Three-phase switched reluctance motor torque ripple suppression method based on current waveform construction
By constructing a method based on current waveforms, partitioning rotor positions, and designing current setpoint coefficients for hysteresis control, the problem of existing methods relying on model parameters is solved, resulting in a smaller torque ripple rate and more stable motor operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ROBOTICS RESEARCH CENTER OF YUYAO CITY
- Filing Date
- 2026-01-21
- Publication Date
- 2026-05-01
AI Technical Summary
Existing torque ripple control methods for three-phase switched reluctance motors rely on motor model parameter tables, which makes them unapplicable when parameters are unknown, affecting the motor's operational stability and performance.
By obtaining the stator and rotor pole arcs of the motor, dividing the rotor position, designing the current setpoint coefficient, constructing the current waveform, and performing hysteresis control, torque pulsation is suppressed.
Without relying on model parameter tables, it significantly reduces torque ripple rate, improves motor running smoothness, and reduces vibration and noise.
Smart Images
Figure CN121966400A_ABST
Abstract
Description
A method for suppressing torque ripple in a three-phase switched reluctance motor based on current waveform construction. Technical Field
[0001] This invention belongs to the field of motor and control technology, and relates to a method for suppressing torque ripple in a three-phase switched reluctance motor based on current waveform construction. Background Technology
[0002] Switched reluctance motors are a type of doubly salient pole motor, characterized by large torque ripple. Torque ripple directly leads to speed fluctuations, affecting the smoothness of motor operation. It can also cause vibration and noise problems, affecting the stability and performance of the drive system.
[0003] To suppress torque ripple in switched reluctance motors, existing torque control methods are mainly divided into direct control and indirect control. Direct control methods primarily include direct instantaneous torque control (DITC), direct torque control (DTC), and model predictive torque control (MPTC); indirect control methods mainly include torque distribution functions, current profile shaping techniques, and harmonic current injection techniques.
[0004] Existing indirect and direct torque control methods all rely on the torque parameters of the motor model, i.e., the torque parameters of the switched reluctance motor. The table is used for direct instantaneous torque control, direct torque control, and torque distribution functions, all of which require looking up the table to obtain the torque value as feedback for the control system. Model predictive torque control requires obtaining the table in advance for fitting and modeling. Current curve shaping technology and harmonic current injection technology also rely on looking up the table to obtain the given current.
[0005] Due to the actual motor Obtaining the table is quite difficult, requiring the acquisition of the motor's instantaneous torque under different currents and rotor positions. Therefore, it is impossible to obtain the table when the motor parameters are unknown. When using tables, the torque control methods described above cannot be applied. This model dependency causes inconvenience in practical control. Summary of the Invention
[0006] To address the aforementioned technical problems in existing technologies, this invention proposes a method for suppressing torque ripple in a three-phase switched reluctance motor based on current waveform construction, which is independent of torque parameters. The table, and its specific technical solution are as follows:
[0007] A method for suppressing torque ripple in a three-phase switched reluctance motor based on current waveform construction includes the following steps:
[0008] Step 1: Obtain the stator and rotor pole arcs of the motor, determine the inductance rising region where the motor generates driving torque, and divide the rotor position in the phase winding conduction interval into zones.
[0009] Step 2: Design the current setpoint coefficient according to the location zone and construct the current waveform;
[0010] Step 3: Obtain the actual three-phase current feedback and perform hysteresis control based on the constructed current waveform to suppress motor torque pulsation.
[0011] Furthermore, in step one, the stator pole arc of the motor is obtained from the motor drawings. With rotor pole arc With the position where the stator salient pole coincides with the center of the rotor groove as 0°, the number of stator poles is set to... The number of rotor poles is The inductance rise region of the motor is determined from the position where the stator and rotor edges coincide until the stator and rotor overlap angle reaches the position. Where the leading edges of the stator and rotor just coincide, the rotor angle is... When the stator and rotor overlap angle reaches the position The rotor angle is .
