Single-phase permanent magnet motor torque ripple suppression method and device, medium and program product

Abstract

The invention provides a single-phase permanent magnet motor torque ripple suppression method and device, a medium and a program product, and the method comprises the steps: obtaining a current motor current, and obtaining a load torque, a fundamental component of the corresponding motor current, and a lookup table of the combination of a plurality of odd-order harmonic components; extracting a fundamental wave actual value and a harmonic wave actual value from the current motor current; taking the torque reference value as a value of a load torque, and obtaining a fundamental wave reference value and a harmonic wave reference value based on the torque reference value and the lookup table; respectively obtaining component difference values of the reference values and the corresponding actual values; each component difference generates a voltage reference value component through a corresponding current controller, the sum of all the voltage reference value components serves as a voltage reference value, and a switching signal of a single-phase inverter power device is controlled according to the voltage reference value. According to the invention, through the injection of the harmonic current, the torque ripple of the motor is effectively reduced, and meanwhile, the delay caused by the extraction of the fundamental wave and the harmonic wave and the adverse effect on the system performance are avoided.

Description

Technical Field

[0001] The present disclosure relates to the field of motor technology, and in particular to a method, device, medium and program product for suppressing torque pulsation of a single-phase permanent magnet motor. Background Art

[0002] Single-phase permanent magnet motors have been widely used in fans, pumps, compressors and other fields due to their simple structure and low cost. The closed-loop control method of existing single-phase permanent magnet motors mainly generates a power device drive signal with a fixed relative position to the rotor through a specific modulation method based on the rotor position to ensure that the voltage input to the stator end of the motor is a sine wave or square wave.

[0003] The magnetomotive force formed by the stator current of a single-phase permanent magnet motor is pulsating, which is its inherent characteristic. This leads to torque pulsation of the single-phase permanent magnet motor. Currently, torque pulsation is usually reduced by optimizing the design of the motor body, but there is a lack of control means to suppress torque pulsation. Summary of the invention

[0004] The technical problem to be solved by the present disclosure is to overcome the defect in the prior art that there is a lack of means to suppress the torque pulsation of a single-phase permanent magnet motor, and to provide a method, device, medium and program product for suppressing the torque pulsation of a single-phase permanent magnet motor.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] The present disclosure provides a method for suppressing torque pulsation of a single-phase permanent magnet motor, the method comprising:

[0007] Obtain the current motor current, and obtain a lookup table of the load torque and the corresponding motor current fundamental component and several odd-order harmonic component combinations; wherein the fundamental component and harmonic component combination is obtained with the goal of minimizing the pulsation of the shaft output torque;

[0008] Extracting fundamental wave actual value and harmonic wave actual value from the current motor current;

[0009] Taking a torque reference value as the value of the load torque, a fundamental wave reference value and a harmonic wave reference value are obtained based on the torque reference value and the lookup table; wherein the torque reference value is obtained by a speed regulator through a difference between a set speed and an actual speed;

[0010] Respectively obtain component differences between the fundamental wave reference value and the harmonic reference value and the corresponding fundamental wave actual value and harmonic wave actual value;

[0011] Each of the component differences generates a voltage reference value component through a corresponding current controller, and the sum of all the voltage reference value components is used as the voltage reference value. The switching signal of the single-phase inverter power device is controlled according to the voltage reference value.

[0012] Optionally, the single-phase permanent magnet motor torque pulsation suppression method further includes:

[0013] The no-load back EMF and cogging torque waveforms of the motor are obtained through electromagnetic simulation of the motor. The no-load back EMF is decomposed by Fourier to obtain the no-load back EMF expression containing the amplitude and phase information of the fundamental wave and each harmonic.

[0014] Injecting several odd-order harmonics into the current to suppress torque ripple, and obtaining the current expression containing harmonics and the torque expression of the motor;

[0015] According to the no-load back electromotive force expression, the current expression and the torque expression, the torque component generated by the interaction between the i-th harmonic of the back electromotive force and the j-th harmonic of the current is obtained; wherein i and j are both positive odd numbers;

[0016] According to the no-load back electromotive force expression, the current expression, the torque expression, the torque component and the output condition expression, with the goal of minimizing the pulsation of the shaft output torque, the values ​​of the fundamental component and the combination of odd-order harmonic components of the current corresponding to each load torque are calculated and constructed into the lookup table; wherein the output condition expression indicates that the average value of the total torque output by the motor is equal to the load torque value of the motor.

[0017] Optionally, the no-load back electromotive force expression, the current expression, the torque expression, the torque component and the output condition expression are expressed by the following formula:

[0018]

[0019]

[0020] The shaft output torque pulsation is minimized as the target expressed as:

[0021]

[0022] Wherein, E0 represents the no-load back electromotive force, i represents the harmonic order of the back electromotive force, ψ i represents the harmonic amplitude of permanent magnet flux linkage, represents the initial phase of the back EMF harmonic, ω represents the electrical angular frequency of the motor, t represents time, i s Represents the motor current including harmonics, T e represents the electromagnetic torque of the motor, Tc represents the cogging torque, Ω represents the mechanical angular velocity of the motor, T ij represents the torque component, T ampij represents the average value of the corresponding torque component generated by the i-th harmonic of the back electromotive force and the j-th harmonic of the current, Represents the average value of the total torque output by the motor, T L Indicates the load torque value of the motor.

