Electro-magnetic doubly salient motor torque ripple suppression method based on harmonic double closed-loop control

Abstract

The invention discloses an electro-magnetic doubly salient motor torque ripple suppression method based on harmonic double closed-loop control, and the method comprises the steps: constructing the harmonic double closed-loop control of a torque ripple outer ring and a current harmonic inner ring in an electro-magnetic doubly salient motor current source type drive system of a multiplexing excitation winding; a torque pulsation outer ring observes electromagnetic torque through a model reference adaptive method, pulsation components of the torque pulsation outer ring are extracted in combination with an adaptive notch filter, and a current harmonic inner ring given value is output through closed-loop regulation; the current harmonic inner ring extracts harmonic current by constructing a harmonic space decoupling transformation matrix and combining with a rotating coordinate system of corresponding subharmonics, current harmonics counteracting torque pulsation of the electro-magnetic doubly salient motor are generated through closed-loop adjustment, and the output characteristic of the motor is improved. According to the method provided by the invention, the torque ripple amplitude can be suppressed in a closed-loop manner, the given value of the harmonic current can be automatically adjusted, specific current harmonic injection is realized, the output torque ripple of the electro-magnetic doubly salient motor is eliminated, and the problems that a traditional harmonic injection method is not matched under different operation conditions of the motor and depends on motor parameters are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, and in particular relates to a method for suppressing torque pulsation of an electrically excited double-salient-pole motor based on harmonic double closed-loop control. Background Art

[0002] Currently, electric vehicle motors primarily utilize induction motors, permanent magnet synchronous motors, and switched reluctance motors (SRMs), each with its own advantages and disadvantages. The electrically excited doubly salient motor (EEDM), a novel motor structure developed based on the SRM, boasts controllable excitation current, simplifying speed regulation, improving reliability, and reducing costs. Furthermore, the use of a current source inverter allows the EDM's field winding to be reused as the inverter's DC-side energy storage inductor, further reducing costs while increasing system power density. Torque ripple in drive motors significantly impacts their output characteristics and smooth operation. Traditional square-wave controlled EDMs often employ commutation angle optimization to suppress torque ripple, but their output torque characteristics still lag behind those of sinusoidal-wave driven motors. However, due to armature reaction, EDMs experience increased saturation in local circuits, causing the back EMF to become sinusoidal. Therefore, a sinusoidal drive method can be adopted, significantly reducing torque ripple in EDMs. In sinusoidally driven motors, torque ripple is typically suppressed by injecting armature current harmonics. The injected harmonic current interacts with nonlinear factors to counteract the motor's torque ripple. Current research on suppressing torque ripple through harmonic injection primarily involves calculating harmonic current setpoints based on a torque model and then injecting harmonics by adjusting the duty cycle during switching control. This approach requires pre-measurement of the motor's flux and back EMF to generate a torque ripple calculation model. To address this issue, some researchers have proposed a second approach. This approach, based on the proportional relationship between the speed ripple amplitude and the torque ripple amplitude, automatically generates a setpoint for injected harmonics by constructing a closed-loop speed ripple control system. However, methods based on torque models are often significantly affected by motor parameters, and their nonlinear characteristics are difficult to accurately capture. Furthermore, methods based on a closed-loop speed ripple control system often suffer from poor speed extraction accuracy and poor disturbance immunity in practical applications. In addition, most current harmonic control methods rely on low-pass or band-pass filters to achieve harmonic decoupling and extraction, which also brings challenges to filter bandwidth design under different operating conditions, affecting the system's steady-state and dynamic performance.

[0003] Therefore, in order to suppress the torque ripple of the electrically excited doubly salient motor drive system based on a current source inverter, a harmonic injection control method is urgently needed that can take into account the adaptability of parameters and working conditions while achieving high steady-state accuracy. Summary of the Invention

[0004] Purpose of the invention: The present invention provides a method for suppressing torque pulsation of an electrically excited doubly salient pole motor based on harmonic double closed-loop control, which solves the problem that the conventional harmonic injection method depends on motor parameters and operating conditions in the current source drive system of the electrically excited doubly salient pole motor, and realizes the suppression of its torque pulsation.

