Method for controlling synchronous operation of double-switch reluctance motor system through single converter

Abstract

The invention discloses a method for regulating and controlling synchronous operation of a dual-switch reluctance motor system by a single converter, the system adopts an asymmetric half-bridge power converter topological structure, the single converter is connected with a controller, the controller generates a control signal according to a collected dual-motor operation state signal, and the control signal is transmitted to the dual-switch reluctance motor system. And the double motors are controlled to keep synchronous operation under the unbalanced load. According to the method, the topological structure of a traditional single-converter dual-motor control system is not changed, only one set of power converter is needed and connected with one controller, from the perspective of control, the position angle difference between the two motors is prevented from being further enlarged by coupling the rotating speed signals and the position signals of the two motors, and the control precision is improved. Therefore, synchronous operation of the two switched reluctance motors under different loads is achieved, and certain stability and reliability are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of controlling a doubly switched reluctance motor using a single converter, and particularly to a method for synchronously operating a system for controlling a doubly switched reluctance motor by a single converter. Background Art

[0002] Due to its advantages such as simple structure, low cost, and high reliability, the switched reluctance motor has long maintained good competitiveness in the field of electric drive. In some fields, a single-motor control system can no longer meet the requirements, and dual-motor systems are increasingly used in industrial applications, such as in coal mining transportation of mining rail trams and locomotive traction applications, as well as in precision, high-speed multi-axis machining operations and complex motions of multi-degree-of-freedom robots. It is often difficult to operate relying solely on a single motor. In addition, under the same output torque condition, compared with a single motor, the total moment of inertia of a dual motor is less, which means less power consumption during operation.

[0003] In the existing doubly switched reluctance motor system, multi-motor synchronous operation is mainly achieved through non-cross-coupling control theories and cross-coupling control methods including master control and master-slave control, as well as strategies derived therefrom. These control methods have their own advantages, but inevitably require multiple sets of converters to achieve synchronous operation of multiple motors.

[0004] For some fields using dual-motor systems, the high cost and large size brought by two sets of converters will make them lack competitiveness. Therefore, in many fields such as industrial traction, the demand for driving multiple motors with a single converter is increasing. Using a single set of converters not only reduces the use of switching devices in terms of quantity, and since a single power converter is usually cheaper than two smaller half-power converters, and the price difference gradually expands as the power decreases, the single-converter multi-motor system can significantly reduce costs. In addition, using a single power converter to drive multiple motors also simplifies repetitive components such as protection circuits, rectifiers, filters, and controllers, greatly reducing the usage space and cost.

[0005] As an effective solution to reduce the overall cost, the single-converter multi-motor system has been more focused on induction motors and permanent magnet synchronous motors in previous studies. However, due to different motor structures and working principles, the single-converter multi-motor control strategies for induction motors and permanent magnet synchronous motors are not applicable to switched reluctance motors.

[0006] For switched reluctance motor systems, some scholars have proposed new stator winding connection methods; some scholars have also proposed a new power converter topology to achieve synchronous operation of a doubly switched reluctance motor using a single set of converters. However, these methods are all innovative in creating a completely new topology from the perspective of hardware connection and cannot be applied to traditional control systems, having certain particularity and limitations.

[0007] The patent document with the publication number CN105939134B discloses a running control system for a dual switched reluctance motor driven by a single power converter. This system of the present invention only requires one power converter to realize the running drive of two switched reluctance motors. The two motors are independently controlled. Since the stator coils of each phase are connected to different bridge arms, the currents of each phase will not affect each other. At the same time, without increasing the system cost and faults, the present invention can output a larger torque to carry a larger load, ensuring the stability and reliability of the motor running system. However, its solution also has the following problems: 1. It changes the topological structure of the motor control system and cannot be applied to traditional control systems, having certain particularity and limitations. 2. It does not disclose the principle formula of the regulation process. Summary of the Invention

[0008] Aiming at the above technical defects existing in the prior art, the purpose of the implementation of the present invention is to provide a control method for the synchronous operation of a dual switched reluctance motor driven by a single power converter, without changing the topological structure of the traditional single converter dual motor control system, only requiring a set of power converters, and realizing the synchronous operation of two switched reluctance motors under unbalanced loads from the perspective of control.

