Torque ripple suppression method and control device of synchronous permanent magnet motor

Abstract

The invention discloses a torque ripple suppression method and control device based on compensation current negative feedback control, and the method comprises the steps: employing negative feedback control, and enabling a compensation current generation part to generate compensation current; back electromotive force is speculated according to an IPM motor voltage equation; harmonic components are separated from the d-axis counter electromotive force and the q-axis counter electromotive force; respectively calculating the magnetic flux harmonic amplitudes and phases of q-axis and d-axis magnetic steel; amplitude instructions and phase instructions of d-axis and q-axis compensation currents are calculated; separating the amplitude and the phase of a harmonic component from the d-axis actual current and the q-axis actual current; enabling the amplitude and phase of the current harmonic component to respectively follow the corresponding amplitude instruction and phase instruction through negative feedback control; and the output of the negative feedback control is injected into q-axis and d-axis current instructions, so that the torque ripple suppression control of the motor is realized. Through compensation current negative feedback control, the amplitude and phase of the harmonic content of the magnetic flux of the magnetic steel are automatically extracted, and the amplitude instruction and phase instruction of the compensation current are automatically generated.

Description

Technical Field

[0001] The present invention relates to a synchronous permanent magnet motor, and more particularly to a method and a control device for suppressing torque ripple used in torque control of a synchronous permanent magnet motor. Background Art

[0002] The synchronous permanent magnet motor is the heart of an electromechanical system, which realizes the conversion between electrical energy and mechanical energy, and generates torque through the interaction between the rotating magnetic field generated by the stator coil and the magnetic field of the rotor permanent magnet. If there is a torque ripple component during the operation of the synchronous motor, it will cause resonance and noise generation in the components connected to the motor, or reduce the position accuracy and speed accuracy of the servo motor, or damage other components; the representative reasons for generating torque ripple include the existence of harmonic components of the magnetic flux of the motor rotor permanent magnet, Figure 9 The figure shows the typical harmonic orders of the magnetic flux that generates torque ripple.

[0003] In the prior art, the torque ripple suppression method commonly used to solve the torque ripple phenomenon of the motor is: directly inject a compensation current, and use the ripple generated by the compensation current to cancel the original ripple to achieve the desired torque ripple cancellation effect (see Figure 10 , Figure 11 ).

[0004] Motor torque = original torque + original ripple + ripple generated by compensation current Or, inject a compensation voltage to indirectly generate a compensation current.

[0005] The above methods for suppressing torque ripple based on motor control technology include the feedforward control method - data table method using the compensation current Iqh* (see Figure 7 ) and the negative feedback control method using the compensation current Iqh* (see Figure 8 ).

[0006] The permanent magnet type synchronous motor control device disclosed in Japanese Patent Publication No. 3852289 has the problem that: the harmonic content and its phase of the magnetic flux of the permanent magnet used in the derivation of the compensation current are used as known conditions. However, for individual synchronous motors, the harmonic amplitude and its phase will deviate and are not fixed values; the motor control device disclosed in Japanese Patent Publication No. 7218700 has the problem that: the command generation unit uses a fixed command 0 or a data table. Since the harmonic components for each individual synchronous motor are not fixed values, the suppression effect on torque ripple will deviate; moreover, this patent corresponds to torque ripple caused by current harmonics and cannot be used for suppressing torque ripple caused by harmonic components of the magnetic flux of the permanent magnet; even if it is applied to suppressing torque ripple caused by harmonic components of the magnetic flux of the permanent magnet, this patent does not consider the phase deviation between the fundamental wave and the harmonic wave of the individual motor. Summary of the Invention

[0007] In the present invention, when suppressing the torque ripple control of a synchronous motor, due to the deviations in the magnet size and embedding position of individual motors, the magnitude and phase of the flux harmonic change, resulting in different torque ripple suppression effects for individual motors. In addition, different compensation currents are required when the motor load varies and the rotational speed changes. A novel torque ripple negative feedback control method is provided for torque ripple suppression of interior permanent magnet (IPM) motors, enabling good torque ripple suppression effects even if there are deviations in the magnets of individual motors.