[0023] Optionally, extracting the fundamental wave actual value and the harmonic wave actual value from the current motor current includes:

[0024] The current motor current is virtualized as the phase current of an m-phase motor; wherein m is the highest order of harmonics to be extracted, and m is an odd number greater than 1;

[0025] The phase current is decoupled in an m-phase vector space to map the fundamental wave and several harmonics to n subspaces respectively; wherein one subspace corresponds to the fundamental wave or an odd-order harmonic, and n=(m+1) / 2.

[0026] Optionally, the virtualizing the current motor current as a phase current of an m-phase motor includes:

[0027] Performing m-1 phase shifts on the current motor current, each phase shift causes the phase of the current motor current to lag by an electrical angle of 2π / m to construct the m-phase motor, and obtaining the phase current of the m-phase motor;

[0028] The m-phase vector space decoupling of the phase current to map the fundamental wave and several order harmonics to n subspaces respectively includes:

[0029] The phase current is converted from the m-phase vector to the decoupled vector space through a transformation matrix; wherein, for the fundamental wave and harmonics below m-2, there is a pair of mutually orthogonal fundamental wave components or harmonic components on the two axes of the corresponding subspace; for the m-th harmonic, the m-th harmonic is located on one axis of the corresponding subspace.

[0030] Optionally, the phase current of the m-phase motor, the phase current in the decoupled vector space, and the transformation matrix are expressed by the following formula:

[0031]

[0032] [i α i β i z1 i z2 … i o1 ] T =T VSD[i1 i2 i3 … i m ] T ;

[0033]

[0034] α=2π / m;

[0035] Among them, i s Indicates the motor current containing harmonics, i1...i m represents the phase current of each phase, ω represents the electrical angular frequency of the motor, t represents time, m represents the number of phases of the virtual motor, f(ωt) represents the current motor current, T VSD represents the transformation matrix, [i α i β i z1 i z2 … i o1 ] represents the phase current in the decoupled vector space, i α and i β Represents a pair of mutually orthogonal fundamental wave components in the subspace corresponding to the fundamental wave, i z1 and i z2 Represents a pair of mutually orthogonal harmonic components in the subspace corresponding to the third harmonic, and so on until the m-2nd harmonic, i o1 Represents the harmonic component of the subspace corresponding to the mth harmonic.

[0036] Optionally, each of the component differences generates a voltage reference value component through a corresponding current controller, and the sum of all the voltage reference value components is used as the voltage reference value, including:

[0037] For the fundamental wave and harmonics below m-2, each pair of orthogonal components mapped into the corresponding subspace is transformed into a rotating coordinate system of the corresponding frequency through Park transformation, a pair of first DC components on dq axes are obtained in each subspace, and a difference between each first DC component and a reference value of the corresponding component is used to generate a first voltage reference value component through a PI controller;

[0038] For the mth harmonic, an AC component mapped to an axis in a corresponding subspace is used, and a difference between the AC component and a reference value of the corresponding component is used to generate a second voltage reference value component through a PR controller;

[0039] The α-axis component obtained after the inverse Park transformation of the first voltage reference value component is used as the voltage reference value, and the sum of the α-axis component and the second voltage reference value component is used as the voltage reference value.

[0040] The present disclosure also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and used to run on the processor, and the processor implements the aforementioned single-phase permanent magnet motor torque pulsation suppression method when executing the computer program.

[0041] The present disclosure also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the aforementioned method for suppressing torque pulsation of a single-phase permanent magnet motor is implemented.

[0042] The present disclosure also provides a computer program product, including a computer program, which, when executed by a processor, implements the method for suppressing torque pulsation of a single-phase permanent magnet motor as described above.

[0043] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0044] The positive progressive effect of the present disclosure is that the present disclosure converts the current motor current into the phase current of a virtual multi-phase motor, performs multi-phase vector space decoupling on the phase current to map the fundamental and harmonic waves to different subspaces for extraction, and then injects harmonic current into the motor current based on the extracted fundamental and harmonic waves. The injection of harmonic current effectively reduces the torque pulsation of the motor, while avoiding the delay caused by the extraction of fundamental and harmonic waves, and avoiding adverse effects on the performance of the single-phase permanent magnet motor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A flow chart of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0046] Figure 2 A flowchart of a specific implementation of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Example 1 of the present disclosure;

[0047] Figure 3 A flowchart of a specific implementation of step S12 of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Example 1 of the present disclosure;

[0048] Figure 4 A flowchart of a specific implementation of step S15 of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Example 1 of the present disclosure;

