Permanent magnet synchronous motor position parameter estimation method and system based on CIC filter

Abstract

The invention relates to the field of motor control, and discloses a permanent magnet synchronous motor position parameter estimation method and system based on a CIC filter, and the method comprises the following steps: carrying out the coordinate transformation of the voltage and current under the alpha-beta axis of a permanent magnet synchronous motor, and obtaining the voltage and current under the gamma-delta axis; and then taking the voltage and the current under the gamma-delta axis and the speed estimation information fed back by the synchronous phase-locked loop as the input of a sliding-mode observer so as to obtain the back electromotive force. Wherein the sliding mode algorithm adopts a switching function to suppress high-frequency buffeting in the back electromotive force, harmonic disturbance in the back electromotive force is filtered by a high-flatness CIC filter, and the back electromotive force under the gamma axis passes through a synchronous phase-locked loop to obtain rotor estimation speed and position information. The filter based on the high-flatness CIC can be applied to a permanent magnet synchronous motor sensorless control system, motor position parameters can be reliably and accurately identified, and the control performance of a motor driving system is improved.

Description

Technical Field

[0001] The present invention relates to the field of motor control, and in particular to a method and system for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter. Background Art

[0002] Permanent magnet synchronous motors are widely used in industrial automation, transportation and other fields due to their advantages such as high efficiency, high power density, high control accuracy and high reliability. At present, field-oriented control is considered to be a typical control technology in the field of PMSM drive, and accurate rotor position and speed information is essential for achieving high-performance FOC. In order to reduce costs and improve system reliability, sensorless control has gradually replaced traditional mechanical position sensors to observe the required rotor position and speed information. Based on this, many scholars have conducted extensive research on position sensorless estimation strategies to further improve PMSM drive performance.

[0003] At present, the position estimation strategies are mainly divided into two categories: one is the high-frequency signal injection strategy suitable for the zero-speed operation area. This strategy is to instantaneously excite the PMSM and detect the spatial direction of the motor anisotropy by injecting high-frequency signals to estimate the rotor position, but this will inevitably lead to power loss and acoustic noise. The other is a model-based strategy, which is suitable for medium and high-speed operation areas, involving disturbance observer methods, model reference adaptive systems, and sliding mode observer methods. Among them, the estimation strategy based on the sliding mode observer has the advantages of high robustness, easy digital control, and good dynamic performance, and has been widely used in position sensorless control. However, due to the influence of inverter nonlinearity and rotor flux spatial harmonics, harmonic jitter will appear in the back electromotive force obtained by the sliding mode observer, resulting in inaccurate position estimation and even IPMSM drive failure, which will reduce the performance of position sensorless control. Therefore, a permanent magnet synchronous motor position parameter estimation method and system based on CIC filter is proposed, which can suppress the harmonic jitter in the back electromotive force. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a permanent magnet synchronous motor position parameter estimation method and system based on a CIC filter. The present invention has good harmonic suppression effect, can accurately estimate the rotor position parameters of the permanent magnet synchronous motor, and effectively improve the motor's position sensorless control performance.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted is as follows:

[0006] A method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter comprises the following steps:

[0007] S1. Using sensors to sample the stator voltage and current components of the permanent magnet synchronous motor drive system, and performing coordinate transformation to obtain the voltage and current under the γδ axes;

[0008] S2, taking the voltage and current under the γδ axis and the estimated rotor speed fed back from the synchronous phase-locked loop as the input of the sliding mode observer, and obtaining the back electromotive force observation value containing the harmonic component;

[0009] S3, inputting the component of the obtained back electromotive force under the γ axis into a high flatness CIC filter, filtering out the harmonic signal, and obtaining the γ axis back electromotive force containing only the DC component;

[0010] S4. Input the back electromotive force under the γ axis into the synchronous phase-locked loop to obtain the estimated rotor position and speed for the control of the permanent magnet synchronous motor drive system.

