A Full-Frequency Harmonic Suppression Method for Permanent Magnet Synchronous Motors Based on Cooperative Observation and Spectrum Spreading

Abstract

This invention discloses a full-frequency harmonic suppression method for permanent magnet synchronous motors (PMSMs) based on cooperative observation and spectrum extension, belonging to the field of PMSM control technology. It aims to solve the problems of low-order harmonics introduced by inverter nonlinearity, high-frequency sideband harmonics introduced by fixed carrier frequency, and increased low-order harmonic amplitude after optimization of asymmetric rotor structures in existing PMSMs. The method of this invention suppresses low-order harmonics by constructing an active disturbance rejection control module and suppresses high-frequency sideband harmonics by designing a random SVPWM modulation module, forming a full-frequency harmonic cooperative suppression strategy. This method can effectively reduce the amplitude of the 5th and 7th current harmonics, the amplitude of high-frequency sideband current harmonics, and the carrier vibration amplitude, significantly improving the operating stability and NVH performance of PMSMs, and is suitable for PMSM drive systems in electric vehicles.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet synchronous motor control technology, and in particular to a method for full-frequency harmonic suppression of permanent magnet synchronous motors based on cooperative observation and spectrum extension. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in electric vehicles due to their high power density and efficiency. However, as the demands for power density and speed of drive motors in new energy vehicles continue to increase, the electromagnetic excitation intensity of the motor system is significantly enhanced, and the vibration frequency range is continuously expanding, making it easier to generate electromagnetic and mechanical vibrations. Furthermore, considering the core causes of harmonic generation, the inverter, as a key component in motor power supply, introduces low-order harmonic currents and high-frequency sideband harmonic currents due to its dead-time effect, switching transistor voltage drop, and carrier frequency. The time-varying electromagnetic force generated by the interaction of these harmonic currents with the harmonic magnetic field of the rotor permanent magnet further exacerbates the high-frequency vibration response of the motor, severely impacting the driving comfort and reliability of pure electric vehicles.

[0003] Currently, research on harmonic suppression in permanent magnet synchronous motors generally suffers from limitations in frequency band coverage: one type of research focuses on improving control algorithms, such as repetitive control and resonant controllers, to achieve targeted suppression of low-order harmonics; another type of research aims to disperse high-frequency harmonic energy by adjusting modulation strategies, such as random PWM and variable switching frequency PWM. However, these technical solutions cannot simultaneously cover both the low-order and high-frequency key bands, lacking a comprehensive full-frequency domain solution that can effectively suppress both low-order and high-frequency harmonics to meet the practical needs of electric vehicle drive motors for wide-spectrum harmonic suppression.

[0004] Therefore, there is an urgent need to design a full-frequency domain harmonic suppression method that can effectively suppress both low-order current harmonics and high-frequency sideband harmonics, so as to comprehensively improve the operational stability of permanent magnet synchronous motors. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a full-frequency harmonic suppression method for permanent magnet synchronous motors based on collaborative observation and spectrum extension. By extending the state observer to suppress low-order harmonics and using random SVPWM to disperse high-frequency harmonics, it achieves full-frequency harmonic collaborative suppression, thereby improving the operating stability and NVH performance of permanent magnet synchronous motors and meeting the application requirements of electric vehicle drive systems.

[0006] The technical solution adopted by this invention to solve its technical problem is: a full-frequency harmonic suppression method for permanent magnet synchronous motors based on cooperative observation and spectrum spread, characterized by including the following steps:

[0007] S1: Construct a vector control system for a permanent magnet synchronous motor, the vector control system including a speed loop PI controller, an MTPA regulator, a current loop PI controller, a coordinate transformation module, an SVPWM modulation module, and an inverter;

[0008] S2: In the current loop of the vector control system, an extended state observer is introduced based on the core logic of the active disturbance rejection control algorithm to expand the comprehensive system disturbance generated during motor operation into a new system state variable. The comprehensive system disturbance includes the dynamic coupling term of the dq axis current and the voltage offset introduced by the inverter nonlinearity. The disturbance is estimated in real time through nonlinear state error feedback to generate a voltage compensation amount to offset the disturbance.

