A switched reluctance drive system and control method

Abstract

The present invention relates to a switched reluctance drive system and control method. The switched reluctance drive system and control method of the present invention realize true closed-loop vector control based on the two physical quantities torque and speed output by the motor based on accurate current and rotor position detection, so that the current, torque and speed control precision is high. The current control precision is high, which effectively suppresses the generation of large current spikes and also reduces the motor noise; the torque control precision is high, which greatly reduces the torque pulsation, has little impact on the power module, and improves the reliability during operation; the speed control precision is high, which ensures the stability of the overall control performance; the efficiency is high and the heat is small under frequent startup and overload conditions, and the internal temperature and power regulation curve are matched, thereby optimizing the performance of the switched reluctance drive system. In view of the above reasons, the present invention can be widely used in the field of motor drive.

Description

Technical Field

[0001] The present invention relates to the field of motor driving, and in particular to a switched reluctance driving system and a control method. Background Art

[0002] Switched Reluctance Drive (SRD) is the latest generation of stepless speed regulation system developed after the variable frequency speed regulation system and brushless DC motor speed regulation system. It is a high-tech optical, mechanical and electrical integration technology that integrates modern microelectronics technology, digital technology, power electronics technology, infrared optoelectronic technology and modern electromagnetic theory, design and manufacturing technology. It has the advantages of both DC and AC speed regulation systems. Economically developed countries such as the United Kingdom and the United States started research on switched reluctance motor speed regulation systems early and have achieved remarkable results. The product power levels range from several W to hundreds of kW and are widely used in household appliances, aviation, aerospace, electronics, machinery and switched reluctance drive system vehicles.

[0003] At present, the commonly used switched reluctance drive system has the following characteristics:

[0004] 1) The motor has a simple structure, low cost and is suitable for high speed. The switched reluctance motor has no windings, permanent magnets, slip rings, etc. on the rotor, and only simple concentrated windings on the stator, with short winding ends and no interphase jumper wires. Therefore, the structure of the switched reluctance motor is simpler than that of the squirrel cage induction motor.

[0005] 2) The power circuit is simple, and each phase works independently, which can form a highly reliable system. Because the direction of the motor torque is independent of the direction of the winding current, that is, only a single-direction winding current is required, the power circuit can have one power switch per phase. From the electromagnetic structure of the motor, the windings and magnetic circuits of each phase are independent of each other, and each generates electromagnetic torque within a certain shaft angle range. Unlike in general motors, a circular rotating magnetic field must be generated under the joint action of each phase winding and magnetic circuit for the motor to operate normally.

[0006] 3) High starting torque, low starting current. The controller absorbs less current from the power supply side and obtains a larger starting torque on the motor side, which is a major feature of this system. This makes the current impact small during the starting method, and the heat generation of the motor and controller is smaller than that during continuous rated operation, which is suitable for frequent starting and stopping and forward and reverse rotation.

[0007] 4) There are many controllable parameters and good speed regulation performance. There are at least four main operating parameters and common methods for controlling the switched reluctance motor: phase opening angle, related breaking angle, phase current amplitude, and phase winding voltage.

[0008] 5) High efficiency and low loss SRD system is a very efficient speed regulation system. It can meet various special use requirements through the unified and coordinated design of the machine and the electricity.

[0009] 6) There is obvious torque pulsation and large vibration during drive operation.

[0010] 7) The switched reluctance motor has high noise, which affects its application scenarios.

[0011] In summary, the switched reluctance drive system currently commonly used in the market has many advantages in terms of its characteristics, but it also has fatal disadvantages, which limits its application occasions and scope and prevents it from being used in a wider field.

[0012] The main problems currently exist are as follows:

[0013] 1) There is obvious torque pulsation and the torque control accuracy is low;

[0014] 2) Vibration occurs during operation and the stability performance is poor;

[0015] 3) The switched reluctance motor has high noise;

[0016] 4) The switched reluctance drive system lacks overall optimization. Summary of the invention

[0017] The technical problem to be solved by the present invention is: in order to solve the problem of obvious torque pulsation in the prior art, which leads to vibration and high motor noise, the present invention provides a switched reluctance drive system and a control method to solve the above problems.

[0018] The technical solution adopted by the present invention to solve its technical problems is: a switched reluctance drive system, characterized in that: it includes a controller, a user control device, a switched reluctance motor and a magnetoelectric encoder; wherein the controller is respectively connected to the user control device and the switched reluctance motor, and the switched reluctance motor is connected to the magnetoelectric encoder; the user control device provides the controller with a control signal for the operation of the drive system, the magnetoelectric encoder detects the absolute angular position signal of the motor rotor of the switched reluctance motor and transmits it to the controller, the controller provides the control signal for the operation of the drive system according to the absolute angular position signal of the motor rotor and the user control device, and outputs two-way U, V, W PWM drive signals to the switched reluctance motor through current closed-loop vector control, torque control and speed closed-loop, thereby controlling the load driven by the drive system to work.

[0019] The driving system also includes a battery pack, which is connected to the controller and is used to provide positive and negative power sources to the controller.

