and a loading area on the basis of a system water temperature loading deviation delta Tadd, a slow loading deviation delta TS-add, a system water temperature unloading deviation delta Tsub and a slow unloading deviation delta TS-sub, wherein each interval is provided with a corresponding heating control strategy;

the division conditions of the loading and unloading intervals are as follows;

when the temperature T of the system outlet water_outSatisfy T_out≤T_H-set-ΔT_S-addWhen the condition is met, the system executes a control strategy of the loading area;

when the temperature T of the system outlet water_outSatisfy T_H-set-ΔT_S-add＜T_out≤T_H-set-ΔT_addWhen the condition is met, the system executes a control strategy of the slow loading area;

when the temperature T of the system outlet water_outSatisfy T_H-set+ΔT_sub＜T_out≤T_H-set+ΔT_S-subWhen the condition is met, the system executes an unloading area control strategy;

when the temperature T of the system outlet water_outSatisfy T_H-set＜T_out≤T_H-set+ΔT_subWhen the condition is met, the system executes a control strategy of the slow unloading area;

when the temperature T of the system outlet water_outSatisfy T_H-set-ΔT_add＜T_out≤T_H-setIf the condition is met, the system executes a holding area control strategy;

when the temperature T of the system outlet water_outSatisfy T_out≥T_H-set+ΔT_S-subAnd when the condition is met, the system executes the emergency stop zone control strategy.

9. The frequency control method of the full-direct-current variable-frequency air-cooled module machine press according to claim 8, characterized in that:

in the heating mode, the system executes a loading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting the frequency calculation result delta F ((n +1) · tau), accumulating the output results, adjusting the frequency of the direct current frequency conversion compressor when the energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the heating mode, the system executes the control strategy of the slow loading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the heating mode, the system executes the holding zone control strategy as follows:

keeping the current frequency state of the press, exiting the press frequency calculation control mode, and outputting a required frequency change value which is constantly delta F ((n + 1). tau) ═ 0, namely the frequency conversion press which is started maintains the current running frequency, and the compressor which is not started any more;

in the heating mode, the system executes the control strategy of the slow unloading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating the output results, and aligning when reaching an energy distribution period thetaThe flow frequency conversion compressor adjusts the frequency, when the energy distribution period theta is not reached, the current system water outlet temperature T is detected again_outAnd the ambient temperature T_o；

In the heating mode, the system executes the unloading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is not less than 0, if yes, judging that delta F ((n +1) · tau) is 0, if no, outputting the frequency calculation result delta F ((n +1) · tau), accumulating the output results, adjusting the frequency of the direct current frequency conversion compressor when the energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the heating mode, the system executes the emergency stop zone control strategy as follows:

for opened presses, according to a press balancing mode, selecting the frequency conversion press with the longest running time in turn and every other press scram interval t_JAnd stopping the machine.

10. The frequency control method of the full-direct-current variable-frequency air-cooled module machine press according to claim 9, characterized in that: frequency variation value calculation formula:

wherein:

tau is an energy calculation period when the normal energy regulation process is carried out, the system is controlled to sample the system outlet water temperature once every time tau, and the change value delta T of the system outlet water temperature at the current (n +1) th time is calculated_out(n +1) · tau), and calculating a variation value deltaF of the required frequency of the press for the (n +1) th time according to the variation value of the temperature of the system outlet water for the (n +1) th time;

T_outthe system detected when ((n + 1). tau) is the (n +1) th energy calculation cycleThe outlet water temperature is unified;

T_out(n.tau) is the system effluent temperature detected during the nth energy calculation cycle;

Δf_Hfrequency is regularly adjusted for the down-conversion compressor in the heating operation mode;

k_Hadjusting the coefficient for the heating operation frequency;

the Δ f_HAnd k is_HCorresponding numerical values are set in different loading and unloading intervals.

Background

When the existing direct-current variable-frequency compressor is used for loading and unloading control, the problems of change of actual load requirements of system users, capacity of the compressor under different working conditions, temperature difference between system water temperature and target set water and the like cannot be simultaneously considered, and the water temperature can be quickly adjusted to quickly reach the set target according to different working conditions in the actual loading and unloading control.

Disclosure of Invention

In view of the above, the present invention is directed to a frequency control method for a full dc frequency conversion air-cooled module press, so as to solve the above-mentioned disadvantages.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a frequency control method for a full-direct-current variable-frequency air-cooled module machine press comprises the following steps:

(1) after the press operates stably, judging the loading and unloading section based on the collected system outlet water temperature and the set target outlet water temperature;

(2) each loading and unloading interval is correspondingly provided with a corresponding frequency adjusting coefficient and a constant adjusting frequency of the variable frequency press; the frequency adjusting coefficients of different loading and unloading intervals are different from the constant adjusting frequency of the variable frequency press; in the same loading and unloading interval, when the loading and unloading interval is in different modes, the corresponding frequency adjusting coefficient and the constant adjusting frequency of the variable frequency press are different;

(3) calculating the frequency variation value of the compressor according to the frequency regulation coefficient, the constant regulation frequency of the variable frequency compressor and the energy calculation period tau

(4) Accumulating the frequency change value;

(5) and judging the accumulated result, judging whether the energy distribution period is reached, meeting the conditions, and adjusting the frequency of the variable frequency compressor.