[0005] Technical solution: The present invention describes a method for suppressing torque pulsation of an electrically excited double-pole motor based on harmonic dual closed-loop control. In the current source drive control system of the electrically excited double-pole motor with multiplexed excitation winding, a harmonic dual closed-loop control of a torque pulsation outer loop and a current harmonic inner loop is constructed. The torque pulsation outer loop observes the electromagnetic torque through a model reference adaptive method, and extracts its pulsating component in combination with an adaptive notch filter. The output current harmonic inner loop is closed-loop regulated to a given value. The current harmonic inner loop extracts harmonic current by constructing a harmonic space decoupling transformation matrix in combination with a coordinate transformation method. The closed-loop regulation generates a harmonic given value of the current-type inverter SVPWM modulation, generates corresponding subharmonic current, and offsets the torque pulsation of the electrically excited double-pole motor under the sinusoidal wave drive mode.

[0006] The specific steps include:

[0007] Step 1: Collect the motor's electrical angular velocity ω e , three-phase armature current i a 、i b 、i c And the three-phase filter capacitor voltage u a 、u b 、u c , the current i in the rotor coordinate system is obtained by coordinate transformation d 、i q and voltage u d 、u q , the observed motor back electromotive force parameter e is obtained through the model reference adaptive system df 、e qf ;

[0008] Step 2: Observe the motor back electromotive force parameter e df 、e qf Combined current i d 、i q and the motor electrical angular velocity ω e Calculate the torque signal T e , after the adaptive notch filter, the signal T is obtained 6d 、T 6q 、T 12d 、T 12q ;

[0009] Step 3: Set the given value of the four-way torque pulsation outer loop to 0, T 6d 、T 6q 、T12d 、T 12q As the feedback value of the four-way torque pulsation outer loop, the output signal is output through two PI regulators

[0010] Step 4: Collect the three-phase armature current i a 、i b 、i c The signal i is obtained by performing a phase delay of 20° and 40° respectively. a_v1 、i b_v1 、i c_v1 andi a_v2 、i b_v2 、i c_v2 , through the harmonic space decoupling transformation matrix T decomp Get signal i α 、i β 、

[0011] Step 5: Transmit the signal and After the inverse Clarke transform, the signal i is obtained by five and seven synchronous rotation coordinate transformations respectively. d5th 、i q5th andi d7th 、i q7th ;

[0012] Step 6: Set the given value of the inner loop of harmonic current to will i d5th 、i q5th andi d7th 、i q7th As the feedback value of the harmonic current inner loop, the Clark transformation is performed after the output of the four-way PI regulator to obtain the harmonic current i injected in the αβ coordinate system α5th 、i β5th 、i α7th 、i β7th ;

[0013] Step 7: Transmit signal i α5th 、i α7th and i β5th 、i β7th Superimposed on the current signal i α 、i β In the embodiment, the driving signals S1 to S6 of the switch tubes are obtained by the seven-segment SVPWM modulation method.

[0014] Furthermore, in step 1, the motor electrical angular velocity ω is collected e , three-phase armature current i a 、i b 、i c And the three-phase filter capacitor voltage ua 、u b 、u c , the current i in the rotor coordinate system is obtained by coordinate transformation d 、i q and voltage u d 、u q , the observed motor back electromotive force e obtained by the model reference adaptive system df 、e qf satisfy:

[0015]

[0016] where R s is the armature winding resistance, L d 、L q is the self-inductance of the d-axis winding and the q-axis winding, ω e is the motor electrical angular velocity.

[0017] Furthermore, in step 1, the observed motor back electromotive force e is obtained by the model reference adaptive system. df 、e qf , the model reference adaptive system includes the adjustable system for observing the back electromotive force:

[0018]

[0019] The adaptive law for observing back EMF is:

[0020]

[0021] Where x=[i d i q ] T ,u=[u d u q ] T ,e=[e df e qf ] T , f1, f2, g1, and g2 are observer gains.

