1. A load simulation testing device of a mining variable-frequency belt conveyor comprises a driving motor II, a driving roller, a cleaning part, a supporting roller, a conveying belt, a direction-changing roller, a tensioning device, a tensioning steel rope and a tensioning hanging block, and is characterized in that the load simulation testing device comprises a base (1), a variable-frequency driving mechanism (2), a first coupler (3), a torque and speed sensor (4), a second coupler (5), a programmable logic controller (6), an upper computer (7) and a dynamic loading mechanism (8) are arranged on the base (1), the variable-frequency driving mechanism (2) is connected with the torque and speed sensor (4) through the first coupler (4), the dynamic loading mechanism (8) is connected with the torque and speed sensor (4) through the second coupler (5), the variable-frequency driving mechanism (2) is connected with the programmable logic controller (6), the torque and rotating speed sensor (4) is in communication connection with the programmable logic controller (6), the dynamic loading mechanism (8) is connected with the programmable logic controller (6), and the programmable logic controller (6) is in communication connection with the upper computer (7).

2. The load simulation testing device of the mining variable-frequency belt conveyor according to claim 1, characterized in that the variable-frequency driving mechanism (2) comprises a driving frequency converter (21) and a driving motor I (22), the driving frequency converter (21) is connected with the driving motor I (22), the driving frequency converter (21) and the driving motor I (22) are both mounted on the base (1), the driving motor I (22) is connected with the torque and rotation speed sensor (4) through a first coupling (3), and the driving frequency converter (21) is connected with the programmable logic controller (6).

3. The load simulation testing device of the mining variable-frequency belt conveyor according to claim 2, characterized in that the dynamic loading mechanism (8) comprises a load frequency converter (81) and a load motor (82), the load frequency converter (81) is connected with the load motor (82), the load frequency converter (81) and the load motor (82) are both mounted on the base (1), the load motor (82) is connected with the torque and rotation speed sensor (4) through a second coupling (5), and the load frequency converter (81) is connected with the programmable logic controller (6).

4. A load simulation test method of a mining variable-frequency belt conveyor, which adopts the load simulation test device of the mining variable-frequency belt conveyor according to claim 3, and is characterized by comprising the following steps:

S1：calculating the load torque T of a driving motor II of the mining variable-frequency belt conveyor according to the no-load section linear resistance Fk, the bearing section linear resistance Fz, the acceleration resistance Fa during loading, the side plate resistance Fb at the loading position and the cleaning component resistance Fc_L ^*；

S2: according to the load torque T_L ^*The upper computer calculates a similarity coefficient Z of the load torque of the driving motor I and the load torque of the driving motor II in the mining variable-frequency belt conveyor_T；

S3: according to the similarity coefficient Z_TThe upper computer calculates the load torque T of the driving motor I_L＝T_L ^*/Z_TAnd applying said load torque T_LAnd sending the torque value to the load frequency converter as a given torque value, applying the given torque value to the driving motor I by the load frequency converter through the load motor, and carrying out simulation test on the speed regulation control performance of the driving frequency converter by the load frequency converter through controlling the output torque magnitude and direction of the load motor.

5. The load simulation test method of the mining variable-frequency belt conveyor according to claim 4, wherein the calculation formula of the no-load section linear resistance Fk is as follows:

F_k＝gL[(q_t+q_d)·ω₁·cosβ-q_dsinβ]

the calculation formula of the linear resistance Fz of the bearing section is as follows:

F_z＝gL[(q+q_t+q_d)·ω₂·cosβ-(q+q_d)sinβ]

the calculation formula of the acceleration resistance Fa under load is as follows:

the calculation formula of the side plate resistance Fb at the loading position is as follows:

F_b＝l(16B²γ+70)

the formula for calculating the cleaning member resistance Fc is:

F_c＝200B

the load torqueWherein g is the gravitational acceleration, L is the length of the conveyor belt, v is the conveying speed of the conveyor belt, q_tFor the support roll line quality, q_dBeta is the average inclination angle of the conveyor belt, q is the linear mass of the material on the conveyor belt, omega₁And ω₂And the sealing coefficient of the supporting roller, the width of the conveying belt, the material collecting and distributing density, the length of a side plate of the material guide chute and the diameter of the driving roller are respectively represented by B, gamma and l.