[0020] The controller includes a control module, a power module, a power module, a current detection module, a position detection module and an interface module; wherein the control module is respectively connected to the power module, the power module, the current detection module, the position detection module and the interface module, and the power module is also connected to the power module, the current detection module, the position detection module and the battery pack; the power module is respectively connected to the current detection module and the switched reluctance motor; the position detection module is connected to the magnetoelectric encoder; the interface module is connected to the user control device; the power module provides control power to the control module, provides power to the power module, and provides detection power to the current detection module and the position detection module respectively. source; the control module receives the motor rotor absolute angular position signal of the switched reluctance motor provided by the position detection module, and the motor current feedback signal of the switched reluctance motor provided by the current detection module, and obtains the PWM drive signals of two inputs and two outputs U, V, W for driving the switched reluctance motor through current closed-loop vector control, torque control and speed closed-loop control algorithms, and transmits them to the power module; the power module generates U, V, W motor three-phase signals to drive the switched reluctance motor according to the power supply provided by the power supply module and the PWM signal provided by the control module; the control module receives the control signal of the drive system operation provided by the user control device through the interface module, and realizes the specific function control of the drive system.

[0021] The magnetoelectric encoder includes a rotor and a stator: the rotor adopts a magnetic steel ring, which is sleeved on the tail shaft of the switched reluctance motor and rotates synchronously with the rotor of the switched reluctance motor; the stator adopts a stator bracket, a Hall magnetic induction element, and a PCB circuit board; the Hall magnetic induction element is positioned and installed on the stator bracket, the pins of the Hall magnetic induction element are welded on the PCB circuit board, and the PCB circuit board is fixed on the stator bracket; the stator bracket is installed and fixed on the rear flange of the switched reluctance motor; the Hall magnetic induction element senses the magnetic field change signal generated by the magnetic steel ring rotating synchronously with the rotor of the switched reluctance motor, and converts the magnetic field change signal into an analog voltage signal and transmits it to the PCB circuit board, and the signal interface of the PCB circuit board is output to the position detection module of the controller.

[0022] A control method for a switched reluctance drive system, comprising the following steps: 1) using motor speed as the horizontal coordinate and motor torque as the vertical coordinate to divide quadrants, wherein the first quadrant needs to meet the conditions of speed>0, torque>0; the second quadrant needs to meet the conditions of speed<0, torque>0; the third quadrant needs to meet the conditions of speed<0, torque<0; and the fourth quadrant needs to meet the conditions of speed>0, torque<0; 2) after entering each quadrant control, current closed-loop vector control, torque control and speed closed-loop control are performed on the drive system; 3) the control conversion method between quadrants is as follows: the first step, after entering the current quadrant control, firstly, according to the current speed feedback, a two-step turn-off angle advance angle calculation is performed; the second step, the speed feedback is speed-limited, and at the same time, temporary speed feedback and calculation of the limit lag conduction angle are obtained; the third step, according to the current command output by the torque processor or the speed controller and each control The first step is to calculate the turn-on angle compensation value and the turn-off angle compensation value according to the change of the control cycle electrical angle; the fourth step is to judge the speed according to the current speed feedback, which is divided into low speed zone, high speed zone and medium speed zone; the fifth step is to calculate the turn-on angle according to the turn-on angle setting value, the turn-on angle compensation value and the limit lag turn-on angle in each speed interval; the turn-off angle is calculated according to the turn-off angle setting value and the turn-off angle compensation value; and the turn-on angle and the turn-off angle are processed with dead zone angles respectively: the turn-on angle is subtracted from the set dead zone angle to obtain the turn-on angle output value, and the turn-off angle is subtracted from the set dead zone angle to obtain the turn-off angle output value; the two-step turn-off angle is calculated according to the turn-off angle after dead zone angle processing and the two-step turn-off angle advance angle; the sixth step is to limit the angle range of the turn-on angle, the turn-off angle and the two-step turn-off angle; the seventh step is to determine the conduction or closing type by designing a phase-on controller according to the calculated turn-on angle, the turn-off angle and the two-step turn-off angle, and end the current quadrant control.

[0023] In the step 2), the method for current vector control is as follows: in the first step, after the current control interruption starts, the current sampling is triggered to obtain the motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb and W-phase current feedback Iw_fb respectively, and the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder is read at the same time; in the second step, the current command I_ref is transmitted to the U-phase current command Iu_ref, the V-phase current command Iv_ref, and the W-phase current command Iw_ref respectively, that is, I_ref=Iu_ref=Iv_ref=Iw_ref; the U-phase current PID controller is based on the difference ΔI between the U-phase current command Iu_ref and the U-phase current feedback Iu_fb u outputs the U-phase drive voltage ΔUu by calculation; the V-phase current PID controller outputs the V-phase drive voltage ΔUv by calculation according to the difference ΔIv between the V-phase current command Iv_ref and the V-phase current feedback Iv_fb; the W-phase current PID controller outputs the W-phase drive voltage ΔUw by calculation according to the difference ΔIw between the W-phase current command Iw_ref and the W-phase current feedback Iw_fb; the third step is to design a phase power-on controller to judge and convert the three-phase drive voltages ΔUu, ΔUv, ΔUw, and the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder into a PWM drive signal output, and then generate U, V, and W three-phase currents through the power module to control the switched reluctance motor.

[0024] In the step 2), the method for torque control is as follows: the first step is to trigger current sampling to obtain the motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb and W-phase current feedback Iw_fb respectively after the torque control interruption starts, and read the motor rotor absolute angular position signal θ_fb output by the magnetoelectric encoder detection at the same time; the second step is to output the speed feedback V_fb after the motor rotor absolute angular position signal θ_fb is calculated by a differentiator; the third step is to design a torque processor to calculate and process the output current command I_ref according to the torque command T_ref and the speed feedback V_fb provided by the user control device, and input it into the three-phase independent current control; the fourth step is to finally realize the outer loop torque control of the drive system by running the current control inner loop.