[0011] As a further improvement of the present invention, in step S2, the sliding mode observer is based on a switching function, and its observation formula is as follows:

[0012]

[0013] Among them, u y 、u δ are the voltages on the γ-axis and δ-axis, i y 、i δ are the currents in the γ and δ axes, are the estimated currents in the γ and δ axes, respectively, is the estimated rotor angular velocity, L d , L q is the inductance under the d-axis and q-axis, R is the stator resistance, z γ 、z δ is the estimated value of the back EMF obtained by the switching function in the sliding mode observer, k SMO is the sliding mode gain, which is a constant greater than 0;

[0014] The voltage equation of the permanent magnet synchronous motor under the γ axis and δ axis is:

[0015]

[0016] Among them, s is the differential operator, ω e is the actual angular velocity of the rotor, e γ ,e δ is the equivalent back electromotive force under the γ axis and the δ axis, and its expression is:

[0017]

[0018] Among them, i d ,i q is the current along the d-axis and q-axis, ψf is the permanent magnet flux, θ e is the actual rotor position, is the estimated rotor position.

[0019] As a further improvement of the present invention, in step S3, the high flatness CIC filter normalization function is:

[0020]

[0021] Among them, M i (i=1, 2, ...n) represents the extraction factor, L i (i=1, 2, ...n) represents the repetition coefficient of each order, K is the total order of the high flat CIC filter,

[0022] Let z = e jω , then the frequency response characteristics of the high flatness CIC filter are:

[0023]

[0024] Among them, ω = 2πf represents the angular frequency;

[0025] It can be seen that the amplitude-frequency response characteristics and phase-frequency response characteristics of the high-flatness CIC filter are:

[0026]

[0027]

[0028] As a further improvement of the present invention, in order to simplify the filter structure, let L i =1(i=1,2,…K), that is, M at different orders i (i=1,2,…K) are different, by selecting a set of appropriate M i (i=1,2,…K), the high flatness CIC filter can completely retain the DC component and eliminate the (±6k)th harmonic.

[0029] As a further improvement of the present invention, the harmonic suppression capability of the high flatness CIC filter depends on the selection of parameters, including the total order K and the extraction factor Mi. The parameter selection needs to consider the following factors:

[0030] The larger K is, the more cascaded parts of the high flatness CIC filter are, the greater the ability to suppress (±6k) subharmonics, and at the same time, the greater the group delay is, and the worse the dynamic performance of the control system will be;

[0031] When K is constant, the larger Mi is, the greater the ability to suppress (±6k) subharmonics is. At the same time, the larger the group delay is, the worse the dynamic performance of the control system will be.

[0032] Therefore, it is necessary to make a trade-off between harmonic suppression capability and system dynamic performance. To this end, a genetic algorithm is used to optimize the structural parameters of the high flatness CIC filter (including K and M). i ).

[0033] As a further improvement of the present invention, the high flatness CIC filter is designed for attenuation of the (±6k) subharmonic frequency range of the motor under medium and high speed conditions, without the need for additional frequency adaptive structure design. The steps for optimizing the filter structure parameters based on the genetic algorithm are as follows:

[0034] (1) Assume that the maximum and minimum speeds of the motor are n max and n min , determine the frequency range of (±6k) subharmonics, assuming the total order of the filter is K;

[0035] (2) Calculate M max and M min , the calculation formula is as follows:

[0036] M max =f s / f h6.min

[0037] M min =f s / f h6.max

[0038] Among them, f s represents the switching frequency of the inverter, f h6.min and f h6.max Corresponding to the motor in n min and n max (±6k) subharmonic frequency below;

[0039] (3) Using genetic algorithm to perform dual-objective optimization, the optimization objectives are harmonic amplitude gain and group delay, and the relationship between the harmonic amplitude gain and group delay is obtained;

[0040] (4) Output the final structural parameters (K and M) as needed i ).

[0041] As a further improvement of the present invention, in step S4, the back electromotive force under the γ axis is input into the synchronous phase-locked loop to obtain the estimated rotor position and speed for controlling the permanent magnet synchronous motor drive system, which specifically includes the following steps:

[0042] S4-1. Calculate the rotor position error using the filtered γ-axis back electromotive force:

[0043]

[0044] S4-2, comparing the back electromotive force under the γ axis with the reference value and inputting the difference into the PI regulator to obtain the estimated rotor speed, and then integrating the estimated value of the rotor speed to obtain the estimated rotor position;

[0045]

[0046] Among them, k p and k i is the gain of the PI controller.

