Ripple current suppression method for bus capacitor of permanent magnet synchronous motor driver

Abstract

The invention discloses a ripple current suppression method for a bus capacitor of a permanent magnet synchronous motor driver. The method is applicable to a driver circuit connected with a permanent magnet synchronous motor, and specifically comprises the following steps: determining a phase of a virtual admittance connected in parallel with a bus capacitor based on a driver equivalent admittance model; dynamically matching the initial amplitude of the virtual admittance according to the equivalent admittance model of the driver and the power attribute of the permanent magnet synchronous motor; constructing an admittance amplitude adaptive mechanism; and determining an inverter switching tube control signal to suppress the ripple current. According to the suppression method, the initial amplitude of the virtual admittance can be dynamically matched according to the motor operation power state, the iteration efficiency of the algorithm during variable-speed operation is improved, an admittance amplitude self-adaptive mechanism can be constructed, the convergence speed and the anti-interference capability of the suppression process are considered, closed-loop control is formed by using voltage feedback, and the suppression efficiency is improved. And the stability of the ripple current suppression effect is ensured, so that the consistency of the ripple current suppression effect can be kept in a relatively wide power range.

Description

TECHNICAL FIELD

[0001] The application relates to a bus capacitor ripple current suppression method for a permanent magnet synchronous motor driver and belongs to the technical field of permanent magnet synchronous motor control. BACKGROUND

[0002] Permanent magnet synchronous motors have advantages such as high power density, high power factor and high efficiency, and have been widely used in the field of air conditioner compressors. An air conditioner compressor driver is usually composed of a rectifier, a power factor correction (PFC) converter and an inverter. The PFC converter can improve the power factor at the grid side and reduce the harmonic content of the input current at the grid side. A bus electrolytic capacitor is usually arranged between the PFC converter and the inverter, which is usually used to balance power and stabilize the bus voltage. However, the low tolerance of the electrolytic capacitor to ripple current has made it one of the key links affecting the reliability of the system. According to statistics, more than 60% of driver failures are caused by electrolytic capacitor aging. Therefore, how to effectively suppress the capacitor ripple current is the key to improving the operation reliability of the driving system.

[0003] At present, the bus capacitor ripple current suppression method for a permanent magnet synchronous motor driver mainly includes a hardware method and a software method. The hardware method suppresses the capacitor ripple current by adding additional hardware, which has a low cost performance. The software method can be divided into a harmonic injection method and an active damping method. The harmonic injection method compensates for the power difference on both sides of the bus by directly injecting harmonics, thereby suppressing the capacitor ripple current. The suppression effect of this method is often affected and limited by the bandwidth of the controller. The active damping method adjusts the overall characteristics of the system based on the equivalent damping model, has clear physical meaning and is convenient for parameter design. However, the traditional fixed damping method cannot meet the suppression requirements of the bus capacitor ripple current of the driver when the motor operates in a wide power range. SUMMARY

[0004] The application discloses a bus capacitor ripple current suppression method for a permanent magnet synchronous motor driver.

[0005] The bus capacitor ripple current suppression method for a permanent magnet synchronous motor driver in the application is suitable for a driver circuit connected to a permanent magnet synchronous motor, and the method specifically comprises the following steps. Based on a pre-established equivalent admittance model of the driver, the phase of a virtual admittance connected in parallel with the bus capacitor is determined according to the amplitude attribute of the bus capacitor ripple current. The initial amplitude of the virtual admittance is dynamically matched according to the equivalent admittance model of the driver and the power attribute of the permanent magnet synchronous motor. According to the virtual admittance and the amplitude attribute of the bus capacitor ripple current, the bus voltage of the driver circuit is indirectly represented based on the virtual admittance, an adaptive mechanism of the amplitude of the virtual admittance is constructed to determine the adaptive amplitude of the virtual admittance; According to the phase of the virtual admittance, the adaptive amplitude of the virtual admittance, the electrical parameters of the permanent magnet synchronous motor and the electrical parameters of the driver circuit, an inverter switch control signal is determined to control the working state of the switch tube of the inverter in the driver circuit and suppress the ripple current.

[0006] In some embodiments, the driver equivalent admittance model comprises a motor-side input admittance model and a bus capacitor admittance model, and the formula of the motor-side input admittance model is as follows:

[0007] Wherein: is the motor-side input admittance, s is a frequency domain operator, is the direct current component of the input current of the inverter in the driver circuit, is the direct current component of the bus voltage of the driver circuit, is the switching period of the inverter, e is the base of natural logarithm, is the equivalent sampling bus voltage direct current component, is the stator resistance of the permanent magnet synchronous motor, is the d-axis inductance of the permanent magnet synchronous motor, is the direct current component of the d-axis reference voltage of the permanent magnet synchronous motor, is the transfer function of the d-axis current regulator of the permanent magnet synchronous motor, is the rotor angular velocity of the permanent magnet synchronous motor, is the q-axis inductance of the permanent magnet synchronous motor, is the direct current component of the q-axis reference voltage of the permanent magnet synchronous motor, is the transfer function of the q-axis current regulator of the permanent magnet synchronous motor, is the direct current component of the d-axis current of the permanent magnet synchronous motor, is the direct current component of the d-axis voltage of the permanent magnet synchronous motor, is the direct current component of the q-axis current of the permanent magnet synchronous motor, is the direct current component of the q-axis voltage of the permanent magnet synchronous motor; The formula of the bus capacitor admittance model is as follows:

[0008] Wherein: is the bus capacitor admittance, Ca capacitance value of a bus capacitor in the driver circuit, an equivalent series resistance of the bus capacitor.

[0009] In some embodiments, the phase of the virtual admittance in parallel with the bus capacitor is determined according to an amplitude attribute of the bus capacitor ripple current based on the pre-established driver equivalent admittance model, including: an expression of the grid double-frequency ripple current amplitude of the bus capacitor after determining the virtual admittance in parallel according to the driver equivalent admittance model, the expression being specifically as follows:

[0010]

[0011] wherein: the grid double-frequency ripple current amplitude of the bus capacitor, a power of the permanent magnet motor, a virtual admittance in parallel with the bus capacitor, an actual amplitude of the virtual admittance, a phase of the virtual admittance, j an imaginary unit, a double grid angular frequency; and the phase of the virtual admittance in parallel with the bus capacitor is determined according to an amplitude attribute of the bus capacitor ripple current based on the expression of the grid double-frequency ripple current amplitude of the bus capacitor under the condition that a preset condition is met.