[0008] The specific technical solution adopted by the present invention to solve the above technical problems is as follows: A torque ripple suppression method based on compensation current negative feedback control, characterized in that: A1. Adopt compensation current negative feedback control, and a compensation current generation unit generates the compensation current; A2. Estimate the back electromotive force according to the voltage equation of an interior permanent magnet synchronous motor (IPM motor); A3. Separate the harmonic components from the d-axis and q-axis back electromotive forces; A4. Calculate the amplitude and phase of the q-axis magnet flux harmonic; A5. Calculate the amplitude and phase of the d-axis magnet flux harmonic; A6. Calculate the amplitude commands and phase commands of the d-axis and q-axis compensation currents; A7. Separate the amplitudes and phases of the harmonic components from the actual d-axis and q-axis currents; A8. Make the amplitudes and phases of the current harmonic components follow the corresponding amplitude commands and phase commands respectively through negative feedback control; A9. The output of the negative feedback is injected into the q-axis and d-axis current commands to achieve torque ripple suppression control of the motor.

[0009] Good torque ripple suppression effects can be achieved when the magnitude and phase of the flux harmonic change due to the deviations in the magnet size and embedding position of individual motors, as well as when the motor load varies and the rotational speed changes.

[0010] A compensation current amplitude command generation unit is provided in the compensation current generation unit. In the compensation current amplitude command generation unit, the d-axis and q-axis components of the estimated back electromotive force are multiplied by the operators sin and cos with the motor rotation angle as the variable, respectively calculating the amplitude and phase of the d-axis magnet flux harmonic component and the amplitude and phase of the q-axis magnet flux harmonic component, and then respectively estimating the amplitude commands of the d-axis compensation current and the q-axis compensation current. This improves the torque ripple suppression effect when the magnitude of the magnet flux harmonic changes.

[0011] A compensation current phase command generation unit is provided in the compensation current generation unit. In the compensation current phase command generation unit, the d-axis and q-axis components of the estimated back electromotive force are respectively multiplied by the operators sin and cos that take the motor rotation angle as a variable, and the amplitudes and phases of the d-axis permanent magnet flux harmonic components and the amplitudes and phases of the q-axis permanent magnet flux harmonic components are respectively calculated. Then, the phase commands of the d-axis compensation current and the q-axis compensation current are respectively estimated. The suppression effect on the motor torque ripple when the phase of the permanent magnet flux harmonic changes is improved.

[0012] A phase control unit is provided in the compensation current generation unit. In the phase control unit, through negative feedback control, the phases of the actual currents on the d-axis and q-axis respectively follow the calculated phase commands; or the cosine of the difference between the phase command and the phase of the actual current is obtained and made to follow the target value of 0.5 for negative feedback control. The suppression effect on the motor torque ripple when the phase of the permanent magnet flux harmonic changes is improved.

[0013] In the compensation current amplitude command generation unit, the d-axis and q-axis components of the estimated back electromotive force are respectively subjected to band-pass filtering. By searching for the maximum value in one cycle or multiple cycles of the filtered signal, the maximum value is used as the amplitude of the permanent magnet flux harmonic; the filtered signal is divided by the amplitude, and then multiplied by the operators sin and cos that take the motor rotation angle as a variable to respectively calculate the phases of the d-axis and q-axis permanent magnet flux harmonic components. Then, the amplitude commands of the d-axis compensation current and the q-axis compensation current are respectively estimated. The suppression effect on the motor torque ripple when the amplitude of the permanent magnet flux harmonic changes is improved.

[0014] In the compensation current amplitude command generation unit, the d-axis and q-axis components of the estimated back electromotive force are respectively subjected to band-pass filtering. By searching for the maximum value in one cycle or multiple cycles of the filtered signal, the maximum value is used as the amplitude of the permanent magnet flux harmonic; the filtered signal is divided by the amplitude, and then multiplied by the operators sin and cos that take the motor rotation angle as a variable to respectively calculate the phases of the d-axis and q-axis permanent magnet flux harmonic components. Then, the phases of the d-axis compensation current and the phase commands of the q-axis compensation current are respectively estimated. The suppression effect on the motor torque ripple when the phase of the permanent magnet flux harmonic changes is improved.

[0015] In the compensation current generation unit, the speed or rotation angle of the motor is estimated using voltage and current instead of a speed sensor, and the generated speed and angle are used for the generation of the d-axis and q-axis compensation currents above.

[0016] The calculation formula for estimating the torque ripple of an interior permanent magnet synchronous motor (IPM motor) is expressed as follows.