[0025] In the step 2), the method for speed control is as follows: the first step is to trigger current sampling to obtain the motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb, and W-phase current feedback Iw_fb respectively after the speed control interruption starts, and at the same time read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder; the second step is to output the speed feedback V_fb after the motor rotor absolute angular position signal θ_fb is calculated by a differentiator; the third step is to output the current command I_ref according to the speed command V_ref and the speed feedback V_fb by the speed PID controller, and input it into the three-phase independent current control; the fourth step is to finally realize the outer loop speed control of the drive system by running the current control inner loop.

[0026] In the method for current vector control, independent decoupled feedforward current closed-loop vector control is performed on the U phase of the switched reluctance motor, including the following steps: the first step is to trigger current sampling to obtain the motor U phase current feedback Iu_fb after the current control interruption starts, and at the same time read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder; the second step is to output the speed feedback V_fb after the motor rotor absolute angular position signal θ_fb is calculated by a differentiator; the third step is to output the driving voltage ΔUu by the U phase current controller according to the difference ΔIu between the U phase current command Iu_ref and the U phase current feedback Iu_fb; the fourth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the fourth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the fourth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the fifth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the fifth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the fifth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the sixth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the sixth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the sixth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the seventh step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the eighth step is to output the U phase current feedback V_fb by calculating the U phase current feedback V_fb; the eighth step is to output the U phase current feedback V_fb; the eighth step is to output the U phase current feedback V_fb The feedforward controller calculates and outputs the U-phase feedforward voltage FF_Uu according to the U-phase current command Iu_ref and the speed feedback V_fb provided by the differentiator; the U-phase drive voltage ΔUu and the U-phase feedforward voltage FF_Uu are added to obtain the U-phase intermediate drive voltage Δ`Uu; in the fifth step, the U-phase final drive voltage Δ``Uu is obtained after voltage limiting processing; in the sixth step, a phase power-on controller is designed to calculate and judge according to the final drive voltage Δ``Uu and the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder (400), and convert it into a PWM drive signal output, and then generate a U-phase current through a power module to control the switched reluctance motor.

[0027] The beneficial effects of the present invention are as follows: the switch reluctance drive system and control method of the present invention adopt a four-quadrant control strategy based on the two physical quantities torque and speed output by the motor, and in each quadrant, based on the accurate detection of the motor rotor position, a closed-loop vector control of the current and a closed-loop control mode of the speed are realized. The four-quadrant control strategy is adopted to realize the overall optimization of the switch reluctance drive system; based on the accurate current and rotor position detection, a true closed-loop vector control is realized, so that the current, torque and speed control precision is high. The current control precision is high, which effectively suppresses the generation of large current spikes and also reduces the motor noise; the torque control precision is high, which greatly reduces the torque pulsation, has little impact on the power module, and improves the reliability during operation; the speed control precision is high, which ensures the stability of the overall control performance; the efficiency is high and the heat is small under frequent startup and overload conditions, and the internal temperature and power regulation curve are matched, thereby optimizing the performance of the switch reluctance drive system. In view of the above reasons, the present invention can be widely used in the field of motor drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0029] Figure 1 is an overall block diagram of the switched reluctance drive system of the present invention;

[0030] Figure 2 It is a structural diagram of the switched reluctance motor and the magnetoelectric encoder of the present invention;

[0031] Figure 3 It is the overall schematic diagram of the assembly of the magnetoelectric encoder on the switched reluctance motor;

[0032] Figure 4 yes Figure 3 A top view of

[0033] Figure 5 It is a quadrant diagram formed by motor speed and motor torque;

[0034] Figure 6 It is a principle block diagram of the motor entering each quadrant from the initial state and the mutual transformation between quadrants;

[0035] Figure 7 It is the control flow chart of the first quadrant;

[0036] Figure 8 It is the control flow chart of the second quadrant;

[0037] Fig. 9 It is a control flow chart of the third quadrant;

[0038] Fig.10 It is a control flow chart of the fourth quadrant;

[0039] Fig.11 It is a current control block diagram of the switch reluctance drive system control method of the present invention;

[0040] Fig.12 is a current control flow chart of the switch reluctance drive system control method of the present invention;

[0041] Fig.13 It is a torque control block diagram of the switch reluctance drive system control method of the present invention;

[0042] Fig.14 is a torque control flow chart of the switch reluctance drive system control method of the present invention;

[0043] Fig.15 It is a speed control block diagram of the switch reluctance drive system control method of the present invention;

[0044] Fig.16 is a speed control flow chart of the switch reluctance drive system control method of the present invention;

[0045] Fig.17 It is a current loop U-phase decoupling feedforward control block diagram of the switch reluctance drive system control method of the present invention;

[0046] Fig.18 It is the flow chart of the current loop U-phase decoupling feedforward control. DETAILED DESCRIPTION

[0047] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0048] The switch reluctance drive system and control method of the present invention adopts a four-quadrant control strategy based on the two physical quantities torque and speed output by the motor, and in each quadrant, based on the accurate detection of the motor rotor position, realizes closed-loop vector control of current and closed-loop control of speed. The four-quadrant control strategy is adopted to realize the overall optimization of the switch reluctance drive system; based on accurate current and rotor position detection, true closed-loop vector control is realized, so that the current, torque and speed control precision is high. The current control precision is high, which effectively suppresses the generation of large current spikes and also reduces the motor noise; the torque control precision is high, which greatly reduces the torque pulsation, has little impact on the power module, and improves the reliability during operation; the speed control precision is high, which ensures the stability of the overall control performance; the efficiency is high and the heat is small under frequent startup and overload conditions, and the internal temperature and power regulation curve are matched, thereby optimizing the performance of the switch reluctance drive system.