[0049] Figure 5 A structural diagram of a driving circuit of a single-phase permanent magnet motor according to an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0050] Figure 6A no-load back electromotive force waveform of a single-phase permanent magnet motor of an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0051] Figure 7 The no-load back electromotive force FFT result of a single-phase permanent magnet motor of an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0052] Figure 8 An overall control block diagram of a single-phase permanent magnet motor according to an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0053] Fig. 9 A virtual five-phase motor as an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0054] Fig.10 Current decoupling of a virtual five-phase motor in an example of a method for suppressing torque ripple of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0055] Fig.11 A motor current waveform diagram before and after harmonic injection in an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0056] Fig.12 A waveform diagram of the fundamental wave in the motor current before and after harmonic injection in an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0057] Fig.13 A waveform diagram of the third harmonic in the motor current before and after harmonic injection in an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0058] Fig.14 A waveform diagram of the fifth harmonic in the motor current before and after harmonic injection in an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0059] Fig.15 A waveform diagram of the shaft output torque and electromagnetic torque of the motor before and after harmonic injection in an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0060] Fig.16 A waveform diagram of the motor speed before and after harmonic injection in an example of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided in Embodiment 1 of the present disclosure;

[0061] Fig.17 A schematic diagram of the structure of an electronic device provided in Embodiment 2 of the present disclosure. DETAILED DESCRIPTION

[0062] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0063] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.

[0064] Example 1

[0065] Figure 1 A flowchart of a method for suppressing torque pulsation of a single-phase permanent magnet motor provided by an exemplary embodiment of the present disclosure, the method for suppressing torque pulsation of a single-phase permanent magnet motor comprising:

[0066] S11, obtaining the current motor current, obtaining a lookup table of the load torque and the corresponding motor current fundamental component and several odd-order harmonic component combinations, wherein the fundamental component and the harmonic component combination are obtained with the goal of minimizing the pulsation of the shaft output torque.

[0067] S12. Extract the fundamental wave actual value and the harmonic wave actual value from the current motor current.

[0068] S13, taking the torque reference value as the value of the load torque, and obtaining the fundamental wave reference value and the harmonic wave reference value based on the torque reference value and the lookup table, wherein the torque reference value is obtained by the difference between the set speed and the actual speed through the speed regulator.

[0069] S14, respectively obtaining component differences between the fundamental wave reference value and the harmonic wave reference value and the corresponding fundamental wave actual value and harmonic wave actual value.

[0070] S15. Each component difference generates a voltage reference value component through a corresponding current controller, and the sum of all voltage reference value components is used as the voltage reference value. The switching signal of the single-phase inverter power device is controlled according to the voltage reference value.

[0071] Among them, the magnetomotive force formed by the stator current of the single-phase permanent magnet motor is pulsating, which is its inherent characteristic. When using the traditional sine wave control method, under the combined effect of pulsating magnetomotive force, cogging torque and other factors, the motor torque pulsates greatly, usually reaching about 200%, resulting in poor steady-state speed response of the motor.

[0072] The torque of the motor current is actually equal to the sum of the fundamental wave, 3rd harmonic, 5th harmonic and other harmonics of the current multiplied by the sum of the fundamental wave, 3rd harmonic, 5th harmonic and other harmonics of the back electromotive force divided by the mechanical angular velocity of the motor. Expanding the result of this multiplication, the total torque is equal to the sum of the torque components generated by the interaction between the fundamental wave of the current and the 1st, 3rd, 5th, ... harmonics of the back electromotive force, the torque components generated by the interaction between the 3rd harmonic of the current and the 1st, 3rd, 5th, ... harmonics of the back electromotive force, the torque components generated by the interaction between the 5th harmonic of the current and the 1st, 3rd, 5th, ... harmonics of the back electromotive force, ... and so on.

[0073] The fundamental and harmonic waves of the back electromotive force interact with the fundamental and harmonic waves of the motor current, and some of them will cancel each other out. For example, the interaction between the 1st order (i.e., the fundamental wave) and the 1st order will produce the 0th and 2nd order torque components; the interaction between the 1st and 3rd order will produce the 2nd and 4th order torque components; the interaction between the 7th and 9th order will produce the 2nd and 16th order torque components. When i=j, the 0th and i+jth order torque components are generated; when i≠j, the ij and i+jth order torque components are generated. When no harmonic injection is performed, there are 2nd order torque fluctuations in the motor; after harmonic injection, as long as the order and size of the harmonics are reasonably allocated, the torque components of the same order generated by the current or back electromotive force harmonics of different orders will cancel each other out (for example, the 2nd order torque component generated by 1+1 and the 2nd order torque component generated by 1+3), which can minimize the total torque fluctuation. The total torque fluctuation = (maximum torque - minimum torque) / average torque value.

[0074] The voltage reference value is converted into a switching signal of a single-phase inverter power device through single-phase PWM (pulse width modulation) modulation, thereby controlling the operation of the motor.