[0022] Furthermore, in step 2, the observed motor back electromotive force parameter e df 、e qf Combined current i d 、i q and electrical angular velocity ω e Calculate the torque signal T e , after the adaptive notch filter, the signal T is obtained 6d 、T 6q 、T 12d 、T 12q .

[0023] The calculated torque signal T e for:

[0024]

[0025] Where p is the number of motor pole pairs.

[0026] When the torque signal T contains pulsating components e Meet T e =T0+T6cos(6θ e +φ6)+T 12 cos(12θ e +φ 12 ), the corresponding signal T 6d 、T 6q 、T 12d 、T 12q They are:

[0027]

[0028] Among them, T0 is the average torque, T6, T 12 are the 6th and 12th torque pulsation component amplitudes, φ6, φ 12 are the initial phases of the 6th and 12th torque ripples, T 6d 、T 6q 、T 12d 、T 12q It is a DC quantity containing the 6th and 12th order torque pulsation amplitude and phase information.

[0029] Furthermore, in step 4, the collected three-phase armature current i a 、i b 、i c The signal i is obtained by performing a phase delay of 20° and 40° respectively. a_v1 、i b_v1 、i c_v1 andi a_v2 、i b_v2 、i c_v2 , through the harmonic space decoupling transformation matrix T decomp Get signal i α 、i β 、 This harmonic space decoupling transformation matrix T decomp for:

[0030]

[0031] Among them, the matrix T(λ) is:

[0032] When the phase current ia satisfy When the harmonic space decoupling transformation matrix T decomp The obtained signal i α 、i β 、 for:

[0033]

[0034] Where ω is the motor electrical angular velocity, are the initial phases of the fundamental, 5th harmonic and 7th harmonic currents respectively; I1, I5 and I7 are the amplitudes of the fundamental, 5th harmonic and 7th harmonic currents respectively.

[0035] Furthermore, step 5 converts the signal The signal i is obtained by five synchronous rotation coordinate transformations d5th 、i q5th ,Signal The signal i is obtained by seven synchronous rotation coordinate transformations d7th 、i q7th When the phase current i a satisfy When i d5th 、i q5th 、i d7th 、i q7th They are:

[0036]

[0037] Furthermore, step 6 sets the given value of the inner loop of harmonic current to will i d5th 、i q5th andi d7th 、i q7th As the feedback value of the harmonic current inner loop, the Clark transformation is performed after the output of the four-way PI regulator to obtain the harmonic current i injected in the αβ coordinate system α5th 、i β5th 、i α7th 、i β7th There is no need to solve the phase of the injected harmonic current based on the harmonic back electromotive force. The harmonic current closed loop is directly adjusted by the signal Inject the 5th harmonic to adjust the signal T 6d 、T 6q Achieve 6-fold torque ripple closed-loop suppression; by adjusting the signal Inject the 7th harmonic to adjust the signal T 12d 、T 12q Achieve 12-order torque pulsation closed-loop suppression.

[0038] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the present invention realizes harmonic injection to suppress the torque pulsation amplitude through the torque pulsation closed loop and the harmonic current closed loop, and solves the problem of the traditional harmonic injection method being incompatible with different operating conditions of the motor and the problem of dependence on motor parameters; the model reference adaptive system and the adaptive notch filter are applied to the observation and extraction of torque pulsation, so that the torque pulsation control has higher accuracy; the harmonic space decoupling is used to realize the current harmonic extraction without the need for a filter, so that the current harmonic control has better adaptability to working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a system control block diagram of the present invention;

[0040] Figure 2 1 is a structural diagram of the adaptive notch filter in the present invention;

[0041] Figure 3 This is a structural diagram of the torque ripple extraction and control part based on the adaptive notch filter in the present invention;

[0042] Figure 4 This is a structural diagram of the harmonic extraction and control part based on harmonic spatial decoupling combined with a rotating coordinate system in the present invention;

[0043] Figure 5 This is a diagram showing the harmonic back electromotive force and torque observation results in the rotor coordinate system based on the model reference adaptive system when the given speed is 200 rpm and the given load torque is 5 N·m in the present invention;