Further, the system loading and unloading zone in the refrigeration mode is divided into an emergency stop zone, an unloading zone, a slow unloading zone, a holding zone, a slow loading zone and a loading zone based on the system water temperature loading deviation delta Tadd, the slow loading deviation delta TS-add, the system water temperature unloading deviation delta Tsub and the slow unloading deviation delta TS-sub, and each zone is provided with a corresponding refrigeration control strategy;

the division conditions of the loading and unloading intervals are as follows;

when the temperature T of the system outlet water_outSatisfy T_out≥T_C-set+ΔT_S-addWhen the condition is met, the system executes a control strategy of the loading area;

when the temperature T of the system outlet water_outSatisfy T_C-set+ΔT_add＜T_out＜T_C-set+ΔT_S-addWhen the condition is met, the system executes a control strategy of the slow loading area;

when the temperature T of the system outlet water_outSatisfy T_C-set-ΔT_S-sub≤T_out＜T_C-set-ΔT_subWhen the condition is met, the system executes an unloading area control strategy;

when the temperature T of the system outlet water_outSatisfy T_C-set-ΔT_sub≤T_out＜T_C-setWhen the condition is met, the system executes a control strategy of the slow unloading area;

when the temperature T of the system outlet water_outSatisfy T_C-set≤T_out＜T_C-set+ΔT_addIf the condition is met, the system executes a holding area control strategy;

when the temperature T of the system outlet water_outSatisfy T_out≤T_C-set-ΔT_S-subAnd when the condition is met, the system executes the emergency stop zone control strategy.

Further, in the cooling mode, the system executes a loading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting a required frequency change value delta F ((n +1) · tau), accumulating output results, adjusting the frequency of the direct current variable frequency compressor when an energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the cooling mode, the system executes the control strategy of the slow loading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the cooling mode, the system implements a holding zone control strategy as follows:

keeping the current frequency state of the press, exiting the press frequency calculation control mode, and keeping the output required frequency change value as constant as delta F ((n + 1). tau) ═ 0, namely the frequency conversion press which is opened maintains the current operation frequency, and the compressor which is not opened any more

In the cooling mode, the system executes the control strategy of the slow unloading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the cooling mode, the system executes the unloading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor; judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting a required frequency change value delta F ((n +1) · tau), accumulating output results, adjusting the frequency of the direct current variable frequency compressor when an energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd environmentTemperature T_o；

In the cooling mode, the system executes the emergency stop zone control strategy as follows:

for opened presses, according to a press balancing mode, selecting the frequency conversion press with the longest running time in turn and every other press scram interval t_JAnd stopping the machine.

Further, the frequency variation value calculation formula is:

wherein:

tau is an energy calculation period when the normal energy regulation process is carried out, the system is controlled to sample the system outlet water temperature once every time tau, and the change value delta T of the system outlet water temperature at the current (n +1) th time is calculated_out(n + 1). tau) and adjusting the frequency delta f of the frequency down-conversion compressor in the cooling operation mode according to the variation value of the temperature of the system outlet water of the (n +1) th time_CCalculating the variation value delta F ((n +1) · tau) of the required frequency of the (n +1) th press;

T_out(n + 1). tau) is the system effluent temperature detected in the (n +1) th energy calculation cycle;

T_out(n.tau) is the system effluent temperature detected during the nth energy calculation cycle;

Δf_Cfrequency is regularly adjusted for the frequency conversion compressor in the refrigeration operation mode;

k_Cadjusting the coefficient for the refrigeration operation frequency;

the Δ f_CAnd k is_CCorresponding numerical values are set in different loading and unloading intervals.

Further, the method comprises the following steps of:

giving a starting command based on the system water outlet temperature T_outAnd the system ambient temperature T_OThe one-time startup is carried out, and the energy can be adjusted quickly according to the outlet water temperature T of the current system_outAnd the target outlet water temperature T is set by the user_C-setDifferential value is started and is quickly adjusted down frequency conversion press needing to be openedCalculating a number;

in the process of starting up the frequency conversion press, the time interval t is adjusted according to the quick energy_KSequentially starting to the rated operation rotating speed N of refrigeration or heating_C-ratedAnd in turn maintaining a start-up settling time t_OAnd then entering a normal energy regulation process.

Further, the calculation formula for rapidly adjusting the number of the variable frequency presses to be started when the refrigerator is started in the refrigeration mode is as follows:

M_ALLthe total number of frequency conversion presses which have no faults and are not forbidden in the system;

M_OPthe number of the frequency conversion presses needing to be started can be adjusted for starting the system quickly, the calculated result is rounded up according to the rounding, and if the number of the frequency conversion presses needing to be started exceeds the total number of the frequency conversion presses which have no faults and are not forbidden in the system, the frequency conversion presses needing to be started are calculated according to M_ALLThe frequency conversion press is started, and the selection mode of the frequency conversion press needing to be started in system control is as follows: sequencing according to the accumulated running time of the press, and sequentially selecting the frequency conversion press which has no fault, is not forbidden and has the shortest accumulated running time to be started.

Further, the calculation formula for rapidly adjusting the number of the variable frequency presses to be started in the heating mode is as follows:

when the ambient temperature T_OThe conditions are satisfied: t is_OThe calculation formula of the number of the variable frequency presses needing to be started can be adjusted when the machine is started to be more than or equal to 0:

when the ambient temperature T_OThe conditions are satisfied: t is_OIf the voltage is less than 0, the calculation formula of the number of the frequency conversion presses needing to be started can be adjusted when the machine is started quickly as follows:

wherein M is_ALLThe total number of frequency conversion presses which have no faults and are not forbidden in the system;

M_OPthe number of the frequency conversion presses needing to be started can be adjusted for starting the system quickly, the calculated result is rounded up according to the rounding, and if the number of the frequency conversion presses needing to be started exceeds the total number of the frequency conversion presses which have no faults and are not forbidden in the system, the frequency conversion presses needing to be started are calculated according to M_ALLThe frequency conversion press is started, and the selection mode of the frequency conversion press needing to be started in system control is as follows: sequencing according to the accumulated running time of the press, and sequentially selecting the frequency conversion press which has no fault, is not forbidden and has the shortest accumulated running time to be started.