[0012] Furthermore, in step one, let the turn-on angle and turn-off angle of each phase of the three-phase switched reluctance motor be respectively... and And the shut-off angle Located in the inductance rising region, the rotor position within the phase winding conduction interval is divided into zones, namely:
[0013] Region I: Rotor angle is In this region, the current conducting phase of the three-phase switched reluctance motor is simultaneously conducting with the previous conducting phase, which is in the commutation overlap region. The motor torque is mainly provided by the previous conducting phase, which is still in the inductance rising region, while the stator-rotor overlap angle of the current conducting phase is 0°.
[0014] Region II: Rotor angle is In this region, the previous conducting phase is turned off, the current decreases, and the currently conducting phase has not yet reached the inductance rise region.
[0015] Region III: Rotor angle is In this region, the currently conducting phase is in the inductance rising region.
[0016] Furthermore, in step two, a given current obtained through the speed loop is applied. Apply a coefficient To obtain the actual current given By changing the coefficient in different regions To change the actual reference value of the current in each phase Where the given current The difference between the motor speed and the given speed is obtained by passing the speed through a PI loop.
[0017] Furthermore, in Region I, That is, the actual reference value of the current. Linear increase, This is an adjustable parameter, with a value range of [value range missing]. ;in, , A value of 0 represents the starting point of each region. 1 represents the end point of each region.
[0018] Furthermore, in Region II: , , Less than 0, , A value of 0 represents the starting point of each region. 1 represents the end point of each region; the beginning of region II. =0, Continuing from the end of region I, eventually when When =1, =1.
[0019] Furthermore, in Region III: =1, in this region, current chopping control is performed on the conducting phase, given... And the current is continuous with the current at the end of region II.
[0020] Furthermore, in step three, the actual reference value of the current for each phase is... The reference current for hysteresis control is used, and the actual three-phase current feedback is obtained by acquiring the phase current of the drive circuit. Then, the hysteresis width is set. The switching control signal of the drive circuit's switching transistor is obtained to control the actual current, making it follow the signal. This helps to suppress motor torque pulsation.
[0021] Compared to traditional current chopper control methods, the method of constructing current waveforms by rotor position partitioning in this invention does not depend on model parameters. In the case of a table, the torque ripple rate is smaller, thus effectively ensuring the smooth operation of the motor. Attached Figure Description
[0022] Figure 1 is a block diagram of the switched reluctance motor control system to which the torque ripple suppression method for a three-phase switched reluctance motor based on current waveform construction is applied in this embodiment.
[0023] Figure 2 is a waveform diagram of motor current and electromagnetic torque controlled by the conventional control method of current chopping in this embodiment;
[0024] Figure 3 is a waveform diagram of motor current and electromagnetic torque using the method of the present invention in this embodiment. Detailed Implementation
[0025] To make the objectives, technical solutions, and technical effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0026] This embodiment provides a method for suppressing torque ripple in a three-phase switched reluctance motor based on current waveform construction. The method is applied to the switched reluctance motor control system shown in Figure 1, and specifically includes the following steps:
[0027] Step 1: Obtain the stator and rotor pole arcs of the motor, determine the inductance rising region of the motor, and divide the rotor position in the phase winding conduction region into zones.
[0028] Specifically, based on the principle that switched reluctance motors generate driving torque in the inductance rising region, in order to determine the inductance rising region of the actual motor, the stator pole arc of the motor can first be obtained from the motor drawings. With rotor pole arc Taking the position where the stator salient pole coincides with the center of the rotor groove as 0°, the number of stator poles is set to... The number of rotor poles is The inductance rising region of the switched reluctance motor is located from the point where the leading edges of the stator and rotor just coincide until the stator-rotor overlap angle reaches the position. At the point where the leading edges of the stator and rotor exactly overlap, the rotor angle is... When the stator and rotor overlap angle reaches the position The rotor angle is .