[0009] The purpose of the present invention can be achieved through the following technical solutions: A method for regulating the synchronous operation of a dual switched reluctance motor system by a single converter. The system adopts an asymmetric half-bridge power converter topological structure. The single converter is connected with a controller. The controller generates a control signal according to the collected operation state signals of the dual motors, and regulates the dual motors to maintain synchronous operation under unbalanced loads.

[0010] Further, the operation state signals of the dual motors collected by the controller include the position signals θ1 and θ2 of the dual motors, the winding currents i1 and i2 of the motors, and the rotational speeds ω1 and ω2 of the dual motors obtained according to the position signals θ1 and θ2 of the dual motors.

[0011] Further, according to the difference between the position signals θ1 and θ2 of the dual motors, the regulation method of the dual motors under unbalanced loads is determined.

[0012] Further, the regulation methods of the dual motors under unbalanced loads include:

[0013] When θ1 - θ2 < δ, self-regulation control is performed by using the single converter dual switched reluctance motor system;

[0014] When θ1 - θ2 ≥ δ, control is performed by using the controller;

[0015] Among them, θ1 is the position signal of the normal motor, θ2 is the position signal of the overloaded motor, and δ is the judgment threshold.

[0016] Further, when the single-converter dual switched reluctance motor system is used for self-regulating control, it includes:

[0017] When θ1 - θ2 < δ, calculate the current change rates of the overloaded motor and the normal motor within the conduction interval. The formula is:

[0018]

[0019] where k = 1 or 2. When k = 1, it represents the normal motor; when k = 2, it represents the overloaded motor.

[0020] Based on the fact that di2 / dθ > di1 / dθ during the excitation stage and the current drops of the two motors are almost the same during the freewheeling stage, perform self-regulating control on the single-converter dual switched reluctance motor system.

[0021] Further, when the controller is used for control, it includes:

[0022] When θ1 - θ2 ≥ δ, obtain the position signal θ fed back to the controller. According to the difference between the speeds ω1 and ω2 of the two motors, select the value of the position signal θ fed back to the controller. The formula is:

[0023]

[0024] where ε is the position signal switching threshold.

[0025] Further, the position signal switching threshold ε ≈ 0.

[0026] Further, when the controller is used for control, a double-loop control of the speed loop locking circuit and the current loop locking circuit is adopted to regulate the speeds ω1 and ω2 of the two motors to the normal speed. The process includes:

[0027] S11. Obtain the speed of each motor, and calculate the difference between the reference speed and the speeds of the two motors according to the set reference speed. The formula is expressed as:

[0028] error(t) = 2*ω * -(ω1 + ω2) (6)

[0029] where ω * is the set reference speed of the motor, and error(t) is the error value;

[0030] S12. Based on the obtained error value error(t), perform proportional-integral regulation to obtain the reference current I * , and the formula is:

[0031] I* = K p *(error(t)) + K i *∫error(t)*dt (7)

[0032] Among them, K p and K i are the proportional and integral constants respectively.

[0033] S13. Obtain the closed-loop chopping current I based on the difference between the reference current I * and the motor winding currents i1 and i2. The formula is expressed as: Δ

[0034] I * -(I1 + I2) = I Δ (8)

[0035] S14. Based on the chopping current I Δ obtain the auxiliary control signal to restore the speeds of the dual motors to the reference speed.

[0036] Furthermore, the controller includes:

[0037] A comparator that obtains the speeds ω1 and ω2 of the dual motors and compares them to obtain the speed difference of the dual motors;

[0038] A selector that obtains the speed difference of the dual motors and selects the value of the position signal θ according to the difference;

[0039] A control signal generator that generates a control signal according to the value of the position signal θ to control the single power converter.

[0040] Furthermore, the controller further includes:

[0041] A speed controller that obtains the speeds ω1 and ω2 of the dual motors and compares them with the set motor reference speed ω * to obtain the reference current I * ;

[0042] A current controller that obtains the motor winding currents i1 and i2 and compares them with the reference current I * to obtain the chopping current I Δ and the auxiliary control signal generator controls the single power converter.

