A dual-motor drive control method for a scraper conveyor

Abstract

The invention discloses a dual-motor drive control method for a scraper conveyor, comprising dividing the dual motors into a main drive motor and a slave drive motor, wherein the main drive motor adopts current model predictive control, and the slave drive motor adopts direct torque model predictive control. The method of the invention is simple, easy to implement, can be effectively applied to the dual-motor drive system of the scraper conveyor, can solve the problem of power imbalance, and while maintaining the advantages of vector control and direct torque control, gives play to the advantages of model predictive control, has a significant effect, and is easy to promote.

Description

Technical Field

[0001] The invention belongs to the technical field of underground fully mechanized mining working face mining in coal mines, and in particular relates to a dual-motor drive control method for a scraper conveyor. Background Art

[0002] With the development of society and industrial technology, energy consumption is increasing, and coal remains the country's main energy source for a long time. However, in recent years, coal mining in various parts of my country has become increasingly difficult. Due to the sedimentation changes caused by long-term mining in coal mines, it is urgent to use high-tech to improve coal mining efficiency, safety and reliability. In the realization of a highly intensive production model of one mine, one shaft and one face, as the main equipment of the fully mechanized mining face, the scraper conveyor is crucial to the production capacity of the fully mechanized mining face.

[0003] Due to the narrow space of the underground comprehensive mining working face, the working environment of the scraper conveyor is harsh. At the same time, the increase in transportation volume, transportation distance and power leads to frequent heavy-load starting of the scraper conveyor, and the power loss becomes larger. At the same time, when the scraper conveyor is under dual-motor drive, the two motors are affected by various factors and the parameters are inconsistent, resulting in unbalanced power distribution of the two motors. It is common for one machine to be overloaded and the other underloaded. The unbalanced motor power will cause the life of each motor to be different, and the advantages of dual-motor drive cannot be fully utilized.

[0004] The variable frequency control strategy of the scraper conveyor drive motor determines whether the scraper conveyor can operate efficiently and stably. In the prior art, the scraper conveyor drive system often uses vector control and direct torque control as its variable frequency control method, but these two control methods still have some disadvantages, and the robustness and dynamic performance need to be improved. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a dual-motor drive control method for a scraper conveyor in view of the deficiencies in the above-mentioned prior art. The method is simple and easy to implement. The main drive motor adopts current model predictive control, and the slave drive motor adopts direct torque model predictive control. It can be effectively applied to the dual-motor drive system of the scraper conveyor, can solve the power imbalance problem, and while maintaining the advantages of vector control and direct torque control, it also gives play to the advantages of model predictive control. The method has significant effects and is easy to promote.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a dual-motor drive control method for a scraper conveyor, the method comprising dividing the dual motors into a main drive motor and a slave drive motor, the main drive motor adopts current model predictive control, and the slave drive motor adopts direct torque model predictive control.

[0007] In the above-mentioned dual-motor drive control method for a scraper conveyor, the objective function of the main drive motor in the current model predictive control is:

[0008]

[0009] Where g1 represents the objective function in current model predictive control, is the given value of the stator current excitation component of the main drive motor, is the predicted value of the excitation component of the stator current of the main drive motor, is the given value of the stator current torque component of the main drive motor, It is the predicted value of the stator current torque component of the main drive motor.

[0010] In the above-mentioned dual-motor drive control method for a scraper conveyor, the stator current prediction value of the main drive motor using the current model predictive control is:

[0011]

[0012] in, represents the stator current value of the main drive motor at time k+1, represents the stator current value of the main drive motor at time k, represents the rotor flux value of the main drive motor at time k, Represents the stator voltage vector of the main drive motor, T s1 is the stator time constant of the main drive motor, τ σ1 is the stator transient time constant of the main drive motor, and σ is the leakage inductance coefficient of the main drive motor, L s1 The stator leakage inductance of the main drive motor, R σ1 is the equivalent resistance of the main drive motor, and R s1 The stator resistance of the main drive motor, R r1 The rotor resistance of the main drive motor, k r1 is the rotor leakage inductance coefficient of the main drive motor, and L m1 is the stator mutual inductance of the main drive motor, L r1 The rotor inductance of the main drive motor, τ r1 is the attenuation coefficient, and ω m1 The speed of the main drive motor;

[0013] The observed value of the rotor flux of the main drive motor is:

[0014]

[0015] in, The stator current vector of the main drive motor.