[0047] A permanent magnet synchronous motor position parameter estimation system based on a high flatness CIC filter, comprising:

[0048] Sampling module, used to collect voltage and current of permanent magnet synchronous motor;

[0049] A back electromotive force calculation module, including a sliding mode observer, for obtaining a back electromotive force observation value;

[0050] A filtering module, including a high-flatness CIC filter, for filtering out harmonics in the γ-axis component of the back-EMF;

[0051] An estimation module, used to obtain the estimated position and speed of the rotor through a synchronous phase-locked loop;

[0052] A microprocessor is connected to the sampling module, the back electromotive force calculation module, the filtering module, the estimation module and the memory respectively, and the microprocessor is programmed or configured to execute any one of the above-mentioned permanent magnet synchronous motor position parameter estimation methods based on the high flatness CIC filter.

[0053] A computer-readable storage medium may store a computer program, wherein the computer program is used to be programmed or configured by a microprocessor to execute any one of the above-mentioned permanent magnet synchronous motor position parameter estimation methods based on a CIC filter.

[0054] The beneficial effects of the present invention are as follows: the method for estimating position parameters of a permanent magnet synchronous motor based on a high-flatness CIC filter provided by the present invention is a new and feasible harmonic suppression method, which filters the back electromotive force observed by the sliding mode observer by constructing a high-flatness CIC filter, that is, extracting the DC component and filtering out the harmonic component, thereby avoiding the phase delay and amplitude attenuation caused by the traditional low-pass filter to the back electromotive force. Therefore, while ensuring the accurate elimination of the harmonic component in the back electromotive force, the present invention avoids the introduction of phase delay and does not require additional compensation measures, which increases the feasibility of the IPMSM position sensorless control system and effectively improves the accuracy of rotor position estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0056] Figure 1 This is a block diagram of an IPMSM sensorless drive vector control based on a high flatness CIC filter in an embodiment of the present invention;

[0057] Figure 2 It is a structural block diagram of a position observer based on a sliding mode observer and a high flatness CIC filter in an embodiment of the present invention;

[0058] Figure 3 A structural block diagram of a high flatness CIC filter in an embodiment of the present invention;

[0059] Figure 4 is the relationship between harmonic amplitude gain and group delay;

[0060] Figure 5 This is the amplitude-frequency response characteristic of the high flatness CIC filter. DETAILED DESCRIPTION

[0061] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0062] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0063] like Figure 1As shown, a method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter comprises the following steps:

[0064] S1. Using sensors to sample the stator voltage and current components of the permanent magnet synchronous motor drive system, and performing coordinate transformation to obtain the voltage and current under the γδ axes;

[0065] S2, taking the voltage and current under the γδ axis and the estimated rotor speed fed back from the synchronous phase-locked loop as the input of the sliding mode observer, and obtaining the back electromotive force observation value containing the harmonic component;

[0066] S3, inputting the component of the obtained back electromotive force under the γ axis into a high flatness CIC filter, filtering out the harmonic signal, and obtaining the γ axis back electromotive force containing only the DC component;

[0067] S4. Input the back electromotive force under the γ axis into the synchronous phase-locked loop to obtain the estimated rotor position and speed for the control of the permanent magnet synchronous motor drive system.

[0068] In step S2, the sliding mode observer is based on the switching function, and its observation formula is as follows:

[0069]

[0070] Among them, u y 、u δ are the voltages on the γ-axis and δ-axis, i y 、i δ are the currents in the γ and δ axes, are the estimated currents in the γ and δ axes, respectively, is the estimated rotor angular velocity, L d , L q is the inductance under the d-axis and q-axis, R is the stator resistance, z γ 、z δ is the estimated value of the back EMF obtained by the switching function in the sliding mode observer, k SMO is the sliding mode gain, which is a constant greater than 0;

[0071] The voltage equation of the permanent magnet synchronous motor under the γ axis and δ axis is:

[0072]

[0073] Among them, s is the differential operator, ω e is the actual angular velocity of the rotor, e γ ,e δ is the equivalent back electromotive force under the γ axis and the δ axis, and its expression is:

[0074]

[0075] Among them, i d ,i q is the current along the d-axis and q-axis, ψ f is the permanent magnet flux, θ e is the actual rotor position, is the estimated rotor position.