[0044] FIG6 is a steady-state waveform diagram of torque ripple suppression in the present invention, wherein FIG6(a) shows the phase current waveform and torque waveform after harmonic injection at a given speed of 200 rpm and a given load torque of 5 N·m; FIG6(b) shows the Fourier analysis results of the phase current and torque after harmonic injection;

[0045] Figure 7 is a steady-state waveform diagram of the torque pulsation suppression under different operating conditions in the present invention, wherein Figure 7(a) shows the phase current waveform and torque waveform diagram before and after harmonic injection at a given speed of 100 rpm and a given load torque of 2.5 N·m; Figure 7(b) shows the phase current waveform and torque waveform diagram before and after harmonic injection at a given speed of 300 rpm and a given load torque of 7.5 N·m. DETAILED DESCRIPTION

[0046] The present invention will be further explained below with reference to the accompanying drawings.

[0047] like Figure 1 As shown, the present invention provides a method for suppressing torque ripple of an electrically excited doubly salient motor based on a harmonic double closed-loop control strategy, comprising the following steps:

[0048] S1: Collect the motor's electrical angular velocity ω e , three-phase armature current i a 、i b 、i c And the three-phase filter capacitor voltage u a 、u b 、u c , the current i in the rotor coordinate system is obtained by coordinate transformation d 、i q and voltage u d 、u q , the observed motor back electromotive force parameter e is obtained through the model reference adaptive system df 、e qf .

[0049] S2: Observed motor back electromotive force parameter e df 、e qf Combined current i d 、i q and the motor electrical angular velocity ω e Calculate the torque signal T e , after the adaptive notch filter, the signal T is obtained 6d 、T 6q 、T 12d 、T 12q .

[0050] S3: Set the given value of the four-way torque pulsation outer loop to 0, T 6d 、T 6q 、T 12d 、T 12q As the feedback value of the four-way torque pulsation outer loop, the output signal is output through two PI regulators

[0051] S4: The collected three-phase armature current i a 、i b 、i c The signal i is obtained by performing a phase delay of 20° and 40° respectively. a_v1 、i b_v1 、i c_v1 andi a_v2 、i b_v2 、i c_v2 , through the harmonic space decoupling transformation matrix T decomp Get signal i α 、i β 、

[0052]

[0053] S5: The signal and After the inverse Clarke transform, the signal i is obtained by five and seven synchronous rotation coordinate transformations respectively. d5th 、i q5th andi d7th 、i q7th .

[0054] S6: Set the given value of the inner loop of harmonic current to The signal i d5th 、i q5th andi d7th 、i q7th As the feedback value of the harmonic current inner loop, the Clark transformation is performed after the output of the four-way PI regulator to obtain the harmonic current i injected in the αβ coordinate system α5th 、i β5th 、i α7th 、i β7th .

[0055] S7: Signal i α5th 、i α7th and i β5th 、i β7th Superimposed on the current signal i α 、i β In the embodiment, the driving signals S1 to S6 of the switch tubes are obtained by the seven-segment SVPWM modulation method.

[0056] Reference Figure 1 In step S1, the motor electrical angular velocity ω is collected e , three-phase armature current i a 、i b 、i c And the three-phase filter capacitor voltage u a 、u b 、u c , the current i in the rotor coordinate system is obtained by coordinate transformation d 、i q and voltage u d 、u q , the observed motor back electromotive force e obtained by the model reference adaptive system df 、e qf satisfy:

[0057]

[0058] where R s is the armature winding resistance, L d 、L q is the self-inductance of the d-axis winding and the q-axis winding, ω e is the motor electrical angular velocity.

[0059] The observed motor back electromotive force e obtained by the model reference adaptive system df、e qf , the model reference adaptive system includes the adjustable system for observing the back electromotive force:

[0060]

[0061] The adaptive law for observing back EMF is:

[0062]

[0063] Where x=[i d i q ] T ,u=[u d u q ] T ,e=[e df e qf ] T , f1, f2, g1, and g2 are observer gains.