[0012] In some embodiments, the phase of the virtual admittance in parallel with the bus capacitor is determined according to an amplitude attribute of the bus capacitor ripple current based on the expression of the grid double-frequency ripple current amplitude of the bus capacitor, including: the phase of the virtual admittance in parallel with the bus capacitor is determined based on the expression of the grid double-frequency ripple current amplitude of the bus capacitor under the condition that the grid double-frequency ripple current amplitude of the bus capacitor is equal to a target ripple current amplitude and the amplitude of the virtual admittance is minimum; wherein the amplitude attribute of the bus capacitor ripple current includes the target ripple current amplitude, and the target ripple current amplitude is a preset fixed value.

[0013] In some embodiments, the initial amplitude of the virtual admittance is dynamically matched according to the driver equivalent admittance model and a power attribute of the permanent magnet synchronous motor, including: the initial amplitude is determined by performing fitting on the expression of the grid double-frequency ripple current amplitude of the bus capacitor after the virtual admittance is connected in parallel according to a least square method, and the formula is specifically as follows:

[0014] wherein the coordinates are the points on the surface corresponding to the expression of the grid double-line frequency ripple current amplitude of the bus capacitance after the parallel of the virtual admittance, represent different powers of the permanent magnet synchronous motor, represent different amplitudes of the virtual admittance, is the average of is the average of is the average of is the average of is the initial amplitude, is the normalized power of the permanent magnet synchronous motor, satisfies the following formula:

[0015] wherein is the reference voltage vector of the d-axis of the permanent magnet synchronous motor, is the reference voltage vector of the q-axis of the permanent magnet synchronous motor, is the current vector of the d-axis of the permanent magnet synchronous motor, is the current vector of the q-axis of the permanent magnet synchronous motor, is the power base value of the permanent magnet synchronous motor.

[0016] In some embodiments, the indirect representation of the ripple current based on the bus voltage of the driver circuit according to the virtual admittance and the amplitude attribute of the bus capacitance ripple current constructs an admittance amplitude adaptive mechanism to determine an adaptive virtual admittance amplitude, comprising: determining the target amplitude of the grid double-line frequency ripple voltage of the bus according to the target ripple current amplitude, and the specific formula is as follows:

[0017] wherein is the target amplitude of the grid double-line frequency ripple voltage of the bus, is the target ripple current amplitude; and performing iteration according to the target amplitude of the grid double-line frequency ripple voltage of the bus, the actual amplitude of the grid double-line frequency ripple voltage of the bus and the virtual admittance, and constructing the admittance amplitude adaptive mechanism to determine the adaptive virtual admittance amplitude.

[0018] In some embodiments, the actual amplitude of the grid double-line frequency ripple voltage of the bus satisfies the following expression:

[0019] wherein: is the actual amplitude of the grid double-line frequency ripple voltage of the bus, The iterative relationship of the admittance amplitude adaptive mechanism is as follows:

[0020] wherein: n is the algebra of iteration, n ≥1, is the forgetting factor, and is the preset iteration learning gain, is the virtual admittance amplitude correction quantity of the n-th iteration, n is the virtual admittance amplitude correction quantity of the n-1-th iteration, is the iteration error of the n-th iteration, n is the iteration error of the n-1-th iteration, is the actual amplitude of the grid double-line frequency ripple voltage of the bus at the n-th iteration, n is the running time of the driver circuit, is the initial amplitude, and the adaptive virtual admittance amplitude can be determined according to the initial amplitude and the virtual admittance amplitude correction quantity. n In some embodiments, the determination of the inverter switch tube control signal according to the phase of the virtual admittance, the adaptive virtual admittance amplitude, the electrical parameters of the permanent magnet synchronous motor and the electrical parameters of the driver circuit comprises: n determination of the power of the virtual admittance according to the phase of the virtual admittance, the adaptive virtual admittance amplitude and the electrical parameters of the driver circuit; t determination of the admittance voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor according to the power of the virtual admittance and the electrical parameters of the permanent magnet synchronous motor; determination of the inverter switch tube control signal according to the admittance voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor and the reference voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor.

[0021] In some embodiments, the calculation formula of the power of the virtual admittance is as follows: wherein:

[0022] is the power of the virtual admittance, is the phase of the grid double-line frequency voltage of the bus of the driver circuit, is the power of the virtual admittance, is the phase of the grid double-line frequency voltage of the bus of the driver circuit,

[0023] is the power of the virtual admittance, is the phase of the grid double-line frequency voltage of the bus of the driver circuit, is the power of the virtual admittance, is the phase of the grid double-line frequency voltage of the bus of the driver circuit.The calculation formula of the admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor is as follows:

[0024] Wherein, is the admittance voltage vector of the d-axis of the permanent magnet synchronous motor, is the admittance voltage vector of the q-axis of the permanent magnet synchronous motor.

[0025] In some embodiments, the determination of the inverter switch tube control signal according to the admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor and the reference voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor comprises: determining the reference voltage vector of the a-axis and the b-axis of the permanent magnet synchronous motor based on inverse Park transformation according to the admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor and the reference voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor; determining the inverter switch tube control signal through space vector pulse width modulation according to the reference voltage vector of the a-axis and the b-axis of the permanent magnet synchronous motor.