[0016] In the above-mentioned dual-motor drive control method for a scraper conveyor, the specific process of the main drive motor adopting current model predictive control includes:

[0017] Step A1: Collect the stator current of the main drive motor at time k and speed ω m1 (k), and the DC side voltage u of the main drive motor inverter dc1 (k);

[0018] Step A2: Calculate the rotor flux of the main drive motor at time k

[0019] Step A3: Obtain the given value of the stator current excitation component of the main drive motor at time k according to the speed of the main drive motor and the outer flux ring. and the stator current torque component given value And construct the objective function;

[0020] Step A4: predict the stator current value of the main drive motor at time k+1

[0021] Step A5: cyclically calculate the voltage vectors of the eight switching states, calculate the objective function, and select the switching vector with the smallest objective function as the optimal voltage vector S for controlling the main drive motor. opt1 .

[0022] In the above-mentioned dual-motor drive control method for a scraper conveyor, the objective function of the direct torque model predictive control of the slave drive motor is:

[0023]

[0024] Where g2 represents the objective function in direct torque model predictive control, is the torque given by the drive motor, is the torque prediction value from the drive motor, is the given value of the stator flux from the drive motor, is the predicted value of the stator flux from the drive motor.

[0025] In the above-mentioned dual-motor drive control method for a scraper conveyor, the stator flux observation value in the direct torque model predictive control of the slave drive motor is:

[0026]

[0027] The observed rotor flux is:

[0028]

[0029] Among them, ψ s2αis the component of the stator flux value of the drive motor on the α coordinate axis, ψ s2β is the component of the stator flux value of the drive motor on the β coordinate axis, u s2α is the component of the voltage from the drive motor on the α axis, u s2β is the component of the voltage from the drive motor on the β axis, i s2α is the component of the stator current of the driving motor on the α coordinate axis, i s2β is the component of the stator current of the driving motor on the β axis, R s2 is the stator resistance of the drive motor, T r2 is the rotor time constant of the slave drive motor, and L r2 is the leakage inductance from the drive motor rotor, R r2 is the rotor resistance of the drive motor, ψ r2α is the component of the rotor flux of the driving motor on the α coordinate axis, ψ r2β is the component of the rotor flux of the driving motor on the β coordinate axis, L m2 is the stator mutual inductance of the drive motor, ω r2 is the rotor angular velocity of the slave drive motor;

[0030] The predicted value of the stator flux from the drive motor is:

[0031]

[0032] in, It represents the stator flux value of the drive motor at time k+1, It represents the stator flux value of the drive motor at time k, represents the stator voltage vector of the drive motor at time k, represents the stator current of the drive motor at time k, T s2 is the stator time constant of the slave drive motor;

[0033] The predicted value of the driving motor torque is:

[0034]

[0035] Among them, T e2 (k+1) represents the torque value of the drive motor at time k+1, represents the stator current of the drive motor at time k+1, n P is the number of pole pairs of the slave drive motor.

[0036] In the above-mentioned dual-motor drive control method for a scraper conveyor, the specific process of adopting direct torque model predictive control from the drive motor includes:

[0037] Step B1: Collect the stator current of the drive motor at time k and speed ω m2 (k), and the DC side voltage u from the drive motor inverter dc2 (k);

[0038] Step B2: Calculate the stator flux of the drive motor at time k and electromagnetic torque T e2 (k);

[0039] Step B3: Obtain the torque given value from the drive motor according to the torque distribution And construct the objective function;

[0040] Step B4: predict the stator flux of the drive motor at time k+1 and electromagnetic torque T e2 (k+1);

[0041] Step B5: cyclically calculate the voltage vectors of the eight switching states, calculate the objective function, and select the switching vector with the smallest objective function as the optimal voltage vector S for controlling the slave drive motor. opt2 .

[0042] Compared with the prior art, the present invention has the following advantages: the method is simple and easy to implement. The main drive motor adopts current model predictive control, and the slave drive motor adopts direct torque model predictive control. It can be effectively applied to the dual-motor drive system of the scraper conveyor, can solve the power imbalance problem, and while maintaining the advantages of vector control and direct torque control, it also gives play to the advantages of model predictive control. The effect is remarkable and easy to promote.

