A drive control method for a permanent magnet synchronous motor without electrolytic capacitor

Abstract

The present invention provides a drive control method for a permanent magnet synchronous motor without an electrolytic capacitor. The method comprises the following steps: using a bandpass filter to extract harmonics from a DC bus voltage value collected from a permanent magnet synchronous motor drive system without an electrolytic capacitor, and obtaining harmonics of different frequencies; then weighted summing is performed on the harmonics of different frequencies to obtain a correction coefficient; then, the correction coefficient is used to correct a reference voltage output by a controller of the permanent magnet synchronous motor without an electrolytic capacitor, and obtaining a control voltage; finally, using an inverter in the permanent magnet synchronous motor drive system to modulate the control voltage, and generating a drive control signal to drive and control the permanent magnet synchronous motor without an electrolytic capacitor; the method can effectively improve the quality of the input current and enhance the stability of the system.

Description

Technical Field

[0001] The present invention relates to the field of permanent magnet motor drive control, and in particular to a drive control method for a permanent magnet synchronous motor without an electrolytic capacitor. Background Art

[0002] The reliability, operating life, and power density of permanent magnet motor drive control systems have gradually become the focus of attention. Electrolytic capacitors in permanent magnet motors are core components of traditional motor drives and are used to stabilize the DC bus voltage and filter the input current. However, they have problems such as large size, short life, and the risk of explosion. In contrast, film capacitors have significant advantages such as long life, small size, and high power density. Therefore, the development of "electrolytic capacitor-free drive system" technology, which replaces electrolytic capacitors with small-capacity film capacitors, is of great significance for extending the overall service life of the system and improving system reliability. However, since the capacitance of film capacitors in electrolytic capacitor-free motor drive systems is significantly lower than that of electrolytic capacitors, the system is prone to instability under heavy load / low line impedance conditions, and the quality of the input current is also significantly reduced.

[0003] In order to solve this problem, the prior art provides a control method for a permanent magnet synchronous motor without electrolytic capacitors based on active damping injection. The method is based on collecting grid input power and inverter output power, establishing an active damping control strategy, adding an RD damping circuit to the active damping control strategy, performing decoupling calculation on the RD damping circuit, obtaining decoupling parameters, and fully decoupling control of the d-axis component and the q-axis component of the synchronous motor according to the decoupling parameters; the focus of the method is to reduce the difficulty of obtaining voltage and current control instructions in the control system without affecting the control accuracy and performance of the entire system; however, when the method is used for suppressing grid-side current harmonics in a non-electrolytic capacitor motor system, it will cause an increase in machine-side harmonics and its power decoupling circuit is relatively complex, increasing the size of the equipment, which is inconsistent with the development trend of low cost and miniaturization of non-electrolytic capacitor frequency conversion systems; there is also provided a non-electrolytic capacitor based on multi-port impedance optimization. A harmonic suppression method for a capacitive permanent magnet synchronous motor drive system is proposed. The impedance control voltage at the machine side port and the impedance control voltage at the grid side port are obtained by calculation. The entropy weighted TOPSIS method is used to calculate the optimal angle of the impedance control voltage at the machine-grid side port. The impedance control voltage at the machine-grid side port is synthesized into a coordinated voltage, which is decomposed into the coordinated voltage d-axis component and q-axis component, and then superimposed on the dq-axis voltage given to obtain the controlled dq-axis voltage given. The adjusted αβ-axis voltage given is obtained by inverse Park transform, and the pulse control signal of the inverter is obtained by SVPWM control, thereby achieving harmonic suppression on the machine-grid side of the drive system. The focus of this method is that the proposed algorithm realizes coordinated suppression of harmonics on the machine-grid side. However, this method mainly performs impedance reshaping on the inherent harmonics near the resonant frequency, which may have limited effect on harmonic control of other frequencies, and the complex control strategy increases the complexity of the system. Summary of the Invention

[0004] The present invention provides a drive control method for a permanent magnet synchronous motor without an electrolytic capacitor, the purpose of which is to improve the input current quality and the stability of the system under heavy load / low line impedance conditions.