[0049] The switch reluctance drive system control method of the present invention adopts a four-quadrant control strategy according to two physical quantities, torque and speed, output by the motor. Taking the first quadrant as an example, after the first quadrant control enters, firstly, the two-step method is used to calculate the advance angle of the turn-off angle according to the current speed feedback; the speed feedback is speed-limited, and the temporary speed feedback is obtained and the limit lag conduction angle is calculated at the same time; the opening angle compensation value and the turn-off angle compensation value are calculated according to the current command and the change of the electrical angle in each control cycle; the speed is judged according to the current speed feedback, which is divided into low speed zone, high speed zone and medium speed zone; in each speed range, the opening angle is calculated according to the opening angle setting value, the opening angle compensation value and the limit lag conduction angle; the turn-off angle is calculated according to the turn-off angle setting value and the turn-off angle compensation value; and the dead zone angle processing is performed on the opening angle and the turn-off angle respectively; the two-step method turn-off angle is calculated according to the turn-off angle after the dead zone angle processing and the two-step method turn-off angle advance angle; the angle range of the opening angle, the turn-off angle, the two-step method turn-off angle, etc. is limited; the conduction and closing type is judged by designing a phase-on controller according to the calculated opening angle, the turn-off angle and the two-step method turn-off angle, and the first quadrant control ends.

[0050] The control method of the switched reluctance drive system of the present invention includes the control methods of current, torque and speed in each quadrant. The current control is to perform independent current closed-loop vector control on the three phases U, V and W of the switched reluctance motor, and according to the absolute angular position signal of the motor rotor provided by the magnetoelectric encoder detection, the current control of the switched reluctance drive system is finally realized by designing a phase-on controller. The torque control is based on the above three-phase independent current control as the inner loop, and the speed feedback is obtained by the differentiator according to the absolute angular position signal of the motor rotor provided by the magnetoelectric encoder detection; the torque processor is designed to calculate and process the output current instruction according to the speed feedback and the torque instruction, and transmit it to the current control inner loop, so as to finally realize the outer loop torque control of the switched reluctance drive system. The speed control is based on the above three-phase independent current control as the inner loop, and the speed feedback is obtained by the differentiator according to the absolute angular position signal of the motor rotor provided by the magnetoelectric encoder detection; the speed controller is designed to calculate and output the current instruction according to the speed feedback and the speed instruction, and transmit it to the current control inner loop, so as to finally realize the outer loop speed control of the switched reluctance drive system. Among them, the current closed-loop vector control method also includes a decoupling feedforward control method, which improves the control response characteristics of the current loop and has a good improvement effect on the control performance of the torque control, speed control and switched reluctance drive system.

[0051] like Figure 1 As shown, a switched reluctance drive system includes a controller 100 , a user control device 200 , a switched reluctance motor 300 and a magnetoelectric encoder 400 .

[0052] The controller 100 is connected to the user control device 200 and the switched reluctance motor 300 respectively, and the switched reluctance motor 300 is connected to the magnetoelectric encoder 400 .

[0053] The user control device 200 provides the controller 100 with a control signal for the operation of the switched reluctance drive system. The control signal for the operation of the switched reluctance drive system includes but is not limited to a command signal, a forward signal, a reverse signal, a brake signal, etc. The magnetoelectric encoder 400 detects the absolute angular position signal of the motor rotor of the switched reluctance motor 300 and transmits it to the controller 100. The controller 100, as the core of the switched reluctance drive system, outputs two PWM drive signals of U, V, and W to the switched reluctance motor 300 through current closed-loop vector control, torque control, and speed closed-loop, based on the absolute angular position signal of the motor rotor of the switched reluctance motor 300 provided by the magnetoelectric encoder 400 and the control signal for the operation of the switched reluctance drive system provided by the user control device 200, thereby controlling the switched reluctance drive system to drive the load to work. The above-mentioned magnetoelectric encoder 400 can accurately detect the absolute mechanical position of the rotor of the switched reluctance motor 300, that is, the absolute angular position signal of the motor rotor.

[0054] like Figure 1 As shown, a switched reluctance drive system further includes a battery pack 500 , which is connected to the controller 100 and is used to provide positive and negative power supplies to the controller 100 .

[0055] like Figure 1 As shown, the controller 100 includes a control module 101 , a power module 102 , a power module 103 , a current detection module 104 , a position detection module 105 and an interface module 106 .

[0056] The control module 101 is respectively connected to the power module 102, the power module 103, the current detection module 104, the position detection module 105 and the interface module 106, and the power module 102 is also connected to the power module 103, the current detection module 104, the position detection module 105 and the battery pack 500. The power module 103 is respectively connected to the current detection module 104 and the switched reluctance motor 300. The position detection module 105 is connected to the magnetoelectric encoder 400. The interface module 106 is connected to the user control device 200.

[0057] The power module 102 provides control power (such as 5V or 3.3V) for the control module 101 , provides power for the power module 103 , and provides detection power for the current detection module 104 and the position detection module 105 .

[0058] The control module 101 is the core of the controller 100. The control module 101 receives the motor rotor absolute angular position signal of the switched reluctance motor 300 provided by the position detection module 105 and the motor current feedback signal of the switched reluctance motor 300 provided by the current detection module 104, and obtains six PWM signals, namely UP, UN, VP, VN, WP, and WN, for driving the switched reluctance motor 300 through current closed-loop vector control, torque control, and speed closed-loop control algorithms, and transmits them to the power module 103; the power module 103 generates U, V, and W motor three-phase signals to drive the switched reluctance motor 300 according to the power supply provided by the power module 102 and the PWM signal provided by the control module 101; at the same time, the control module 101 receives the control signal for the operation of the switched reluctance drive system provided by the user control device 200 through the interface module 106, so as to realize the specific functional control of the switched reluctance drive system.