[0075] In this embodiment, the current motor current is converted into the phase current of a virtual multi-phase motor, and the phase current is decoupled in a multi-phase vector space to map the fundamental and harmonic waves to different subspaces for extraction. Harmonic current is then injected into the motor current based on the extracted fundamental and harmonic waves. The injection of harmonic current effectively reduces the torque pulsation of the motor, while avoiding delays caused by the extraction of fundamental and harmonic waves, thereby avoiding adverse effects on the performance of the single-phase permanent magnet motor system.

[0076] In one embodiment, referring to Figure 2 , the method for suppressing torque pulsation of a single-phase permanent magnet motor also includes:

[0077] S21. The no-load back EMF and cogging torque waveforms of the motor are obtained through motor electromagnetic simulation. The no-load back EMF is subjected to Fourier decomposition to obtain an expression for the no-load back EMF containing the amplitude and phase information of the fundamental wave and each harmonic.

[0078] S22. Inject a number of odd-order harmonics into the current to suppress torque pulsation, and obtain a current expression containing harmonics and a torque expression of the motor.

[0079] S23. Obtain the torque component generated by the interaction between the i-th harmonic of the back electromotive force and the j-th harmonic of the current according to the no-load back electromotive force expression, the current expression and the torque expression, wherein i and j are both positive odd numbers.

[0080] S24, according to the no-load back electromotive force expression, current expression, torque expression, torque component and output condition expression, with the goal of minimizing the pulsation of the shaft output torque, calculate the value of the combination of the fundamental component and odd-order harmonic component of the current corresponding to each load torque and construct a lookup table. Among them, the output condition expression indicates that the average value of the total torque output by the motor is equal to the load torque value of the motor.

[0081] The reference values ​​of the current fundamental wave and each harmonic component corresponding to each load torque are obtained by offline calculation and made into a lookup table.

[0082] Preferably, the phase of the harmonic current is the same as the phase of the corresponding secondary back-EMF.

[0083] In one embodiment, the following formulas are used to express the no-load back electromotive force expression, current expression, torque expression, torque component and output condition expression:

[0084]

[0085] The goal of minimizing the pulsation of the shaft output torque is expressed as:

[0086]

[0087] Where E0 represents the no-load back EMF, i represents the harmonic order of the back EMF, ψ i represents the harmonic amplitude of permanent magnet flux linkage, represents the initial phase of the back EMF harmonic, ω represents the electrical angular frequency of the motor, t represents time, i s Represents the motor current including harmonics, T e Represents the electromagnetic torque of the motor, T c represents the cogging torque, Ω represents the mechanical angular velocity of the motor, T ij Represents the torque component, T ampij It represents the average value of the corresponding torque component generated by the i-th harmonic of the back electromotive force and the j-th harmonic of the current, Represents the average value of the total torque output by the motor, T L Indicates the load torque value of the motor.

[0088] The mechanical angular velocity Ω of the motor is equal to 1 / p of the electrical angular velocity ω, where p is the number of motor pole pairs.

[0089] The torque T of the motor current e From the torque expression, we can see that the torque of the motor current is actually equal to the sum of the fundamental wave, 3rd harmonic, 5th harmonic and other harmonics of the current multiplied by the sum of the fundamental wave, 3rd harmonic, 5th harmonic and other harmonics of the back electromotive force divided by the mechanical angular velocity of the motor. Expanding the result of this multiplication, the total torque is equal to the sum of the torque components generated by the interaction between the fundamental wave of the current and the 1st, 3rd, 5th, ... harmonics of the back electromotive force, the torque components generated by the interaction between the 3rd harmonic of the current and the 1st, 3rd, 5th, ... harmonics of the back electromotive force, the torque components generated by the interaction between the 5th harmonic of the current and the 1st, 3rd, 5th, ... harmonics of the back electromotive force, ... and so on.

[0090] The torque component T ij From the expression, we can know that the torque component is generated by the interaction between the i-th harmonic of the back electromotive force and the j-th harmonic of the current or the i-th harmonic of the back electromotive force and the j-th harmonic of the current. For example, the interaction between the 1st and 1st will produce the 0th and 2nd torque components; the interaction between the 1st and 3rd will produce the 2nd and 4th torque components; the interaction between the 7th and 9th will produce the 2nd and 16th torque components. When i=j, the 0th and i+jth torque components are generated; when i≠j, the ij and i+jth torque components are generated. When no harmonic injection is performed, there are 2nd torque fluctuations in the motor; after harmonic injection, as long as the order and size of the harmonics are reasonably allocated, the torque components of the same order generated by the current or back electromotive force harmonics of different orders will cancel each other (for example, the 2nd torque component generated by 1+1 and the 2nd torque component generated by 1+3), which can minimize the total torque fluctuation. The total torque fluctuation = (maximum torque - minimum torque) / average torque value.

[0091] When i=j, T ij It is composed of a DC component (average component) and an i+j-order component. The sum of the torques of the DC components generated by the interaction between the fundamental wave of the current and the 3rd, 5th, ..., mth harmonics and the components of the corresponding orders of the back electromotive force (i.e. the average value of the total torque output by the motor) must be equal to the load torque value T of the motor. L , that is, the output conditional expression is obtained.