[0026] The beneficial effects of the present application are: the permanent magnet synchronous motor driver bus capacitor ripple current suppression method in the embodiments of the present application can dynamically match the initial amplitude of the virtual admittance according to the motor operating power state, improve the iteration efficiency of the algorithm during variable speed operation, and can construct an admittance amplitude adaptive mechanism with a forgetting factor, so as to balance the convergence speed and anti-interference ability of the ripple current suppression process, and at the same time, the voltage vector is used to form a control signal to control the inverter switch tube, and the voltage feedback is performed to the admittance amplitude adaptive mechanism to form a closed loop control, so as to ensure the stability of the ripple current suppression effect, so that the consistency of the ripple current suppression effect can be maintained in a wide power range. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is one of the flowcharts of the permanent magnet synchronous motor driver bus capacitor ripple current suppression method in the embodiments of the present application; Figure 2 is a circuit structure schematic diagram of the driver circuit in the embodiments of the present application; Figure 3 is a flowchart of the permanent magnet synchronous motor driver bus capacitor ripple current suppression method in the embodiments of the present application; Figure 4 is a corresponding relationship thermodynamic diagram between the virtual admittance amplitude, the ripple current amplitude and the virtual admittance phase under a plurality of different permanent magnet synchronous motor powers in the embodiments of the present application; Figure 5is the three-dimensional surface thermal diagram corresponding to the expression of the grid double-frequency ripple current amplitude of the bus capacitor in the embodiment of the application; Figure 6 is the fourth flowchart of the bus capacitor ripple current suppression method of the permanent magnet synchronous motor driver in the embodiment of the application; Figure 7 is the fourth flowchart of the bus capacitor ripple current suppression method of the permanent magnet synchronous motor driver in the embodiment of the application; Figure 8 is the fifth flowchart of the bus capacitor ripple current suppression method of the permanent magnet synchronous motor driver in the embodiment of the application; Figure 9 is one of the experimental result diagrams corresponding to embodiment 1; Figure 10 is one of the experimental result diagrams corresponding to embodiment 1; Figure 11 is one of the experimental result diagrams corresponding to embodiment 1; Figure 12 is one of the experimental result diagrams corresponding to embodiment 1; Figure 13 is one of the experimental result diagrams corresponding to embodiment 1; Figure 14 is one of the experimental result diagrams corresponding to embodiment 1.

[0028] wherein: U g , external power grid; 11, rectifier; 12, Boost power factor corrector; D1, rectifier diode; D2, rectifier diode; D3, rectifier diode; D4, rectifier diode; L P , boost inductor; S P , switch tube; D P , correction diode; C M , bus capacitor; INV, inverter; M, permanent magnet synchronous motor. DETAILED DESCRIPTION

[0029] Please refer to Figure 1 The bus capacitor ripple current suppression method of the permanent magnet synchronous motor driver in the embodiment of the application is suitable for a driver circuit connected to a permanent magnet synchronous motor, and the above method specifically comprises the following steps: Step 01: Based on the pre-established equivalent admittance model of the driver, the phase of the virtual admittance connected in parallel with the bus capacitor is determined according to the amplitude attribute of the bus capacitor ripple current.

[0030] Specifically, for the driver circuit connected to the permanent magnet synchronous motor in the embodiment of the application, the circuit structure can be referred to Figure 2, the driver circuit specifically includes a rectifier 11, a Boost power factor corrector 12 (hereinafter referred to as PFC), a bus capacitor C M and an inverter INV four parts, and is connected with a permanent magnet synchronous motor M. Among them, the rectifier 11 introduces power from the external power grid U g , which specifically includes a plurality of rectifier diodes arranged in the same direction to form a positive output end and a negative output end, in Figure 2 the case shown, the rectifier includes four rectifier diodes D1~D4. The PFC includes a boost inductor L P , a switch tube S P and a correction diode D P three parts, wherein the switch tube S P may be selected as a bipolar transistor. The bus capacitor C M may generally be selected as a small electrolytic capacitor. The bus capacitor C M and the specific connection mode of the PFC are as follows: the first end of the boost inductor L P is connected to the positive output end of the rectifier 11, the second end of the boost inductor L P is connected to the anode of the correction diode D P and the collector of the switch tube S P , the cathode of the correction diode D P is connected to the anode of the bus capacitor C M , the cathode of the bus capacitor C M is connected to the negative output end of the rectifier 11, in addition, the negative output end of the rectifier 11 is also connected to the emitter of the switch tube S P , and the base of the switch tube S P is introduced with a corresponding control signal to realize the control of the switch tube S P on-off. The inverter INV includes a plurality of inverter switch tubes, which can generally be MOS, IGBT and other devices, in terms of connection relationship, the input end of the inverter INV is generally directly connected between the two poles of the bus capacitor C M , and the permanent magnet synchronous electrode M is also connected to the output end of the inverter INV, and the bus capacitor C M is directly connected in parallel on the DC bus of the driver circuit.

[0031] Then on this basis, the bus capacitor ripple current suppression method for the permanent magnet synchronous motor driver suitable for the above-mentioned driver circuit in the embodiment of the application, first establishes the equivalent admittance model of the driver, and on the basis of the model, according to the ripple current amplitude attribute of the bus capacitor itself, determines the phase of the virtual admittance in parallel with the bus capacitor. The core of this step is to build the equivalent admittance model of the driver, which provides the calculation basis for the whole method, and at the same time, the fixed phase of the virtual admittance can be determined based on the model, which provides the data basis for generating the inverter switch tube control signal subsequently.

[0032] Specifically, in certain embodiments, the equivalent admittance model of the driver generally includes a motor side input admittance model and a bus capacitor admittance model. The above-mentioned equivalent admittance model mainly describes the virtual admittance in parallel with the bus capacitor, and the motor side input admittance model and the bus capacitor admittance model respectively describe the admittance exhibited by the bus capacitor close to the permanent magnet synchronous motor side and the admittance exhibited by the bus capacitor close to the driver circuit DC bus side. The mathematical formula of the motor side input admittance model is as follows:

[0033] Among them, is the motor side input admittance, s is the frequency domain operator, is the DC component of the input current of the inverter in the driver circuit, is the DC component of the bus voltage of the driver circuit, is the switching period of the inverter, e is the base of natural logarithm, is the equivalent sampled bus voltage DC component, is the stator resistance of the permanent magnet synchronous motor, is the d-axis inductance of the permanent magnet synchronous motor, is the DC component of the d-axis reference voltage of the permanent magnet synchronous motor, is the transfer function of the d-axis current regulator of the permanent magnet synchronous motor, is the rotor angular velocity of the permanent magnet synchronous motor, is the q-axis inductance of the permanent magnet synchronous motor, is the DC component of the q-axis reference voltage of the permanent magnet synchronous motor, is the transfer function of the q-axis current regulator of the permanent magnet synchronous motor, is the DC component of the d-axis current of the permanent magnet synchronous motor, is the DC component of the d-axis voltage of the permanent magnet synchronous motor, is the DC component of the q-axis current of the permanent magnet synchronous motor, is the DC component of the q-axis voltage of the permanent magnet synchronous motor.