[0043] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the method of the present invention;

[0045] Figure 2 A flow chart of a method for using a current model predictive control method for a main drive motor of the present invention;

[0046] Figure 3 A flow chart of a method for using direct torque model predictive control from a drive motor according to the present invention;

[0047] Figure 4 This is a simulation effect diagram of the main drive motor and the slave drive motor of the present invention when the torque distribution is 1:1;

[0048] Figure 5 This is a simulation effect diagram of the main drive motor and the slave drive motor of the present invention when the torque distribution is 1:1.2;

[0049] Figure 6 This is a simulation effect diagram when the power of the main drive motor and the slave drive motor of the present invention are inconsistent. DETAILED DESCRIPTION

[0050] like Figure 1 As shown, the dual-motor drive control method of the scraper conveyor of the present invention includes dividing the dual motors into a main drive motor and a slave drive motor, the main drive motor adopts current model predictive control, and the slave drive motor adopts direct torque model predictive control.

[0051] In this method, the objective function of the current model predictive control of the main drive motor is:

[0052]

[0053] Where g1 represents the objective function in current model predictive control, is the given value of the stator current excitation component of the main drive motor, is the predicted value of the excitation component of the stator current of the main drive motor, is the given value of the stator current torque component of the main drive motor, It is the predicted value of the stator current torque component of the main drive motor.

[0054] In this method, the stator current prediction value of the main drive motor using the current model predictive control is:

[0055]

[0056] in, represents the stator current value of the main drive motor at time k+1, represents the stator current value of the main drive motor at time k, represents the rotor flux value of the main drive motor at time k, Represents the stator voltage vector of the main drive motor, T s1 is the stator time constant of the main drive motor, τ σ1 is the stator transient time constant of the main drive motor, and σ is the leakage inductance coefficient of the main drive motor, L s1 The stator leakage inductance of the main drive motor, R σ1 is the equivalent resistance of the main drive motor, and R s1 The stator resistance of the main drive motor, R r1 The rotor resistance of the main drive motor, k r1 is the rotor leakage inductance coefficient of the main drive motor, and L m1 is the stator mutual inductance of the main drive motor, Lr1 The rotor inductance of the main drive motor, τ r1 is the attenuation coefficient, and ω m1 The speed of the main drive motor;

[0057] The observed value of the rotor flux of the main drive motor is:

[0058]

[0059] in, The stator current vector of the main drive motor.

[0060] In this method, if Figure 2 As shown, the specific process of the main drive motor adopting the current model predictive control includes:

[0061] Step A1: Collect the stator current of the main drive motor at time k and speed ω m1 (k), and the DC side voltage u of the main drive motor inverter dc1 (k);

[0062] Step A2: Calculate the rotor flux of the main drive motor at time k

[0063] Step A3: Obtain the given value of the stator current excitation component of the main drive motor at time k according to the speed of the main drive motor and the outer flux ring. and the stator current torque component given value And construct the objective function;

[0064] Step A4: predict the stator current value of the main drive motor at time k+1

[0065] Step A5: cyclically calculate the voltage vectors of the eight switching states, calculate the objective function, and select the switching vector with the smallest objective function as the optimal voltage vector S for controlling the main drive motor. opt1 .

[0066] In specific implementation, the optimal voltage vector S opt1 Controls the power switch of the main drive motor inverter.

[0067] In this method, the objective function of the direct torque model predictive control of the slave drive motor is:

[0068]

[0069] Where g2 represents the objective function in direct torque model predictive control, is the torque given by the drive motor, is the torque prediction value from the drive motor, is the given value of the stator flux from the drive motor, is the predicted value of the stator flux from the drive motor.

[0070] In this method, the stator flux observation value in the direct torque model predictive control of the slave drive motor is:

[0071]

[0072] The rotor flux observation value is:

[0073]

[0074] Among them, ψ s2α is the component of the stator flux value of the drive motor on the α coordinate axis, ψ s2β is the component of the stator flux value of the drive motor on the β coordinate axis, u s2α is the component of the voltage from the drive motor on the α axis, u s2β is the component of the voltage from the drive motor on the β axis, i s2α is the component of the stator current of the driving motor on the α coordinate axis, i s2β is the component of the stator current of the driving motor on the β axis, R s2 is the stator resistance of the drive motor, T r2 is the rotor time constant of the slave drive motor, and L r2 is the leakage inductance from the drive motor rotor, R r2 is the rotor resistance of the drive motor, ψ r2α is the component of the rotor flux of the driving motor on the α coordinate axis, ψ r2β is the component of the rotor flux of the driving motor on the β coordinate axis, L m2 is the stator mutual inductance of the drive motor, ω r2 is the rotor angular velocity of the slave drive motor;

[0075] The predicted value of the stator flux from the drive motor is:

[0076]

[0077] in, It represents the stator flux value of the drive motor at time k+1, It represents the stator flux value of the drive motor at time k, represents the stator voltage vector of the drive motor at time k, represents the stator current of the drive motor at time k, T s2 is the stator time constant of the slave drive motor;

[0078] The predicted value of the drive motor torque is:

[0079]

[0080] Among them, T e2 (k+1) represents the torque value of the drive motor at time k+1, represents the stator current of the drive motor at time k+1, n P is the number of pole pairs of the slave drive motor.