[0092] The output condition expression can calculate an infinite number of different current fundamental and harmonic combinations. On this basis, the optimal combination is selected with the goal of minimizing the pulsation of the shaft output torque (i.e., the combined torque of the electromagnetic torque and the cogging torque). The shaft output torque is the combined torque of the electromagnetic torque and the cogging torque, and the torque pulsation is defined as: (maximum torque - minimum torque) / average torque.

[0093] The reference values ​​of the current fundamental wave and each harmonic component corresponding to each load torque are obtained by offline calculation and made into a lookup table. In the actual double closed-loop control system, the actual speed value of the motor is calculated by the signal of the Hall sensor. The error between the reference speed value (i.e. the target speed value) and the actual speed value passes through the speed regulator. Since the output Tref of the speed regulator is different from T L The units are the same and the values ​​are similar. The output T of the speed regulator ref Can replace T L as input to the lookup table.

[0094] Preferably, the bandwidth of the speed regulator is set to a relatively low value, so that the current reference value can be obtained.

[0095] In one embodiment, referring to Figure 3 , step S12 comprises:

[0096] S121, virtualizing the current motor current as the phase current of the m-phase motor, wherein m is the highest order of harmonics to be extracted, and m is an odd number greater than 1.

[0097] S122, decouple the phase currents in an m-phase vector space to map the fundamental wave and several harmonics to n subspaces, respectively, wherein one subspace corresponds to the fundamental wave or an odd-order harmonic, and n=(m+1) / 2.

[0098] Among them, the current motor current of the single-phase permanent magnet motor can be obtained by sampling the analog-to-digital converter.

[0099] In one embodiment, step S121 includes:

[0100] The current motor current is phase-shifted m-1 times, and each phase shift causes the phase of the current motor current to lag by an electrical angle of 2π / m to construct an m-phase motor and obtain the phase current of the m-phase motor.

[0101] Step S122 includes:

[0102] The phase current is converted from the m-phase vector to the decoupled vector space through the transformation matrix. For the fundamental wave and harmonics below m-2, there is a pair of mutually orthogonal fundamental wave components or harmonic components on the two axes of the corresponding subspace. For the m-th harmonic, the m-th harmonic is located on one axis of the corresponding subspace.

[0103] In order to extract and control the fundamental wave and 3 to m odd-order current harmonics, the current motor current is software-shifted m-1 times. Each phase shift causes the current phase to lag by 2π / m (i.e., α) electrical angle, thus constructing a virtual m-phase motor system.

[0104] The m-phase current components formed by phase shifting are decoupled in the m-phase vector space through a transformation matrix to obtain n subspaces, where n=(m+1) / 2.

[0105] The subspace obtained by transforming the 1st and 2nd rows of the transformation matrix is ​​the αβ subspace, to which the fundamental wave is mapped, and the α and β axes are a pair of mutually orthogonal fundamental wave components; the subspace obtained by transforming the 3rd and 4th rows is the z1z2 subspace, and the subspace obtained by transforming the 5th and 6th rows is the Z3z4 subspace, and so on, the 3rd to m-2nd harmonics are located in these subspaces, and each subspace has a pair of mutually orthogonal harmonic components on its two axes; the o1 subspace is obtained by transforming the mth row, and the mth harmonic is located on the o1 axis. The fundamental wave and harmonics of the current, a total of n components, are transformed into n subspaces respectively.

[0106] In one embodiment, the following formulas are used to represent the phase current of the m-phase motor, the phase current in the decoupled vector space, and the transformation matrix:

[0107]

[0108] [i α i β i z1 i z2 … i o1 ] T =T VSD [i1 i2 i3 … i m ] T .

[0109]

[0110] α=2π / m.

[0111] Among them, i s Indicates the motor current containing harmonics, i1...i m represents the phase current of each phase, ω represents the electrical angular frequency of the motor, t represents time, m represents the number of phases of the virtual motor, f(ωt) represents the current motor current, T VSD represents the transformation matrix, [i α i β i z1 i z2 … i o1 ] T represents the phase current in the vector space after decoupling, i α and i β Represents a pair of mutually orthogonal fundamental wave components in the subspace corresponding to the fundamental wave, i z1 and i z2 Represents a pair of mutually orthogonal harmonic components in the subspace corresponding to the third harmonic, and so on until the m-2nd harmonic, io1 Represents the harmonic component of the subspace corresponding to the mth harmonic.

[0112] Among them, the transformation matrix T VSD The subspace obtained by transforming the 1st and 2nd rows is the αβ subspace, to which the fundamental wave is mapped, and the α and β axes are a pair of mutually orthogonal fundamental wave components; the subspace obtained by transforming the 3rd and 4th rows is the z1z2 subspace, and the subspace obtained by transforming the 5th and 6th rows is the z3z4 subspace, and so on, the 3rd to m-2nd harmonics are located in these subspaces, and each subspace has a pair of mutually orthogonal harmonic components on its two axes; the o1 subspace is obtained by transforming the mth row, and the mth harmonic is located on the o1 axis. The fundamental wave and harmonics of the current, a total of n components, are transformed into n subspaces respectively.