[0034] And for the bus capacitance admittance model, the formula is as follows:

[0035] Wherein: is the bus capacitance admittance, C is the capacitance value of the bus capacitance, is the equivalent series resistance of the bus capacitance.

[0036] The frequency domain operator involved in the above two formulas s Generally, the grid frequency of the input driver can be used, and specific embodiments can be referred to as follows.

[0037] Further, please refer to Figure 3 In some embodiments, step 01 specifically includes: Step 011: According to the driver equivalent admittance model, determine the expression of the grid double-frequency ripple current amplitude of the bus capacitance after parallel virtual admittance; Step 012: Based on the expression of the grid double-frequency ripple current amplitude of the bus capacitance, according to the amplitude attribute of the bus capacitance ripple current, determine the phase of the virtual admittance in parallel with the bus capacitance under the condition of meeting the preset condition.

[0038] Specifically, on the basis of the above embodiments, when the driver equivalent admittance model has been determined, the specific phase fixed value of the virtual admittance in parallel with the bus capacitance can be obtained based on the above model, using the calculation process of the grid double-frequency ripple current amplitude of the bus capacitance after parallel virtual admittance, and combining the attribute parameters of the bus capacitance itself.

[0039] Then first, for step 011, the calculation of the grid double-frequency ripple current amplitude of the bus capacitance after parallel virtual admittance, exemplarily, under the condition of ignoring the inverter loss, the expression is as follows:

[0040] Wherein is the grid double-frequency ripple current amplitude of the bus capacitance, is the normalized power of the permanent magnet motor, is the virtual admittance in parallel with the bus capacitance, j is the imaginary unit, is the double grid angular frequency, The whole can act as the frequency domain operator of the equivalent admittance model in the above embodiments.

[0041] For the in the above formula, the calculation formula is as follows:

[0042] in This is the actual amplitude of the virtual admittance. The phase of the virtual admittance.

[0043] Then, in the above formula and Two items, that is, by using This frequency domain operator can be substituted into the equivalent admittance model in the above implementation to obtain the result.

[0044] In some embodiments, step 012 further includes: Based on the expression for the amplitude of the second harmonic ripple current of the bus capacitor grid, the phase of the virtual admittance connected in parallel with the bus capacitor is determined when the amplitude of the second harmonic ripple current of the bus capacitor grid is equal to the target ripple current amplitude and the amplitude of the virtual admittance is minimized. The amplitude attribute of the bus capacitor ripple current includes the target ripple current amplitude, which is a preset fixed value.

[0045] Specifically, based on the expression for the grid second harmonic ripple current amplitude of the bus capacitor after parallel virtual admittance has been determined in the above embodiments, the amplitude attribute of the bus capacitor ripple current can be obtained by consulting the bus capacitor's manual or other publicly available information, including the target amplitude of the bus capacitor grid second harmonic ripple current (corresponding to the target ripple current amplitude). For example, it was found through research that... Figure 2 The target ripple current amplitude of the bus capacitor used in the circuit shown is... It is 1.287A.

[0046] For example, the amplitude of the grid second harmonic ripple current in the bus capacitor Compared with the target ripple current amplitude found When they are equal, based on the above expression for the amplitude of the grid's second-harmonic ripple current after parallel virtual admittance and the formula for virtual admittance, a thermodynamic diagram showing the correspondence between the virtual admittance amplitude, ripple current amplitude, and virtual admittance phase under multiple different permanent magnet synchronous motor powers can be drawn, such as... Figure 4 As shown. It is worth noting that... Figure 4 In the case shown, the power of the permanent magnet synchronous motor The figure shows the normalized power after normalization calculation. It illustrates the thermodynamic relationship between the virtual admittance amplitude, ripple current amplitude, and virtual admittance phase under four power conditions: 0.4 pu, 0.6 pu, 0.8 pu, and 1 p.u. It can be observed that the virtual admittance amplitude varies under the four power conditions. At its minimum, it has a common phase, specifically 0.245 pu. Considering the consistency of the suppression effect of the permanent magnet synchronous motor driver bus capacitor ripple current suppression method in the above embodiment when operating over a wide power range, 0.245 pu can be used as a fixed value for the phase of the above virtual admittance, thereby providing a data basis for the subsequent process of determining the inverter switching control signal.

[0047] Please continue reading. Figure 1 In some embodiments, the method for suppressing ripple current of the permanent magnet synchronous motor driver bus capacitor further includes: Step 02: Based on the equivalent admittance model of the driver and the power properties of the permanent magnet synchronous motor, dynamically match the initial amplitude of the virtual admittance.

[0048] Specifically, based on the driver equivalent admittance model determined in the above embodiments, the initial amplitude of the virtual admittance connected in parallel across the bus capacitor can be dynamically matched using this model and the power attributes of the permanent magnet synchronous motor. According to the driver equivalent admittance model in the above embodiments, the virtual admittance needs to change with the power of the permanent magnet synchronous motor to maintain the stability of the bus capacitor ripple current. Therefore, by fitting the power-virtual admittance relationship included in the expression for the second harmonic ripple current amplitude of the bus capacitor obtained from the driver equivalent admittance model, a relatively optimal solution for dynamically matching the initial amplitude of the virtual admittance based on the power of the permanent magnet synchronous motor can be achieved.

[0049] Therefore, based on this, step 02 specifically includes: The expression for the magnitude of the grid second harmonic ripple current of the bus capacitor after parallel virtual admittance is fitted using the least squares method to determine the initial magnitude.