[0043] Advantages of the present invention:

[0044] ​1. The method of the present invention realizes the synchronous operation of two switched reluctance motors under unbalanced loads from the perspective of control by not changing the topology of the traditional single-converter dual-motor control system, only requiring a set of power converters and connecting a controller. When the load difference between the two motors is small, the self-regulation mechanism of the system under small unbalanced loads without an algorithm is revealed. When the unbalanced load between the two motors exceeds its self-regulation ability, a synchronous strategy based on position signal switching control is provided. By coupling the speed signals and position signals of the two motors, the further expansion of the position angle difference between the two motors is prevented, and thus the synchronous operation of the two switched reluctance motors under different loads can be achieved with only a set of power converters, having a certain stability and reliability.

[0045] 2. The present invention adopts a double-closed-loop structure of a speed loop and a current loop. Under the action of the double closed loops (speed loop and current loop), the closed-loop control of the single-converter dual-switched reluctance motor system is realized, so that the speeds of the two motors can be restored to the set reference speed after stalling and adjustment, ensuring the stable operation of the dual-motor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a schematic structural diagram of the single-converter dual-switched reluctance motor system of the present invention;

[0047] Figure 2 is a schematic structural diagram of the controller of the present invention;

[0048] Figure 3 is a characteristic diagram of the phase inductance and its change rate of the two motors within one cycle of the present invention;

[0049] Figure 4 is a distribution diagram of the position relationship and inductance change rate of the two motors under balanced loads of the present invention;

[0050] Figure 5 is a distribution diagram of the inductance change rate and inductance of the two motors under small unbalanced loads of the present invention;

[0051] Figure 6 is a distribution diagram of the inductance and inductance change rate of the two motors under large unbalanced loads of the present invention;

[0052] Figure 7 is the position relationship and inductance change rate distribution of the two motors under large unbalanced loads after the position signal is switched of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0054] As Figure 1 shown, the present invention discloses a method for regulating the synchronous operation of a dual switched reluctance motor system by a single converter. The system adopts an asymmetric half-bridge single power converter topology. The single converter is connected to a controller. The controller generates a control signal based on the collected operating state signals of the dual motors, and regulates the dual motors to maintain synchronous operation under unbalanced loads.

[0055] Embodiment 1: The asymmetric half-bridge single power converter topology is as Figure 1 shown, and includes a DC power supply, a single power converter (single converter), two switched reluctance motors, two position detectors, six current sensors, and a controller.

[0056] Among them: The DC power supply supplies power to the dual-motor system. The single converter can simultaneously control the on-off of the stator windings of each phase of the two switched reluctance motors. The two switched reluctance motors can adopt three-phase 12 / 8 structure motors and have the same model. The two position detectors are respectively used to detect and obtain the rotor position and speed information of the two switched reluctance motors. The six current sensors are respectively used to detect the three-phase stator winding currents of the two motors;

[0057] The connection and control mode between components are as Figure 1 shown. Two switched reluctance motors 1 and 2 adopt three-phase stator windings A1, A2, B1, B2, C1, C2, and are respectively connected in parallel to the midpoints of each arm of the asymmetric half-bridge single converter. The stator currents of the two motors 1 and 2 are jointly fed back to the controller. The position signals of the two motors 1 and 2 are also fed back to the controller through a selector according to the speed difference. The speeds of the two motors 1 and 2 are also jointly fed back to the controller.

[0058] The controller is connected to the single converter. The controller selects a position signal according to the speed difference of the dual motors, and generates a control signal based on the position signal and the chopping current signal to regulate the dual motors under unbalanced loads. The operating state signals of the dual motors collected by the controller include the dual-motor position signals θ1 and θ2, the motor winding currents i1 and i2. Among them, i1 includes (i a 1 , i b 1 , i c 1 ), i2 includes (i a 2 , i b 2 , i c 2 ); The dual-motor speeds ω1 and ω2 obtained based on the dual-motor position signals θ1 and θ2.