[0009] S3: The random SVPWM modulation algorithm is used to replace the traditional fixed frequency SVPWM algorithm to generate the PWM signal to drive the inverter;

[0010] S4: The disturbance observation value output by the extended state observer is fed forward to compensate the voltage command of the current loop. The random SVPWM modulation algorithm generates a PWM signal based on the compensated voltage command. The two work together to drive the permanent magnet synchronous motor to achieve full-frequency harmonic suppression.

[0011] The construction of the extended state observer and the implementation of nonlinear state error feedback in step S2 are as follows:

[0012] The extended state equations established after introducing the extended state observer are as follows:

[0013] ;

[0014] In the formula, It is an estimation error. This is the actual output of the system. and These are the estimated values ​​of the output variable and the total disturbance, respectively. and They represent and rate of change, and It is the gain of the output error. It is a compensation factor. It is the output of the controller. and Here, is a nonlinear state error feedback function, where, and As a tracking factor, and The filter factor;

[0015] The expression for nonlinear state error feedback is as follows:

[0016] ;

[0017] In the formula, It is the error between the estimated value and the actual value of the output variable; It is a tracking factor; It is the filter factor.

[0018] Furthermore, the specific process for handling the system's overall disturbance in step S2 is as follows:

[0019] Let the voltage disturbance introduced by the inverter's nonlinearity be represented on the dq axis as follows: and Substituting this into the voltage equation of the motor, we obtain the voltage equation containing voltage disturbance as follows:

[0020] ;

[0021] in, and These are the voltages on the dq axes, respectively. and These represent the voltage perturbations on the dq axes, respectively. For stator resistance, Electric angular velocity, This refers to the quadrature-axis current component of the motor. This represents the direct-axis current component of the motor. For the quadrature axis inductance of the motor, It is a direct-axis inductor. It is a permanent magnet flux linkage. This refers to the electric angular velocity; as the motor's operating speed increases, the cross-coupling term... and The amplitude increases significantly, and its dynamic coupling effect will mask the real control quantity, leading to the accumulation of current tracking error;

[0022] To reduce the impact of coupling terms, the current decoupling error caused by coupling terms and the voltage offset caused by inverter nonlinearity are both considered as disturbances in the system.

[0023] ;

[0024] make , , , The above formula can be rewritten as:

[0025] ;

[0026] The voltage equations of a permanent magnet synchronous motor are first-order; therefore, the extended state observer for the dq-axis voltage can be designed as follows:

[0027] ;

[0028] In the formula, It is the error between the estimated and measured values ​​of the d-axis current. and These are the dq-axis current values ​​output by the motor, respectively. and They represent and rate of change, It is the d-axis voltage value of the input motor. It is the d-axis current value estimated by the extended state observer. express rate of change, and These represent the total disturbances on the dq axes. and These are the control gains for the dq axes, respectively. It is the total d-axis perturbation estimated by the extended state observer. express The rate of change.

[0029] Furthermore, the random SVPWM modulation algorithm described in step S3 specifically involves: adjusting the carrier frequency... At the center frequency The variation within a random bandwidth in the vicinity is expressed as:

[0030] ;

[0031] In the formula, It is the center frequency; R is at the center frequency. Changing random numbers; It is the spread spectrum range of the RSF-PWM strategy.

[0032] Furthermore, the collaborative control logic for full-frequency domain harmonic suppression described in step S4 is specifically as follows:

[0033] The speed loop PI controller receives the motor speed feedback signal and outputs a torque reference value. The MTPA regulator generates a dq-axis current reference value based on the torque reference value. The current loop PI controller, combined with the voltage compensation output by the extended state observer, corrects the initial voltage command of the current loop and outputs a compensated voltage command. The SVPWM modulation module converts the compensated voltage command into an inverter switching signal, driving the inverter to output three-phase voltage to the permanent magnet synchronous motor. Simultaneously, the dq-axis current signal of the motor is collected in real time and fed back to the extended state observer, and the motor speed signal is collected and fed back to the speed loop PI controller, forming a closed-loop control.

[0034] The beneficial effects of this invention;

[0035] 1. Compared with existing single-band suppression methods, this invention combines active disturbance rejection control for low-frequency disturbances with random modulation technology for high-frequency harmonics, achieving effective suppression of wide-spectrum harmonics and solving the limitation of single technologies that can only target specific frequency bands; it can effectively reduce the amplitude of low-order harmonics of phase current, such as the 5th and 7th harmonics and high-frequency harmonics, reduce torque ripple, and significantly reduce the vibration response of the motor near the carrier frequency, thus comprehensively improving the NVH performance of the motor.