6. The load simulation test method of the mining variable-frequency belt conveyor according to claim 5, wherein the step S2 specifically includes:

s21: obtaining a motion equation of a driving motor II in the mining variable-frequency belt conveyor:

wherein, T_eIs the output torque of the drive roller, J_rIs the moment of inertia of the driving roller, J_mIs the moment of inertia of the drive motor II, ω is the rotational speed of the drive drum, n_pThe number of pole pairs of the driving motor II is N, and the transmission ratio between the driving roller and the driving motor II is N;

s22: obtaining a motion equation of a driving motor I in the load simulation test device:

wherein, J₁Is the moment of inertia of the drive motor I, ω is the rotational speed of the drive motor I, T₁Is the electromagnetic torque, T, of the drive motor I_LIs the load torque of the drive motor I, n_p1Is the number of pole pairs, J, of the drive motor I_C1Is the moment of inertia of the first coupling;

s23: according to a similar principle, a similarity coefficient of the load torque of the driving motor I and the load torque of the driving motor II is obtained as

7. The load simulation test method of the mining variable-frequency belt conveyor according to claim 6, characterized by further comprising:

s4: constructing a motion equation of the load simulation test device:

wherein, T₂Is the electromagnetic torque of the load motor, J₂Is the moment of inertia of the loaded motor, n_p2Is the pole pair number, J, of the load motor_C2Is the moment of inertia, P, of the second coupling_m2For mechanical losses of said loaded motor, P_a2For additional torque losses, P, of the loaded motor_m1For mechanical losses, P, of the drive motor I_a1An additional torque loss for the drive motor I;

s5: adopting a direct torque control principle for the driving motor I and the load motor to enable the driving motor I to work in an electric state and the load motor to work in a power generation state; by designing a constant torque loading control strategy, the driving motor I and the load motor form a torque closed loop, and the torque loading error of the load simulation testing device is compensated and controlled.

Background

The mining variable-frequency belt conveyor has the advantages of low unit transportation cost, stable operation, large transportation capacity, long distance and the like, and is a preferred device of a coal mine raw coal main transportation system. The driving modes of the mining variable-frequency belt conveyor mainly comprise alternating-current variable-frequency speed regulation, CST, a hydraulic motor, water resistance, a speed regulation type hydraulic coupler, liquid viscosity soft start and the like. In recent years, an alternating current variable frequency speed regulation driving scheme is favored by customers, and particularly in transportation occasions with large transportation capacity, long distance and complex arrangement, the operating efficiency is improved, and the energy consumption and the space are saved. The practically used variable frequency belt conveyor for the mine mainly comprises a driving motor II, a driving roller, a cleaning component, a supporting roller, a conveying belt, a bend roller, a tensioning device, a tensioning steel rope and a tensioning suspension block, wherein the conveying belt is sleeved on the driving roller and the bend roller, the supporting roller is arranged below the conveying belt and is in contact with the conveying belt, the cleaning component is connected with the driving roller, the tensioning device is connected with the bend roller, the tensioning steel rope is connected with the tensioning device, and the tensioning suspension block is connected with the tensioning steel rope. The driving motor II can drive the driving roller to rotate through the speed reducer or adopt a permanent magnetic direct-drive/semi-direct-drive system, the conveyer belt is moved by the friction force between the driving roller and the conveyer belt, the supporting roller can support the conveyer belt, the cleaning part can clean coal blocks on the driving roller, and the resistance of the driving roller during rotation is reduced.