[0059] For the convenience of understanding, the working principle of the present invention is introduced first: the magnetic field distribution of the switched reluctance motor changes with the relative position of the stator and rotor, so the winding inductance changes periodically with the rotor position; at the aligned position, that is, when the magnetic pole axes of the stator and rotor coincide, the winding inductance is the maximum value L max , at the completely unaligned position, that is, the axis between the rotor magnetic poles coincides with the stator magnetic pole axis, it is the minimum value L min .

[0060] Select the characteristic diagram of the phase inductance at a certain current, as Figure 3 shown. Ignoring the edge effect of the magnetic poles and the influence of mutual inductance, and not considering magnetic circuit saturation, the torque output equation of the switched reluctance motor can be simplified as:

[0061]

[0062] where L aa , L bb , L cc are the self-inductances of the windings of phases a, b, and c respectively.

[0063] It can be seen from formula (1) that the electromagnetic torque of the switched reluctance motor is the sum of the torques of each phase, and the torque of each phase is positively correlated with the rate of change of its inductance.

[0064] From the characteristic diagram of the phase inductance, the characteristic diagram of the rate of change of the phase inductance with respect to the position can be obtained, as Figure 4 shown. Select a suitable turn-on angle θ on and turn-off angle θ off , and take the region with a larger rate of change of inductance as the conduction region to generate a larger electromagnetic torque.

[0065] From Figure 1 the system structure, it can be seen that two switched reluctance motors are connected in parallel under a single converter, and the terminal voltages of the two motors are the same. At the same time, the initial positions of the two motors can be made the same through calibration; when the loads of motors 1 and 2 are the same, for two identical switched reluctance motors, they have the same performance, and the rates of change of the inductances of the two motors with respect to the position are the same, as Figure 4 shown. At this time, arbitrarily select the position signal of one motor (such as the position signal of motor 1) and feedback it to the controller. In an ideal situation, the synchronous operation of the two motors can be achieved.

[0066] However, in actual situations, when there are certain differences between two motors of the same model, resulting in different motor loads, these differences can be caused by motor manufacturing, motor usage environment, etc., resulting in the inability of the two motors to achieve synchronous operation.

[0067] When the two motors are not operating synchronously, the control method of the two motors under unbalanced loads can be determined based on the difference between the position signals θ1 and θ2 of the two motors. The control methods include:

[0068] When θ1 - θ2 < δ, a single-converter dual switched reluctance motor system is used for self-regulation control; when θ1 - θ2 ≥ δ, a controller is used for control.

[0069] Among them, θ1 is the normal motor position signal, θ2 is the overloaded motor position signal, and δ is the judgment threshold, which is obtained by presetting in advance.

[0070] When the single-converter dual switched reluctance motor system is used for self-regulation control, at this time the position angle difference θ1 - θ2 < δ, there are certain manufacturing differences in the dual motors themselves or the load differences between the dual motors are small.

[0071] Taking the case where the load of motor 2 is slightly greater than that of motor 1 as an example: there will be a certain position angle difference θ1 - θ2 between motors 1 and 2. At this time, the position angle of motor 2 lags behind that of motor 1.

[0072] Without adopting other strategies, the position signal of motor 1 is fed back to the controller, that is, the on-off control of the controller is carried out under the position signal of motor 1. For motor 1, dL1(θ) / dθ remains unchanged; for motor 2, its conduction interval changes due to the position signal of motor 1. Since the original conduction interval is the region where the inductance change rate is large, after the conduction region changes, dL2(θ) / dθ will become relatively smaller within one cycle, as Figure 5 (a) shows. Obviously, this is not conducive to the generation of electromagnetic torque and is likely to cause the speed of motor 2 to further decrease.

[0073] However, while the change in the conduction interval causes a change in dL(θ) / dθ, it also causes a change in the inductance L(θ), as Figure 5 (b) shows. The position angle difference between the motors makes L2(θ) less than L1(θ) within the same conduction interval. Therefore, due to the existence of the position angle difference, the average value of dL2(θ) / dθ and the value of L2(θ) within one cycle are both less than the average value of dL1(θ) / dθ and the value of L1(θ), as shown in Equation (2).