[0036] 2. This invention proposes for the first time a synergistic scheme of accurate compensation for low-order disturbances and active expansion of high-frequency spectrum: the voltage compensation output by the expansion state observer directly corrects the modulation wave reference of random SVPWM, so that high-frequency modulation and low-order compensation form a closed-loop linkage, solving the technical difficulty that a single method cannot cover the entire frequency domain.

[0037] 3. Traditional ESOs often only address single disturbances. This invention combines inverter nonlinearity and dq-axis coupling terms into a comprehensive system disturbance. Through independent dq-axis ESO design, the disturbance estimation error is significantly reduced, and the estimation accuracy is significantly improved compared to traditional single-axis ESOs. In existing random modulation techniques, the center frequency and spread spectrum range are mostly set empirically. This solution quantitatively determines the center frequency and spread spectrum range through loss and noise analysis, and introduces a random number limiting filter mechanism to avoid inverter stress fluctuations caused by carrier abrupt changes, thus achieving an optimal balance between high-frequency harmonic suppression and system reliability. Attached Figure Description

[0038] Figure 1 This is a block diagram of the full-frequency domain harmonic suppression strategy of the present invention.

[0039] Figure 2 This is a spectrum diagram of the fixed carrier modulation voltage and current of the present invention.

[0040] Figure 3 This is a schematic diagram of the random switching frequency pulse width modulation technology of the present invention.

[0041] Figure 4 This is a comparison diagram of the current waveform and spectrum before and after global harmonic suppression at a motor speed of 1000 rpm in this invention.

[0042] Figure 5 This is a comparison diagram of the current waveform and spectrum before and after global harmonic suppression at a motor speed of 2000 rpm in this invention.

[0043] Figure 6 This is a spectrum of the motor vibration response before and after global harmonic suppression at a motor speed of 2000 rpm in this invention. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to the accompanying drawings.

[0045] This invention discloses a full-frequency harmonic suppression method for permanent magnet synchronous motors based on collaborative observation and spectrum extension.

[0046] Reference Figure 1 A full-frequency harmonic suppression method for permanent magnet synchronous motors based on cooperative observation and spectrum spread includes the following steps:

[0047] S1: Construct a vector control system for a permanent magnet synchronous motor. The vector control system includes a speed loop PI controller, an MTPA regulator (maximum torque-current ratio regulator), a current loop PI controller, a coordinate transformation module, an SVPWM modulation module (space vector pulse width modulation module), and an inverter. Among them, the coordinate transformation module is used to realize the Clark transformation between the three-phase stationary coordinate system and the two-phase stationary coordinate system, and the Park transformation between the two-phase stationary coordinate system and the rotating coordinate system.

[0048] The specific method for constructing a vector control system for a permanent magnet synchronous motor is as follows:

[0049] Without considering the influence of harmonic currents, the three-phase currents ABC can be regarded as three independent sinusoidal signals with a phase difference of 120°, and their expressions are as follows:

[0050]

[0051] In the formula, This represents the peak value of the three-phase current, in amperes (A). The electric angular velocity of the motor is expressed in rad / s. Time, in seconds; The power factor angle of the motor is expressed in rad.

[0052] In controlling a permanent magnet synchronous motor (PMSM), to simplify the mathematical model of the three-phase PMSM in the natural coordinate system, Clark and Park transformations are typically used to convert the model to stationary and rotating coordinate systems for control. The Clark transformation formula and the inverse Clark transformation formula are as follows:

[0053]

[0054] In the formula, This represents variables such as voltage, current, or inductance of the motor. , and Let A, B, and C represent the physical quantities of phase A, phase B, and phase C respectively in a three-phase stationary coordinate system. For zero-order components, and These are the two stationary coordinate systems after the transformation. shaft and Components on the axis, and The coordinate transformation matrix can be represented as:

[0055]

[0056] The formulas for the Park transform and the inverse Park transform are:

[0057]

[0058] In the formula, and These represent the components along the d-axis and q-axis of the transformed rotated coordinate system, respectively. and The Park transformation matrix and its inverse can be represented as:

[0059]

[0060] In the formula, The value is an electrical angle, in rad. Combining Clark and Park transformations, the transformation formulas and inverse transformation formulas from the ABC natural coordinate system to the dq-axis rotating coordinate system are as follows:

[0061]

[0062] In the formula and Let be the transformation matrix and inverse matrix from the natural coordinate system ABC to the rotated coordinate system dq, which can be expressed as:

[0063]

[0064] In a rotating coordinate system, the voltage equation of the stator of the permanent magnet synchronous motor is:

[0065]

[0066] The electromagnetic torque of the motor is:

[0067] In the formula, and These are the voltages on the d-axis and q-axis, respectively, in V; Stator resistance, unit: ; Electric angular velocity, in rad / s; This represents the number of pole pairs of the motor. This represents the quadrature-axis current component of the motor, expressed in amperes (A). This represents the direct-axis current component of the motor, expressed in amperes (A). This refers to the quadrature-axis inductance of the motor, measured in ohms (H). It is a direct-axis inductance, with units of ohms (H). This refers to the flux linkage of a permanent magnet, measured in Wb.

[0068] In a rotating coordinate system, the relationship between stator current and maximum current is as follows:

[0069]

[0070] In the formula, This represents the maximum current amplitude.

[0071] The maximum output voltage of the inverter is limited by the DC bus voltage. During motor operation, the combined dq-axis voltage cannot exceed this limit. Under steady-state conditions, the dq-axis voltage and stator voltage are expressed as follows:

[0072]

[0073]

[0074] In the formula, The voltage limit amplitude is determined by the DC bus voltage. Decide, .

[0075] When the target torque of the motor is determined, the dq-axis current is dynamically adjusted via MTPA control to minimize the stator current under constant torque. The expression for the dq-axis current is:

[0076]

[0077]

[0078]

[0079]

[0080] In the formula, Reference torque, in N·m; This represents the number of pole pairs of the motor. This is a reference value for the stator current amplitude, in A. The flux linkage of a permanent magnet is measured in Wb. This is the actual amplitude of the stator current, in amperes (A). This represents the maximum permissible stator current amplitude of the motor, expressed in amperes (A). This is the reference current for the d-axis under the MTPA control strategy, in amperes (A). This is the reference current for the q-axis under the MTPA control strategy, in amperes (A). and These are the inductances of the motor's d and q axes, respectively, in H.

[0081] S2: In the current loop of the vector control system, an extended state observer (ESO) is introduced based on the core logic of the active disturbance rejection control algorithm. This extends the comprehensive system disturbance generated during motor operation into a new system state variable. The comprehensive system disturbance includes the dynamic coupling term of the dq axis current and the voltage offset introduced by the inverter nonlinearity. The comprehensive system disturbance is estimated in real time through nonlinear state error feedback (NLSEF) to generate the voltage compensation amount used to cancel the disturbance.

[0082] The mathematical model of a first-order active disturbance rejection control system can be reconstructed as follows:

[0083]

[0084] In the formula, It is the total disturbance; It controls the gain; It is the system input.

[0085] The extended state equations established after introducing the Extended State Observer (ESO) are as follows:

[0086]

[0087] In the formula, It is an estimation error. This is the actual output of the system. and These are the estimated values ​​of the output variable and the total disturbance, respectively. and They represent and rate of change, and It is the gain of the output error. It is a compensation factor. It is the output of the controller. and Here, is a nonlinear state error feedback function, where, and As a tracking factor, and This is the filter factor.

[0088] The NLSEF control algorithm is based on the principle of adaptive gain adjustment of error magnitude, and employs a piecewise nonlinear function, such as... The function dynamically adjusts the gain across different error ranges: high gain is used for small errors to accelerate the response, and low gain is used for large errors to avoid overshoot, thus achieving fast and stable adjustment. Its expression is as follows:

[0089]

[0090] In the formula, It is the error between the estimated value and the actual value of the output variable; It is a tracking factor; It is the filter factor.