[0050] Specifically, for the specific implementation of the above fitting, for example, when the phase of the virtual admittance is 0.245 pu, according to the expression for the amplitude of the grid second harmonic ripple current of the bus capacitor after parallel virtual admittance in the above embodiment, a three-dimensional surface heat map describing the relationship between the power of the permanent magnet synchronous motor, the amplitude of the virtual admittance, and the amplitude of the bus capacitor ripple current can be formed, such as... Figure 5 As shown, and Figure 5 The target ripple current amplitude of the bus capacitor is shown in the figure. The plane corresponding to (1.287A). Then, according to the least squares method, based on the above expression and surface diagram, for the coordinate points... Perform least squares fitting, where This indicates different power ratings for permanent magnet synchronous motors, which correspond to... Figure 5 middle Coordinates on the axis represents the different amplitude of the virtual admittance, that is, corresponding to Figure 5 the coordinate on the axis, and the specific fitting method is as follows:

[0051] wherein is the average value of is the average value of is the initial amplitude of the virtual admittance, is the normalized power of the permanent magnet synchronous motor, and the calculation method of the normalized power is shown in the following formula:

[0052] wherein, is the reference voltage vector of the d-axis of the permanent magnet synchronous motor, is the reference voltage vector of the q-axis of the permanent magnet synchronous motor, is the current vector of the d-axis of the permanent magnet synchronous motor, is the current vector of the q-axis of the permanent magnet synchronous motor, is the power base value of the permanent magnet synchronous motor, and each of the above-mentioned voltage vectors and current vectors can be obtained by direct measurement, and the power base value of the permanent magnet synchronous motor is the power attribute of the permanent magnet synchronous motor, which can be obtained from the nameplate or working manual of the permanent magnet synchronous motor.

[0053] In this way, regardless of the actual working power of the permanent magnet synchronous motor, the initial amplitude of the virtual admittance can be dynamically matched to the relatively optimal value through the above-mentioned method, which can provide a relatively optimal iteration starting point for generating an adaptively changed admittance amplitude through iteration, thereby greatly shortening the convergence time, and also being able to minimize the fluctuation of the iteration error in the iteration process, improving the operation efficiency and stability of the iteration process.

[0054] Please continue to refer to Figure 1 The bus capacitor ripple current suppression method of the permanent magnet synchronous motor driver in the embodiment of the application further comprises: Step 03: According to the amplitude attribute of the virtual admittance and the bus capacitor ripple current, the ripple current is indirectly represented based on the bus voltage of the driver circuit, and an admittance amplitude adaptive mechanism is constructed to determine the adaptive virtual admittance amplitude.

[0055] ​​​Specifically, on the basis of the above-mentioned embodiments, further, according to the definition of admittance, the amplitude attribute of the bus capacitor ripple current can be used to indirectly represent the bus capacitor ripple current by using the bus voltage of the driver circuit, and then further taking the initial amplitude of the virtual admittance determined in the above-mentioned embodiments as the iteration starting point, the iteration error is calculated by using the bus voltage of the driver circuit while introducing the iteration learning gain, so as to form a closed-loop negative feedback correction after forming the inverter switch tube control signal subsequently, in addition, in order to avoid the decline of anti-interference ability caused by the accumulation of historical errors, a forgetting factor can be further introduced, and finally an admittance amplitude adaptive mechanism based on iterative calculation is constructed, so as to determine the virtual admittance amplitude with adaptive variation characteristics in real time based on the current working state of the driver circuit and the permanent magnet synchronous motor, and provide a data basis for generating the inverter switch tube control signal subsequently.

[0056] Then further, please refer to Figure 6 , step 03 specifically includes: Step 031: determining the target amplitude of the grid double-frequency ripple voltage of the bus according to the target ripple current amplitude; Step 032: performing iteration according to the target amplitude of the grid double-frequency ripple voltage of the bus, the actual amplitude of the grid double-frequency ripple voltage of the bus and the virtual admittance, and constructing an admittance amplitude adaptive mechanism to determine the adaptive virtual admittance amplitude.

[0057] Specifically, for the method of indirectly representing the bus capacitor ripple current by using the bus voltage of the driver circuit, the target ripple current amplitude, the driver equivalent admittance model and the definition of admittance in the above-mentioned embodiments are mainly based on, and the specific formula is as follows:

[0058] Among them, is the target amplitude of the grid double-frequency ripple voltage of the bus, is the target ripple current amplitude.

[0059] Then based on the bus capacitor admittance model in the driver equivalent admittance model, the above formula can also be rewritten as:

[0060] And for the construction process of the admittance amplitude adaptive mechanism, the calculation of the iteration error needs the actual amplitude of the grid double-frequency ripple voltage of the bus in addition to the target amplitude of the grid double-frequency ripple voltage of the bus. Then based on the expression of the grid double-frequency ripple current amplitude of the bus capacitor in the above-mentioned embodiments, combined with the definition of admittance, the following formula can be obtained:

[0061] wherein is the actual amplitude of the grid double frequency ripple voltage of the busbar.

[0062] Then the iterative relationship of the admittance amplitude adaptive mechanism constructed on this basis is as follows:

[0063] wherein: n is the algebra of iteration, n ≥1, is the forgetting factor, and is the preset iteration learning gain, is the virtual admittance amplitude correction amount of the n-th iteration, n is the virtual admittance amplitude correction amount of the n-1-th iteration, is the iteration error of the n-th iteration, n is the iteration error of the n-1-th iteration, is the actual amplitude of the grid double frequency ripple voltage of the busbar at the n-th iteration, n is the actual amplitude of the grid double frequency ripple voltage of the busbar at the n-1-th iteration, is the initial amplitude of the virtual admittance, which is dynamically matched according to the method provided in the above-mentioned embodiments, n is the running time of the driver circuit, and the iteration error is a function of the running time of the driver circuit , so that the virtual admittance amplitude correction amount n including the iteration error and the actual amplitude of the grid double frequency ripple voltage of the busbar at the n-th iteration is also a function of t . t In particular, for the actual amplitude of the grid double frequency ripple voltage of the busbar, the iteration starting point is n , which is calculated when the initial amplitude of the virtual admittance is taken as t , that is satisfies:

[0064]

[0065] Further, for the iteration error, the iteration starting point should be a constant function with respect to the running time t , which is specifically:

[0066] ​​​​​And according to the iterative relationship, the iteration starting point of the amplitude of the virtual admittance is the initial amplitude of the virtual admittance , when n =1, according to the iterative definition, the virtual admittance amplitude correction amount of the first n -1 iteration should be 0, and the amplitude of the virtual admittance in the first iteration (i.e. corresponding to the adaptive virtual admittance amplitude) is the initial amplitude of the virtual admittance n . And the amplitude of the virtual admittance in the second n iteration is the sum of the virtual admittance amplitude correction amount of the first -1 iteration and the virtual admittance amplitude correction amount of the second -1 iteration.