Further, the system loading and unloading zone in the heating mode is divided into an emergency stop zone, an unloading zone, a slow unloading zone, a holding zone, a slow loading zone and a loading zone based on the system water temperature loading deviation delta Tadd, the slow loading deviation delta TS-add, the system water temperature unloading deviation delta Tsub and the slow unloading deviation delta TS-sub, and each zone is provided with a corresponding heating control strategy;

the division conditions of the loading and unloading intervals are as follows;

when the temperature T of the system outlet water_outSatisfy T_out≤T_H-set-ΔT_S-addWhen the condition is met, the system executes a control strategy of the loading area;

when the temperature T of the system outlet water_outSatisfy T_H-set-ΔT_S-add＜T_out≤T_H-set-ΔT_addWhen the condition is met, the system executes a control strategy of the slow loading area;

when the temperature T of the system outlet water_outSatisfy T_H-set+ΔT_sub＜T_out≤T_H-set+ΔT_S-subWhen the condition is met, the system executes an unloading area control strategy;

when the temperature T of the system outlet water_outSatisfy T_H-set＜T_out≤T_H-set+ΔT_subWhen the condition is met, the system executes a control strategy of the slow unloading area;

when the temperature T of the system outlet water_outSatisfy the requirement ofT_H-set-ΔT_add＜T_out≤T_H-setIf the condition is met, the system executes a holding area control strategy;

when the temperature T of the system outlet water_outSatisfy T_out≥T_H-set+ΔT_S-subAnd when the condition is met, the system executes the emergency stop zone control strategy.

Further, in the heating mode, the system executes a load area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting the frequency calculation result delta F ((n +1) · tau), accumulating the output results, adjusting the frequency of the direct current frequency conversion compressor when the energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the heating mode, the system executes the control strategy of the slow loading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the heating mode, the system executes the holding zone control strategy as follows:

keeping the current frequency state of the press, exiting the press frequency calculation control mode, and outputting a required frequency change value which is constantly delta F ((n + 1). tau) ═ 0, namely the frequency conversion press which is started maintains the current running frequency, and the compressor which is not started any more;

in the heating mode, the system executes the control strategy of the slow unloading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the heating mode, the system executes the unloading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is not less than 0, if yes, judging that delta F ((n +1) · tau) is 0, if no, outputting the frequency calculation result delta F ((n +1) · tau), accumulating the output results, adjusting the frequency of the direct current frequency conversion compressor when the energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the heating mode, the system executes the emergency stop zone control strategy as follows:

for opened presses, according to a press balancing mode, selecting the frequency conversion press with the longest running time in turn and every other press scram interval t_JAnd stopping the machine.

Further, the frequency variation value calculation formula is:

wherein:

tau is an energy calculation period when the normal energy regulation process is carried out, the system is controlled to sample the system outlet water temperature once every time tau, and the change value delta T of the system outlet water temperature at the current (n +1) th time is calculated_out((n + 1). tau), andcalculating a variation value delta F ((n +1) · tau) of the required frequency of the press at the (n +1) th time according to the variation value of the temperature of the system effluent at the (n +1) th time;

T_out(n + 1). tau) is the system effluent temperature detected in the (n +1) th energy calculation cycle;

T_out(n.tau) is the system effluent temperature detected during the nth energy calculation cycle;

Δf_Hfrequency is regularly adjusted for the down-conversion compressor in the heating operation mode;

k_Hadjusting the coefficient for the heating operation frequency;

the Δ f_HAnd k is_HCorresponding numerical values are set in different loading and unloading intervals.

Compared with the prior art, the frequency control method of the full-direct-current variable-frequency air-cooled module machine press has the following advantages:

the frequency control method of the full-direct-current variable-frequency air-cooled module machine press, provided by the invention, has the advantages that the change of the actual load demand of a system user, the capacity of the press under different working conditions, the temperature difference between the system water temperature and the target set water temperature and the like are taken into consideration in the loading and unloading process, the running time and the running frequency of each variable-frequency press are balanced, the balanced running of the variable-frequency presses is ensured, the conditions of overshooting and untimely temperature rise of the system water temperature are prevented, the accurate control of the system water temperature is ensured, and the balance between the running frequency of the variable-frequency presses and the accumulated running time is fully considered in the loading and unloading process, so that the stable, reliable and energy-saving control running of a unit is realized.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of normal energy modulation process control logic in a cooling mode according to an embodiment of the present invention;

FIG. 2 is a schematic view of a loading/unloading section in a cooling mode according to an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating normal process control logic in a heating mode according to an embodiment of the present invention;

fig. 4 is a schematic view of loading and unloading intervals in the heating mode according to the embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

As shown in fig. 1 to 4, a frequency control method for a full-dc frequency conversion air-cooled module machine press includes the following steps:

(1) after the press operates stably, judging the loading and unloading section based on the collected system outlet water temperature and the set target outlet water temperature;

(2) each loading and unloading interval is correspondingly provided with a corresponding frequency adjusting coefficient and a constant adjusting frequency of the variable frequency press; the frequency adjusting coefficients of different loading and unloading intervals are different from the constant adjusting frequency of the variable frequency press; in the same loading and unloading interval, when the loading and unloading interval is in different modes, the corresponding frequency adjusting coefficient and the constant adjusting frequency of the variable frequency press are different;

(3) calculating the frequency change value of the compressor according to the frequency regulation coefficient, the constant regulation frequency of the variable frequency compressor and the energy calculation period tau;

(4) accumulating the frequency change value;

(5) and judging the accumulated result, judging whether the energy distribution period is reached, meeting the conditions, and adjusting the frequency of the variable frequency compressor.

And normal energy adjustment is carried out after the press operates stably, and quick energy adjustment is carried out for starting the press before the press operates stably.

Dividing a system loading and unloading interval in a refrigeration mode into an emergency stop area, an unloading area, a slow unloading area, a holding area, a slow loading area and a loading area on the basis of a system water temperature loading deviation delta Tadd, a slow loading deviation delta TS-add, a system water temperature unloading deviation delta Tsub and a slow unloading deviation delta TS-sub, wherein each interval is provided with a corresponding refrigeration control strategy;

the division conditions of the loading and unloading intervals are as follows;

when the temperature T of the system outlet water_outSatisfy T_out≥T_C-set+ΔT_S-addWhen the condition is met, the system executes a control strategy of the loading area;

when the temperature T of the system outlet water_outSatisfy T_C-set+ΔT_add＜T_out＜T_C-set+ΔT_S-addWhen the condition is met, the system executes a control strategy of the slow loading area;

when the temperature T of the system outlet water_outSatisfy T_C-set-ΔT_S-sub≤T_out＜T_C-set-ΔT_subWhen the condition is met, the system executes an unloading area control strategy;

when the temperature T of the system outlet water_outSatisfy T_C-set-ΔT_sub≤T_out＜T_C-setWhen the condition is met, the system executes a control strategy of the slow unloading area;

when the temperature T of the system outlet water_outSatisfy T_C-set≤T_out＜T_C-set+ΔT_addIf the condition is met, the system executes a holding area control strategy;

when the temperature T of the system outlet water_outSatisfy T_out≤T_C-set-ΔT_S-subAnd when the condition is met, the system executes the emergency stop zone control strategy.