[0017] Assuming only the 6th and 12th torque ripples are considered, and assuming that the d-axis and q-axis inductances are known and expressed as: Then the motor torque is expressed as: Where: ω m is the mechanical angular velocity, P n is the number of magnetic pole pairs of the permanent magnet, and the calculation formula for the electrical speed ω e is: ω e = P n ×ω m ; Inject the q-axis and d-axis compensation currents I q6h , I q12h , I d6h , I d12h to generate a new pulsation, and the new pulsation cancels out the original torque pulsation, so that the torque pulsation becomes 0; Making the torque pulsations in ② - ⑤ of formula (6) be 0 respectively, the compensation currents can be obtained as follows: .

[0018] Taking formulas (7a) and (7b) as examples, it can be further expressed as: Where: .

[0019] Another object of the present invention is to provide a torque pulsation suppression control device based on compensation current negative feedback control, including a compensation current negative feedback torque pulsation suppression control device, which is characterized in that: it adopts the torque pulsation suppression method based on compensation current negative feedback control described in one of the above technical solutions. When multiple compensation current generation parts are used, the multiple compensation current generation parts respectively generate multiple d-axis and q-axis compensation currents, and the multiple d-axis and q-axis compensation currents are respectively injected into the converted d-axis current output and q-axis current output of the current command conversion part of the compensation current negative feedback torque pulsation suppression control device to suppress multiple components of the torque pulsation.

[0020] The beneficial effect of the present invention is that it can automatically extract and calculate the harmonic content and phase of the permanent magnet magnetic flux and generate the amplitude command and phase command of the compensation current, and automatically calculate the amplitude command of the compensation current when the motor load and speed change, so as to maintain a good torque pulsation suppression effect. Brief Description of the Drawings

[0021] Figure 1 is a schematic diagram of the overall composition principle block diagram of the torque pulsation suppression method and control device based on compensation current negative feedback control of the present invention.

[0022] Figure 2 It is a schematic diagram of the principle block diagram of the first embodiment of the torque ripple suppression method and control device based on the compensation current negative feedback control of the present invention.

[0023] Figure 3 It is a schematic diagram of the principle block diagram of the second embodiment of the torque ripple suppression method and control device based on the compensation current negative feedback control of the present invention.

[0024] Figure 4 It is a schematic diagram of the principle block diagram of the third embodiment of the torque ripple suppression method and control device based on the compensation current negative feedback control of the present invention.

[0025] Figure 5 It is a schematic diagram of the principle block diagram of the fourth embodiment of the torque ripple suppression method and control device based on the compensation current negative feedback control of the present invention.

[0026] Figure 6 It is a schematic diagram of the principle block diagram of the fifth embodiment of the torque ripple suppression method and control device based on the compensation current negative feedback control of the present invention.

[0027] Figure 7 It is the compensation principle block diagram of the feedforward control method - data table method for compensating the compensation current of the synchronous motor torque ripple in the prior art qh *

[0028] Figure 8 It is the compensation principle block diagram of the negative feedback control method for compensating the compensation current I qh * of the synchronous motor torque ripple in the prior art.

[0029] Figure 9 It is a schematic diagram of the typical harmonic order of the rotor magnet flux that generates torque ripple in the synchronous motor.

[0030] Figure 10 It is a schematic diagram of the torque ripple compensation principle of the method for suppressing torque ripple by using motor control technology for the synchronous motor torque ripple in the prior art.

[0031] Figure 11 It is by using Figure 10 A schematic diagram of the torque ripple compensation effect obtained after the compensation technology method.

[0032] Figure 12 It is a schematic diagram of the search amplitude range period of the torque ripple suppression method and control device based on the compensation current negative feedback control of the present invention. Specific embodiments

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1: Figure 1 , Figure 2 In the illustrated embodiment, a torque ripple suppression method based on compensated current negative feedback control adopts the following torque ripple suppression control method: A1. Adopt compensated current negative feedback control, and a compensated current generation unit generates a compensated current; A2. Estimate the back electromotive force according to the voltage equation of an interior permanent magnet synchronous motor (IPM motor); A3. Separate the harmonic components from the d-axis and q-axis back electromotive forces; A4. Calculate the amplitude and phase of the q-axis permanent magnet flux harmonic; A5. Calculate the amplitude and phase of the d-axis permanent magnet flux harmonic; A6. Calculate the amplitude command and phase command of the d-axis and q-axis compensated currents; A7. Separate the amplitude and phase of the harmonic components from the actual d-axis and q-axis currents; A8. Make the amplitude and phase of the harmonic components of the current follow the corresponding amplitude command and phase command respectively through negative feedback control; A9. The output of the negative feedback is injected into the q-axis and d-axis current commands to achieve torque ripple suppression control of the motor.