[0064] Reference Figure 2 and Figure 3 In step S2, the motor back electromotive force parameter e is observed df 、e qf Combined current i d 、i q and electrical angular velocity ω e Calculate the torque signal T e , after the adaptive notch filter, the signal T is obtained 6d 、T 6q 、T 12d 、T 12q .

[0065] The calculated torque signal T e for:

[0066]

[0067] Where p is the number of motor pole pairs.

[0068] The torque signal T containing the pulsating component e It can be expressed as:

[0069] T e =T0+T6cos(6θ e +φ6)+T 12 cos(12θ e +φ 12 )

[0070] The recursive formula of the adaptive notch filter is:

[0071]

[0072] Wherein, the reference vector X=[cos(6θ e ),sin(6θ e ),cos(12θ e ),sin(12θ e )], d is the input signal mixed with harmonics, y is the detected harmonic component, e is the error signal between the input signal and the detected harmonic component, W is the coefficient vector of the input signal, X is the constant component and the orthogonal reference vector of the input signal, and μ is the step size.

[0073] The output signal T of the adaptive notch filter 6d 、T 6q 、T 12d 、T 12q for:

[0074]

[0075] Reference Figure 4 In step S4, the three-phase current i containing harmonic components is collected. a 、i b 、i c for:

[0076]

[0077] The harmonic space decoupling transformation matrix T decomp for:

[0078]

[0079] Among them, the matrix T(λ) is:

[0080]

[0081] The harmonic space decoupling transformation matrix T decomp The obtained signal i α 、i β 、 for:

[0082]

[0083] refer to Figure 4 In step S5, the coordinate transformation matrix of the 5th and 7th synchronous rotations is:

[0084]

[0085] The signal i obtained after the rotation coordinate transformation d5th 、i q5th 、id7th 、i q7th for:

[0086]

[0087] refer to Figure 4 , step S6 sets the given value of the harmonic current inner loop to will i d5th 、i q5th 、i d7th 、i q7th As the feedback value of the harmonic current inner loop, the Clark transformation is performed after the output of the four-way PI regulator to obtain the harmonic current i injected in the αβ coordinate system α5th 、i β5th 、i α7th 、i β7th There is no need to solve the phase of the injected harmonic current based on the harmonic back electromotive force. The harmonic current closed loop is directly adjusted by the signal Inject the 5th harmonic to adjust the signal T 6d 、T 6q Achieve 6-fold torque ripple closed-loop suppression; by adjusting the signal Inject the 7th harmonic to adjust the signal T 12d 、T 12q Achieve 12-order torque pulsation closed-loop suppression.

[0088] Reference Figure 1 In step S7, the signal i α5th 、i α7th and i β5th 、i β7th Superimposed on the current signal i α 、i β In the process, the seven-segment SVPWM modulation method is used to finally obtain the driving signals S1 to S6 of the switch tube.

[0089] Compared with the existing torque pulsation suppression method based on harmonic injection, the above-mentioned torque pulsation suppression method of the electrically excited double-pole motor based on harmonic dual closed-loop control constructs a complete torque pulsation suppression system, solves the problem of the traditional harmonic injection method's incompatibility with different motor operating conditions and dependence on motor parameters, and has higher steady-state accuracy.

[0090] The design principle of the present invention is as follows: a harmonic dual closed-loop control system consisting of a torque pulsation outer loop and a current harmonic inner loop is constructed, wherein the torque pulsation outer loop observes the electromagnetic torque through a model reference adaptive method, extracts its pulsating component in combination with an adaptive notch filter, and closes the loop to adjust the output current harmonic inner loop given value; the current harmonic inner loop extracts harmonic current by constructing a harmonic space decoupling transformation matrix in combination with a coordinate transformation method, and closes the loop to adjust the generated harmonic given value of the current-type inverter SVPWM modulation, thereby generating corresponding subharmonic currents and offsetting the torque pulsation of the electrically excited double-pole motor under the sinusoidal wave drive mode.