Due to the complex and severe coal mine environment, if the frequency converter fails in the using process, shutdown and production halt are caused, and the mining frequency converter is required to be subjected to loading test before leaving a factory so as to improve the reliability of products. However, at present, for the loading test of the mining frequency converter, a simulation load with a rated torque percentage is adopted, and a large difference exists between the simulation load and the load torque of the mining belt conveyor under an actual working condition environment. In addition, the parameters of the actual system and the simulation system are different, the transmission structures of the actual system and the simulation system cannot be kept consistent, and the control performance of the frequency converter cannot be comprehensively and accurately measured.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to solve the technical problem that the loading test of the mining frequency converter in the prior art cannot accurately simulate the actual working condition of the load, the invention provides the load simulation test device and method of the mining frequency conversion belt conveyor, which can improve the effectiveness and reliability of the frequency conversion speed regulation control performance test of the frequency converter.

The technical scheme adopted by the invention for solving the technical problems is as follows: a load simulation test device of a mining variable-frequency belt conveyor comprises a drive motor II, a drive roller, a cleaning part, a support roller, a conveyor belt, a direction-changing roller, a tensioning device, a tensioning steel rope and a tensioning hanging block, wherein the load simulation test device comprises a base, a variable-frequency drive mechanism, a first coupler, a torque and rotation speed sensor, a second coupler, a programmable logic controller, an upper computer and a dynamic loading mechanism are arranged on the base, the variable-frequency drive mechanism is connected with the torque and rotation speed sensor through the first coupler, the dynamic loading mechanism is connected with the torque and rotation speed sensor through the second coupler, the variable-frequency drive mechanism is connected with the programmable logic controller, the torque and rotation speed sensor is in communication connection with the programmable logic controller, and the dynamic loading mechanism is connected with the programmable logic controller, and the programmable logic controller is in communication connection with the upper computer.

Further, specifically, the variable frequency driving mechanism comprises a driving frequency converter and a driving motor I, the driving frequency converter is connected with the driving motor I, the driving frequency converter and the driving motor I are both installed on the base, the driving motor I is connected with the torque and speed sensor through a first coupler, and the driving frequency converter is connected with the programmable logic controller.

Further, specifically, the dynamic loading mechanism comprises a load frequency converter and a load motor, the load frequency converter is connected with the load motor, the load frequency converter and the load motor are both mounted on the base, the load motor is connected with the torque and rotation speed sensor through a second coupling, and the load frequency converter is connected with the programmable logic controller.

The load simulation testing device of the mining variable-frequency belt conveyor simulates the actual working condition of the load of the conveying belt through the output torque of the dynamic loading mechanism and applies the output torque to the driving motor I, so that the speed regulation control performance of the driving frequency converter is tested.

The invention also provides a load simulation test method of the mining variable-frequency belt conveyor, which adopts the load simulation test device of the mining variable-frequency belt conveyor and comprises the following steps:

s1: according to the no-load of the mining variable-frequency belt conveyorCalculating the load torque T of the driving motor II of the variable frequency belt conveyor by using the section linear resistance Fk, the bearing section linear resistance Fz, the acceleration resistance Fa during loading, the side plate resistance Fb at the loading position and the cleaning component resistance Fc_L ^*；

S2: according to the load torque T_L ^*The upper computer calculates a similarity coefficient Z of the load torque of the driving motor I and the load torque of the driving motor II in the mining variable-frequency belt conveyor_T；

S3: according to the similarity coefficient Z_TThe upper computer calculates the load torque T of the driving motor I_L＝T_L ^*/Z_TAnd applying said load torque T_LAnd sending the torque value to the load frequency converter as a given torque value, applying the given torque value to the driving motor I by the load frequency converter through the load motor, and carrying out simulation test on the speed regulation control performance of the driving frequency converter by the load frequency converter through controlling the output torque magnitude and direction of the load motor.