In the cooling mode, the system executes the following loading area control strategy:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting a required frequency change value delta F ((n +1) · tau), accumulating output results, adjusting the frequency of the direct current variable frequency compressor when an energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the cooling mode, the system executes the control strategy of the slow loading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the cooling mode, the system implements a holding zone control strategy as follows:

keeping the current frequency state of the press, exiting the press frequency calculation control mode, and outputting a required frequency change value which is constantly delta F ((n + 1). tau) ═ 0, namely the frequency conversion press which is started maintains the current running frequency, and the compressor which is not started any more;

in the cooling mode, the system executes the control strategy of the slow unloading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the cooling mode, the system executes the unloading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the outlet water temperature of the system according to a frequency regulation coefficient set in a refrigeration mode and a constant regulation frequency of the variable frequency compressor; judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting a required frequency change value delta F ((n +1) · tau), accumulating output results, adjusting the frequency of the direct current variable frequency compressor when an energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the cooling mode, the system executes the emergency stop zone control strategy as follows:

for opened presses, according to a press balancing mode, selecting the frequency conversion press with the longest running time in turn and every other press scram interval t_JAnd stopping the machine.

Frequency variation value calculation formula:

wherein:

tau is an energy calculation period when the normal energy regulation process is carried out, the system is controlled to sample the system outlet water temperature once every time tau, and the change value delta T of the system outlet water temperature at the current (n +1) th time is calculated_out(n + 1). tau) and adjusting the frequency delta f of the frequency down-conversion compressor in the cooling operation mode according to the variation value of the temperature of the system outlet water of the (n +1) th time_CCalculating the variation value delta F ((n +1) · tau) of the required frequency of the (n +1) th press;

T_out(n + 1). tau) is the system effluent temperature detected in the (n +1) th energy calculation cycle;

T_out(n.tau) is the system effluent temperature detected during the nth energy calculation cycle;

Δf_Cfrequency is regularly adjusted for the frequency conversion compressor in the refrigeration operation mode;

k_Cadjusting the coefficient for the refrigeration operation frequency;

the Δ f_CAnd k is_CCorresponding numerical values are set in different loading and unloading intervals.

When the temperature T of the system outlet water_outThe conditions are satisfied: t is_out≥T_C-set+ΔT_S-addThat is, the temperature of the water in the system is in the loading area,

Δf_C＝Δf_OC

when the temperature T of the system outlet water_outThe conditions are satisfied: t is_C-set+ΔT_add＜T_out＜T_C-set+ΔT_S-addNamely, when the water temperature of the system is in the slow loading area,

when the temperature T of the system outlet water_outThe conditions are satisfied: t is_C-set-ΔT_S-sub≤T_out＜T_C-set-ΔT_subI.e. the system water temperature is in the unloading zone,

Δf_C＝-Δf_OC

when the system goes outTemperature T of water_outThe conditions are satisfied: t is_C-set-ΔT_sub≤T_out＜T_C-setWhen the water temperature of the system is in a slow unloading area

Wherein Δ f_OCFrequency (unit: rps) regulated for reference stability of frequency converter in refrigeration mode of operation

k_CAdjusting the coefficient for the refrigeration operation frequency:

when the temperature T of the system outlet water_outThe conditions are satisfied:

T_out≥T_C-set+ΔT_S-addor T_C-set-ΔT_S-sub≤T_out＜T_C-set-ΔT_subI.e. the system water temperature is in the load or unload region,

k_C＝k_OC

when the temperature T of the system outlet water_outThe conditions are satisfied: t is_C-set+ΔT_add＜T_out＜T_C-set+ΔT_S-addThat is, the water temperature of the system is in the slow loading area

When the temperature T of the system outlet water_outThe conditions are satisfied: t is_C-set-ΔT_sub≤T_out＜T_C-setNamely when the water temperature of the system is in a slow unloading area

Wherein k is_OCAdjusting coefficient for refrigeration operation frequency reference:

α_C、β_Ccorrecting a refrigeration operation frequency adjustment coefficient;

△T_C-ratedthe water temperature difference (unit:. degree. C.) is defined for the refrigerating operation frequency adjustment system.

Calculating a required frequency change value (unit: rps) when the Delta F ((n +1) · tau) is the n +1 energy calculation period;

T_Ois the current system ambient temperature (unit:. degree. C.);

T_C-setis the system target outlet water temperature (unit:. degree. C.) set in the refrigeration mode.

The control method before the stable operation of the press comprises the following steps:

giving a starting command based on the system water outlet temperature T_outAnd the system ambient temperature T_OThe one-time startup is carried out, and the energy can be adjusted quickly according to the outlet water temperature T of the current system_outAnd the target outlet water temperature T is set by the user_C-setCalculating the difference value to quickly adjust the number of the variable frequency presses needing to be started when the machine is started;

in the process of starting up the frequency conversion press, the time interval t is adjusted according to the quick energy_KSequentially starting to the rated operation rotating speed N of refrigeration or heating_C-ratedAnd in turn maintaining a start-up settling time t_OAnd then entering a normal energy regulation process.