[0035] A compensated current amplitude command generation unit is provided in the compensated current generation unit. For the compensated current amplitude command generation unit, the d-axis and q-axis components of the estimated back electromotive force are respectively multiplied by the operators sin and cos with the motor rotation angle as a variable to calculate the amplitude and phase of the d-axis permanent magnet flux harmonic component and the amplitude and phase of the q-axis permanent magnet flux harmonic component, and then the amplitude command of the d-axis compensated current and the amplitude command of the q-axis compensated current are respectively estimated.

[0036] A compensated current phase command generation unit is provided in the compensated current generation unit. For the compensated current phase command generation unit, the d-axis and q-axis components of the estimated back electromotive force are respectively multiplied by the operators sin and cos with the motor rotation angle as a variable to calculate the amplitude and phase of the d-axis permanent magnet flux harmonic component and the amplitude and phase of the q-axis permanent magnet flux harmonic component, and then the phase command of the d-axis compensated current and the phase command of the q-axis compensated current are respectively estimated.

[0037] The technical principle of torque ripple suppression in this embodiment is as follows.

[0038] First, the harmonics of the permanent magnet flux are defined as follows.

[0039] In the magnetic flux linkage where the permanent magnet flux couples to the UVW-phase coils, there are generally the 3rd, 5th, 7th, 9th, 11th, 13th harmonics, etc. The 3rd and 9th harmonics do not cause torque ripple and are not considered. The magnetic flux linkage can be expressed as: where: Φ1 is the fundamental wave amplitude; Φ5~Φ13 are the harmonic amplitudes; δ5~δ13 are the harmonic initial phases, ω e is the electrical angular velocity.

[0040] Then, the back electromotive force of the motor is described. It is the differential of the above magnetic flux linkage, so it can be expressed as: The back electromotive force of formula (2) is expressed in the stationary coordinate system UVW. After transformation in the rotating coordinate system dq, it can be expressed as: where: Φf is the main magnetic amplitude, ψfs5 = Φ5×cos(δ5), ψfc5 = Φ5×sin(δ5), ψfs7, ψfc7, ψfs11, ψfc11, ψfs13, ψfc13 and so on.

[0041] Then, the suppression of torque ripple of the permanent magnet embedded synchronous motor (IPM motor) is described.

[0042] Assume that only the 6th and 12th torque ripples are considered, and assume that the d-axis and q-axis inductances are known and expressed as: Then the motor torque is expressed as: where: ω m is the mechanical angular velocity, P n is the number of pole pairs of the permanent magnet, and the calculation formula for the electrical speed ω e is: ω e =P n ×ω m .

[0043] Inject the q-axis and d-axis compensation currents I q6h , I q12h , I d6h , I d12h to generate a new ripple, and the new ripple cancels out the original torque ripple, so that the torque ripple becomes 0: Making the torque ripples of ②~⑤ in formula (6) be 0 respectively, the compensation currents can be obtained as follows: .