[0059] like Figure 2 As shown, the magnetoelectric encoder 400 includes a rotor and a stator. The rotor adopts a magnetic steel ring 401. The magnetic steel ring 401 is sleeved on the tail shaft 409 of the switched reluctance motor 300 and bonded with special magnetic steel glue. It rotates synchronously with the rotor of the switched reluctance motor 300, that is, the rotor of the magnetoelectric encoder 400 rotates synchronously with the rotor of the switched reluctance motor 300.

[0060] The stator adopts a stator bracket 402, a Hall magnetic induction element 403, a PCB circuit board 404 and a self-tapping screw 405. The Hall magnetic induction element 403 is positioned and installed on the stator bracket 402, and its pins are welded on the PCB circuit board 404. The self-tapping screw 405 fixes the PCB circuit board 404 to the stator bracket 402; the stator bracket 402 is installed and fixed on the rear flange 408 of the switched reluctance motor 300, and the rear cover 406 is installed after the installation is completed.

[0061] The Hall magnetic induction element 403 senses the magnetic field change signal generated by the synchronous rotation of the magnetic steel ring 401 with the rotor of the switched reluctance motor 300, and converts the magnetic field change signal into an analog voltage signal, and transmits the analog voltage signal to the PCB circuit board 404, and outputs it to the position detection module 105 of the controller 100 through the signal interface of the PCB circuit board 404, that is, the signal is the absolute angular position signal of the motor rotor.

[0062] like Figure 3 As shown, the installation structure of the magnetoelectric encoder 400 on the switched reluctance motor 300 is compact, the required axial size and space are small, and it is easy to use.

[0063] like Figure 4As shown, the stator bracket 402 of the magnetoelectric encoder 400 has four evenly distributed mounting slots 407. When fixed on the rear flange 408 of the switched reluctance motor 300, it can rotate freely with the tail shaft 409 of the switched reluctance motor 300 as the axis, so it is convenient to determine the magnetic field position of the switched reluctance motor 300. At the same time, there is a gap between the outer diameter of the magnetic steel ring 401 (rotor) of the magnetoelectric encoder 400 and the inner ring of the stator bracket 402, which is in a non-contact state. Therefore, there will be no mechanical wear in harsh environments such as high-speed rotation of the motor or large temperature changes, dust and oil pollution, etc., thereby improving reliability and service life.

[0064] The control method of the switched reluctance drive system of the present invention adopts a four-quadrant control strategy according to two physical quantities, torque and speed, output by the motor, to achieve overall optimization of the switched reluctance drive system.

[0065] 1) If Figure 5 As shown in the figure, the motor speed is used as the horizontal coordinate and the motor torque is used as the vertical coordinate to divide the four quadrants, and the intersection of the two coordinates is 0. Figure 5 As shown, the first quadrant needs to meet the conditions of speed>0, torque>0; the second quadrant needs to meet the conditions of speed<0, torque>0; the third quadrant needs to meet the conditions of speed<0, torque<0; and the fourth quadrant needs to meet the conditions of speed>0, torque<0.

[0066] 2) After entering each quadrant control, current closed-loop vector control, torque control and speed closed-loop control are performed on the switched reluctance drive system;

[0067] 3) If Figure 6 As shown, the motor enters each quadrant from the initial state and the principle block diagram of the mutual transformation between the quadrants.

[0068] The arrow direction indicates the direction of quadrant conversion, and ① and ② indicate two quadrant conversion conditions. ① represents the need to meet the quadrant division conditions, for example, when converting from the initial state to the first quadrant, the speed>0 and torque>0 conditions need to be met. ② represents the need to meet the quadrant switching speed conditions. Specifically, when converting from the first quadrant to the second quadrant, the current speed < - quadrant switching speed must be met; when converting from the second quadrant to the first quadrant, the current speed > quadrant switching speed must be met; when converting from the third quadrant to the fourth quadrant, the current speed > quadrant switching speed must be met; when converting from the fourth quadrant to the third quadrant, the current speed < - quadrant switching speed must be met.

[0069] like Figure 7 , Figure 8 , Fig. 9 and Fig.10 As shown in the figure, the four-quadrant control flow chart. The following takes the first quadrant as an example to illustrate the steps of the quadrant control strategy.

[0070] In the first step, after entering the first quadrant control, the two-step method of shut-off angle advance angle calculation is first performed based on the current speed feedback; the above two-step method of shut-off angle is a technical means commonly used by technical personnel in this field, so it will not be described in detail.

[0071] The second step is to perform speed limiting processing on the speed feedback, and at the same time obtain temporary speed feedback and calculate the limit lag conduction angle; the above speed limiting processing on the speed feedback is a common technical means used by those skilled in the art, so it will not be described in detail.

[0072] The third step is to calculate the turn-on angle compensation value and the turn-off angle compensation value respectively according to the current command output by the torque processor or the speed controller and the electrical angle change in each control cycle;

[0073] The fourth step is to judge the speed according to the current speed feedback, which is divided into a low speed zone, a high speed zone and a medium speed zone. The above low speed zone, high speed zone and medium speed zone are commonly used technical means by technicians in this field, so they will not be described in detail.