The load simulation test method of the mining variable-frequency belt conveyor obtains the load torque T of the actual drive motor II by calculating different resistance parameters of the mining variable-frequency belt conveyor which is actually used_L ^*According to the similarity coefficient Z_TCalculating the load torque T of the drive motor I by the host computer_LApplying a load torque T_LThe load frequency converter is applied to the driving motor I as a given torque value, the speed regulation control performance of the driving frequency converter can be subjected to simulation test by controlling the output torque and the output torque direction of the load motor, and the effectiveness and the reliability of the frequency converter loading test result can be improved.

Further, specifically, the calculation formula of the no-load section linear resistance Fk is as follows:

F_k＝gL[(q_t+q_d)·ω₁·cosβ-q_dsinβ]

the calculation formula of the linear resistance Fz of the bearing section is as follows:

F_z＝gL[(q+q_t+q_d)·ω₂·cosβ-(q+q_d)sinβ]

the calculation formula of the acceleration resistance Fa under load is as follows:

the calculation formula of the side plate resistance Fb at the loading position is as follows:

F_b＝l(16B²γ+70)

the formula for calculating the cleaning member resistance Fc is:

F_c＝200B

the load torqueWherein g is the gravitational acceleration, L is the length of the conveyor belt, v is the conveying speed of the conveyor belt, q_tFor the support roll line quality, q_dBeta is the average inclination angle of the conveyor belt, q is the linear mass of the material on the conveyor belt, omega₁And ω₂And the sealing coefficient of the supporting roller, the width of the conveying belt, the material collecting and distributing density, the length of a side plate of the material guide chute and the diameter of the driving roller are respectively represented by B, gamma and l.

Further, specifically, the step S2 specifically includes:

s21: obtaining a motion equation of a driving motor II in the mining variable-frequency belt conveyor:

wherein, T_eIs the output torque of the drive roller, J_rIs the moment of inertia of the driving roller, J_mIs the moment of inertia of the drive motor II, ω is the rotational speed of the drive drum, n_pThe number of pole pairs of the driving motor II is N, and the transmission ratio between the driving roller and the driving motor II is N;

s22: obtaining a motion equation of a driving motor I in the load simulation test device:

wherein, J₁Is the moment of inertia of the drive motor I, ω is the rotational speed of the drive motor I, T₁Is the electromagnetic torque, T, of the drive motor I_LIs the load torque of the drive motor I, n_p1Is the number of pole pairs, J, of the drive motor I_C1Is the moment of inertia of the first coupling;

s23: according to a similar principle, a similarity coefficient of the load torque of the driving motor I and the load torque of the driving motor II is obtained as

According to a similar principle, the physical parameters of the variable-frequency belt conveyor are in a proportional relation with the corresponding physical parameters of the load simulation test device, and the vector directions of all the physical quantities are consistent.

Further, specifically, the method further includes:

s4: constructing a motion equation of the load simulation test device:

wherein, T₂Is the electromagnetic torque of the load motor, J₂Is the moment of inertia of the loaded motor, n_p2Is the pole pair number, J, of the load motor_C2Is the moment of inertia, P, of the second coupling_m2For mechanical losses of said loaded motor, P_a2For additional torque losses, P, of the loaded motor_m1For mechanical losses, P, of the drive motor I_a1An additional torque loss for the drive motor I;

s5: adopting a direct torque control principle for the driving motor I and the load motor to enable the driving motor I to work in an electric state and the load motor to work in a power generation state; by designing a constant torque loading control strategy, the driving motor I and the load motor form a torque closed loop, and the torque loading error of the load simulation testing device is compensated and controlled.