[0005] In order to achieve the above object, the present invention provides a drive control method for a permanent magnet synchronous motor without an electrolytic capacitor, comprising:

[0006] Step 1: collecting the DC bus voltage value of the electrolytic capacitor-free permanent magnet synchronous motor drive system;

[0007] Step 2: Using a bandpass filter to extract harmonics from the DC bus voltage to obtain harmonics of different frequencies;

[0008] Step 3: Perform weighted summation on harmonics of different frequencies to obtain a correction coefficient;

[0009] Step 4, using the correction coefficient to correct the reference voltage output by the electrolytic capacitor-free permanent magnet synchronous motor controller to obtain a control voltage;

[0010] Step 5: Use the inverter in the electrolytic capacitor-free permanent magnet synchronous motor drive system to modulate the control voltage to generate a drive control signal to drive and control the electrolytic capacitor-free permanent magnet synchronous motor.

[0011] Furthermore, the bandpass filter has a center frequency of 6kf. g The bandpass filter, the transfer function of the bandpass filter G BPF,k (s) is:

[0012]

[0013] Where s represents the Laplace operator, ω c，k represents the bandwidth frequency of the kth harmonic bandpass filter, ω g Indicates the input / grid angular frequency, represents the compensation phase for the kth harmonic, k = 1, 2, 3, ....

[0014] Furthermore, the DC bus voltage value is subjected to harmonic extraction using a bandpass filter, and the calculation expressions for harmonics of different frequencies are obtained as follows:

[0015] u dck =G BPF,k (s)u dc

[0016] Among them, u dck Indicates the kth harmonic of the DC bus voltage, u dc Indicates the DC bus voltage.

[0017] Furthermore, the calculation expression of the correction coefficient is:

[0018]

[0019] Among them, γ represents the correction coefficient, g k represents the weighting coefficient of the kth harmonic, and N represents the frequency of the harmonic.

[0020] More specifically, step 4 includes:

[0021] When the electrolytic capacitor-free permanent magnet synchronous motor controller is implemented on the dq axis, the reference voltage output by the dq axis is corrected using the correction coefficient to obtain the control voltage of the dq axis;

[0022] When the electrolytic capacitor-free permanent magnet synchronous motor controller is implemented on the αβ axis, the reference voltage output by the αβ axis is corrected using the correction coefficient to obtain the control voltage of the αβ axis.

[0023] Furthermore, the calculation expression of the control voltage of the dq axis is:

[0024]

[0025] in, Respectively represent the reference voltage of dq axis output, Represent the control voltages of the dq axes respectively.

[0026] Furthermore, the calculation expression of the control voltage of the αβ axis is:

[0027]

[0028] in, Respectively represent the reference voltage output by the α and β axes, They represent the control voltages of the α and β axes respectively.

[0029] More specifically, the electrolytic capacitor-free permanent magnet synchronous motor controller includes:

[0030] a first PI control unit, a second PI control unit, and a third PI control unit;

[0031] The first PI control unit is used to process the expected speed of the permanent magnet synchronous motor without electrolytic capacitor and the actual speed of the permanent magnet synchronous motor without electrolytic capacitor to obtain a q-axis current reference value;

[0032] The second PI control unit is used to process the q-axis current and the q-axis current reference value of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system to obtain a reference voltage of the q-axis output;

[0033] The third PI control unit is used to process the d-axis current and the d-axis current reference value of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system to obtain a reference voltage of the d-axis output.

[0034] Furthermore, the q-axis current and d-axis current of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system are obtained by transforming the input current of the permanent magnet synchronous motor without electrolytic capacitor. The transformation expression is:

[0035]

[0036] Among them, i u 、i v 、i w They represent the input current of each phase of the permanent magnet synchronous motor without electrolytic capacitor, θ represents the rotor flux angle, i d 、i q They represent the d-axis current and g-axis current of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system respectively.