[0044] Taking equations (7a) and (7b) as an example, they can be further expressed as: ; where: The above is the description of the technical principle for suppressing torque ripple of interior permanent magnet synchronous motor (IPM motor). Next, the specific calculation steps for suppressing its torque ripple are described: Step 1: Estimate the back electromotive force according to the voltage equation: Assuming that the inductances Ld and Lq are known as in equations (4a) and (4b), the back electromotive force can be calculated according to equation (10) as follows: where: Vd is the d-axis voltage, Vq is the q-axis voltage, Id is the d-axis current, Iq is the q-axis current, and R is the phase resistance of the motor; Step 2: Separate the harmonic components from the estimated d-axis and q-axis back electromotive forces. For example, the method for separating the q-axis component of the 6th harmonic is as follows: The red part in equation (12) is DC, and the other parts are AC. Therefore, if a LPF (low-pass filter) is applied to eqh_sincos, the DC part can be separated: ; Step 3: Calculate the amplitude and phase of the q-axis permanent magnet flux harmonic. Divide the back electromotive force obtained above by ω e . The amplitude of the harmonic component of the permanent magnet flux can be obtained according to the following formula. For example, the q-axis component of the 6th harmonic: ; Step 4: Process the back electromotive force component obtained in Step 2 to obtain the phase of the harmonic component of the permanent magnet flux: For example, for the 6th compensation current of the q-axis, its phase command is from equation (13): ; Step 5: Calculate the amplitude and phase of the d-axis permanent magnet flux harmonic. For the harmonic component of the d-axis permanent magnet flux, repeat Steps 2 and 3 for similar processing, and similarly its amplitude can be obtained: ; Step 6: Process the back electromotive force obtained in Step 2 to obtain the phase command of the harmonic component of the d-axis permanent magnet flux: ; Step 7: Calculate the amplitude command and phase command of the compensation current; For example, for the d-axis and q-axis commands of the 6th compensation current, substituting equations (14) to (17) into equations (9a) to (9d), the amplitude command and phase command can be obtained respectively.

[0045] Step 8: For the actual current of the motor, similar to the processing of equations (12) to (15), the amplitude and phase of the current harmonic components can be obtained.

[0046] For example, for the q-axis current iqh, the separation method of its 6th harmonic is as follows: ; The red part in equation (18) is DC, and the other parts are AC. Therefore, if iqh_sincos is applied with an LPF (low-pass filter), the DC part can be separated: ; From equation (19), the amplitude and phase of the 6th harmonic current of the q-axis are: ; Similarly, the amplitude and phase of the 6th harmonic current of the d-axis are: ; Step 9: Through negative feedback control, make the amplitude and phase of the harmonic currents of the q-axis and d-axis follow the amplitude command and phase command of the compensation currents of the q-axis and d-axis respectively.

[0047] For example, for the 6th compensation current, the following PI controller is used: ; where: y out is the output of the controller, e(t) is the input of the controller, such as e(t)=I q6h_amp∗ -i q6h , or e(t)=ζ q6h∗ -σ q6h , Kp is the proportional coefficient of the controller, k I is the integral coefficient of the controller.

[0048] Thus, the amplitude and phase of the q-axis current in equations (20a) to (20b) follow the amplitude command and phase command in equations (9a) to (9b) respectively; make the amplitude and phase of the d-axis current in equations (21a) to (21b) follow the amplitude command and phase command in equations (9c) to (9d) respectively; Step 10: Inject the output of the negative feedback in Step 9 into the q-axis and d-axis current commands to achieve the torque ripple suppression control of the motor; For example, for the q-axis injected current of the sixth compensation current, the outputs of the amplitude negative feedback controller and the phase negative feedback controller are respectively I q6h_PI , ζ q6h_PI , and their form is: ; Similarly, for the d-axis injected current of the sixth compensation current, the outputs of the amplitude negative feedback controller and the phase negative feedback controller are respectively I q6h_PI , ζ q6h_PI , and their form is: ; Step 11: For the generation of multiple compensation currents, the same processing as in Steps 2-10 can be performed.

[0049] Embodiment 2: Figure 1 , Figure 3 In the embodiments shown in

[0050] , for the phase control of the d-axis and q-axis in Step 9, it can also be achieved in the following manner. For example, for the q-axis component of the sixth compensation current: q6h_cmd Step 12-1: Calculate the unit trigonometric function I q6h_act of the q-axis compensation current (Formula 8a) and the unit trigonometric function I ; Step 12-2: Perform a multiplication operation on (Formula 25) and (Formula 26); Step 12-3: The second term in Formula (27) is a direct current, which is separated by an LPF filter; Step 12-4: Set the command value to 0.5, and through negative feedback control, make the separated value in the previous step follow the command value 0.5.

[0051] The negative feedback control of the amplitude of the harmonic component of the current and the injection of the obtained controller output into the d- and q-axis currents are the same as in Embodiment 1.

[0052] Embodiment 3: Figure 4 , Figure 12 In the embodiments shown in Figure 12), the maximum value is used as the amplitude of the permanent magnet flux harmonic; the filtered signal is divided by the amplitude, and then multiplied by the operators sin and cos with the motor rotation angle as the variable to calculate the phases of the permanent magnet flux harmonic components on the d-axis and q-axis respectively. Subsequently, the amplitude commands of the d-axis compensation current and the q-axis compensation current are respectively deduced; and the phase commands of the d-axis compensation current and the q-axis compensation current are respectively deduced. The rest is the same as in Embodiment 1 or Embodiment 2.