[0091] Based on the above scheme, in order to verify the torque ripple suppression method of the electrically excited doubly salient motor based on harmonic double closed-loop control, a mathematical model of the electrically excited doubly salient motor was constructed. The current source type electrically excited doubly salient motor drive control system reused the excitation winding. The torque ripple observation, extraction and control module and the harmonic current extraction and control module were built for simulation verification. The main parameter settings during the test are shown in Table 1:

[0092] Table 1 Simulation setting parameters

[0093]

[0094]

[0095] The specific simulation results and analysis are as follows:

[0096] Figure 5 Waveforms of harmonic back EMF and torque observations based on the model reference adaptive system under sinusoidal drive before harmonic injection. The waveforms show that under sinusoidal drive, the harmonic components in the back EMF cause large torque ripples, with a peak-to-peak value of approximately 0.4 N·m.

[0097] Figure 6(a) shows the steady-state waveform of torque pulsation suppression at a given speed of 200 rpm and a given load torque of 5 N·m, and Figure 6(b) shows the Fourier analysis results of the phase current and torque. After harmonic injection, the phase current is distorted, with a THD of 3.0%, of which the fifth harmonic accounts for 2.7% and the seventh harmonic accounts for 1.3%. The peak-to-peak value of the torque pulsation is reduced from 0.4 N·m to within 0.04 N·m. This shows that the torque pulsation suppression method for the electrically excited doubly salient-pole motor based on the harmonic dual closed-loop control strategy adopted in the present invention is effective, with high harmonic injection accuracy and significant torque pulsation suppression effect.

[0098] Figure 7(a) shows the steady-state waveform of torque pulsation suppression at a given speed of 100 rpm and a given load torque of 2.5 N·m. After harmonic injection, the peak-to-peak value of torque pulsation is reduced from 0.35 N·m to 0.04 N·m. Figure 7(b) shows the steady-state waveform of torque pulsation suppression at a given speed of 300 rpm and a given load torque of 7.5 N·m. After harmonic injection, the peak-to-peak value of torque pulsation is reduced from 0.55 N·m to 0.08 N·m. It can be seen that the torque pulsation suppression method for an electrically excited doubly salient-pole motor based on a harmonic double-closed-loop control strategy adopted in the present invention has a significant torque pulsation suppression effect under different speed and load conditions.

Claims

1. A method for suppressing torque ripple of an electrically excited doubly salient motor based on harmonic double closed-loop control, characterized in that: In the current source drive control system of the electrically excited doubly salient pole motor with multiplexed excitation winding, a harmonic dual closed-loop control consisting of a torque pulsation outer loop and a current harmonic inner loop is constructed. The torque pulsation outer loop observes the electromagnetic torque through a model reference adaptive method, and extracts its pulsating component in combination with an adaptive notch filter. The output current harmonic inner loop is closed-loop regulated to a given value. The current harmonic inner loop extracts harmonic currents by constructing a harmonic space decoupling transformation matrix combined with a coordinate transformation method. The closed-loop regulation generates a harmonic given value for the SVPWM modulation of the current source inverter, generates corresponding subharmonic currents, and offsets the torque pulsation of the electrically excited doubly salient pole motor under the sinusoidal wave drive mode.