[0091] For automotive permanent magnet synchronous motors, the voltage disturbance introduced by the inverter's nonlinearity is set to be respectively on the dq axis. and Substituting this into the voltage equation of the motor, we obtain the voltage equation containing voltage disturbances as follows:

[0092]

[0093] In the above formula, and These are the voltages on the d-axis and q-axis, respectively, in V; Stator resistance, unit: ; Electric angular velocity, in rad / s; This represents the quadrature-axis current component of the motor, expressed in amperes (A). This represents the direct-axis current component of the motor, expressed in amperes (A). This refers to the quadrature-axis inductance of the motor, measured in ohms (H). It is a direct-axis inductance, with units of ohms (H). The flux linkage of the permanent magnet is measured in Wb; as the motor speed increases, the cross-coupling term... and The amplitude of the coupling term increases significantly, and its dynamic coupling effect masks the true control quantity, leading to the accumulation of current tracking error. Therefore, to reduce the impact of the coupling term, the current decoupling error generated by the coupling term and the voltage deviation generated by the inverter nonlinearity are both considered as disturbances in the system, i.e.:

[0094]

[0095] make , , , The above formula can be rewritten as:

[0096]

[0097] The voltage equations of a permanent magnet synchronous motor are first-order; therefore, the extended state observer for the dq-axis voltage can be designed as follows:

[0098]

[0099] In the formula, It is the error between the estimated and measured values ​​of the d-axis current. and This is the dq axis current value output by the motor, in amperes (A). and They represent and rate of change, This is the d-axis voltage value of the input motor, in V; This is the d-axis current value estimated by the extended state observer, in amperes (A). express rate of change, and These represent the total disturbances on the dq axes. and These are the control gains for the dq axes, respectively. It is the total d-axis perturbation estimated by the extended state observer. express The rate of change.

[0100] S3: The random SVPWM modulation algorithm is used to replace the traditional fixed frequency SVPWM algorithm to generate the PWM signal to drive the inverter; the random SVPWM modulation algorithm achieves the dispersion of high-frequency sideband harmonic energy by changing the carrier frequency within a random bandwidth near the preset center frequency.

[0101] The specific method is as follows: In the traditional SVPWM modulation algorithm, the inverter switching signal is calculated by comparing the carrier wave and the modulating wave. Generally, the modulating wave is a saddle wave, and the carrier wave is a triangular wave. It employs a fixed switching frequency pulse width strategy, FSF-PWM, meaning the inverter's switching frequency remains fixed. Its switching frequency can be expressed as:

[0102]

[0103] In the formula, It is a fixed switching frequency value.

[0104] like Figure 2 As shown, when fixed carrier modulation is used, voltage and current will generate high-frequency harmonics with large amplitudes near the switching frequency.

[0105] With the modulation signal unchanged, the switching period of the inverter's switching signal can be altered by changing the frequency of the triangular carrier wave. Randomizing the switching period value enables Random Switch Frequency Pulse Width Modulation (RSF-PWM). The carrier frequency under RSF-PWM can be expressed as:

[0106]

[0107] In the formula, It is the center frequency, measured in Hz; R is... Changing random numbers; It represents the spread spectrum range of the RSF-PWM strategy, in Hz.

[0108] like Figure 3 As shown, when using random switching frequency pulse width modulation technology, the period size is different at different times.

[0109] Spread spectrum range in step S3 Simulation analysis determined that the optimal spread spectrum range was 1500Hz, in order to disperse the high-frequency sideband harmonic energy to the frequency bands on both sides of the center frequency and reduce the harmonic amplitude near the switching frequency.

[0110] S4: The disturbance observation value output by the extended state observer is used to feedforward the voltage command of the current loop for compensation. The random SVPWM modulation algorithm generates a PWM signal based on the compensated voltage command. The two work together to drive the permanent magnet synchronous motor to achieve full-frequency harmonic suppression.

[0111] The specific collaborative control logic for full-frequency domain harmonic suppression is as follows:

[0112] After receiving the motor speed feedback signal, the speed loop PI controller outputs a torque reference value. The MTPA regulator generates a dq-axis current reference value based on the torque reference value. The current loop PI controller, combined with the voltage compensation output from the extended state observer, corrects the initial voltage command of the current loop and outputs a compensated voltage command. The SVPWM modulation module converts the compensated voltage command into an inverter switching signal, driving the inverter to output three-phase voltage to the permanent magnet synchronous motor. Simultaneously, the dq-axis current signal of the motor is collected in real time and fed back to the extended state observer, and the motor speed signal is collected and fed back to the speed loop PI controller, forming a closed-loop control.