Through the motion equation of the load simulator, the actual rotating speed omega of the driving motor I can be calculated, and then the steady-state error caused by the mechanical loss and the additional torque loss of the load motor can be obtained. The method comprises the steps that a direct torque control principle is adopted, a driving motor I is started in a rotating speed control mode, a load motor provides loading torque for the driving motor I in the torque control mode, a constant torque loading control strategy is designed, an output torque value of the load motor is collected in real time through a torque rotating speed sensor, a difference value X1 between a given torque value and the output torque value and a difference value X2 between a steady-state error of the load motor and the output torque value are calculated, the difference values X1 and X2 are input to a PI controller, and the PI controller dynamically compensates the loading torque error caused by rotating speed change, so that the driving motor I and the load motor form a torque closed loop, and the accuracy of torque loading simulation is improved.

The load simulation test device and the method for the mining variable-frequency belt conveyor have the advantages that the actual working condition of the load of the conveyor belt is simulated through the output torque of the dynamic loading mechanism, the output torque is applied to the driving motor I, so that the speed regulation control performance of the driving frequency converter is tested, the upper computer can control the magnitude and the direction of the output torque of the loading motor, and the load working condition environment can be accurately simulated; a transmission ratio parameter N is introduced into a motion equation of the driving motor II, so that load simulation of an actual permanent magnet roller, a permanent magnet electric direct-drive system, a permanent magnet semi-direct-drive system and an asynchronous motor and speed reducer system can be considered; introducing a similarity coefficient Z_TThe motor parameter of the actual conveyor and the difference of the motor parameter of the simulation device are combined, so that the validity and the authenticity of the simulation test result can be improved; by using a constantThe torque loading control strategy can improve the output torque tracking capability, realize the accurate output of the output torque in the dynamic state and the steady state of the actual rotating speed omega, and optimize the loading performance of the system. The invention can simulate the actual working condition of the conveyor to load and simulate the frequency converter, and can improve the effectiveness and reliability of the frequency converter loading test result.

Drawings

The invention is further illustrated with reference to the following figures and examples.

Fig. 1 is a schematic structural diagram of a mining variable-frequency belt conveyor in the prior art.

Fig. 2 is a load simulation test device of the mining variable-frequency belt conveyor.

Fig. 3 is a flow chart of the load simulation test method of the mining variable-frequency belt conveyor.

Fig. 4 is a flowchart illustrating step S2 according to the present invention.

Fig. 5 is another flow chart of the load simulation test method of the mining variable-frequency belt conveyor.

In the figure: 1. the device comprises a base, 2, a variable frequency driving mechanism, 3, a first coupling, 4, a rotating speed torque sensor, 5, a second coupling, 6, a programmable logic controller, 7, an upper computer, 8, a dynamic loading mechanism, 21, a driving frequency converter, 22, driving motors I, 81, a load frequency converter, 82, a load motor, 101, driving motors II, 102, driving rollers, 103, a cleaning part, 104, supporting rollers, 105, a conveying belt, 106, a direction-changing roller, 107, a tensioning device, 108, a tensioning steel rope, 109 and a tensioning suspension block.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention. Furthermore, a feature defined as "first" or "second" 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 meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The torque is a basic load form of a transmission shaft of various working machines, is closely related to factors such as working capacity, energy consumption, efficiency, operation life and safety performance of a power machine, and has important significance on determination and control of the load of the transmission shaft, strength design of working parts of a transmission system, selection of the capacity of a prime mover and the like. The electromagnetic torque is a rotational torque formed on the rotor by interaction of magnetic fluxes of respective poles of a rotating magnetic field of the motor with a rotor current. The load torque is the torque required by the motor to drive the load, and is also the motor output torque. The electromagnetic torque and the load torque differ by the mechanical losses of the motor.