[0113] In one embodiment, referring to Figure 4 In step S15, "each component difference generates a voltage reference value component through a corresponding current controller, and the sum of all voltage reference value components is used as the voltage reference value", including:

[0114] S151. For the fundamental wave and harmonics below m-2, each pair of orthogonal components mapped into the corresponding subspace is transformed into a rotating coordinate system of the corresponding frequency through Park transformation, and a pair of first DC components on the dq axes are obtained in each subspace. The difference between each first DC component and the reference value of the corresponding component is used to generate a first voltage reference value component through a PI controller.

[0115] S152. For the mth harmonic, the AC component mapped to an axis in the corresponding subspace is used, and the difference between the AC component and the reference value of the corresponding component is used to generate a second voltage reference value component through a PR controller.

[0116] S153. Obtain an α-axis component after inverse Park transformation of the first voltage reference value component, and use the sum of the α-axis component and the second voltage reference value component as the voltage reference value.

[0117] Among them, the fundamental wave and the 3~m-2th harmonics mapped to each subspace such as αβ, z1z2, z3z4 are transformed into the rotating coordinate system of the corresponding frequency through Park transformation. After Park transformation, a pair of DC components on the dq axis are obtained in each subspace. Each component is controlled by a PI controller, and the mth harmonic mapped to the o1 axis is controlled by a PR controller. The α-axis component obtained by the output of all PI controllers after inverse Park transformation and the output controlled by the PR controller are added as the voltage reference value of the motor.

[0118] The following is an introduction using an example of a method for suppressing torque ripple of a single-phase permanent magnet motor.

[0119] A four-pole, four-slot single-phase permanent magnet synchronous motor, the inverter used to drive the single-phase permanent magnet synchronous motor is as follows Figure 5 As shown, U dc Indicates bus voltage, C dc Represents bus capacitance, S A \S A ' and S B \S B ' represents four power switch tubes and their anti-parallel diodes, and M represents a single-phase permanent magnet synchronous motor.

[0120] At 1500rpm (revolutions per minute), the no-load back EMF waveform and FFT (Fourier transform) results of the single-phase permanent magnet synchronous motor are as follows: Figure 7 and Figure 8 shown.

[0121] The overall control block diagram of a single-phase permanent magnet synchronous motor is as follows: Fig. 9 As shown, the control method can be implemented in a single-chip microcomputer (or CPU, MCU, etc.) and its peripheral circuits. The motor speed n and rotor position θ are calculated from the output of the position sensor. The error between the given speed and the actual speed passes through a PI regulator, and then the input of the aforementioned lookup table is replaced by the load torque and the output of the speed PI regulator is put into a closed loop.

[0122] The single-phase current is obtained by sampling with an analog-to-digital converter (AD), and the single-phase current is software-shifted 4 times. Each phase shift makes the current phase lag by 2π / 5 electrical degrees, thus constructing a virtual 5-phase motor system.

[0123] The phase current of the virtual 5-phase motor is:

[0124]

[0125] The five-phase current components formed by phase shifting are decoupled in the five-phase vector space to obtain three subspaces. The transformation can be expressed as:

[0126] [i α i β i z1 i z2 i o1 ] T =T VSD [i1 i2 i3 i4 i5] T .

[0127] Transformation matrix T VSD for:

[0128]

[0129] Where α=2π / 5. The subspace obtained by the transformation of the 1st and 2nd rows of the above equation is the αβ subspace, to which the fundamental wave is mapped, and the α and β axes are a pair of mutually orthogonal fundamental wave components; the subspace obtained by the transformation of the 3rd and 4th rows is the z1z2 subspace, to which the third harmonic is mapped; the z1 and z2 axes are a pair of mutually orthogonal fundamental wave components; the o1 subspace is obtained by the transformation of the 5th row, and the 5th harmonic is located on the o1 axis. The virtual five-phase system and current decoupling are shown in the figure. Fig.10 and Fig.10 shown.

[0130] The orthogonal components of the fundamental wave and the third harmonic mapped to the αβ and Z1z2 subspaces are transformed to the synchronous rotating coordinate system and the triple frequency synchronous rotating coordinate system respectively through Park transformation. After Park transformation, a pair of DC components on the dq axis are obtained in the αβ and z1z2 subspaces. Each component is controlled by a PI controller, and the fifth harmonic mapped to the o1 axis is controlled by a PR controller. The output of all PI controllers is transformed by the inverse Park to obtain the α-axis component and the output controlled by the PR controller as the voltage reference value of the motor.

[0131] The simulation results of this example are as follows Figure 11-Figure 16 As shown in the figure, the motor speed and load torque are set to 750rpm and 0.3Nm (Newton meter) respectively. There is only fundamental current before 0.5s (seconds), and harmonic current is injected after 0.5s. Fig.11 , Fig.12 , Fig.13 and Fig.14 They are the waveforms of the reference value and actual value of the phase current, the fundamental wave of the phase current, the third harmonic, and the fifth harmonic. Fig.16 and Fig.16 The waveforms of shaft output torque, electromagnetic torque and speed are shown. It can be seen that the harmonic current extraction and control effect is good, the system steady-state response is good, and the torque pulsation and torque fluctuation are well suppressed.