[0074] The fifth step is to calculate the turn-on angle in each speed range according to the turn-on angle setting value, the turn-on angle compensation value, and the limited lag conduction angle; calculate the turn-off angle according to the turn-off angle setting value and the turn-off angle compensation value; and perform dead zone angle processing on the turn-on angle and the turn-off angle respectively, that is, the turn-on angle output value is obtained by subtracting the set dead zone angle from the turn-on angle, and the turn-off angle output value is obtained by subtracting the set dead zone angle from the turn-off angle; calculate the two-step turn-off angle according to the turn-off angle after dead zone angle processing and the two-step turn-off angle advance angle;

[0075] Step 6: Limit the angle range of the turn-on angle, turn-off angle, two-step turn-off angle, etc. The above angle range limitation is a common technical means used by those skilled in the art, so it will not be described in detail;

[0076] The seventh step is to determine the on or off type, i.e. on or off, by designing a phase-connected controller based on the calculated on angle, off angle and two-step off angle, thus ending the first quadrant control.

[0077] The following takes the three-phase switched reluctance motor 300 as an example to specifically describe the control method of the current, torque and speed in each quadrant of the switched reluctance drive system of the present invention, that is, the content in step 2) is described in detail.

[0078] like Fig.11 As shown, the current control is to perform independent current closed-loop vector control on the three phases U, V, and W of the switched reluctance motor 300, and based on the absolute angular position signal of the motor rotor provided by the magnetoelectric encoder 400, the current closed-loop vector control of the switched reluctance drive system is finally realized by designing a phase-on controller, so that the current control accuracy is high, the generation of large current spikes is effectively suppressed, and the motor noise is also reduced.

[0079] like Fig.11 and Fig.12 As shown, the current closed-loop vector control method is as follows:

[0080] In the first step, after the current control interruption starts, current sampling is triggered to obtain the motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb and W-phase current feedback Iw_fb respectively, and at the same time read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder 400;

[0081] In the second step, the current command I_ref is transmitted to the U-phase current command Iu_ref, the V-phase current command Iv_ref, and the W-phase current command Iw_ref respectively, that is, I_ref=Iu_ref=Iv_ref=Iw_ref;

[0082] The U-phase current PID controller calculates and outputs the U-phase drive voltage ΔUu according to the difference ΔIu between the U-phase current command Iu_ref and the U-phase current feedback Iu_fb;

[0083] The V-phase current PID controller calculates and outputs the V-phase drive voltage ΔUv according to the difference ΔIv between the V-phase current command Iv_ref and the V-phase current feedback Iv_fb;

[0084] The W-phase current PID controller calculates and outputs the W-phase drive voltage ΔUw according to the difference ΔIw between the W-phase current command Iw_ref and the W-phase current feedback Iw_fb;

[0085] The third step is to design a phase-on controller to judge and convert the three-phase drive voltage ΔUu, ΔUv, ΔUw and the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder 400 into a PWM drive signal output, and then generate U, V, W three-phase current to control the switched reluctance motor 300 through the power module 103.

[0086] like Fig.13 As shown, the torque control is based on the above-mentioned three-phase independent current control as the inner loop, and the speed feedback is obtained through calculation by the differentiator according to the absolute angular position signal of the motor rotor provided by the magnetoelectric encoder 400; the torque processor is designed to calculate and process the output current command according to the speed feedback and the torque command, and transmit it to the current control inner loop, thereby finally realizing the outer loop torque control of the switched reluctance drive system, with high torque control accuracy, greatly reducing torque pulsation, small impact on the power module 103, and improving reliability during operation.

[0087] like Fig.13 and Fig.14 As shown, the torque control method is as follows:

[0088] In the first step, after the torque control interruption starts, current sampling is triggered to obtain the motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb and W-phase current feedback Iw_fb respectively, and at the same time read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder 400;

[0089] In the second step, the motor rotor absolute angular position signal θ_fb is calculated by the differentiator and then output as speed feedback V_fb;

[0090] The third step is to design a torque processor to calculate and process the output current command I_ref according to the torque command T_ref and the speed feedback V_fb provided by the user control device and input it into the above three-phase independent current control;

[0091] The fourth step is to control the outer loop torque of the switched reluctance drive system by running the inner loop of current control.

[0092] like Fig.15 As shown, the speed control is based on the above-mentioned three-phase independent current control as the inner loop, and the speed feedback is obtained through the differentiator calculation according to the absolute angular position signal of the motor rotor provided by the magnetoelectric encoder 400; the speed controller 100 then calculates the output current command based on the speed feedback and the speed command and transmits it to the current control inner loop, thereby finally realizing the outer loop speed control of the switched reluctance drive system, with high speed control accuracy, ensuring the stability of the overall control performance.

[0093] like Fig.15 and Fig.16 As shown, the speed control method is as follows:

[0094] In the first step, after the speed control interruption starts, the current sampling is triggered to obtain the motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb, and W-phase current feedback Iw_fb respectively, and at the same time read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder 400;

[0095] In the second step, the motor rotor absolute angular position signal θ_fb is calculated by the differentiator and then output as speed feedback V_fb;

[0096] In the third step, the speed PID controller calculates the output current command I_ref according to the speed command V_ref and the speed feedback V_fb and inputs it into the above three-phase independent current control;

[0097] The fourth step is to realize the outer loop speed control of the switched reluctance drive system by running the inner loop of current control.