[0067] In this way, by constructing the admittance amplitude adaptive mechanism, an adaptive and changing virtual admittance amplitude can be generated, so that the ripple current can approach the target ripple current amplitude, and a forgetting factor is introduced, so that the convergence time of data processing and the overall anti-interference ability of the ripple current suppression process can be considered. In addition, since the ripple current is indirectly represented based on the bus voltage, the iteration error can directly represent the difference between the actual amplitude of the bus grid double-frequency ripple voltage and the target amplitude. In the subsequent control of the inverter operating state by using the inverter switch tube control signal, the current of the bus capacitor will change, which will be fed back to the iteration error through the above-mentioned indirect representation relationship, forming a negative feedback closed loop, so as to drive the admittance amplitude adaptive mechanism to adaptively correct the value of the virtual admittance amplitude again, thereby ensuring that the actual amplitude of the bus capacitor ripple current can be stabilized near the target ripple current amplitude, and finally forming the suppression effect of the ripple current.

[0068] Please continue to refer to Figure 1 , the bus capacitor ripple current suppression method of the permanent magnet synchronous motor driver in the embodiment of the application further comprises: Step 04: determining the inverter switch tube control signal according to the phase of the virtual admittance, the adaptive virtual admittance amplitude, the electrical parameters of the permanent magnet synchronous motor and the electrical parameters of the driver circuit, to control the working state of the switch tube of the inverter in the driver circuit and suppress the ripple current.

[0069] Specifically, on the basis of the above-mentioned embodiment, based on the logical basis of the equivalent admittance model of the driver, the dynamic matching of the initial amplitude of the virtual admittance can be realized on the basis of the determination of the phase of the virtual admittance, and further the adaptive adjustment of the actual amplitude of the virtual admittance can be realized. Then, the control signal for controlling the working state of each switch tube of the inverter can be generated by using the phase of the virtual admittance and the adaptively adjusted virtual admittance amplitude, combined with the current, voltage and other parameters of the driver circuit and the permanent magnet synchronous motor, and finally the suppression effect of the ripple current can be realized.

[0070] Please refer toFigure 7 In some embodiments, step 04 specifically comprises: Step 041: determining the power of the virtual admittance according to the phase of the virtual admittance, the adaptive virtual admittance amplitude, and the electrical parameters of the driver circuit; Step 042: determining the admittance voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor according to the power of the virtual admittance and the electrical parameters of the permanent magnet synchronous motor; Step 043: determining the inverter switch tube control signal according to the admittance voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor and the reference voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor.

[0071] Specifically, for the determination process of the inverter switch tube control signal, the power of the virtual admittance needs to be determined first, and then the admittance voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor is determined.

[0072] For the power of the virtual admittance, the formula is as follows:

[0073] Wherein P is the power of the virtual admittance, is the phase of the grid double-frequency voltage of the bus of the driver circuit, and in addition, is the DC component of the bus voltage of the driver circuit, is the actual amplitude of the grid double-frequency ripple voltage of the bus.

[0074] And on this basis, the calculation formula of the admittance voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor is as follows:

[0075] Wherein: is the admittance voltage vector of the d-axis of the permanent magnet synchronous motor, is the admittance voltage vector of the q-axis of the permanent magnet synchronous motor, and in addition, is the current vector of the d-axis of the permanent magnet synchronous motor, is the current vector of the q-axis of the permanent magnet synchronous motor.

[0076] After the admittance voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor is determined, the admittance voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor is further superimposed on the reference voltage vector of the d-axis and q-axis of the permanent magnet synchronous motor, and the inverter switch tube control signal is obtained by further operation based on the superimposed amount, finally realizing the suppression of the ripple current.

[0077] Please refer to Figure 8 In some embodiments, step 043 further comprises: Step 0431: determining the reference voltage vector of the permanent magnet synchronous motor α-axis and β-axis based on the inverse Park transformation according to the admittance voltage vector of the permanent magnet synchronous motor d-axis and q-axis and the reference voltage vector of the permanent magnet synchronous motor d-axis and q-axis; Step 0432: determining the inverter switch control signal through space vector pulse width modulation according to the reference voltage vector of the permanent magnet synchronous motor α-axis and β-axis.

[0078] Specifically, on the basis of the above-mentioned embodiments, for the reference voltage vector of the permanent magnet synchronous motor d-axis and q-axis, generally obtained by cooperating with the speed controller, the current controller and the position observer matched with the permanent magnet synchronous motor. For example, in the process of operation of the permanent magnet synchronous motor, the rotor angular velocity and the rotor position angle of the motor can be measured through the position observer, and the current vector of the d-axis and the current vector of the q-axis can be obtained through the Clark transformation and the Park transformation based on the two measurement results. Then, the known rotor speed reference value of the permanent magnet synchronous motor is subtracted from the measured rotor angular velocity , and the difference obtained is passed through the speed controller to generate the current reference vector of the d-axis and the current reference vector of the q-axis . Then, the current reference vector of the d-axis is subtracted from the current vector of the d-axis , and the difference obtained is passed through the current controller to generate the reference voltage vector of the d-axis , and the reference voltage vector of the q-axis can be obtained in the same way. The α-axis and the β-axis of the permanent magnet synchronous motor belong to the execution layer coordinate system, which is connected to the SVPWM hardware, while the d-axis and the q-axis belong to the regulation layer coordinate system, which is connected to the ripple current suppression method in the above-mentioned embodiments. The two coordinate systems can be converted to each other through the Park transformation or the inverse Park transformation, so that the regulation instruction and the execution signal can be converted to each other.