[0053] Embodiment 4: Figure 5 In the shown embodiment, multiple d-axis and q-axis compensation currents are respectively generated to suppress multiple components of the torque ripple. When multiple compensation current generation units are used, the multiple compensation current generation units respectively generate multiple d-axis and q-axis compensation currents, and the multiple d-axis and q-axis compensation currents respectively correspond to the converted d-axis current output and q-axis current output of the current command conversion unit of the compensation current negative feedback torque ripple suppression control device to suppress multiple components of the torque ripple. The rest is the same as in Embodiment 1 or Embodiment 2.

[0054] Embodiment 5: Figure 6 In the shown embodiment, the speed or rotation angle of the motor is deduced using voltage, current, etc. to replace the speed sensor, and the generated speed and angle are used for the generation of the above-mentioned d-axis and q-axis compensation currents. The rest is the same as in Embodiment 1 or Embodiment 2.

[0055] Embodiment 6: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 In the shown embodiment, a torque ripple suppression control device based on compensation current negative feedback control includes a compensation current negative feedback torque ripple suppression control device, and also includes one or more compensation current generation units, and adopts the torque ripple suppression method based on compensation current negative feedback control described in one of the above embodiments. The compensation current of each compensation current generation unit is injected into the output end of the current command conversion unit of the compensation current negative feedback torque ripple suppression control device and mixed with it, and then mixed with the current after conversion by the uvw / dq conversion unit of the compensation current negative feedback torque ripple suppression control device and injected into the current controller; the d-axis voltage Vd and q-axis voltage Vq outputs output by the current controller are injected into the compensation current generation unit, and the electrical rotation angle θe output by the position and speed calculation unit is respectively injected into the compensation current generation unit, dq / uvw conversion unit, and uvw / dq conversion unit. The electrical speed ω output by the position and speed calculation unit e is respectively injected into the compensation current generation unit and the controller command mixing input end.

[0056] Figure 1 The compensation current negative feedback torque ripple suppression control device shown in the figure includes a speed controller, a current controller, a current command generation unit, a dq / uvw conversion unit, an inverter, a uvw / dq conversion unit, a motor, a speed sensor, a position and speed calculation unit, and a compensation current generation unit. The speed controller receives command inputs. The speed controller is provided in the front stage of the current command generation unit, and the current controller, the dq / uvw conversion unit, and the inverter are sequentially provided in the rear stage of the current command generation unit. The current controller includes a d-axis current controller and a q-axis current controller. The dq / uvw conversion unit forms three-phase uvw after inversion by the inverter and respectively inputs them to the three-phase uvw input terminals of the motor and the uvw / dq conversion unit. After being converted by the uvw / dq conversion unit, the q-axis current Iq and the d-axis current Id are respectively output and fed back to the q-axis current Iq and d-axis current Id input terminals corresponding to the d-axis current controller and the q-axis current controller in the front stage of the dq / uvw conversion unit. The motor is equipped with a speed sensor and is connected to the position and speed calculation unit through the speed sensor. The speed sensor obtains the mechanical rotation angle of the motor. And outputs it to the position and speed calculation unit. The position and speed calculation unit is respectively connected to the dq / uvw conversion unit, the uvw / dq conversion unit, and the input terminal of the controller. The d-axis compensation current Idnh and the q-axis compensation current Iqnh of the compensation current generation unit are respectively injected into the converted d-axis command output Id* and the q-axis command output Iq* of the current command conversion unit and mixed with them. After being mixed with the d-axis current and the q-axis current converted by the uvw / dq conversion unit, they are respectively injected into the d-axis current controller and the q-axis current controller. The d-axis current and the q-axis current converted by the uvw / dq conversion unit are fed back and input to the compensation current generation unit. The d-axis voltage output by the d-axis current controller and the q-axis voltage output by the q-axis current controller are fed back and input to the compensation current generation unit. The electrical rotation angle θe output by the position and speed calculation unit is input to the compensation current generation unit.