[0098] The current control of the switch reluctance drive system control method of the present invention also includes a decoupling feedforward control method. As mentioned above, the current control is to perform independent current closed-loop vector control on the three phases U, V, and W of the switch reluctance motor 300. Therefore, the following specific description is made by taking the U phase as an example. Fig.17 and Fig.18 As shown, the current loop U-phase decoupling feedforward control method is as follows:

[0099] In the first step, after the current control interruption starts, the current sampling is triggered to obtain the motor U-phase current feedback Iu_fb, and at the same time, the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder 400 is read;

[0100] In the second step, the motor rotor absolute angular position signal θ_fb is calculated by the differentiator and then output as speed feedback V_fb;

[0101] In the third step, the U-phase current controller calculates the output drive voltage ΔUu according to the difference ΔIu between the U-phase current command Iu_ref and the U-phase current feedback Iu_fb;

[0102] In the fourth step, the U-phase feedforward controller calculates and outputs the U-phase feedforward voltage FF_Uu according to the U-phase current command Iu_ref and the speed feedback V_fb provided by the differentiator; the U-phase drive voltage ΔUu and the U-phase feedforward voltage FF_Uu are added to obtain the U-phase intermediate drive voltage Δ`Uu,

[0103] Step 5, after voltage limiting processing, the final driving voltage Δ``Uu of phase U is obtained;

[0104] The sixth step is to design a phase-on controller to calculate and judge the final driving voltage Δ``Uu and the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder 400 and convert it into a PWM driving signal output, and then generate a U-phase current through the power module 103 to control the switched reluctance motor 300.

[0105] The current loop decoupling feedforward control method improves the control response characteristics of the current loop, and has a good improvement effect on the torque control, speed control and control performance of the switched reluctance drive system.

[0106] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A control method for a switched reluctance drive system, characterized in that: The switched reluctance drive system comprises a controller (100), a user control device (200), a switched reluctance motor (300) and a magnetoelectric encoder (400); Wherein, the controller (100) is respectively connected to the user control device (200) and the switched reluctance motor (300), and the switched reluctance motor (300) is connected to the magnetoelectric encoder (400); The user control device (200) provides a control signal for the operation of the drive system to the controller (100); the magnetoelectric encoder (400) detects the absolute angular position signal of the motor rotor of the switched reluctance motor (300) and transmits the signal to the controller (100); the controller (100) provides a control signal for the operation of the drive system according to the absolute angular position signal of the motor rotor and the user control device (200); and outputs two-way U, V, and W PWM drive signals to the switched reluctance motor (300) through current closed-loop vector control, torque control, and speed closed-loop control, thereby controlling the operation of the load driven by the drive system; The drive system further comprises a battery pack (500), wherein the battery pack (500) is connected to the controller (100) and is used to provide positive and negative power sources to the controller (100); The controller (100) comprises a control module (101), a power module (102), a power module (103), a current detection module (104), a position detection module (105) and an interface module (106); The control module (101) is respectively connected to the power module (102), the power module (103), the current detection module (104), the position detection module (105) and the interface module (106), and the power module (102) is also connected to the power module (103), the current detection module (104), the position detection module (105) and the battery pack (500); the power module (103) is respectively connected to the current detection module (104) and the switched reluctance motor (300); the position detection module (105) is connected to the magnetoelectric encoder (400); and the interface module (106) is connected to the user control device (200); The power supply module (102) provides control power for the control module (101), provides power for the power module (103), and provides detection power for the current detection module (104) and the position detection module (105); The control module (101) receives the motor rotor absolute angular position signal of the switched reluctance motor (300) provided by the position detection module (105) and the motor current feedback signal of the switched reluctance motor (300) provided by the current detection module (104), obtains two-way PWM drive signals U, V, and W for driving the switched reluctance motor (300) through current closed-loop vector control, torque control, and speed closed-loop control algorithms, and transmits the signals to the power module (103); the power module (103) generates three-phase motor signals U, V, and W to drive the switched reluctance motor (300) based on the power supply provided by the power supply module (102) and the PWM signal provided by the control module (101); the control module (101) receives the control signal for the operation of the drive system provided by the user control device (200) through the interface module (106), and implements specific functional control of the drive system; The magnetoelectric encoder (400) comprises a rotor and a stator: The rotor adopts a magnetic steel ring (401), and the magnetic steel ring (401) is sleeved on the tail shaft (409) of the switched reluctance motor (300) and rotates synchronously with the rotor of the switched reluctance motor (300); The stator comprises a stator bracket (402), a Hall magnetic induction element (403), and a PCB circuit board (404); the Hall magnetic induction element (403) is positioned and mounted on the stator bracket (402), the pins of the Hall magnetic induction element (403) are welded on the PCB circuit board (404), and the PCB circuit board (404) is fixed on the stator bracket (402); The stator bracket (402) is mounted and fixed on the rear flange (408) of the switched reluctance motor (300); The Hall magnetic induction element (403) senses a magnetic field change signal generated by the synchronous rotation of the magnetic steel ring (401) with the rotor of the switched reluctance motor (300), and converts the magnetic field change signal into an analog voltage signal and transmits it to the PCB circuit board (404); the signal interface of the PCB circuit board (404) outputs the signal to the position detection module (105) of the controller (100); The switch reluctance drive system control method comprises the following steps: 1) Use motor speed as the horizontal axis and motor torque as the vertical axis to divide the quadrants, where the first quadrant needs to meet the conditions of speed>0 and torque>0; The second quadrant needs to meet the conditions of speed < 0, torque > 0; The third quadrant needs to meet the conditions of speed < 0 and torque < 0; The fourth quadrant needs to meet the conditions of speed>0 and torque<0; 2) After entering each quadrant control, current closed-loop vector control, torque control and speed closed-loop control are performed on the drive system; 3) The control conversion method between quadrants is as follows: In the first step, after the current quadrant control is entered, the two-step shutdown angle advance angle calculation is performed based on the current speed feedback; The second step is to limit the speed feedback, obtain temporary speed feedback and calculate the limit hysteresis conduction angle; The third step is to calculate the turn-on angle compensation value and the turn-off angle compensation value respectively according to the current command output by the torque processor or the speed controller and the electrical angle change in each control cycle; The fourth step is to judge the speed according to the current speed feedback and divide it into low speed zone, high speed zone and medium speed zone; The fifth step is to calculate the turn-on angle in each speed range according to the turn-on angle setting value, the turn-on angle compensation value, and the limited lag conduction angle; calculate the turn-off angle according to the turn-off angle setting value and the turn-off angle compensation value; and perform dead zone angle processing on the turn-on angle and the turn-off angle respectively: subtract the set dead zone angle from the turn-on angle to obtain the turn-on angle output value, and subtract the set dead zone angle from the turn-off angle to obtain the turn-off angle output value; calculate the two-step turn-off angle according to the turn-off angle after dead zone angle processing and the two-step turn-off angle advance angle; Step 6: Limit the angle range of the turn-on angle, turn-off angle, and two-step turn-off angle; The seventh step is to determine the on or off type by designing a phase-on controller based on the calculated on angle, off angle, and two-step off angle, and end the current quadrant control.