[0029] Let the turn-on angle and turn-off angle of each phase of the three-phase switched reluctance motor be respectively... and Furthermore, to avoid negative torque during the demagnetization phase, the turn-off angle... The current position is still within the inductance rising region. Therefore, the rotor position within the phase winding conduction range can be divided into zones:
[0030] Region I: Rotor angle is This region is where the current conducting phase of the three-phase switched reluctance motor conducts simultaneously with the previous conducting phase, forming a commutation overlap region. Torque is primarily provided by the previous conducting phase, which is still in the inductance rising region. The stator-rotor overlap angle of the current conducting phase is 0°, its inductance value is small, and its inductance change rate is low, resulting in weak torque output capability. Therefore, its main task is to establish the conducting current, creating conditions for torque output in subsequent regions.
[0031] Region II: Rotor angle is Region. In this region, the previous conducting phase is turned off, and the current drops rapidly. Since the current conducting phase has not yet reached the inductance rise region, a torque drop phenomenon will occur in this region. It is necessary to increase the current setpoint of the current conducting phase in this region to compensate for the instantaneous torque drop.
[0032] Region III: Rotor angle is Region. In this region, the currently conducting phase is in the inductance rising region, with strong torque output capability, and can stably provide drive torque.
[0033] Step 2: Based on the location partition design current set coefficient, construct the set current of the currently conducting phase in each partition and construct the current waveform.
[0034] Specifically, based on the location partitioning principle in step one, the given current of the currently conducting phase in the three regions is constructed. Since in switched reluctance motor control systems, the traditional control method that does not rely on model parameters is mainly current chopper control (CCC), that is, obtaining the given current value through the speed loop PI control. Direct hysteresis control is used. However, this method, in order to suppress torque ripple, provides control through the speed loop. Apply a coefficient To obtain the actual current given By changing the coefficient in different regions To change the actual reference value of the current in each phase This achieves the purpose of regulating torque and suppressing torque pulsation.
[0035] To simplify the construction process, let's assume... , A value of 0 represents the starting point of each region. Let 1 represent the endpoint of each region. Then the coefficients for the construction of each region... as follows:
[0036] Area I: ,Right now Linear increase, These are adjustable parameters. Since the torque output capability is weak in Region I, but Region II requires increased current to compensate for the instantaneous torque drop, the phase current needs to reach a certain value at the end of Region I. It should not be too small; the general range is [value range missing]. .
[0037] Area II: , This is an adjustable parameter, generally less than 0. (At the start of the region) , It is continuous with the end of region I. This region resembles a downward-opening quadratic function, meaning it first rises and then falls. This aligns with the initial need to increase current to compensate for the torque drop after the previous phase disconnection. Then, as the inductance rate increases, the torque output capability of the conducting phase strengthens, requiring a corresponding decrease in current. Ultimately, when... hour, .
[0038] Area III: This means that in this region, the conducting phase is actually subjected to current chopping control, i.e., CCC control, and its given value is... Furthermore, the current is continuous with the current at the end of region II. This region is in the inductance rising region, and the output torque is relatively stable, so a constant can be used as the coefficient.
[0039] Step 3: Obtain the actual three-phase current feedback and, based on the constructed current waveform, perform hysteresis control to obtain the switching signal of the drive circuit switching transistor, which is used to control the energizing state of the winding to reduce torque ripple.
[0040] Specifically, the actual reference values of phase current under different partitions constructed in step two will be used. This serves as the reference current for hysteresis control. By acquiring the phase current of the drive circuit, the motor control system can obtain the actual three-phase current feedback and set the hysteresis width. Control the actual current to make it follow Ultimately, this achieves the goal of suppressing motor torque pulsation.
[0041] The obtained switching signal of the drive circuit switching transistor is used to control the energizing state of the winding.
[0042] A simulation analysis was conducted using a 6 / 4-pole three-phase switched reluctance motor. The torque ripple rate of the motor under current chopper control, a traditional control method that does not rely on models, was compared with that of the present invention. The details are as follows:
[0043] As shown in Figure 2, using the traditional current chopper control method, when the motor load is 0.2 N·m, the instantaneous maximum torque is 0.4 N·m, the minimum torque is 0.01 N·m, the average torque is 0.2 N·m, and the torque ripple rate is 195%.