[0079] After the admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor and the reference voltage vector are obtained, the two can be directly superimposed, and the d-axis and q-axis voltage vectors obtained by superimposing are further converted into the reference voltage vectors of the α-axis and the β-axis based on the inverse Park transformation. This step is to enable the d-axis and q-axis voltage vectors to be recognized and applied in the subsequent space vector pulse width modulation (SVPWM) process. For the space vector pulse width modulation (SVPWM), a separately arranged SVPWM hardware is generally relied on. The SVPWM hardware takes the d-axis and q-axis voltage vectors obtained by superimposing as inputs to perform instruction conversion, so as to obtain an inverter switch control signal. The control signal includes a PWM signal for each switch tube gate included in the inverter, so as to control the on-off state of each switch tube in the inverter, and further control the working state of the entire inverter and the permanent magnet synchronous motor and the driver circuit, and finally realize the suppression effect on the ripple current. Moreover, as mentioned in the above embodiment, when the working state of the inverter and the permanent magnet synchronous motor and the driver circuit changes, the current of the bus capacitor will change. The change is indirectly represented by the relationship between the bus voltage and the ripple current and fed back to the iteration error, forming a negative feedback closed loop, so that the adaptive mechanism of the admittance amplitude adaptively modifies the value of the virtual admittance amplitude again, ensures that the actual amplitude of the bus capacitor ripple current can be stabilized near the target ripple current amplitude, and finally forms the suppression effect of the ripple current.

[0080] Next, the technical effect of the method for suppressing the bus capacitor ripple current of the permanent magnet synchronous motor driver in the above embodiment is illustrated by Example 1.

[0081] Example 1 The method for suppressing the bus capacitor ripple current of the permanent magnet synchronous motor driver in the above embodiment is verified on a cascaded Boost PFC converter permanent magnet compressor driving system experimental platform. The parameters of the experimental platform are as follows: external grid voltage 220 Vrms, grid frequency 50 Hz, bus voltage 350 V, stator resistance of the permanent magnet synchronous motor 0.78 Ω, direct-axis inductance 5.4 mH, quadrature-axis inductance 8.4 mH, rotor flux 0.11 Wb, number of pole pairs 3, moment of inertia 0.0003 kg·m², rated power 1200 W, controller bandwidth 500 Hz, bus capacitor capacitance 379.3 μF, equivalent series resistance of the bus capacitor 303.51 mΩ, and inverter switching frequency 10 kHz.

[0082] When the motor operates at the rated power of 1200 W, the experimental comparison results are shown in Figure 9 , Figure 10 and Figure 11 . Wherein the horizontal grid division of each grid represents 1 s. Figure 9 Figure 10 ​The transverse each grid indicates 10 ms, The waveform of the bus capacitance grid double frequency ripple current, The waveform of the bus capacitance grid double frequency ripple current, The waveform of the bus capacitance grid double frequency ripple current, Figure 9 And Figure 10 It can be seen that, in the above embodiment, the bus capacitance grid double frequency ripple current suppression method enables the current capacitance and the bus voltage fluctuation is significantly reduced. Referring to Figure 11 , Figure 11 The bus capacitance grid double frequency ripple current amplitude is represented, and the maximum amplitude of the capacitance grid double frequency ripple current is 3.180 A before the method is enabled, and the maximum amplitude of the capacitance grid double frequency ripple current is reduced to 1.286 A after the method is enabled, which is basically consistent with the target amplitude of the ripple current 1.287 A, thereby proving the effectiveness of the bus capacitance grid double frequency ripple current suppression method of the permanent magnet synchronous motor drive in the above embodiment.

[0083] When the motor works in the range of 0.6-1 times the rated power (i.e. 720W-1200W), the experimental comparison results are as shown in Figure 12 And Figure 13 , P g The waveform of the DC component of the motor grid side power, The waveform of the bus voltage of the drive circuit, The current waveform of the bus capacitance, and the transverse each grid indicates the time length of 10s. Then according to Figure 12 It can be seen that, before the above method is enabled, the ripple current of the bus capacitance and the fluctuation of the bus voltage are increased with the increase of the grid side power. Further combining Figure 13 It can be seen that, after the above method is enabled, in the process of dynamic variable load, the amplitude difference of the capacitance grid double frequency ripple current is 2.57 A, which is about twice the target amplitude 1.287 A, that is, the capacitance grid double frequency ripple current can be effectively suppressed near the target ripple current amplitude (1.287 A), and the amplitude difference of the bus voltage is also stabilized at about 10.28 V.

[0084] Further, taking 120W as a step, the experiment is carried out again in the power range of 0.4-1.2 times the rated power (480W-1200W), and the experimental comparison results are as shown in Figure 14As shown, under different grid-side power conditions, after the above method is enabled, the capacitor grid double-frequency ripple current can always be effectively suppressed near the target ripple current amplitude (1.287A), thereby proving that the application can quickly achieve suppression of the bus capacitor ripple current in a wide power range, thereby ensuring the stability of the bus capacitor ripple current.

[0085] The above is only a preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above with a preferred embodiment, it is not intended to limit the application. Any person skilled in the art can make minor changes or modifications to the above disclosed technical content without departing from the scope of the application, and any simple modification, equivalent replacement and improvement of the above embodiments, as long as it does not deviate from the technical solution of the application, and is within the spirit and principles of the application, shall be within the protection scope of the application.

Claims

1. A method for bus capacitor ripple current suppression for permanent magnet synchronous motor drives, the method is applicable to a drive circuit connected to a permanent magnet synchronous motor, characterized in that, The method comprises: determining the phase of the virtual admittance in parallel with the bus capacitor according to the amplitude attribute of the bus capacitor ripple current based on the pre-established driver equivalent admittance model; dynamically matching the initial amplitude of the virtual admittance according to the driver equivalent admittance model and the power attribute of the permanent magnet synchronous motor; constructing an admittance amplitude adaptive mechanism to determine the adaptive virtual admittance amplitude based on the bus voltage of the driver circuit indirectly representing the ripple current according to the virtual admittance and the amplitude attribute of the bus capacitor ripple current; determining the inverter switch control signal to control the working state of the switch tube of the inverter in the driver circuit and suppress the ripple current according to the phase of the virtual admittance, the adaptive virtual admittance amplitude, the electrical parameters of the permanent magnet synchronous motor and the electrical parameters of the driver circuit.