[0076] like Figure 2 As shown, the present invention example constructs a position observation structure based on a sliding mode observer and a high flatness CIC filter, specifically, the sliding mode observer is constructed using the IPMSM voltage equation and the switching function.

[0077] In step S3, the high flatness CIC filter normalization function is:

[0078]

[0079] Among them, M i (i=1, 2, ...n) represents the extraction factor, L i (i=1, 2, ...n) represents the repetition coefficient of each order, K is the total order of the high flat CIC filter,

[0080] Let z = e jω , then the frequency response characteristics of the high flatness CIC filter are:

[0081]

[0082] Among them, ω = 2πf represents the angular frequency;

[0083] It can be seen that the amplitude-frequency response characteristics and phase-frequency response characteristics of the high-flatness CIC filter are:

[0084]

[0085]

[0086] To simplify the filter structure, let L i =1(i=1,2,…K), that is, M at different orders i (i=1,2,…K) are different, by selecting a set of appropriate M i (i=1,2,…K), the high flatness CIC filter can completely retain the DC component and eliminate the (±6k)th harmonic.

[0087] The harmonic suppression capability of the high flatness CIC filter depends on the selection of parameters, including the total order K and the extraction factor Mi. The following factors need to be considered in parameter selection:

[0088] The larger K is, the more cascaded parts of the high flatness CIC filter are, the greater the ability to suppress (±6k) subharmonics, and at the same time, the greater the group delay is, and the worse the dynamic performance of the control system will be;

[0089] When K is constant, the larger Mi is, the greater the ability to suppress (±6k) subharmonics is. At the same time, the larger the group delay is, the worse the dynamic performance of the control system will be.

[0090] Therefore, it is necessary to make a trade-off between harmonic suppression capability and system dynamic performance. To this end, a genetic algorithm is used to optimize the structural parameters of the high flatness CIC filter (including K and M). i ).

[0091] Figure 3 The structural diagram of the high flatness CIC filter is shown, specifically involving the optimized design of the structural parameters K and Mi.

[0092] The high flatness CIC filter is designed for attenuation of the (±6k) subharmonic frequency range of the motor under medium and high speed conditions. No additional frequency adaptive structure design is required. The steps for optimizing the filter structure parameters based on the genetic algorithm are as follows:

[0093] (1) Assume that the maximum and minimum speeds of the motor are n max and n min , determine the frequency range of (±6k) subharmonics, assuming the total order of the filter is K;

[0094] (2) Calculate M max and M min , the calculation formula is as follows:

[0095] M max =f s / f h6.min

[0096] M min =f s / f h6.max

[0097] Among them, f s represents the switching frequency of the inverter, f h6.min and f h6.max Corresponding to the motor in n min and n max (±6k) subharmonic frequency below;

[0098] (3) Using genetic algorithm to perform dual-objective optimization, the optimization objectives are harmonic amplitude gain and group delay, and the relationship between the harmonic amplitude gain and group delay is obtained;

[0099] (4) Output the final structural parameters (K and M) as needed i).

[0100] To illustrate the problem more intuitively, taking K = 2 as an example, the relationship between harmonic amplitude gain and group delay is as follows: Figure 4 As shown. It can be seen that the harmonic amplitude gain and group delay are multi-peak functions of M1 and M2, and the harmonic amplitude gain and group delay are not negatively correlated. For high flatness CIC filters with K>2, the situation will be more complicated. Considering the limitation of group delay, the total order K of high flatness CIC filters should not be too high (generally not more than 10 orders), so K can be enumerated and then M i After K is determined, the multi-objective optimization model can be written as:

[0101] M=(M1,M2,...,M K )

[0102]

[0103] sM min ≤M i ≤M max i=1,2,...,K

[0104] f h6.min ≤f≤f h6.max

[0105] in, M represents the decision vector of the optimization problem.