[0037] The above solution of the present invention has the following beneficial effects:

[0038] The present invention uses a bandpass filter to extract harmonics from the collected DC bus voltage value of the electrolytic capacitor-free permanent magnet synchronous motor drive system to obtain harmonics of different frequencies; then weighted summation is performed on the harmonics of different frequencies to obtain a correction coefficient; then the correction coefficient is used to correct the reference voltage output by the electrolytic capacitor-free permanent magnet synchronous motor controller to obtain a control voltage; finally, the control voltage is modulated by the inverter in the electrolytic capacitor-free permanent magnet synchronous motor drive system to generate a drive control signal to drive and control the electrolytic capacitor-free permanent magnet synchronous motor; compared with the prior art, the present invention extracts different harmonic components of the DC bus voltage, calculates the voltage reference correction coefficient, and uses the correction coefficient to adjust the original reference voltage of the motor controller, thereby broadening the stability domain of the electrolytic capacitor-free drive system under low line impedance / heavy load conditions, and can effectively improve the input current quality and enhance the system stability.

[0039] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a driving control flow chart of an embodiment of the present invention;

[0041] Figure 2 A topological structure diagram of a permanent magnet synchronous motor drive system without electrolytic capacitors according to an embodiment of the present invention;

[0042] Figure 3 This is a block diagram of the drive control of a permanent magnet synchronous motor without electrolytic capacitors in an embodiment of the present invention;

[0043] Figure 4 This is a simulation result diagram of the permanent magnet synchronous motor drive control method without using electrolytic capacitors;

[0044] Figure 5 The figure shows the simulation results of the drive control method of permanent magnet synchronous motor without electrolytic capacitor. DETAILED DESCRIPTION

[0045] To make the technical problems, technical solutions, and advantages to be solved by the present invention more clear, the following is a detailed description with reference to the accompanying drawings and specific embodiments. It is obvious that the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0046] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to a locking connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0048] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0049] In view of the existing problems, the present invention provides a drive control method for a permanent magnet synchronous motor without an electrolytic capacitor.

[0050] like Figure 1 As shown, an embodiment of the present invention provides a drive control method for a permanent magnet synchronous motor without an electrolytic capacitor, comprising:

[0051] Step 1: collecting the DC bus voltage value of the electrolytic capacitor-free permanent magnet synchronous motor drive system;

[0052] Step 2: Using a bandpass filter to extract harmonics from the DC bus voltage to obtain harmonics of different frequencies;

[0053] Step 3: Perform weighted summation on harmonics of different frequencies to obtain a correction coefficient;

[0054] Step 4, using the correction coefficient to correct the reference voltage output by the electrolytic capacitor-free permanent magnet synchronous motor controller to obtain a control voltage;

[0055] Step 5: Use the inverter in the electrolytic capacitor-free permanent magnet synchronous motor drive system to modulate the control voltage to generate a drive control signal to drive and control the electrolytic capacitor-free permanent magnet synchronous motor.

[0056] The electrolytic capacitor-free permanent magnet synchronous motor in the embodiment of the present invention is a three-phase synchronous motor, and the topology of its drive system includes a three-phase voltage source on the grid side, a filter inductor L f , uncontrolled rectifier bridge, DC inductor L dc , DC resistance R dc , film capacitor C dc , three-phase inverter, such as Figure 2 As shown;

[0057] The negative terminals of the three-phase voltage sources on the grid side are connected to the output terminals of the three-phase grid, and the positive terminals of the three-phase voltage sources on the grid side are connected to the filter inductor L. f The input terminal is connected to the filter inductor L f The output end of the uncontrolled rectifier bridge is connected to the midpoint of the bridge arm, and one end of the bridge arm of the uncontrolled rectifier bridge is connected to the DC inductor L dc The first end of the DC inductor L dc The second end of the DC resistor R dc The first end is connected to the DC resistor R dc The second end of the film capacitor C dc The first end of the three-phase inverter is connected to the first end of the three-phase inverter, and the other end of the bridge arm of the uncontrolled rectifier bridge is connected to the film capacitor C dc The second end of the three-phase inverter is connected to the second end of the three-phase inverter, the three-phase output end of the three-phase inverter is connected to the three-phase input end of the permanent magnet synchronous motor without electrolytic capacitor, and the control end of the three-phase inverter is connected to the output end of the permanent magnet synchronous motor controller without electrolytic capacitor.

[0058] In the embodiment of the present invention, the filter inductor L f It consists of three inductors, the first end of each inductor is connected to each phase of the grid-side voltage source, and the second end of each inductor is connected to the midpoint of the bridge arm of the uncontrolled rectifier bridge.