2. The method of claim 1, wherein, The driver equivalent admittance model comprises a motor side input admittance model and a bus capacitor admittance model, and the formula of the motor side input admittance model is as follows: wherein: is the motor-side input admittance, s is the frequency domain operator, is the DC component of the input current of the inverter in the drive circuit, is the DC component of the bus voltage of the drive circuit, is the switching period of the inverter, e is the base of the natural logarithm, is the equivalent sampled bus voltage DC component, is the stator resistance of the permanent magnet synchronous motor, is the d-axis inductance of the permanent magnet synchronous motor, is the DC component of the d-axis reference voltage of the permanent magnet synchronous motor, is the transfer function of the d-axis current regulator of the permanent magnet synchronous motor, is the rotor angular velocity of the permanent magnet synchronous motor, is the q-axis inductance of the permanent magnet synchronous motor, is the DC component of the q-axis reference voltage of the permanent magnet synchronous motor, is the transfer function of the q-axis current regulator of the permanent magnet synchronous motor, is the DC component of the d-axis current of the permanent magnet synchronous motor, is the DC component of the d-axis voltage of the permanent magnet synchronous motor, is the DC component of the q-axis current of the permanent magnet synchronous motor, is the DC component of the q-axis voltage of the permanent magnet synchronous motor; The formula of the bus capacitor admittance model is as follows: wherein: Cbus is the bus capacitance, C Cbus is the bus capacitance, Rbus is the equivalent series resistance of the bus capacitor.

3. The method of claim 2, wherein, The method comprises: determining the phase of the virtual admittance in parallel with the bus capacitor according to the amplitude attribute of the bus capacitor ripple current based on the pre-established driver equivalent admittance model; wherein: is the grid double-line frequency ripple current amplitude of the bus capacitor, is the normalized power of the permanent magnet motor, is the virtual admittance in parallel with the bus capacitor, is the actual amplitude of the virtual admittance, is the phase of the virtual admittance, j is the imaginary unit, is the double grid angular frequency; and determining the expression of the grid double-frequency ripple current amplitude of the bus capacitor after the parallel virtual admittance according to the driver equivalent admittance model, and the expression is specifically as follows:

4. The method of claim 3, wherein, determining the phase of the virtual admittance in parallel with the bus capacitor according to the amplitude attribute of the bus capacitor ripple current based on the pre-established driver equivalent admittance model; The method comprises: determining the phase of the virtual admittance in parallel with the bus capacitor according to the amplitude attribute of the bus capacitor ripple current based on the pre-established driver equivalent admittance model; 5. The method of claim 4, wherein, The method comprises: determining the phase of the virtual admittance in parallel with the bus capacitor according to the amplitude attribute of the bus capacitor ripple current based on the pre-established driver equivalent admittance model; wherein the coordinates is the expression of the grid double frequency ripple current amplitude of the bus capacitance after parallelizing the virtual admittance, denotes different powers of the permanent magnet synchronous machine, denotes different amplitudes of the virtual admittance, is the average of is the average of is the average of is the average of is the initial amplitude, is the normalized power of the permanent magnet synchronous machine, satisfies the following formula: wherein, is a reference voltage vector for the d-axis of the permanent magnet synchronous motor, is a reference voltage vector for the q-axis of the permanent magnet synchronous motor, is a current vector for the d-axis of the permanent magnet synchronous motor, is a current vector for the q-axis of the permanent magnet synchronous motor, is a power base value for the permanent magnet synchronous motor.

6. The method of claim 5, wherein, The amplitude attribute of the bus capacitor ripple current comprises the target ripple current amplitude, and the target ripple current amplitude is a preset fixed value. The method comprises: performing fitting on the expression of the grid double-frequency ripple current amplitude of the bus capacitor after the parallel virtual admittance according to the least square method to determine the initial amplitude, and the formula is specifically as follows: The method comprises: determining the target amplitude of the grid double-frequency ripple voltage of the bus according to the target ripple current amplitude, and the specific formula is as follows: wherein is a target amplitude of a grid double frequency ripple voltage of the busbar, is the target ripple current amplitude; and The target amplitude of the grid double-frequency ripple voltage of the bus, the actual amplitude of the grid double-frequency ripple voltage of the bus, and the virtual admittance are iterated to construct the adaptive mechanism of the amplitude of the admittance to determine an adaptive amplitude of the virtual admittance.

7. The method of claim 6, wherein, The actual amplitude of the grid double-frequency ripple voltage of the bus satisfies the following expression: wherein: is the actual amplitude of the grid double frequency ripple voltage of the busbar; The iterative relationship corresponding to the adaptive mechanism of the amplitude of the admittance is as follows: wherein: n is an iteration, n ≥ 1, is a forgetting factor, and is a preset iterative learning gain, is a virtual admittance amplitude correction quantity of the mth n iteration, is a virtual admittance amplitude correction quantity of the mth n -1 iteration, is an iteration error of the mth n -1 iteration, is an iteration error of the mth n iteration, is an actual amplitude of a grid double-frequency ripple voltage of the bus at the mth n iteration, t is a running time of the driver circuit, is the initial amplitude, and the adaptive virtual admittance amplitude can be determined according to the initial amplitude and the virtual admittance amplitude correction quantity.

8. The method of claim 7, wherein, The determination of the inverter switch control signal according to the phase of the virtual admittance, the adaptive amplitude of the virtual admittance, the electrical parameters of the permanent magnet synchronous motor, and the electrical parameters of the driver circuit comprises: The power of the virtual admittance is determined according to the phase of the virtual admittance, the adaptive amplitude of the virtual admittance, and the electrical parameters of the driver circuit. The admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor is determined according to the power of the virtual admittance and the electrical parameters of the permanent magnet synchronous motor. The inverter switch control signal is determined according to the admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor and the reference voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor.

9. The method of claim 8, wherein, The calculation formula of the power of the virtual admittance is as follows: wherein: is the power of the virtual admittance, is the phase of the mains double-line frequency voltage of the bus of the driver circuit; The calculation formula of the admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor is as follows: wherein: is the admittance voltage vector for the d-axis of the permanent magnet synchronous machine, is the admittance voltage vector for the q-axis of the permanent magnet synchronous machine.

10. The method of claim 8, wherein, The determination of the inverter switch control signal according to the admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor and the reference voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor comprises: The reference voltage vector of the α-axis and the β-axis of the permanent magnet synchronous motor is determined according to the admittance voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor and the reference voltage vector of the d-axis and the q-axis of the permanent magnet synchronous motor based on inverse Park transformation. The inverter switch control signal is determined according to the reference voltage vector of the α-axis and the β-axis of the permanent magnet synchronous motor through space vector pulse width modulation.

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