2. A switched reluctance drive system control method according to claim 1, characterized in that: In step 2), the method for current vector control is as follows: The first step is to trigger current sampling to obtain motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb and W-phase current feedback Iw_fb respectively after the current control interruption starts, and simultaneously read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder (400); In the second step, the current command I_ref is transmitted to the U-phase current command Iu_ref, the V-phase current command Iv_ref, and the W-phase current command Iw_ref respectively, that is, I_ref=Iu_ref=Iv_ref=Iw_ref; The U-phase current PID controller calculates and outputs the U-phase drive voltage ΔUu according to the difference ΔIu between the U-phase current command Iu_ref and the U-phase current feedback Iu_fb; The V-phase current PID controller calculates and outputs the V-phase drive voltage ΔUv according to the difference ΔIv between the V-phase current command Iv_ref and the V-phase current feedback Iv_fb; The W-phase current PID controller calculates and outputs the W-phase drive voltage ΔUw according to the difference ΔIw between the W-phase current command Iw_ref and the W-phase current feedback Iw_fb; The third step is to design a phase power-on controller to judge and convert the three-phase drive voltages ΔUu, ΔUv, ΔUw and the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder (400) into a PWM drive signal output, and then generate U, V, W three-phase currents through the power module (103) to control the switched reluctance motor (300).

3. A switched reluctance drive system control method according to claim 1, characterized in that: In step 2), the method for torque control is as follows: The first step is to trigger current sampling to obtain motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb and W-phase current feedback Iw_fb respectively after the torque control interruption starts, and simultaneously read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder (400); In the second step, the motor rotor absolute angular position signal θ_fb is calculated by the differentiator and then output as speed feedback V_fb; The third step is to design a torque processor to calculate and process the output current command I_ref according to the torque command T_ref and speed feedback V_fb provided by the user control device and input it into the three-phase independent current control; The fourth step is to control the outer loop torque of the drive system by running the inner loop of current control.

4. A switched reluctance drive system control method according to claim 1, characterized in that: In the step 2), the method for speed control is as follows: The first step is to trigger current sampling to obtain motor U-phase current feedback Iu_fb, V-phase current feedback Iv_fb, and W-phase current feedback Iw_fb respectively after the speed control interruption starts, and simultaneously read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder (400); In the second step, the motor rotor absolute angular position signal θ_fb is calculated by the differentiator and then output as speed feedback V_fb; In the third step, the speed PID controller calculates the output current command I_ref according to the speed command V_ref and the speed feedback V_fb and inputs it into the three-phase independent current control; The fourth step is to control the outer loop speed of the drive system by running the inner loop of current control.

5. A switched reluctance drive system control method according to claim 2, characterized in that: In the method for current vector control, independent decoupling feedforward current closed-loop vector control is performed on the U phase of the switched reluctance motor (300), comprising the following steps: The first step is to trigger current sampling to obtain the motor U-phase current feedback Iu_fb after the current control interruption starts, and simultaneously read the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder (400); In the second step, the motor rotor absolute angular position signal θ_fb is calculated by the differentiator and then output as speed feedback V_fb; In the third step, the U-phase current controller calculates the output drive voltage ΔUu according to the difference ΔIu between the U-phase current command Iu_ref and the U-phase current feedback Iu_fb; In the fourth step, the U-phase feedforward controller calculates and outputs the U-phase feedforward voltage FF_Uu according to the U-phase current command Iu_ref and the speed feedback V_fb provided by the differentiator; the U-phase drive voltage ΔUu and the U-phase feedforward voltage FF_Uu are added to obtain the U-phase intermediate drive voltage Δ`Uu, Step 5, after voltage limiting processing, the final driving voltage Δ``Uu of phase U is obtained; The sixth step is to design a phase-on controller to calculate and judge the final driving voltage Δ``Uu and the motor rotor absolute angular position signal θ_fb detected and output by the magnetoelectric encoder (400), and convert it into a PWM driving signal output, and then generate a U-phase current through the power module (103) to control the switched reluctance motor (300).

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