[0057] Figure 5 As shown in the figure, the Figure 1 When multiple compensation current generation units are constituted by the compensation current generation unit scheme, the multiple compensation current generation units respectively generate their own d-axis compensation currents and q-axis compensation currents. The multiple d-axis compensation currents and q-axis compensation currents are respectively injected into the converted d-axis current output and q-axis current output of the current command conversion unit of the compensation current negative feedback torque ripple suppression control device. The d-axis current and the q-axis current converted by the uvw / dq conversion unit are fed back and input to the multiple compensation current generation units. The d-axis voltage output by the d-axis current controller and the q-axis voltage output by the q-axis current controller are fed back and input to the multiple compensation current generation units. The electrical rotation angle θe output by the position and speed calculation unit is input to the multiple compensation current generation units. Multiple components of torque ripple are suppressed.

[0058] Figure 6As shown, instead of using a speed sensor, the speed or rotation angle of the motor is estimated by voltage and current, and the generated speed and angle are used to generate the compensation currents for the d-axis and q-axis mentioned above. The d-axis voltage Vd and q-axis voltage Vq output by the d-axis current controller and q-axis current controller are respectively injected into the compensation current generation unit and the position and speed calculation unit. The electrical rotation angle θe output by the position and speed calculation unit is respectively injected into the compensation current generation unit, the dq / uvw conversion unit, and the uvw / dq conversion unit; the electrical speed ω output by the position and speed calculation unit e are respectively injected into the compensation current generation unit and the input mixing end of the controller command. The q-axis current Iq and d-axis current Id output by the uvw / dq conversion unit are respectively injected into the input mixing end of the compensation current generation unit and the q-axis current Iq and d-axis current Id corresponding to the d-axis current controller and q-axis current controller; the q-axis current Iq and d-axis current Id output by the uvw / dq conversion unit are respectively injected into the position and speed calculation unit.

[0059] Example 7: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 12 In the embodiment shown, the following steps are executed: B1 Search for the amplitude (see Figure 12 ): By comparing the numerical values of every two data points, the maximum value is obtained; if the search range is more than 1 cycle, the maximum value can definitely be obtained; B2 Divide the signal by the maximum value (amplitude) to obtain the unit trigonometric function; see formulas (25) and (26) in the above embodiment; B3 Regarding the phase, multiply two unit trigonometric functions; see formula (27) above; B4 Make the amplitude and phase of the harmonic components of the current follow the corresponding amplitude command and phase command respectively through negative feedback control to achieve torque ripple suppression; see formula (22) above B5 Inject the obtained controller output into the d and q axis currents; see formulas (23) and (24) above.

[0060] The above content and structure describe the basic principle, main features, and advantages of the product of the present invention, which should be understood by those skilled in the art. What is described in the above examples and specifications only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for suppressing torque pulsation of a synchronous permanent magnet motor, characterized in that: The following torque pulsation suppression control method is adopted; A1. Compensation current negative feedback control is adopted, and the compensation current generation unit generates the compensation current; A2. Estimate the back electromotive force based on the voltage equation of the magnetic steel embedded synchronous motor; A3. Separate the harmonic components from the d-axis and q-axis back EMF; A4. Calculate the amplitude and phase of the q-axis magnetic steel flux harmonics; A5. Calculate the amplitude and phase of the d-axis magnetic steel flux harmonics; A6. Calculate the amplitude command and phase command of the d-axis and q-axis compensation currents; A7. Separate the amplitude and phase of the harmonic components from the actual current of the d-axis and q-axis; A8. Make the amplitude and phase of the harmonic components of the current follow the corresponding amplitude command and phase command respectively through negative feedback control; A9. The output of negative feedback is injected into the q-axis and d-axis current commands to achieve torque pulsation suppression control of the motor.

2. The method for suppressing torque pulsation of a synchronous permanent magnet motor according to claim 1, characterized in that: A compensation current amplitude instruction generating unit is provided in the compensation current generating unit. In the compensation current amplitude instruction generating unit, the d-axis and q-axis components of the calculated back electromotive force are multiplied by operators sin and cos with motor rotation angle as variables, respectively, and the amplitude and phase of the d-axis magnetic steel flux harmonic component and the amplitude and phase of the q-axis magnetic steel flux harmonic component are calculated, and then the amplitude instruction of the d-axis compensation current and the amplitude instruction of the q-axis compensation current are calculated, respectively.