Example one

As shown in fig. 1-2, the present embodiment provides a load simulation testing device for a mining variable-frequency belt conveyor. The mining variable-frequency belt conveyor mainly comprises a driving motor II101, a driving roller 102, a cleaning part 103, a supporting roller 104, a conveying belt 105, a direction-changing roller 106, a tensioning device 107, a tensioning steel rope 108 and a tensioning suspension block 109, wherein the conveying belt 105 is sleeved on the driving roller 102 and the direction-changing roller 106, the supporting roller 104 is arranged below the conveying belt 105 and is in contact with the conveying belt 105, the cleaning part 103 is connected with the driving roller 102, the tensioning device 107 is connected with the direction-changing roller 106, the tensioning steel rope 108 is connected with the tensioning device 107, and the tensioning suspension block 109 is connected with the tensioning steel rope 108. The driving motor II101 can drive the driving roller 102 to rotate through a speed reducer or a permanent magnetic direct-drive/semi-direct-drive system, the conveying belt 105 moves by means of friction force between the driving roller 102 and the conveying belt 105, the supporting roller 104 can support the conveying belt 105, the cleaning component 103 can clean coal blocks on the driving roller, and resistance when the driving roller 102 rotates is reduced. The load simulation testing device comprises a base 1, a variable frequency driving mechanism 2, a first coupler 3, a torque and rotation speed sensor 4, a second coupler 5, a programmable logic controller 6, an upper computer 7 and a dynamic loading mechanism 8 are arranged on the base 1, the variable frequency driving mechanism 2 is connected with the torque and rotation speed sensor 4 through the first coupler 4, the dynamic loading mechanism 8 is connected with the torque and rotation speed sensor 4 through the second coupler 5, the variable frequency driving mechanism 2 is connected with the programmable logic controller 6, the torque and rotation speed sensor 4 is in communication connection with the programmable logic controller 6, the dynamic loading mechanism 8 is connected with the programmable logic controller 6, and the programmable logic controller 6 is in communication connection with the upper computer 7.

The variable-frequency driving mechanism 2 comprises a driving frequency converter 21 and a driving motor I22, the driving frequency converter 21 is connected with a driving motor I22, the driving frequency converter 21 and the driving motor I22 are both installed on the base 1, the driving motor I22 is connected with the torque and speed sensor 4 through a first coupler 3, and the driving frequency converter 21 is connected with the programmable logic controller 6.

The dynamic loading mechanism 8 comprises a load frequency converter 81 and a load motor 82, the load frequency converter 81 is connected with the load motor 82, the load frequency converter 81 and the load motor 82 are both installed on the base 1, the load motor 82 is connected with the torque and rotation speed sensor 4 through a second coupler 5, and the load frequency converter 81 is connected with the programmable logic controller 6.

According to the load simulation testing device of the mining variable-frequency belt conveyor, the working state of the driving motor I22 is an electric state, the dynamic loading mechanism 8 can simulate various load working conditions of the variable-frequency belt conveyor, for example, different weights (light load, medium load, heavy load and overload) of materials on the conveyor belt are simulated, the load frequency converter 81 is a four-quadrant frequency converter, the working state of the load motor 82 is a power generation state, and the rigidity of the first coupling 4 and the second coupling 5 is very high, so that looseness can be prevented in the rotating process. By adopting a Direct Torque Control (DTC) principle, the driving motor I22 is started in a rotation speed control mode, the load motor 82 provides a simulated load for the driving motor I22 in the Torque control mode, the Torque and rotation speed sensor 4 can collect the output Torque of the load motor 82 in real time, the load frequency converter 81 can control the magnitude and direction of the output Torque of the load motor 82 and apply the output Torque to the driving motor I22, and at the moment, the driving frequency converter 21 controls the driving motor I22 to output corresponding Torque according to the magnitude of the output Torque, so that the speed regulation control performance of the driving frequency converter 21 is tested. The programmable logic controller 6 can monitor and adjust the whole process of the load simulation test in real time, the programmable logic controller 6 can communicate with the upper computer 7, and the upper computer 7 can display, analyze and store state parameters such as torque, speed, current and voltage in the test process in real time. The device simulates the actual load condition through the dynamic loading mechanism 8 to carry out loading test on the variable-frequency driving mechanism 2, thereby knowing the control performance of the driving frequency converter 21 on the driving motor I22, improving the effectiveness and reliability of the frequency-conversion speed-regulation control performance test result of the frequency converter, and improving the satisfaction degree of a client on the product performance.