[0081] In this method, if Figure 3 As shown, the specific process of adopting direct torque model predictive control from the drive motor includes:

[0082] Step B1: Collect the stator current of the drive motor at time k and speed ω m2 (k), and the DC side voltage u from the drive motor inverter dc2 (k);

[0083] Step B2: Calculate the stator flux of the drive motor at time k and electromagnetic torque T e2 (k);

[0084] Step B3: Obtain the torque given value from the drive motor according to the torque distribution And construct the objective function;

[0085] Step B4: predict the stator flux of the drive motor at time k+1 and electromagnetic torque T e2 (k+1);

[0086] Step B5: cyclically calculate the voltage vectors of the eight switching states, calculate the objective function, and select the switching vector with the smallest objective function as the optimal voltage vector S for controlling the slave drive motor. opt2 .

[0087] In the specific implementation, according to the requirements of the model predictive control for the optimization of the objective function, the voltage vectors of the two-level 8 switching states are traversed, and then the appropriate output vector is screened. The screening rule of the output vector is: select the switching vector that can minimize the objective function value as the output vector. In the process of screening the output vector, select any one of the two zero vectors (0,0,0) and (1,1,1). Finally, the optimal voltage vector S opt2 Controls the power switches of the slave drive motor inverter.

[0088] In order to verify the control effect of the method of the present invention, simulation analysis was performed through MATLAB / Simulink.

[0089] The motors with the same parameters are selected for simulation analysis, and the motor parameters are shown in Table 1.

[0090] Table 1 Motor parameters

[0091]

[0092] The motor starts without load. At 2s, a load is suddenly added with a load torque of 200N·m. At 2.5s, the load torque is 0. At 3s, the motor speed increases to 1146r / min. During this process, the torque distribution is always kept at 1:1. The simulation results are as follows: Figure 4 shown.

[0093] The motor starts without load. At 2s, a load is suddenly added with a load torque of 200N·m. At 2.5s, the load torque is 0. At 3s, the motor speed increases to 1146r / min. During this process, the torque distribution is always kept at 1:1.2. The simulation results are as follows: Figure 5 shown.

[0094] contrast Figure 4 and Figure 5 It can be seen that when the torque distribution ratio changes, the speeds of the two motors can remain completely consistent, and the output torques of the master and slave motors also completely conform to the torque distribution ratio. The results show that the control method of the present invention can effectively solve the power imbalance problem when the parameters of the two motors are consistent.

[0095] Keep the power of the main motor unchanged and change the power of the slave motor. The parameters of the slave motor are shown in Table 2.

[0096] Table 2 Motor parameters

[0097]

[0098] The motor starts without load. At 2s, a load is suddenly added with a load torque of 200N·m. At 2.5s, the load torque is 0N·m. At 3s, the motor speed increases to 1146r / min. The simulation results are as follows: Figure 6 shown.

[0099] right Figure 6 Analysis shows that when the power of the master and slave motors is inconsistent, the control method of the present invention can still ensure that the speeds of the two motors are completely consistent. In terms of torque, the followability between the master motor torque and the slave motor torque is good, and the torque distribution ratio is consistent with the power ratio of the two motors. Figure 6 (c) and 6(d) are the ratios of the torques of the two motors when loading and unloading. It can be seen from the figure that the ratio is basically maintained at 2 (±0.25).

[0100] Therefore, the control method of the present invention can effectively solve the power imbalance problem in various situations.