3. The method for suppressing torque pulsation of a synchronous permanent magnet motor according to claim 1, characterized in that: A compensation current phase command generating unit is provided in the compensation current generating unit. In the compensation current phase command generating unit, the d-axis and q-axis components of the calculated back electromotive force are multiplied by operators sin and cos with motor rotation angle as variables, respectively, and the amplitude and phase of the d-axis magnetic steel flux harmonic component and the amplitude and phase of the q-axis magnetic steel flux harmonic component are calculated, and then the phase command of the d-axis compensation current and the phase command of the q-axis compensation current are calculated, respectively.

4. The method for suppressing torque pulsation of a synchronous permanent magnet motor according to claim 1, characterized in that: A phase control unit is provided in the compensation current generating unit. In the phase control unit, the phases of the actual currents of the d-axis and the q-axis are respectively made to follow the calculated phase command through negative feedback control; or the cosine of the difference between the phase command and the actual current is obtained to make it follow the target value 0.5 to perform negative feedback control.

5. The method for suppressing torque pulsation of a synchronous permanent magnet motor according to claim 2, characterized in that: In the compensation current amplitude command generating section, bandpass filtering is applied to the d-axis and q-axis components of the calculated back electromotive force respectively, and the maximum value is searched for one or more cycles after the filtered signal, and the maximum value is used as the amplitude of the magnetic flux harmonic; the filtered signal is divided by the amplitude, and then multiplied with the operators sin and cos with the motor angle as the variable, to calculate the phase of the d-axis and q-axis magnetic flux harmonic components respectively, and then the amplitude command of the d-axis compensation current and the amplitude command of the q-axis compensation current are calculated respectively.

6. The method for suppressing torque pulsation of a synchronous permanent magnet motor according to claim 2 or 5, characterized in that: For the compensation current amplitude command generating unit, bandpass filtering is applied to the d-axis and q-axis components of the calculated back electromotive force respectively, and the maximum value is searched for one or more cycles after the filtered signal, and the maximum value is used as the amplitude of the magnetic flux harmonic; the filtered signal is divided by the amplitude, and then multiplied with the operators sin and cos with the motor angle as the variable, to calculate the phases of the d-axis and q-axis magnetic flux harmonic components respectively, and then the amplitude command of the d-axis compensation current and the phase command of the q-axis compensation current are calculated respectively.

7. The method for suppressing torque pulsation of a synchronous permanent magnet motor according to claim 1, characterized in that: In the compensation current generating unit, the speed or rotation angle of the motor is estimated using voltage and current instead of the speed sensor, and the generated speed and angle are used to generate the compensation current of the above d-axis and q-axis.

8. The method for suppressing torque pulsation of a synchronous permanent magnet motor according to claim 1, characterized in that: The calculation formula of the torque ripple of the magnetic steel embedded synchronous motor is as follows: Assume that only the 6th and 12th order torque ripples are considered, and assume that the d and q axis inductances are known and expressed as: The motor torque is then expressed as: Where: m is the mechanical angular velocity, P n is the number of magnetic pole pairs, electrical speed The calculation formula is ω e =P n ×ω m ; Inject q-axis and d-axis compensation current I q6h ,I q12h ,I d6h ,I d12h To generate a new torque pulsation, this new torque pulsation and the original torque pulsation cancel each other out, so that the torque pulsation becomes 0; If the torque ripples of ② to ⑤ in formula (6) are set to 0 respectively, the compensation current can be obtained as follows: 。 9. The method for suppressing torque ripple of a synchronous permanent magnet motor according to claim 8, characterized in that: The compensation current formula for torque ripple suppression of magnetic steel embedded synchronous motor is as follows: Taking formula (7a) and (7b) as examples, they can be further expressed as: in: 。 10. A torque pulsation suppression control device for a synchronous permanent magnet motor, comprising a compensation current negative feedback torque pulsation suppression control device, characterized in that: The torque pulsation suppression method based on the compensation current negative feedback control as described in one of claims 1 to 9 is adopted. When multiple compensation current generating units are used, the multiple compensation current generating units respectively generate multiple d-axis and q-axis compensation currents. The multiple d-axis and q-axis compensation currents respectively correspond to the converted d-axis current output and q-axis current output of the current command conversion unit injected into the compensation current negative feedback torque pulsation suppression control device, thereby suppressing multiple components of the torque pulsation.

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