Under the refrigeration mode, the calculation formula of the number of the frequency conversion presses needing to be started can be adjusted when the compressor is started up quickly as follows:

M_ALLthe total number of frequency conversion presses which have no faults and are not forbidden in the system;

M_OPthe number of the frequency conversion presses needing to be started can be adjusted for starting the system quickly, the calculated result is rounded up according to the rounding, and if the number of the frequency conversion presses needing to be started exceeds the total number of the frequency conversion presses which have no faults and are not forbidden in the system, the frequency conversion presses needing to be started are calculated according to M_ALLThe frequency conversion press is started, and the selection mode of the frequency conversion press needing to be started in system control is as follows: sequencing according to the accumulated running time of the press, and sequentially selecting the frequency conversion press which has no fault, is not forbidden and has the shortest accumulated running time to be started.

T_OThe temperature of the current system environment temperature (unit:. degree. C.);

△T_C-startthe temperature difference (unit: DEG C) of the first opening of the refrigeration of the unit is shown;

y_Cadjusting coefficient for refrigerating and starting functions of the unit;

b_Cand a water temperature correction coefficient for the refrigeration starting of the unit.

Calculating the frequency requirement of the press according to the change of the water outlet temperature of the system in a refrigeration mode, and timing the change quantity delta T of the water outlet temperature of the system under other conditions_outThe larger the regulation quantity of the frequency of the press is, the larger the variation quantity delta T of the water outlet temperature of the system_outThe smaller the frequency adjustment quantity of the press is, the smaller the frequency adjustment quantity of the press is; simultaneously takes different ring temperatures T into account_OTarget water outlet temperature T of different systems_C-setThe frequency demand calculation of the press is corrected according to the difference of the refrigerating capacities of the following units: the higher the environment temperature is, the lower the target water temperature is, the lower the refrigerating capacity of the unit is, the larger the required compressor frequency adjustment amount is at the moment, the lower the environment temperature is, the higher the water temperature is, the better the refrigerating capacity of the unit is, the smaller the required compressor frequency adjustment amount is at the moment, and on the basis, the outlet water temperature T of the current system is considered_outWith target water temperature T_C-setRelative difference, relative differenceThe larger the frequency regulating quantity of the press, the larger the relative difference valueThe smaller the frequency regulating quantity of the compressor is, the load change trend of a user is fully considered in the loading and unloading mode under the refrigeration mode, and the refrigerating machine has the pre-regulating capacity to ensure the accurate and rapid regulation of the system water temperature at different environment temperatures and different set target water temperatures and the stable and reliable operation of a unit.

The control system calculates the frequency requirement once after the energy calculation period tau, and performs energy regulation once after the energy regulation period theta (the energy regulation period theta is integral multiple of the energy calculation period tau, and theta is larger than or equal to tau). As shown in FIG. 1, the cooling operation mode is divided into a loading region, a slow loading region, a holding region, a slow unloading region, and a fast unloading regionA rapid unloading area and an emergency stop area when the temperature T of the outlet water of the system is_outIn the loading area: t is_out≥T_C-set+ΔT_S-addIf a certain time Δ F ((n) is calculated in this area₁If the sum of +1) tau is less than or equal to 0, the frequency demand calculation is not included, i.e. the calculated change value delta F ((n) of the frequency demand is given₁+1) · τ) ═ 0; when the temperature T of the system outlet water_outIn the unloading area:

T_C-set-ΔT_S-sub≤T_out＜T_C-set-ΔT_subif a certain time Δ F ((n) is calculated in this area₂If + 1). tau) ≥ 0, it is not included in the frequency requirement calculation, i.e. given the frequency requirement calculation variation value Δ F ((n)₂+1) · τ) ═ 0, and when entering the holding region, the frequency adjustment calculation method of the down-conversion compressor in the cooling mode is exited, and at this time, the frequency variation Δ F ((n) is output₃+1) τ) ═ 0, that is, the open frequency conversion press maintains the current running frequency, in the emergency stop area, according to the press balance mode, the frequency conversion press with the longest running time is selected in turn every other press emergency stop interval t_JStopping the machine;

the energy regulation principle is as follows:

when loading (including loading area and slow loading area):

setting the accumulated demand frequency delta F to the frequency conversion press with no fault, no forbiddance and lowest running frequency in the system after each energy regulation period theta, if a plurality of frequency conversion presses in the system meet the conditions, selecting the frequency conversion press with the shortest accumulated running time according to an equalization mode until the frequency of the press is loaded to the refrigerating rated running frequency N_C-rated。

When the frequency conversion presses already running in the system all reach the refrigerating rated operation frequency N_C-ratedJudging whether the variable frequency press is not started or not, if so, carrying out frequency loading accumulation, loading the variable frequency press which is not started, has no fault, is not forbidden and has the shortest accumulated running time, and if the required frequency delta F loaded on the non-started press meets the condition that delta F is less than N after the energy regulation period theta is passed each time in the process_C-minThen the frequency conversion press is not started at the momentThe frequency loading accumulation is continued until the condition that delta F is more than or equal to N is met_C-minAfter the frequency conversion press is started, firstly loading the refrigeration rated operation frequency N_C-ratedStabilized running time t after start-up_OAnd then adjusting the frequency according to a frequency adjustment calculation mode in a refrigeration mode.

If all the frequency conversion presses which are not in fault and are not forbidden in the system are loaded to the refrigerating rated operation frequency N_C-ratedWhen the system still has a loading requirement (namely the temperature of the system outlet water is in the loading area or the slow loading area), selecting a press without fault and with the lowest running frequency for frequency loading after the energy regulation period theta, and if a plurality of presses in the system meet the conditions, selecting a frequency conversion press with the shortest accumulated running time for frequency loading regulation according to a press balancing mode until all the presses are loaded to the maximum refrigerating running frequency N_C-max。

A holding region:

at this time, each variable frequency press keeps the current operating frequency unchanged, the press frequency adjustment calculation mode under the refrigeration mode is quitted in the area, and the delta F is kept equal to 0.