[0101] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A dual-motor drive control method for a scraper conveyor, characterized in that: The method includes dividing the dual motors into a main drive motor and a slave drive motor, wherein the main drive motor adopts current model predictive control, and the slave drive motor adopts direct torque model predictive control; The specific process of the main drive motor adopting the current model predictive control includes: Step A1: Collect the stator current of the main drive motor at time k and speed ωm1(k), and the DC side voltage u of the main drive motor inverter dc1 (k); Step A2: Calculate the rotor flux of the main drive motor at time k Step A3: Obtain the given value of the stator current excitation component of the main drive motor at time k according to the speed of the main drive motor and the outer flux ring. and the stator current torque component given value And construct the objective function; Step A4: predict the stator current value of the main drive motor at time k+1 Step A5: cyclically calculate the voltage vectors of the eight switching states, calculate the objective function, and select the switching vector with the smallest objective function as the optimal voltage vector S for controlling the main drive motor. opt1 ; The specific process of adopting direct torque model predictive control from the drive motor includes: Step B1: Collect the stator current of the drive motor at time k and speed ω m2 (k), and the DC side voltage u from the drive motor inverter dc2 (k); Step B2: Calculate the stator flux of the drive motor at time k and electromagnetic torque T e2 (k); Step B3: Obtain the torque given value from the drive motor according to the torque distribution And construct the objective function; Step B4: predict the stator flux of the drive motor at time k+1 and electromagnetic torque T e2 (k+1); Step B5: cyclically calculate the voltage vectors of the eight switching states, calculate the objective function, and select the switching vector with the smallest objective function as the optimal voltage vector S for controlling the slave drive motor. opt2 ; The objective function of the current model predictive control of the main drive motor is: Where g1 represents the objective function in current model predictive control, is the given value of the stator current excitation component of the main drive motor, is the predicted value of the excitation component of the stator current of the main drive motor, is the given value of the stator current torque component of the main drive motor, It is the predicted value of the stator current torque component of the main drive motor; The objective function of the direct torque model predictive control of the slave drive motor is: Where g2 represents the objective function in direct torque model predictive control, is the torque given by the drive motor, is the torque prediction value from the drive motor, is the given value of the stator flux from the drive motor, is the predicted value of the stator flux from the drive motor.

2. A dual-motor drive control method for a scraper conveyor according to claim 1, characterized in that: The stator current prediction value of the main drive motor using the current model predictive control is: in, represents the stator current value of the main drive motor at time k+1, represents the stator current value of the main drive motor at time k, represents the rotor flux value of the main drive motor at time k, Represents the stator voltage vector of the main drive motor, T s1 is the stator time constant of the main drive motor, τ σ1 is the stator transient time constant of the main drive motor, and σ is the leakage inductance coefficient of the main drive motor, L s1 The stator leakage inductance of the main drive motor, R σ1 is the equivalent resistance of the main drive motor, and R s1 The stator resistance of the main drive motor, R r1 The rotor resistance of the main drive motor, k r1 is the rotor leakage inductance coefficient of the main drive motor, and L m1 is the stator mutual inductance of the main drive motor, L r1 The rotor inductance of the main drive motor, τ r1 is the attenuation coefficient, and ω m1 The speed of the main drive motor; The observed value of the rotor flux of the main drive motor is: in, The stator current vector of the main drive motor.

3. A dual-motor drive control method for a scraper conveyor according to claim 1, characterized in that: The stator flux observation value in the direct torque model predictive control of the slave drive motor is: The rotor flux observation value is: Among them, ψ s2α is the component of the stator flux value of the drive motor on the α coordinate axis, ψ s2β is the component of the stator flux value of the drive motor on the β coordinate axis, u s2α is the component of the voltage from the drive motor on the α axis, u s2β is the component of the voltage from the drive motor on the β axis, i s2α is the component of the stator current of the drive motor on the α coordinate axis, i s2β is the component of the stator current of the driving motor on the β axis, R s2 is the stator resistance of the drive motor, T r2 is the rotor time constant of the slave drive motor, and L r2 is the leakage inductance from the drive motor rotor, R r2 is the rotor resistance of the drive motor, ψ r2α is the component of the rotor flux of the driving motor on the α coordinate axis, ψ r2β is the component of the rotor flux of the driving motor on the β coordinate axis, L m2 is the stator mutual inductance of the drive motor, ω r2 is the rotor angular velocity of the slave drive motor; The predicted value of the stator flux from the drive motor is: in, It represents the stator flux value of the drive motor at time k+1, It represents the stator flux value of the drive motor at time k, represents the stator voltage vector of the drive motor at time k, represents the stator current of the drive motor at time k, T s2 is the stator time constant of the slave drive motor; The predicted value of the drive motor torque is: Among them, T e2 (k+1) represents the torque value of the drive motor at time k+1, represents the stator current of the drive motor at time k+1, n P is the number of pole pairs of the slave drive motor.

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