[0074]

[0075] When the resistance voltage drop of the motor and the change rate of the inductance to the current are small, they can be ignored. The simplified voltage balance equation is:

[0076]

[0077] As can be seen from (3), the changes in dL(θ) / θ and L(θ) caused by the position difference will inevitably cause changes in the phase current i. Based on the size relationship formula (2) of dL(θ) / dθ and L(θ) of the dual motors and the voltage balance equation variant (3), calculate the current change rates of the overloaded motor and the normal motor within the conduction interval. The formula is:

[0078]

[0079] where k = 1 or 2. When k = 1, it represents the normal motor; when k = 2, it represents the overloaded motor.

[0080] As can be seen from (4), when in the excitation stage, that is, the terminal voltage U k = +U dc , and di2(θ) / dθ > di1(θ) / dθ, that is, the current rising speed of motor 2 is faster than that of motor 1. Due to the use of soft chopping, when in the freewheeling stage, that is, the terminal voltage U k = 0, the current drops of the dual motors are almost the same.

[0081] Overall, when θ1 - θ2 < δ, the load difference between the dual motors is small at this time. Under the same conduction voltage, within one cycle, motor 2 can generate a larger phase current compared to motor 1, thereby generating a larger output torque to overcome its larger load. That is, a single-converter dual switched reluctance motor system is used for self-regulating control.

[0082] Therefore, when the load difference between the two motors is small, the resulting position angle difference is small. At this time, even if the synchronous control algorithm is not added and only the position signal of motor 1 is fed back, relying on the current regulation effect, sufficient output torque can still be generated to keep the dual motors running synchronously under unbalanced loads, enabling the dual switched reluctance motor system with a single converter to have a certain self-regulating ability.

[0083] Under a large unbalanced load, the position angle difference between the dual motors is larger. For motor 2, the average value of dL2(θ) / dθ within the conduction interval will decrease significantly, as Figure 6 shown. When the current regulation is not sufficient to generate enough output torque, especially in the region where each phase just conducts (near θ on ), even if a large phase current is generated through current self-regulation at this time, however, since dL2(θ) / dθ is almost zero, the generated output torque is very small, and the speed of motor 2 will further decrease, and the position angle difference between the two motors will further increase, resulting in negative torque generation until it gets out of control.

[0084] Therefore, the self-regulating ability of the dual motors can only maintain the synchronous operation of the dual motors under a small unbalanced load. When the load difference between the dual motors is large and exceeds the self-regulating ability of the dual motors, the simple self-regulating control method cannot ensure the synchronous operation of the two motors.

[0085] When the load difference between the two motors is large, resulting in a large position angle difference, and at this time θ1 - θ2 ≥ δ, a controller can be used for regulation.

[0086] The structure of the controller is as Figure 2 shown. The controller includes: a comparator, a selector, a control signal generator, a speed controller, and a current controller.

[0087] Among them, the comparator obtains the rotational speeds ω1 and ω2 of the two motors, and after comparison, obtains the rotational speed difference between the two motors; the rotational speed difference is transmitted to the selector, and the selector selects the value of the position signal θ according to the difference.

[0088] The controller adjusts the motor speed in a timely manner to prevent the further expansion of the position angle difference. The core of the synchronous control process of the controller lies in the position signal selection. The position signal selector consists of a comparator and a selector. By comparing the rotational speeds of the two motors, the position signal fed back to the selector is switched, so that the rotational speeds of the two motors are intertwined.

[0089] The switching rule satisfies formula (5),

[0090]

[0091] where ω i is the rotational speed of motor i, θ i is the position signal of motor i, and ε is the signal switching threshold.

[0092] Under a large unbalanced load, the rotational speed of motor 2 decreases due to the large load. When the rotational speed is lower than that of motor 1 and the difference exceeds a certain threshold ε, the selector switches the position signal fed back to the controller to the position signal θ2 of motor 2. At this time, the control signal acting on motor 2 is generated by the position signal of motor 2 itself. Motor 2 is within the normal on-off interval, and the average value of dL2(θ) / dθ is large. Therefore, sufficient electromagnetic torque can be generated to overcome its load and increase the rotational speed; for motor 1, at this time, the control signal is generated by the position signal θ2 of motor 2, and the conduction interval changes. The average value of dL1(θ) / dθ within the interval will become relatively smaller, as Figure 4 shown, which is not conducive to the generation of electromagnetic torque, and thus its rotational speed decreases slowly.