Unloading zone (including unloading zone and slow unloading zone)

After the energy regulation period theta passes through the area, the frequency conversion press with the highest fault-free running frequency is selected for frequency unloading, if a plurality of presses in the system meet the conditions, the frequency conversion press with the longest accumulated running time is selected according to the press balancing mode for frequency unloading regulation until all the presses are unloaded to the refrigerating rated running frequency N_C-rated。

If the unloading demand still exists but the system does not enter the emergency stop area (the system outlet water temperature T)_outIn the unloading zone or the slow unloading zone) and all the opened variable frequency presses in the system have unloaded the refrigerating rated operation frequency N at the moment_C-ratedSelecting the frequency conversion press with no fault and the highest operation frequency for frequency unloading through the energy regulation period theta, and selecting the frequency conversion press with the longest accumulated operation time for frequency unloading if a plurality of frequency conversion presses meet the conditions until all opened frequency conversion presses are unloaded to the lowest refrigeration operation frequencyRate N_C-min。

If the unloading requirement exists, frequency unloading accumulation is carried out, and the lowest running frequency N in the opened variable frequency press is reached_C-minAnd stopping the machine with the longest running time, and after an energy regulation period theta, if the frequency delta F required by the variable frequency press meeting the above conditions is distributed to the variable frequency press meeting the conditions that the delta F is less than N_C-minAt the moment, the frequency conversion press continues to carry out frequency unloading accumulation until the condition that the delta F is more than or equal to N is met_C-minAnd stopping the machine after the operation. An emergency stop area:

when the water temperature of the system enters the emergency stop area, sequentially selecting the frequency conversion with the longest running time every emergency stop interval t of the press according to the balance mode of the press at the moment_JAnd stopping the machine.

Under the heating mode, the calculation formula of the number of the frequency conversion presses needing to be started can be adjusted when the machine is started up quickly as follows:

when the ambient temperature T_OThe conditions are satisfied: t is_OThe calculation formula of the number of the variable frequency presses needing to be started can be adjusted when the machine is started to be more than or equal to 0:

when the ambient temperature T_OThe conditions are satisfied: t is_OIf the voltage is less than 0, the calculation formula of the number of the frequency conversion presses needing to be started can be adjusted when the machine is started quickly as follows:

wherein M is_ALLThe total number of frequency conversion presses which have no faults and are not forbidden in the system;

M_OPthe number of the frequency conversion presses needing to be started can be adjusted for starting the system quickly, the calculated result is rounded up according to the rounding, and if the number of the frequency conversion presses needing to be started exceeds the total number of the frequency conversion presses which have no faults and are not forbidden in the system, the frequency conversion presses needing to be started are calculated according to M_ALLThe frequency conversion press is started, and the selection mode of the frequency conversion press needing to be started in system control is as follows: arranging according to the accumulated running time of the pressAnd sequentially selecting the frequency conversion press which has no fault, is not forbidden and has the shortest accumulated running time to be started.

Dividing a system loading and unloading interval in a heating mode into an emergency stop area, an unloading area, a slow unloading area, a holding area, a slow loading area and a loading area on the basis of a system water temperature loading deviation delta Tadd, a slow loading deviation delta TS-add, a system water temperature unloading deviation delta Tsub and a slow unloading deviation delta TS-sub, wherein each interval is provided with a corresponding heating control strategy;

the division conditions of the loading and unloading intervals are as follows;

when the temperature T of the system outlet water_outSatisfy T_out≤T_H-set-ΔT_S-addWhen the condition is met, the system executes a control strategy of the loading area;

when the temperature T of the system outlet water_outSatisfy T_H-set-ΔT_S-add＜T_out≤T_H-set-ΔT_addWhen the condition is met, the system executes a control strategy of the slow loading area;

when the temperature T of the system outlet water_outSatisfy T_H-set+ΔT_sub＜T_out≤T_H-set+ΔT_S-subWhen the condition is met, the system executes an unloading area control strategy;

when the temperature T of the system outlet water_outSatisfy T_H-set＜T_out≤T_H-set+ΔT_subWhen the condition is met, the system executes a control strategy of the slow unloading area;

when the temperature T of the system outlet water_outSatisfy T_H-set-ΔT_add＜T_out≤T_H-setIf the condition is met, the system executes a holding area control strategy;

when the temperature T of the system outlet water_outSatisfy T_out≥T_H-set+ΔT_S-subAnd when the condition is met, the system executes the emergency stop zone control strategy.

In the heating mode, the system executes a loading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is less than or equal to 0, if so, judging that delta F ((n +1) · tau) is 0, otherwise, outputting the frequency calculation result delta F ((n +1) · tau), accumulating the output results, adjusting the frequency of the direct current frequency conversion compressor when the energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the heating mode, the system executes the control strategy of the slow loading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the heating mode, the system executes the holding zone control strategy as follows:

keeping the current frequency state of the press, exiting the press frequency calculation control mode, and outputting a required frequency change value which is constantly delta F ((n + 1). tau) ═ 0, namely the frequency conversion press which is started maintains the current running frequency, and the compressor which is not started any more;

in the heating mode, the system executes the control strategy of the slow unloading area as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

outputting a required frequency change value delta F ((n + 1). tau), accumulating output results, adjusting the frequency of the DC variable frequency compressor when the energy distribution period theta is reached, and detecting the water outlet temperature T of the current system again when the energy distribution period theta is not reached_outAnd the ambient temperature T_o；

In the heating mode, the system executes the unloading area control strategy as follows:

calculating a required frequency change value delta F ((n +1) · tau) of the water outlet temperature of the system according to a frequency regulation coefficient set in a heating mode and a constant regulation frequency of the variable frequency compressor;

judging that delta F ((n +1) · tau) is not less than 0, if yes, judging that delta F ((n +1) · tau) is 0, if no, outputting the frequency calculation result delta F ((n +1) · tau), accumulating the output results, adjusting the frequency of the direct current frequency conversion compressor when the energy distribution period theta is reached, otherwise, detecting and detecting the current system outlet water temperature T again_outAnd the ambient temperature T_o；

In the heating mode, the system executes the emergency stop zone control strategy as follows:

for opened presses, according to a press balancing mode, selecting the frequency conversion press with the longest running time in turn and every other press scram interval t_JAnd stopping the machine.