[0059] In the embodiment of the present invention, the uncontrolled rectifier bridge includes six diodes, wherein two diodes form a group of bridge arms, forming three groups of bridge arms, and the midpoint of each group of bridge arms is connected to the filter inductor L f The first output terminal.

[0060] In an embodiment of the present invention, the three-phase inverter includes six switching tubes, and every two switching tubes form a group of bridge arms, and the midpoint of each bridge arm is connected to one-phase input terminal of the electrolytic capacitor-free permanent magnet synchronous motor.

[0061] Most preferably, the bandpass filter has a center frequency of 6kf g The bandpass filter, the transfer function of the bandpass filter G BPF,k (s) is:

[0062]

[0063] Where s represents the Laplace operator, ω c，k represents the bandwidth frequency of the kth harmonic bandpass filter, ω g Indicates the input / grid angular frequency, ω g =2πf g , f g Indicates input / grid frequency, represents the compensation phase for the kth harmonic, k = 1, 2, 3, ....

[0064] Specifically, the DC bus voltage value is subjected to harmonic extraction using a bandpass filter, and the calculation expressions for harmonics of different frequencies are obtained as follows:

[0065] u dck =G BPF,k (s)u dc

[0066] Among them, u dck Indicates the kth harmonic of the DC bus voltage, u dc Indicates the DC bus voltage.

[0067] In the embodiment of the present invention, each frequency harmonic is multiplied by an adjustable constant gain. These gains can be adjusted according to system requirements to optimize the stability and response speed of the system. The harmonic signals of each frequency after gain adjustment are added to obtain a total compensation signal. The summed compensation signal is used as a correction coefficient. The correction coefficient reflects the response and adjustment of the system to different harmonics. The calculation expression of the correction coefficient is:

[0068]

[0069] Among them, γ represents the correction coefficient, g k Indicates the weighting coefficient of the kth harmonic, g k>0, N represents the frequency of harmonics.

[0070] In the embodiment of the present invention, the weighting coefficient g k The larger the value of is, the stronger the suppression capability of the corresponding kth harmonic is. It should be noted that due to the physical constraints of the actual controller (cannot have infinite output) and stability requirements, the weighting coefficient g is k The choice needs to be designed and debugged according to the actual situation.

[0071] Specifically, step 4 includes:

[0072] When the electrolytic capacitor-free permanent magnet synchronous motor controller is implemented on the dq axis, the reference voltage output by the dq axis is corrected using the correction coefficient to obtain the control voltage of the dq axis;

[0073] When the electrolytic capacitor-free permanent magnet synchronous motor controller is implemented on the αβ axis, the reference voltage output by the αβ axis is corrected using the correction coefficient to obtain the control voltage of the αβ axis.

[0074] Specifically, the calculation expression of the control voltage of the dq axis is:

[0075]

[0076] in, Respectively represent the reference voltage of dq axis output, Represent the control voltages of the dq axes respectively.

[0077] Specifically, the calculation expression of the control voltage of the αβ axis is:

[0078]

[0079] in, Respectively represent the reference voltage output by the α and β axes, They represent the control voltages of the α and β axes respectively.

[0080] Specifically, if Figure 3 As shown in FIG, the electrolytic capacitor-free permanent magnet synchronous motor controller includes:

[0081] a first PI control unit, a second PI control unit, and a third PI control unit;

[0082] The first PI control unit is used to process the expected speed of the permanent magnet synchronous motor without electrolytic capacitor and the actual speed of the permanent magnet synchronous motor without electrolytic capacitor to obtain the q-axis current reference value The calculation expression is:

[0083]

[0084] Among them, K pωrepresents the proportional gain of the first PI control unit, K iω represents the integral gain of the first PI control unit, ω * represents the expected speed of the permanent magnet synchronous motor without electrolytic capacitors, and ω represents the actual speed of the permanent magnet synchronous motor without electrolytic capacitors, which can be obtained by an angle / speed encoder or a sensorless algorithm;

[0085] The second PI control unit is used to process the q-axis current and the q-axis current reference value of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system to obtain the reference voltage of the q-axis output The calculation expression is:

[0086]

[0087] Among them, K pq represents the proportional gain of the third PI control unit, K iq represents the integral gain of the third PI control unit, It represents the d-axis current of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system, which can be obtained by the field weakening controller or the maximum torque per ampere (MTPA) controller;

[0088] The third PI control unit is used to process the d-axis current and the d-axis current reference value of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system to obtain the reference voltage of the d-axis output The calculation expression is:

[0089]

[0090] Among them, K pd represents the proportional gain of the third PI control unit, K id represents the integral gain of the third PI control unit, It represents the d-axis current of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system, which can be obtained by the field weakening controller or the maximum torque per ampere controller.