[0093] Therefore, when the position signal fed back to the controller is switched to the position signal θ2 of Motor 2 for control, the rotational speed of Motor 2 will gradually increase, and the rotational speed of Motor 1 will gradually decrease, preventing the further expansion of the position angle between the two motors. Until the rotational speed of Motor 1 is lower than that of Motor 2 and exceeds a certain threshold ε, at this time, the position signal fed back to the controller is switched to the position signal θ1 of Motor 1, causing the rotational speed of Motor 1 to increase and the rotational speed of Motor 2 to decrease. Repeating this process, the rotational speeds of the two switched reluctance motors are intertwined and basically remain the same, and a small position angle difference is also maintained between the motors. When ε is used as the signal switching threshold, ε can be approximately 0.

[0094] In addition, in order to achieve the closed-loop control of the single-converter dual switched reluctance motor system and ensure the symmetry of the system, a dual closed-loop structure suitable for the dual switched reluctance motor system is adopted; the dual closed-loop structure mainly includes a speed controller and a current controller. The speed controller forms a speed loop, and the current controller forms a current loop, thus forming a dual closed-loop structure of the speed loop and the current loop.

[0095] The speed controller obtains the rotational speeds ω1 and ω2 of the two motors and compares them with the set reference rotational speed ω * of the motor to obtain the reference current I * ; the current controller obtains the winding currents i1 and i2 of the motor and compares them with the reference current I * to obtain the chopping current I Δ The auxiliary control signal generator generates a regulation signal, and the process includes:

[0096] As Figure 2 shown, obtain the rotational speed of each motor, calculate the difference between the reference rotational speed and the rotational speeds of the two motors, and the formula is expressed as:

[0097] error(t) = 2 * ω * - (ω1 + ω2) (6)

[0098] Among them, ω * is the set reference rotational speed of the motor; error(t) is the error value.

[0099] According to the obtained error value error(t), proportional-integral regulation is performed through the proportional-integral regulator PI to obtain the reference current I * , and the formula is:

[0100] I* = K p * (error(t)) + K i * ∫error(t) * dt (7)

[0101] Among them, K p and K i are the proportional and integral constants respectively.

[0102] The output signal of the PI is the reference current I * ,I * As the input signal of the current loop, in the current controller, the real-time current signals (i1, i2) of the two switched reluctance motors are simultaneously acquired and feedback summed, and compared with the reference current I * The chopping current signal is generated through the hysteresis comparator, and the formula is expressed as:

[0103] I * -(I1 + I2) = I Δ (8)

[0104] When the synchronous speed of the dual motors decreases due to a sudden increase in load, the input signal error(t) of the PI regulator increases, and the reference current I output by the PI regulator in formula (7) * will increase accordingly. Under the action of the current loop, the duty cycle of the generated chopping signal will increase, thereby increasing the phase current of the motor; according to formula (8), the generated output torque will increase, causing the speed of the dual motors to continuously rise until the reference speed. The dual motors achieve speed synchronization through the proposed position signal switching control, and then under the action of the double closed-loop (speed loop and current loop), closed-loop control is achieved, enabling the speeds of the dual motors to reach the set reference speed.

[0105] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for regulating the synchronous operation of a dual switched reluctance motor system by a single converter, characterized in that The system adopts an asymmetric half-bridge power converter topology. The single converter is connected to a controller, which generates control signals based on the collected operation status signals of the dual motors to regulate the dual motors to operate synchronously under unbalanced loads.

2. A method for regulating the synchronous operation of a dual switched reluctance motor system by a single converter according to claim 1, characterized in that The operation status signals of the dual motors collected by the controller include the position signals θ1 and θ2 of the dual motors, the motor winding currents i1 and i2, and the rotational speeds ω1 and ω2 of the dual motors obtained based on the position signals θ1 and θ2 of the dual motors.