Frequency variation value calculation formula:

wherein:

tau is an energy calculation period when the normal energy regulation process is carried out, the system is controlled to sample the system outlet water temperature once every time tau, and the change value delta T of the system outlet water temperature at the current (n +1) th time is calculated_out(n +1) · tau), and calculating a variation value deltaF of the required frequency of the press for the (n +1) th time according to the variation value of the temperature of the system outlet water for the (n +1) th time;

T_out(n + 1). tau) is the system effluent temperature detected in the (n +1) th energy calculation cycle;

T_out(n.tau) is the system effluent temperature detected during the nth energy calculation cycle;

Δf_Hfrequency is regularly adjusted for the down-conversion compressor in the heating operation mode;

k_Hadjusting the coefficient for the heating operation frequency;

the Δ f_HAnd k is_HIs provided with in different loading and unloading areasThe corresponding value.

When the temperature T of the system outlet water_outThe conditions are satisfied: t is_out≤T_H-set-ΔT_S-addThat is, the temperature of the water in the system is in the loading area,

Δf_H＝Δf_OH

when the temperature T of the system outlet water_outThe conditions are satisfied: t is_H-set-ΔT_S-add＜T_out≤T_H-set-ΔT_addThat is, the water temperature of the system is in the slow loading area

When the temperature T of the system outlet water_outThe conditions are satisfied: t is_H-set+ΔT_sub＜T_out≤T_H-set+ΔT_S-subI.e. when the system water temperature is in the unloading zone,

Δf_H＝-Δf_OH

when the temperature T of the system outlet water_outThe conditions are satisfied: t is_H-set＜T_out≤T_H-set+ΔT_subNamely when the water temperature of the system is in a slow unloading area

Wherein Δ f_OHFrequency (unit: rps) for reference steady-state adjustment of the frequency converter in the heating mode of operation:

k_Hadjusting the coefficient for the heating operation frequency:

when the temperature T of the system outlet water_outThe conditions are satisfied:

T_out≤T_H-set-ΔT_S-addor T_H-set+ΔT_sub＜T_out≤T_C-set+ΔT_S-subI.e. the system water temperature is in the load or unload region,

k_H＝k_OH

working systemTemperature T of outlet water_outThe conditions are satisfied: t is_H-set-ΔT_S-add＜T_out≤T_H-set-ΔT_addThat is, the water temperature of the system is in the slow loading area

When the temperature T of the system outlet water_outThe conditions are satisfied: t is_H-set＜T_out≤T_H-set+ΔT_subNamely when the water temperature of the system is in a slow unloading area

Wherein k is_OHAdjusting coefficients for heating operation frequency reference:

α_H、β_Hcorrecting the adjustment coefficient of the heating operation frequency;

△T_H-ratedthe water temperature difference (unit: DEG C) is determined for the heating operation frequency adjustment system.

Calculating a required frequency change value (unit: rps) when the Delta F ((n +1) · tau) is the n +1 energy calculation period;

T_Ois the current system ambient temperature (unit:. degree. C.);

T_H-setis the system target outlet water temperature (unit:DEGC) set in the heating mode.

Calculating the frequency requirement of the press according to the change of the system outlet water temperature in the heating mode, and timing the change quantity delta T of the system outlet water temperature under other conditions_outThe larger the regulation quantity of the frequency of the press is, the larger the variation quantity delta T of the water outlet temperature of the system_outThe smaller the frequency adjustment quantity of the press is, the smaller the frequency adjustment quantity of the press is; simultaneously takes different ring temperatures T into account_OTarget water outlet temperature T of different systems_H-setThe frequency demand calculation of the press is corrected according to the difference of the heating capacity of the following units: the higher the ring temperature is, the lower the target water temperature is, the better the heating capacity of the unit is, the smaller the required frequency adjustment amount of the press is, the lower the ring temperature is, the higher the water temperature is, the heating capacity of the unit isThe poorer the capacity, the larger the required frequency adjustment amount of the press, and the consideration of the outlet water temperature T of the current system_outAnd setting a heating target water temperature T_H-setRelative difference, relative differenceThe larger the frequency regulating quantity of the press, the larger the relative difference valueThe smaller the frequency regulating quantity of the press is, the loading and unloading mode under the heating mode fully considers the load variation trend of users, and the heating mode has the capability of pre-regulating to ensure different ring temperatures T_ODifferent set target water temperatures T_H-setThe accurate quick adjustment of lower system temperature and the reliable and stable operation of unit.

The control system calculates the frequency requirement once after the energy calculation period tau, and performs energy regulation once after the energy regulation period theta (the energy regulation period theta is integral multiple of the energy calculation period tau, and theta is larger than or equal to tau). As shown in fig. 3, the heating operation mode is divided into a loading area, a slow loading area, a holding area, a slow unloading area, a fast unloading area and an emergency stop area when the system outlet water temperature T is higher_outIn the loading area: t is_out≤T_H-set-ΔT_S-addIf a certain time Δ F ((n) is calculated in this area₁If +1) tau is less than or equal to 0, not counting in the frequency requirement calculation, that is, giving the frequency requirement calculation change value delta F ((n) at this time₁+1) · τ) ═ 0; when the temperature T of the system outlet water_outIn the unloading area: t is_H-set+ΔT_sub＜T_out≤T_H-set+ΔT_S-subIf a certain time Δ F ((n) is calculated in this area₂If + 1). tau) ≥ 0, it is not included in the frequency requirement calculation, i.e. given the frequency requirement calculation variation value Δ F ((n)₂+1) · τ) ═ 0, and when entering the holding region, the frequency adjustment calculation method of the compressor in the heating mode is exited, and at this time, the frequency variation Δ F ((n) is output₃+1) τ) ═ 0, that is, the open frequency conversion press maintains the current operating frequency, in the emergency stop region, according to the press equalization modeEvery other press scram interval t of frequency conversion press with longest secondary selection running time_JStopping the machine;

the energy regulation principle is as follows:

when loading (including loading area and slow loading area):

setting the accumulated demand frequency delta F to the frequency conversion press with no fault, no forbiddance and lowest operation frequency in the system after each energy regulation period theta, if a plurality of frequency conversion presses in the system meet the conditions, selecting the frequency conversion press with the shortest accumulated operation time according to an equilibrium mode until the press frequency is loaded to the heating rated operation frequency N_H-rated。