[0132] Example 2

[0133] Fig.17 This is a structural schematic diagram of an electronic device shown in an example embodiment of the present disclosure, the electronic device includes a memory, a processor, and a computer program stored in the memory and used to run on the processor, and when the processor executes the computer program, the single-phase permanent magnet motor torque pulsation suppression method described in any of the above embodiments is implemented. Fig.17 The electronic device 90 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0134] like Fig.17As shown, the electronic device 90 may be in the form of a general-purpose computing device, for example, it may be a server device. The components of the electronic device 90 may include, but are not limited to: at least one processor 91, at least one memory 92, and a bus 93 connecting different system components (including the memory 92 and the processor 91).

[0135] The bus 93 includes a data bus, an address bus, and a control bus.

[0136] The memory 92 may include a volatile memory, such as a random access memory (RAM) 921 and / or a cache memory 922 , and may further include a read-only memory (ROM) 923 .

[0137] The memory 92 may also include a program tool 925 (or utility) having a set (at least one) of program modules 924, such program modules 924 including but not limited to: an operating system, one or more application programs, other program modules and program data, each of which or some combination may include an implementation of a network environment.

[0138] The processor 91 executes various functional applications and data processing by running the computer program stored in the memory 92, such as the method for suppressing torque pulsation of a single-phase permanent magnet motor provided in any of the above embodiments.

[0139] The electronic device 90 may also communicate with one or more external devices 94 (e.g., keyboards, pointing devices, etc.). Such communication may be performed via an input / output (I / O) interface 95. Furthermore, the electronic device 90 may also communicate with one or more networks (e.g., local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) via a network adapter 96. As shown, the network adapter 96 communicates with other modules of the electronic device 90 via a bus 93. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 90, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems, etc.

[0140] It should be noted that although several units / modules or sub-units / modules of the electronic device are mentioned in the above detailed description, this division is merely exemplary and not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more units / modules described above can be embodied in one unit / module. Conversely, the features and functions of one unit / module described above can be further divided into multiple units / modules to be embodied.

[0141] Example 3

[0142] An embodiment of the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, and when the program is executed by a processor, the method for suppressing torque pulsation of a single-phase permanent magnet motor provided in any of the above embodiments is implemented.

[0143] The readable storage medium may include but is not limited to: a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical storage device, a magnetic storage device or any suitable combination of the above.

[0144] Example 4

[0145] The embodiment of the present disclosure further provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-mentioned methods for suppressing torque pulsation of a single-phase permanent magnet motor.

[0146] Among them, the program code for executing the computer program product of the present disclosure can be written in any combination of one or more programming languages, and the program code can be executed completely on the user device, partially on the user device, as an independent software package, partially on the user device and partially on a remote device, or completely on the remote device.

[0147] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A method for suppressing torque pulsation of a single-phase permanent magnet motor, characterized in that: The single-phase permanent magnet motor torque pulsation suppression method comprises: Obtain the current motor current, and obtain a lookup table of the load torque and the corresponding motor current fundamental component and several odd-order harmonic component combinations; wherein the fundamental component and harmonic component combination is obtained with the goal of minimizing the pulsation of the shaft output torque; Extracting fundamental wave actual value and harmonic wave actual value from the current motor current; Taking a torque reference value as the value of the load torque, a fundamental wave reference value and a harmonic wave reference value are obtained based on the torque reference value and the lookup table; wherein the torque reference value is obtained by a speed regulator through a difference between a set speed and an actual speed; Respectively obtain component differences between the fundamental wave reference value and the harmonic reference value and the corresponding fundamental wave actual value and harmonic wave actual value; Each of the component differences generates a voltage reference value component through a corresponding current controller, and the sum of all the voltage reference value components is used as the voltage reference value. The switching signal of the single-phase inverter power device is controlled according to the voltage reference value.

2. The method for suppressing torque pulsation of a single-phase permanent magnet motor according to claim 1, characterized in that: The single-phase permanent magnet motor torque pulsation suppression method further includes: The no-load back EMF and cogging torque waveforms of the motor are obtained through electromagnetic simulation of the motor. The no-load back EMF is decomposed by Fourier to obtain the no-load back EMF expression containing the amplitude and phase information of the fundamental wave and each harmonic. Injecting several odd-order harmonics into the current to suppress torque ripple, and obtaining the current expression containing harmonics and the torque expression of the motor; According to the no-load back electromotive force expression, the current expression and the torque expression, the torque component generated by the interaction between the i-th harmonic of the back electromotive force and the j-th harmonic of the current is obtained; wherein i and j are both positive odd numbers; According to the no-load back electromotive force expression, the current expression, the torque expression, the torque component and the output condition expression, with the goal of minimizing the pulsation of the shaft output torque, the values ​​of the fundamental component and the combination of odd-order harmonic components of the current corresponding to each load torque are calculated and constructed into the lookup table; wherein the output condition expression indicates that the average value of the total torque output by the motor is equal to the load torque value of the motor.