[0091] Specifically, the q-axis current and d-axis current of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system are obtained by performing Park transformation on the input current of the permanent magnet synchronous motor without electrolytic capacitor. The transformation expression is:

[0092]

[0093] Among them, i u 、i v 、i w They represent the input current of each phase of the permanent magnet synchronous motor without electrolytic capacitors, θ represents the rotor flux angle, which can be obtained by the angle / speed encoder or the sensorless algorithm, id 、i q They represent the d-axis current and q-axis current of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system respectively.

[0094] In order to verify the effectiveness of the method, the present invention Figure 2 The topology diagram shown in the figure is used to build the simulink simulation diagram. The grid side parameter is the amplitude U of the three-phase voltage source. sm =311V, input grid frequency f g =50Hz, inductance L in =0.2175mH, resistance R in =0.039432Ω, capacitance C x =1.6uF; DC inductor L dc =43uH, film capacitor C dc =80uF; the load side parameter is the stator phase resistance R s =0.083Ω, inductance L q =1.8mH, L d =1.37mH, magnetic flux Φ = 0.1448Wb, inertia J = 0.00433kg.m 2 , the number of pole pairs p = 3, and the simulation test is carried out with the above-mentioned parameters. The test results are as follows Figure 4 and Figure 5 As shown:

[0095] like Figure 4 The figure shows the simulation results without using the method provided by the embodiment of the present invention. Figure 4 (a) and (b) show the simulation waveforms of the DC bus voltage and the grid-side input current, respectively. From the simulation results, it can be seen that without using the method provided in the embodiment of the present invention, the peak-to-peak value of the DC bus voltage reaches 700V, and the peak-to-peak value of the grid-side input current reaches 100A.

[0096] like Figure 4 FIG. 1 shows the simulation results using the method provided by the embodiment of the present invention. Figure 5 (a) and (b) show the simulated waveforms of the DC bus voltage and the grid-side input current, respectively. The simulation results show that when the method provided in the embodiment of the present invention is used, the peak-to-peak value of the DC bus voltage is only 475 V, and the peak-to-peak value of the grid-side input current is only 70 A. This shows that the method provided in the embodiment of the present invention expands the stability domain of the system and improves the reliability of the system.

[0097] The embodiment of the present invention uses a bandpass filter to extract harmonics from the collected DC bus voltage value of the electrolytic capacitor-free permanent magnet synchronous motor drive system to obtain harmonics of different frequencies; then weighted summation is performed on the harmonics of different frequencies to obtain a correction coefficient; then the correction coefficient is used to correct the reference voltage output by the electrolytic capacitor-free permanent magnet synchronous motor controller to obtain a control voltage; finally, the control voltage is modulated by the inverter in the electrolytic capacitor-free permanent magnet synchronous motor drive system to generate a drive control signal to drive and control the electrolytic capacitor-free permanent magnet synchronous motor; compared with the prior art, the embodiment of the present invention can broaden the stability domain of the electrolytic capacitor-free drive system under low line impedance / heavy load conditions by extracting different harmonic components of the DC bus voltage, calculating the voltage reference correction coefficient, and using the correction coefficient to adjust the original reference voltage of the motor controller, and can effectively improve the input current quality and enhance the system stability.