When the frequency conversion presses already running in the system all reach the heating rated operation frequency N_H-ratedJudging whether the variable frequency press is not started or not, if so, carrying out frequency loading accumulation, loading the variable frequency press which is not started, has no fault, is not forbidden and has the shortest accumulated running time, and if the required frequency delta F loaded on the non-started press meets the condition that delta F is less than N after the energy regulation period theta is passed each time in the process_H-minAt the moment, the frequency conversion press is not opened, and frequency loading accumulation is continued until the condition that delta F is more than or equal to N is met_H-minAfter the frequency conversion press is started, the heating rated operation frequency N is loaded firstly_H-ratedStabilized running time t after start-up_OAnd then, carrying out frequency adjustment according to a frequency adjustment calculation mode in a heating mode.

If all the frequency conversion presses which are not in fault and are not forbidden in the system are loaded to the heating rated operation frequency N_H-ratedWhen the system still has a loading requirement (namely the temperature of the system outlet water is in a loading area or a slow loading area), selecting a press without fault and with the lowest running frequency for frequency loading after an energy regulation period theta, and if a plurality of presses in the system meet the conditions, selecting a frequency conversion press with the shortest accumulated running time for frequency loading regulation according to a press balancing mode until all the presses are loaded to the maximum heating running frequency N_H-max。

A holding region:

at this time, each variable frequency press keeps the current operating frequency unchanged, the press frequency adjustment calculation mode under the refrigeration mode is quitted in the area, and the delta F is kept equal to 0.

Unloading zone (including unloading zone and slow unloading zone)

After the energy regulation period theta passes through the area, the frequency conversion press with the highest fault-free running frequency is selected for frequency unloading, if a plurality of presses in the system meet the conditions, the frequency conversion press with the longest accumulated running time is selected according to the press balancing mode for frequency unloading regulation until all the presses are unloaded to the heating rated running frequency N_H-rated。

If the unloading demand still exists but the system does not enter the emergency stop area (the system outlet water temperature T)_outIn the unloading zone or the slow unloading zone) and all the frequency conversion presses which are turned on in the system have unloaded the heating rated operation frequency N at the moment_H-ratedSelecting the frequency conversion press with no fault and the highest operation frequency for frequency unloading through the energy regulation period theta, and selecting the frequency conversion press with the longest accumulated operation time for frequency unloading if a plurality of frequency conversion presses meet the conditions until all opened frequency conversion presses are unloaded to the lowest heating operation frequency N_H-min。

If the unloading requirement exists, frequency unloading accumulation is carried out, and the lowest heating operation frequency N in the opened variable frequency press machine is reached_H-minAnd stopping the machine with the longest running time, and after an energy regulation period theta, if the frequency delta F required by the variable frequency press meeting the above conditions is distributed to the variable frequency press meeting the conditions that the delta F is less than N_H-minAt the moment, the frequency conversion press continues to carry out frequency unloading accumulation until the condition that the delta F is more than or equal to N is met_H-minAnd stopping the machine after the operation.

An emergency stop area:

when the water temperature of the system enters the emergency stop area, sequentially selecting the frequency conversion with the longest running time every emergency stop interval t of the press according to the balance mode of the press at the moment_JAnd stopping the machine.

The following parameters need to be set in the present invention:

the first full-open temperature difference of unit refrigeration: delta T_C-start

The first full-open temperature difference of unit heating: delta T_H-start

Set refrigeration temperature of the unit: t is_C-set

Heating set temperature of the unit: t is_H-set

The unit refrigeration startup function adjustment coefficient is as follows: y is_C

Machine set heating starting function tone coefficient: y is_H

The water temperature correction coefficient of the unit refrigeration starting-up is as follows: b_C

The loop temperature correction coefficient of the unit heating starting-up is as follows: a is_H

The constant adjusting frequency of the refrigeration operation of the press: Δ f_C

The constant adjusting frequency of the refrigeration operation reference of the press is as follows: Δ f_OC

The heating operation of the press is regularly adjusted in frequency: Δ f_H

The constant adjusting frequency of the heating operation reference of the press is as follows: Δ f_OH

Adjusting coefficient of refrigerating operation frequency of the press: k is a radical of_C

Adjusting coefficient of refrigerating operation reference frequency of the press: k is a radical of_OC

The adjustment coefficient of the heating running frequency of the press is as follows: k is a radical of_H

The adjustment coefficient of the heating running frequency of the press is as follows: k is a radical of_OH

Correcting a refrigerating operation frequency adjusting coefficient of a press: alpha is alpha_C、β_C

Correcting the adjustment coefficient of the heating running frequency of the press: alpha is alpha_H、β_H

The unit refrigeration operation frequency adjustment system defines the water temperature difference: delta T_C-rated

The unit heating operation frequency adjusting system sets the water temperature difference: delta T_H-rated

Temperature difference of unit loading water: delta T_add

The temperature difference of the unit slow loading water: delta T_S-add

Temperature difference of unit unloading water: delta T_sub

The temperature difference of the unit slow unloading water: delta T_S-sub

The unit energy calculation cycle is as follows: tau is

The energy regulation period of the unit is as follows: theta

The starting stabilization time of the frequency conversion press is as follows: t is t_O

Refrigerating rated operation frequency of the variable frequency press: n is a radical of_C-rated

Heating rated operation frequency of the variable frequency press: n is a radical of_H-rated

The refrigeration allowable maximum operating frequency of the variable frequency press is as follows: n is a radical of_C-max

The lowest allowable operation frequency of refrigeration of the variable frequency press is as follows: n is a radical of_C-min

Heating allowable maximum operating frequency of the variable frequency press: n is a radical of_H-max

The lowest allowable operation frequency of refrigeration of the variable frequency press is as follows: n is a radical of_H-min

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.