[0106] Based on the above optimization model, this paper uses genetic algorithm to optimize K and M i The two objective functions are optimized, which has the advantages of being independent of the objective function and having strong global convergence. The relationship between the harmonic amplitude gain and group delay of the 1st to 6th order high flatness CIC filter obtained by genetic algorithm is shown in Figure 4 As shown, each point corresponds to a set of non-dominated solutions. Each set of non-dominated solutions represents M i (i=1,2,…K), the harmonic amplitude gain and group delay cannot be reduced at the same time. Therefore, in practical applications, an optimal solution can be selected based on the desired filtering effect and dynamic performance.

[0107] Taking the actual data of the present invention as an example, when n min =500r / min,n max =1500r / min, 100~300Hz is the sixth harmonic frequency band. If the amplitude gain needs to be lower than -40dB to ensure that the harmonic interference can be significantly suppressed within this speed range, you can use Figure 4 The solutions corresponding to the positions shown (K=3, M=74,96,46) achieve the best dynamic performance.

[0108] The amplitude-frequency response of the present invention is as follows: Figure 5 As shown in the figure, for IPMSM, the harmonic distortion in the back EMF can be effectively suppressed in the motor speed range from 500r / min to 1500r / min.

[0109] In step S4, the back electromotive force under the γ axis is input into the synchronous phase-locked loop to obtain the estimated rotor position and speed for controlling the permanent magnet synchronous motor drive system, which specifically includes the following steps:

[0110] S4-1. Calculate the rotor position error using the filtered γ-axis back electromotive force:

[0111]

[0112] S4-2, comparing the back electromotive force under the γ axis with the reference value and inputting the difference into the PI regulator to obtain the estimated rotor speed, and then integrating the estimated value of the rotor speed to obtain the estimated rotor position;

[0113]

[0114] Among them, k p and k i is the gain of the PI controller.

[0115] A permanent magnet synchronous motor position parameter estimation system based on a high flatness CIC filter, comprising:

[0116] Sampling module, used to collect voltage and current of permanent magnet synchronous motor;

[0117] A back electromotive force calculation module, including a sliding mode observer, for obtaining a back electromotive force observation value;

[0118] A filtering module, including a high-flatness CIC filter, for filtering out harmonics in the γ-axis component of the back-EMF;

[0119] An estimation module, used to obtain the estimated position and speed of the rotor through a synchronous phase-locked loop;

[0120] A microprocessor is connected to the sampling module, the back electromotive force calculation module, the filtering module, the estimation module and the memory respectively, and the microprocessor is programmed or configured to execute any one of the above-mentioned permanent magnet synchronous motor position parameter estimation methods based on the high flatness CIC filter.

[0121] A computer-readable storage medium may store a computer program, wherein the computer program is used to be programmed or configured by a microprocessor to execute any one of the above-mentioned permanent magnet synchronous motor position parameter estimation methods based on a CIC filter.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, component splitting or combination, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter, characterized in that: The following steps are involved: S1. Using sensors to sample the stator voltage and current components of the permanent magnet synchronous motor drive system, and performing coordinate transformation to obtain the voltage and current under the γδ axes; S2, taking the voltage and current under the γδ axis and the estimated rotor speed fed back from the synchronous phase-locked loop as the input of the sliding mode observer, and obtaining the back electromotive force observation value containing the harmonic component; S3, inputting the component of the obtained back electromotive force under the γ axis into a high flatness CIC filter, filtering out the harmonic signal, and obtaining the γ axis back electromotive force containing only the DC component; S4. Input the back electromotive force under the γ axis into the synchronous phase-locked loop to obtain the estimated rotor position and speed for the control of the permanent magnet synchronous motor drive system.

2. A method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter according to claim 1, characterized in that: In step S2, the sliding mode observer is based on the switching function, and its observation formula is as follows: Among them, u y 、u δ are the voltages on the γ-axis and δ-axis, i y 、i δ are the currents in the γ and δ axes, are the estimated currents in the γ and δ axes, respectively, is the estimated rotor angular velocity, L d , L q is the inductance under the d-axis and q-axis, R is the stator resistance, z γ 、z δ is the estimated value of the back EMF obtained by the switching function in the sliding mode observer, k SMO is the sliding mode gain, which is a constant greater than 0; The voltage equation of the permanent magnet synchronous motor under the γ axis and δ axis is: Among them, s is the differential operator, ω e is the actual angular velocity of the rotor, e γ ,e δ is the equivalent back electromotive force under the γ axis and the δ axis, and its expression is: Among them, i d ,i q is the current along the d-axis and q-axis, ψ f is the permanent magnet flux linkage, θ e is the actual rotor position, is the estimated rotor position.