3. The method for suppressing torque pulsation of a single-phase permanent magnet motor according to claim 2, characterized in that: The no-load back electromotive force expression, the current expression, the torque expression, the torque component and the output condition expression are expressed by the following formula: The shaft output torque pulsation is minimized as the target expressed as: Wherein, E0 represents the no-load back electromotive force, i represents the harmonic order of the back electromotive force, ψ i represents the harmonic amplitude of permanent magnet flux linkage, represents the initial phase of the back EMF harmonic, ω represents the electrical angular frequency of the motor, t represents time, i s represents the motor current including harmonics, Ω represents the mechanical angular velocity of the motor, T e represents the electromagnetic torque of the motor, T c is the cogging torque, T ij represents the torque component, T ampij represents the average value of the corresponding torque component generated by the i-th harmonic of the back electromotive force and the j-th harmonic of the current, Represents the average value of the total torque output by the motor, T L Indicates the load torque value of the motor.

4. The method for suppressing torque pulsation of a single-phase permanent magnet motor according to claim 1, characterized in that: The extracting of the fundamental wave actual value and the harmonic wave actual value from the current motor current comprises: The current motor current is virtualized as the phase current of the m-phase motor; wherein m is the highest order of the harmonics to be extracted, and m is an odd number greater than 1; The phase current is decoupled in an m-phase vector space to map the fundamental wave and several harmonics to n subspaces respectively; wherein one subspace corresponds to the fundamental wave or an odd-order harmonic, and n=(m+1) / 2.

5. The method for suppressing torque pulsation of a single-phase permanent magnet motor according to claim 4, characterized in that: The virtualizing the current motor current into the phase current of the m-phase motor includes: Performing m-1 phase shifts on the current motor current, each phase shift causes the phase of the current motor current to lag by an electrical angle of 2π / m to construct the m-phase motor, and obtaining the phase current of the m-phase motor; The m-phase vector space decoupling of the phase current to map the fundamental wave and several order harmonics to n subspaces respectively includes: The phase current is converted from the m-phase vector to the decoupled vector space through a transformation matrix; wherein, for the fundamental wave and harmonics below m-2, there is a pair of mutually orthogonal fundamental wave components or harmonic components on the two axes of the corresponding subspace; for the m-th harmonic, the m-th harmonic is located on one axis of the corresponding subspace.

6. The method for suppressing torque pulsation of a single-phase permanent magnet motor according to claim 5, characterized in that: The phase current of the m-phase motor, the phase current in the decoupled vector space, and the transformation matrix are expressed by the following formula: [i α i β i z1 i z2 … i ol ] T =T VSD [i1 i2 i3 … i m ] T ; α＝2π / m； Among them, i s Indicates the motor current containing harmonics, i1…i m represents the phase current of each phase, ω represents the electrical angular frequency of the motor, t represents time, m represents the number of phases of the virtual motor, f(ωt) represents the current motor current, T VSD represents the transformation matrix, [i α i β i z1 i z2 … i ol ] T represents the phase current in the decoupled vector space, i α and i β Represents a pair of mutually orthogonal fundamental wave components in the subspace corresponding to the fundamental wave, i z1 and i z2 Represents a pair of mutually orthogonal harmonic components in the subspace corresponding to the third harmonic, and so on until the m-2nd harmonic, i o1 Represents the harmonic component of the subspace corresponding to the mth harmonic.

7. The method for suppressing torque pulsation of a single-phase permanent magnet motor according to claim 5, characterized in that: Each of the component differences generates a voltage reference value component through a corresponding current controller, and the sum of all the voltage reference value components is used as the voltage reference value, including: For the fundamental wave and harmonics below m-2, each pair of orthogonal components mapped into the corresponding subspace is transformed into a rotating coordinate system of the corresponding frequency through Park transformation, a pair of first DC components on dq axes are obtained in each subspace, and a difference between each first DC component and a reference value of the corresponding component is used to generate a first voltage reference value component through a PI controller; For the mth harmonic, an AC component mapped to an axis in a corresponding subspace is used, and a difference between the AC component and a reference value of the corresponding component is used to generate a second voltage reference value component through a PR controller; The α-axis component obtained after the inverse Park transformation of the first voltage reference value component is used as the voltage reference value, and the sum of the α-axis component and the second voltage reference value component is used as the voltage reference value.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and used to run on the processor, characterized in that: When the processor executes the computer program, the method for suppressing torque pulsation of a single-phase permanent magnet motor according to any one of claims 1 to 7 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for suppressing torque pulsation of a single-phase permanent magnet motor according to any one of claims 1 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method for suppressing torque pulsation of a single-phase permanent magnet motor as described in any one of claims 1 to 7 is implemented.

Images