3. A method for regulating the synchronous operation of a single-converter-controlled dual switched reluctance motor system according to claim 2, characterized in that Based on the difference between the position signals θ1 and θ2 of the dual motors, the regulation method of the dual motors under unbalanced loads is determined.

4. A method for regulating the synchronous operation of a single-converter controlled dual switched reluctance motor system according to claim 3, characterized in that The regulation methods of the dual motors under unbalanced loads include: When θ1 - θ2 < δ, a self-regulation control is performed using a single converter switched reluctance motor system; When θ1 - θ2 ≥ δ, a controller is used for regulation; Among them, θ1 is the position signal of the normal motor, θ2 is the position signal of the overloaded motor, and δ is the judgment threshold.

5. A method for regulating the synchronous operation of a single-converter-controlled dual switched reluctance motor system according to claim 4, characterized in that, When performing self-regulation control using a single converter switched reluctance motor system, it includes: When θ1 - θ2 < δ, calculate the current change rates of the overloaded motor and the normal motor within the conduction interval. The formula is: Among them, k = 1 or 2. When k = 1, it represents the normal motor, and when k = 2, it represents the overloaded motor; Based on the fact that di2 / dθ > di1 / dθ during the excitation phase and the current drops of the dual motors are almost the same during the freewheeling phase, a self-regulation control is performed on the single converter switched reluctance motor system.

6. A method for regulating the synchronous operation of a single-converter-controlled dual switched reluctance motor system according to claim 4, characterized in that When using the controller for regulation, it includes: When θ1 - θ2 ≥ δ, obtain the position signal θ fed back to the controller, and select the value of the position signal θ fed back to the controller based on the difference between the rotational speeds ω1 and ω2 of the dual motors. The formula is: Among them, ε is the position signal switching threshold.

7. A method for regulating the synchronous operation of a single-converter-controlled dual-switched reluctance motor system according to claim 6, characterized in that The position signal switching threshold ε ≈ 0.

8. A method for regulating the synchronous operation of a single-converter-controlled dual-switched reluctance motor system according to claim 6, characterized in that When using the controller for regulation, a dual-loop regulation of the rotational speeds ω1 and ω2 of the dual motors to the normal rotational speed is performed using a speed loop locking circuit and a current loop locking circuit. The process includes: S11. Obtain the rotational speed of each motor, and calculate the difference between the reference rotational speed and the rotational speeds of the dual motors according to the set reference rotational speed. The formula is expressed as: error(t) = 2*ω * -(ω1 + ω2) (6) where ω * is the set reference speed of the motor, and error(t) is the error value; S12. Based on the obtained error value error(t), perform proportional-integral adjustment to obtain the reference current I * , and the formula is: I* = K p *(error(t)) + K i *∫error(t) * dt (7) where K p and K i are the proportional and integral constants, respectively; S13. Obtain the closed-loop chopping current I based on the reference current I * and the difference between the motor winding currents i1 and i2 Δ , which is expressed by the formula as follows: I * -(I1 + I2) = I Δ (8) S14. According to the chopping current I Δ The auxiliary control signal is used to restore the speeds of the two motors to the reference speeds.

9. A method for regulating the synchronous operation of a single-converter controlled dual switched reluctance motor system according to any one of claims 1-8, characterized in that, The controller includes: A comparator that obtains the rotational speeds ω1 and ω2 of the dual motors and compares them to obtain the difference between the rotational speeds of the dual motors; A selector that obtains the difference between the rotational speeds of the dual motors and selects the value of the position signal θ based on the difference; A control signal generator that generates control signals based on the value of the position signal θ to regulate the single power converter.

10. A method for regulating the synchronous operation of a single-converter-controlled dual switched reluctance motor system according to claim 9, characterized in that, The controller further includes: The speed controller obtains the rotational speeds ω1 and ω2 of the dual motors and compares them with the set reference rotational speed ω of the motor to obtain the reference current I * ; * ; A current controller that acquires the motor winding currents i1 and i2 and compares them with a reference current I * and acquires a chopping current I Δ An auxiliary control signal generator regulates a single power converter.

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