3. The method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter according to claim 1 is characterized in that: In step S3, the high flatness CIC filter normalization function is: Among them, M i (i=1, 2, ...n) represents the extraction factor, L i (i=1, 2, ...n) represents the repetition coefficient of each order, K is the total order of the high flat CIC filter, Let z = e jω , then the frequency response characteristics of the high flatness CIC filter are: Where, ω = 2πf represents the angular frequency; It can be seen that the amplitude-frequency response characteristics and phase-frequency response characteristics of the high-flatness CIC filter are:

4. A method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter according to claim 3, characterized in that: To simplify the filter structure, let L i =1(i=1,2,…K), that is, M at different orders i (i=1,2,…K) are different, by selecting a set of appropriate M i (i=1,2,…K), the high flatness CIC filter can completely retain the DC component and eliminate the (±6k)th harmonic.

5. A method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter according to claim 4, characterized in that: The harmonic suppression capability of the high flatness CIC filter depends on the selection of parameters, including the total order K and the extraction factor Mi. The following factors need to be considered in parameter selection: The larger K is, the more cascaded parts of the high flatness CIC filter are, the greater the ability to suppress (±6k) subharmonics, and at the same time, the greater the group delay is, and the worse the dynamic performance of the control system will be; When K is constant, the larger Mi is, the greater the ability to suppress (±6k) subharmonics is. At the same time, the larger the group delay is, the worse the dynamic performance of the control system will be. Therefore, it is necessary to make a trade-off between the harmonic suppression capability and the system dynamic performance. To this end, a genetic algorithm is used to optimize the structural parameters of the high flatness CIC filter.

6. A method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter according to claim 5, characterized in that: The high flatness CIC filter is designed for the attenuation of the sub-harmonic frequency range of the motor under medium and high speed conditions. No additional frequency adaptive structure design is required. The steps for optimizing the filter structure parameters based on the genetic algorithm are as follows: (1) Assume that the maximum and minimum speeds of the motor are n max and n min , determine the frequency range of (±6k) subharmonics, assuming the total order of the filter is K; (2) Calculate M max and M min , the calculation formula is as follows: M max =f s / f h6.min M min =f s / f h6.max Among them, f s represents the switching frequency of the inverter, f h6.min and f h6.max Corresponding to the motor in n min and n max (±6k) subharmonic frequency under (3) Using genetic algorithm to perform dual-objective optimization, the optimization objectives are harmonic amplitude gain and group delay, and the relationship between the harmonic amplitude gain and group delay is obtained; (4) Output the final structural parameters (K and M) as needed i ).

7. The method for estimating position parameters of a permanent magnet synchronous motor based on a CIC filter according to claim 1, characterized in that: In step S4, the back electromotive force under the γ axis is input into the synchronous phase-locked loop to obtain the estimated rotor position and speed for controlling the permanent magnet synchronous motor drive system, which specifically includes the following steps: S4-1. Calculate the rotor position error using the filtered γ-axis back electromotive force: S4-2, comparing the back electromotive force under the γ axis with the reference value and inputting the difference into the PI regulator to obtain the estimated rotor speed, and then integrating the estimated value of the rotor speed to obtain the estimated rotor position; Among them, k p and k i is the gain of the PI controller.

8. A permanent magnet synchronous motor position parameter estimation system based on a high flatness CIC filter, characterized in that: include: Sampling module, used to collect voltage and current of permanent magnet synchronous motor; A back electromotive force calculation module, including a sliding mode observer, for obtaining a back electromotive force observation value; A filtering module, including a high-flatness CIC filter, for filtering out harmonics in the γ-axis component of the back-EMF; An estimation module, used to obtain the estimated position and speed of the rotor through a synchronous phase-locked loop; A microprocessor is respectively connected to the sampling module, the back electromotive force calculation module, the filtering module, the estimation module and the memory, and the microprocessor is programmed or configured to execute the permanent magnet synchronous motor position parameter estimation method based on the high flatness CIC filter as described in any one of claims 1-7.

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