2. The method for suppressing torque ripple of an electrically excited doubly salient motor based on harmonic double closed-loop control according to claim 1, characterized in that: The steps include: Step 1: Collect the motor's electrical angular velocity ω e , three-phase armature current i a 、i b 、i c And the three-phase filter capacitor voltage u a 、u b 、u c , the current i in the rotor coordinate system is obtained by coordinate transformation d 、i q and voltage u d 、u q , the observed motor back electromotive force parameter e is obtained through the model reference adaptive system df 、e qf ; Step 2: Observe the motor back electromotive force parameter e df 、e qf Combined current i d 、i q and the motor electrical angular velocity ω e Calculate the torque signal T e , after the adaptive notch filter, the signal T is obtained 6d 、T 6q 、T 12d 、T 12q ; Step 3: Set the given value of the four-way torque pulsation outer loop to 0, T 6d 、T 6q 、T 12d 、T 12q As the feedback value of the four-way torque pulsation outer loop, the output signal is output through the four-way PI regulator Step 4: Collect the three-phase armature current i a 、i b 、i c The signal i is obtained by performing a phase delay of 20° and 40° respectively. a_v1 、i b_v1 、i c_v1 andi a_v2 、i b_v2 、i c_v2 , through the harmonic space decoupling transformation matrix T decomp Get signal i α 、i β 、 Step 5: Transmit the signal and After the inverse Clarke transform, the signal i is obtained by five and seven synchronous rotation coordinate transformations respectively. d5th 、i q5th andi d7th 、i q7th ; Step 6: Set the given value of the inner loop of harmonic current to will i d5th 、i q5th andi d7th 、i q7th As the feedback value of the harmonic current inner loop, the Clark transformation is performed after the output of the four-way PI regulator to obtain the harmonic current i injected in the αβ coordinate system α5th 、i β5th 、i α7th 、i β7th ; Step 7: Transmit signal i α5th 、i α7th and i β5th 、i β7th Superimposed on the current signal i α 、i β In the embodiment, the driving signals S1 to S6 of the switch tubes are obtained by the seven-segment SVPWM modulation method.

3. The method for suppressing torque ripple of an electrically excited doubly salient motor based on harmonic double closed-loop control according to claim 2, characterized in that: In step 2, the torque signal T is converted to e The AC pulsation component in the torque converter is converted into a DC component containing the amplitude and phase information of each pulsation component, so as to realize the closed-loop control of the torque pulsation. When the torque signal T contains pulsating components e satisfy T e =T0+T6cos(6θ e +φ6)+T 12 cos(12θ e +φ 12 ), the corresponding signal T 6d 、T 6q 、T 12d 、T 12q They are: Among them, T0 is the average torque, T6, T 12 are the 6th and 12th torque pulsation component amplitudes, φ6, φ 12 are the initial phases of the 6th and 12th torque ripples, T 6d 、T 6q 、T 12d 、T 12q It is a DC quantity containing the 6th and 12th order torque pulsation amplitude and phase information.

4. The method for suppressing torque ripple of an electrically excited doubly salient motor based on harmonic double closed-loop control according to claim 2, wherein: In step 4, the harmonic space decoupling transformation matrix T decomp The three-phase armature current i a 、i b 、i c The harmonic components and fundamental components are separated from each other, which facilitates the decoupling control of each harmonic; The harmonic space decoupling transformation matrix T decomp for: Among them, the matrix T(λ) is: When the phase current i a satisfy When the harmonic space decoupling transformation matrix T decomp The obtained signal i α 、i β 、 for: Where ω is the motor electrical angular velocity, are the initial phases of the fundamental, 5th harmonic and 7th harmonic currents respectively; I1, I5 and I7 are the amplitudes of the fundamental, 5th harmonic and 7th harmonic currents respectively.

5. The method for suppressing torque ripple of an electrically excited doubly salient motor based on harmonic double closed-loop control according to claim 2, wherein: In step 5, the decoupled harmonics are converted into DC components containing the amplitude and phase information of each harmonic component through fifth and seventh synchronous rotation coordinate transformations, so as to facilitate closed-loop control of current harmonics. When the phase current i a satisfy When i d5th 、i q5th 、i d7th 、i q7th They are: Where ω is the electrical angular velocity of the motor, I5 and I7 are the initial phases of the 5th and 7th harmonic currents respectively, and I5 and I7 are the amplitudes of the 5th and 7th harmonics.

6. The method for suppressing torque ripple of an electrically excited doubly salient motor based on harmonic double closed-loop control according to claim 2, characterized in that: In step 6, the harmonic current closed loop is adjusted by the signal Inject the 5th harmonic to adjust the signal T 6d 、T 6q Achieve closed-loop suppression of 6-fold torque ripple; by adjusting the signal Inject the 7th harmonic to adjust the signal T 12d 、T 12q Achieve closed-loop suppression of 12-order torque ripple.

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