[0044] As shown in Figure 3, the method based on current waveform construction of the present invention is used: when the motor load is 0.2 N·m, the maximum instantaneous torque is 0.33 N·m, the minimum instantaneous torque is 0.1 N·m, the average torque is 0.2 N·m, and the torque ripple rate is 115%.
[0045] It can be seen that, without depending on model parameters In the case of the table, the torque ripple rate of the present invention is smaller, which is significantly better than current chopper control.
[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Although the implementation process of the present invention has been described in detail above, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for suppressing torque ripple in a three-phase switched reluctance motor based on current waveform construction, characterized in that, Includes the following steps: Step 1: Obtain the stator and rotor pole arcs of the motor, determine the inductance rising region where the motor generates driving torque, and partition the rotor position within the phase winding conduction interval; Step 2: Design the current setpoint coefficient based on the position partition and construct the current waveform; Step 3: Obtain the actual three-phase current feedback and perform hysteresis control based on the constructed current waveform to suppress motor torque pulsation.
2. The method for suppressing torque ripple in a three-phase switched reluctance motor as described in claim 1, characterized in that, In step one, the stator pole arc of the motor is obtained from the motor drawings. With rotor pole arc With the position where the stator salient pole coincides with the center of the rotor groove as 0°, the number of stator poles is set to... The number of rotor poles is The inductance rise region of the motor is determined from the position where the stator and rotor edges coincide until the stator and rotor overlap angle reaches the position. Where the leading edges of the stator and rotor just coincide, the rotor angle is... When the stator and rotor overlap angle reaches the position The rotor angle is 。 3. The method for suppressing torque ripple in a three-phase switched reluctance motor as described in claim 2, characterized in that, In step one, let the turn-on angle and turn-off angle of each phase of the three-phase switched reluctance motor be respectively... and And the shut-off angle Located in the inductance rising region, the rotor position within the phase winding conduction interval is divided into zones: Zone I: Rotor angle is... Region I: In this region, the current conducting phase of the three-phase switched reluctance motor is simultaneously conducting with the previous conducting phase, which is in the commutation overlap region. The motor torque is mainly provided by the previous conducting phase, which is still in the inductance rising region, while the stator-rotor overlap angle of the current conducting phase is 0°; Region II: Rotor angle is In this region, the previous conducting phase is turned off, the current decreases, and the currently conducting phase has not yet reached the inductance rise region. Region III: Rotor angle is In this region, the currently conducting phase is in the inductance rising region.
4. The method for suppressing torque ripple in a three-phase switched reluctance motor as described in claim 3, characterized in that, In step two, the given current obtained through the speed loop is applied. Apply a coefficient To obtain the actual current given By changing the coefficient in different regions To change the actual reference value of the current in each phase Where the given current The difference between the motor speed and the given speed is obtained by passing the speed through a PI loop.
5. The method for suppressing torque ripple in a three-phase switched reluctance motor as described in claim 4, characterized in that, In region I, That is, the actual reference value of the current. Linear increase, This is an adjustable parameter, with a value range of [value range missing]. ;in, ， A value of 0 represents the starting point of each region. 1 represents the end point of each region.
6. The method for suppressing torque ripple in a three-phase switched reluctance motor as described in claim 4, characterized in that, In Region II: ， ， Less than 0, ， A value of 0 represents the starting point of each region. 1 represents the end point of each region; the beginning of region II. =0， Continuing from the end of region I, eventually when When =1, 。 7. The method for suppressing torque ripple in a three-phase switched reluctance motor as described in claim 4, characterized in that, In Region III: In this region, current chopping control is performed on the conducting phase, given... And the current is continuous with the current at the end of region II.
8. The method for suppressing torque ripple in a three-phase switched reluctance motor as described in claim 4, characterized in that, In step three, the actual reference value of the current in each phase is... The reference current for hysteresis control is used, and the actual three-phase current feedback is obtained by acquiring the phase current of the drive circuit. Then, the hysteresis width is set. The switching control signal of the drive circuit's switching transistor is obtained to control the actual current, making it follow the signal. This helps to suppress motor torque pulsation.