Example two

As shown in fig. 3 to 5, the present embodiment provides a load simulation test method for a mining variable-frequency belt conveyor, and the load simulation test device for a mining variable-frequency belt conveyor according to the first embodiment is adopted.

S1: according to mining frequency conversion belt type defeatedCalculating the load torque T of the variable frequency belt conveyor by using the linear resistance Fk of the idle load section, the linear resistance Fz of the bearing section, the acceleration resistance Fa during loading, the side plate resistance Fb at the loading position and the resistance Fc of the cleaning component of the conveyor_L ^*。

The variable-frequency belt conveyor is an actually used variable-frequency belt conveyor, an operation resistance model of the variable-frequency belt conveyor is established according to parameters of idle load section linear resistance Fk, bearing section linear resistance Fz, load acceleration resistance Fa, loading side plate resistance Fb and cleaning component resistance Fc obtained through actual calculation, and load torque T of a driving motor II of the variable-frequency belt conveyor can be obtained according to a transmission principle of force in a conveying belt and by combining a conversion relation between circumferential force and torque_L ^*。

The calculation formula of the linear resistance Fk of the no-load section is as follows:

F_k＝gL[(q_t+q_d)·ω₁·cosβ-q_dsinβ] (1)

the calculation formula of the linear resistance Fz of the bearing section is as follows:

F_z＝gL[(q+q_t+q_d)·ω₂·cosβ-(q+q_d)sinβ] (2)

the calculation formula of the acceleration resistance Fa under load is:

the formula for calculating the side plate resistance Fb at the loading position is as follows:

F_b＝l(16B²γ+70) (4)

the formula for the cleaning member resistance Fc is:

F_c＝200B (5)

then the load torque T_L ^*The calculation formula of (2) is as follows:

wherein g is the acceleration of gravity, L is the length of the conveyer belt, v is the conveying speed of the conveyer belt, q_tTo support the linear mass of the rolls, q_dIs the linear mass of the conveyor belt, beta is the average inclination angle of the conveyor belt, q is the linear mass of the material on the conveyor belt, omega₁And ω₂The sealing coefficient of the supporting roller is B, the width of the conveying belt is B, the gamma is the material collecting and distributing density, the l is the length of the side plate of the material guide groove, and the D is the diameter of the driving roller.

S2: according to the load torque T_L ^*The upper computer calculates a similarity coefficient Z between the load torque of the driving motor I and the load torque of the driving motor II in the variable-frequency belt conveyor_T。

Step S2 includes:

s21: obtaining a motion equation of a driving motor II in the mining variable-frequency belt conveyor:

wherein, T_eIs the output torque of the driving drum, J_rIs the moment of inertia of the driving roller, J_mIs the moment of inertia of the drive motor II, ω is the speed of rotation of the drive drum, n_pAnd N is the transmission ratio between the driving roller and the driving motor II.

S22: obtaining a motion equation of a driving motor I in the load simulation test device:

wherein, J₁To the moment of inertia of the drive motor I, ω is the rotational speed of the drive motor I, T₁Electromagnetic torque, T, for driving motor I_LFor driving the load torque of the motor I, n_p1For the number of pole pairs of the drive motor I, J_C1Is the moment of inertia of the first coupling.