[0098] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A drive control method for a permanent magnet synchronous motor without electrolytic capacitor, characterized in that: include: Step 1: collecting the DC bus voltage value of the electrolytic capacitor-free permanent magnet synchronous motor drive system; Step 2: Using a bandpass filter to extract harmonics from the DC bus voltage value to obtain harmonics of different frequencies; Step 3: Perform weighted summation on harmonics of different frequencies to obtain a correction coefficient; Step 4, using the correction coefficient to correct the reference voltage output by the electrolytic capacitor-free permanent magnet synchronous motor controller to obtain a control voltage; Step 5: Use the inverter in the electrolytic capacitor-free permanent magnet synchronous motor drive system to modulate the control voltage to generate a drive control signal to drive and control the electrolytic capacitor-free permanent magnet synchronous motor.

2. The drive control method of a permanent magnet synchronous motor without electrolytic capacitor according to claim 1, characterized in that: The bandpass filter has a center frequency of 6kf g The band-pass filter has a transfer function G BPF,k (s) is: Where s represents the Laplace operator, ω c，k represents the bandwidth frequency of the kth harmonic bandpass filter, ω g Indicates the input / grid angular frequency, represents the compensation phase for the kth harmonic, k = 1, 2, 3, ....

3. The drive control method of a permanent magnet synchronous motor without electrolytic capacitor according to claim 2, characterized in that: The DC bus voltage value is subjected to harmonic extraction using a bandpass filter, and the calculation expressions for harmonics of different frequencies are obtained as follows: u dck =G BPF,k (s)u dc Among them, u dck Indicates the kth harmonic of the DC bus voltage, u dc Indicates the DC bus voltage.

4. The drive control method of a permanent magnet synchronous motor without electrolytic capacitor according to claim 3, characterized in that: The calculation expression of the correction coefficient is: Among them, γ represents the correction coefficient, g k represents the weighting coefficient of the kth harmonic, and N represents the frequency of the harmonic.

5. The drive control method of a permanent magnet synchronous motor without electrolytic capacitor according to claim 4, characterized in that: The step 4 comprises: When the electrolytic capacitor-free permanent magnet synchronous motor controller is implemented on the dq axis, the reference voltage output by the dq axis is corrected using the correction coefficient to obtain the control voltage of the dq axis; When the electrolytic capacitor-free permanent magnet synchronous motor controller is implemented on the αβ axis, the reference voltage output by the αβ axis is corrected using the correction coefficient to obtain the control voltage of the αβ axis.

6. The drive control method of a permanent magnet synchronous motor without electrolytic capacitor according to claim 5, characterized in that: The calculation expression of the control voltage of the dq axis is: in, Respectively represent the reference voltage of dq axis output, Represent the control voltages of the dq axes respectively.

7. The drive control method of a permanent magnet synchronous motor without electrolytic capacitor according to claim 5, characterized in that: The calculation expression of the control voltage of the αβ axis is: in, Respectively represent the reference voltage output by the α and β axes, They represent the control voltages of the α and β axes respectively.

8. The drive control method of a permanent magnet synchronous motor without electrolytic capacitor according to claim 1, characterized in that: The electrolytic capacitor-free permanent magnet synchronous motor controller includes: a first PI control unit, a second PI control unit, and a third PI control unit; The first PI control unit is used to process the expected speed of the electrolytic capacitor-free permanent magnet synchronous motor and the actual speed of the electrolytic capacitor-free permanent magnet synchronous motor to obtain a q-axis current reference value; The second PI control unit is used to process the q-axis current of the electrolytic capacitor-free permanent magnet synchronous motor and the q-axis current reference value in the dq coordinate system to obtain a reference voltage outputted from the q-axis; The third PI control unit is used to process the d-axis current of the electrolytic capacitor-free permanent magnet synchronous motor in the dq coordinate system and the d-axis current reference value to obtain a reference voltage outputted by the d-axis.

9. The drive control method of a permanent magnet synchronous motor without electrolytic capacitor according to claim 8, characterized in that: The q-axis current and d-axis current of the electrolytic capacitor-free permanent magnet synchronous motor in the dq coordinate system are obtained by transforming the input current of the electrolytic capacitor-free permanent magnet synchronous motor. The transformation expression is: Among them, i u 、i v 、i w They represent the input current of each phase of the permanent magnet synchronous motor without electrolytic capacitor, θ represents the rotor flux angle, i d 、i q They represent the d-axis current and q-axis current of the permanent magnet synchronous motor without electrolytic capacitor in the dq coordinate system respectively.

Images