S23: according to a similar principle, the load of the drive motor I is obtainedCoefficient of similarity Z of torque and load torque of drive motor II_TComprises the following steps:

it should be noted that, according to a similar principle, the physical parameters of the variable frequency belt conveyor are in a proportional relationship with the corresponding physical parameters of the load simulation test device, and the vector directions of the physical quantities are consistent. Therefore, the physical parameters of the variable-frequency belt conveyor are processed in an equivalent scaling mode, and the similarity coefficient Z of the load torque of the driving motor I and the load torque of the driving motor II can be obtained by combining the formulas (7) and (8)_T. Wherein the proportional coefficient of the moment of inertia isThe proportionality coefficient of angular velocity is Z_ω＝ω_m*/ω_mThe proportionality coefficient of the electromagnetic torque is Z_Te＝T_e*/T₁The proportionality coefficient of the load torque is Z_TL＝T_L ^*/T_LElectromagnetic torque T of drive motor I₁With load torque T_LCan be approximately equal, provided that Z_Te＝Z_TL≈Z_TThen equation (7) can be transformed into:

the similarity coefficient Z can be derived by the formula (10)_TIs described in (1).

S3: according to the similarity coefficient Z_TThe upper computer calculates the load torque T of the driving motor I_L＝T_L ^*/Z_TAnd applying a load torque T_LAs given torque value to the load frequency converter, the load frequency converter applies the given torque value to the driving motor I through the load motor, and the load frequency converter controls the output torque of the load motor in magnitude and direction to the driving frequency converterAnd carrying out simulation test on the speed regulation control performance.

It should be noted that, the load frequency converter and the load motor are used as simulated actual working conditions, the magnitude and direction of the output torque of the load motor can represent different working conditions, the load frequency converter applies the output torque of the load motor to the driving motor I, and the driving frequency converter controls the rotation speed change of the driving motor I, so as to realize the test of the speed regulation control performance of the driving frequency converter. The control performance of the driving frequency converter on the driving motor I can be known through loading simulation on the driving motor I.

The present embodiment may further include the following steps:

s4: constructing a motion equation of the load simulation test device:

wherein, T₂For loading the electromagnetic torque of the motor, J₂For loading the moment of inertia of the motor, n_p2For loading the pole pairs of the motor, J_C2Is the moment of inertia, P, of the second coupling_m2For loading mechanical losses of the motor, P_a2For additional torque losses of loaded motors, P_m1Mechanical losses, P, for driving the motor I_a1Additional torque losses for driving the motor I. Equation (11) combines the mechanical loss and the additional torque loss of the drive motor I and the load motor, and the electromagnetic torque T of the drive motor I can be obtained according to equation (11)₁Electromagnetic torque T of load motor₂And the relationship between the rotational speed ω of the drive motor I. When the driving motor I is in the electromagnetic torque T₁And T₂Under the action of (3), the actual rotating speed omega of the driving motor I can be calculated, and then the steady-state error caused by the mechanical loss and the additional torque loss of the load motor can be obtained. Because a differential term of speed exists in the process of solving the actual rotating speed omega, noise interference and system oscillation are easily caused, and filtering processing can be performed through a Low-pass filter (LPF).

S5: a direct torque control principle is adopted for the driving motor I and the load motor, so that the driving motor I works in an electric state, and the load motor works in a power generation state; by designing a constant torque loading control strategy, the driving motor I and the load motor form a torque closed loop, and the torque loading error of the load simulation testing device is compensated and controlled.

It should be noted that, in the present embodiment, a direct torque control principle is adopted, the driving motor I is started in a rotation speed control mode, and the load motor provides a loading torque for the driving motor I in a torque control mode. By designing a constant torque loading control strategy, acquiring an output torque value of a load motor in real time through a torque and rotation speed sensor, calculating a difference value X1 between a given torque value and the output torque value and a difference value X2 between a steady-state error of the load motor and the output torque value, and inputting the difference values X1 and X2 into a PI controller (the PI controller is a linear controller, and forms a control deviation according to the given value and an actual output value, and forms a control quantity by linearly combining the proportion and the integral of the deviation to control a controlled object), wherein the PI controller dynamically compensates a loading torque error caused by rotation speed change, so that a driving motor I and the load motor form a torque closed loop, and the accuracy of torque loading simulation is improved.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the contents of the specification, and must be determined by the scope of the claims.