[0113] To further verify the effectiveness of the proposed global harmonic suppression strategy, this invention takes a permanent magnet synchronous motor (PMSM) of a pure electric vehicle as the research object. A motor electromagnetic field model, a reduced-order housing model, and a PSM vector control model are constructed. A multi-field coupled model of the motor's "mechanical-electrical-magnetic" systems is established using the Simulink-TwinBuilder co-simulation platform. Simulink generates control signals for the inverter based on control requirements and sends them to TwinBuilder. TwinBuilder receives the signals from Simulink and transmits them to the inverter to generate three-phase voltages, which are then transmitted to the reduced-order motor model, enabling motor operation. Simultaneously, the real-time electromagnetic force of the motor is obtained by measuring the dq-axis current and rotor angle, and input into the reduced-order housing model of the electric drive assembly to calculate the vibration response. The filter factor in the ESO is set in the experiment. Tracking factors The value is , Output error gain , The center switching frequency is 10000Hz, and the random SVPWM spread spectrum range is 1500Hz. A full-frequency harmonic suppression strategy is applied at different speeds. Compared with the traditional SVPWM combined with ordinary PI control method, the full-frequency harmonic suppression method for permanent magnet synchronous motors based on cooperative observation and spectrum spread proposed in this invention compensates for voltage deviations caused by system nonlinearity through a state observer and uses a random carrier algorithm to disperse high-frequency sideband harmonic energy, thereby suppressing both low-order and high-frequency sideband harmonics. Based on a multi-field coupling model, the current harmonic suppression effect of this strategy under different operating conditions is comprehensively verified. Figure 4 As shown, after adopting a full-frequency domain harmonic suppression strategy, the amplitudes of the 5th and 7th current harmonics were reduced by a maximum of 81.8%; Figure 5 As shown, the amplitude of high-frequency sideband current harmonics was reduced by a maximum of 62%; Figure 6 As shown, the carrier vibration amplitude was reduced by a maximum of 12.35 dB, proving the effectiveness of the full-frequency domain harmonic suppression strategy proposed in this invention.

[0114] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for full-frequency harmonic suppression of permanent magnet synchronous motors based on cooperative observation and spectrum spread, characterized in that: Includes the following steps: S1: Construct a vector control system for a permanent magnet synchronous motor, the vector control system including a speed loop PI controller, an MTPA regulator, a current loop PI controller, a coordinate transformation module, an SVPWM modulation module, and an inverter; S2: In the current loop of the vector control system, an extended state observer is introduced based on the core logic of the active disturbance rejection control algorithm to expand the comprehensive system disturbance generated during motor operation into a new system state variable. The comprehensive system disturbance includes the dynamic coupling term of the dq axis current and the voltage offset introduced by the inverter nonlinearity. The disturbance is estimated in real time through nonlinear state error feedback to generate a voltage compensation amount to offset the disturbance. S3: The random SVPWM modulation algorithm is used to replace the traditional fixed frequency SVPWM algorithm to generate the PWM signal to drive the inverter; S4: The disturbance observation value output by the extended state observer is fed forward to compensate the voltage command of the current loop. The random SVPWM modulation algorithm generates a PWM signal based on the compensated voltage command. The two work together to drive the permanent magnet synchronous motor to achieve full-frequency harmonic suppression. The construction of the extended state observer and the implementation of nonlinear state error feedback in step S2 are as follows: The extended state equations established after introducing the extended state observer are as follows: ； In the formula, It is an estimation error. This is the actual output of the system. and These are the estimated values ​​of the output variable and the total disturbance, respectively. and They represent and rate of change, and It is the gain of the output error. It is a compensation factor. It is the output of the controller. and Here, is a nonlinear state error feedback function, where, and As a tracking factor, and The filter factor; The expression for nonlinear state error feedback is as follows: ； In the formula, It is the error between the estimated value and the actual value of the output variable; It is the tracking factor, where i takes the values ​​1 and 2; It is the filter factor.

2. The method for full-frequency harmonic suppression of permanent magnet synchronous motors based on cooperative observation and spectrum spread according to claim 1, characterized in that: The specific process for handling the system's overall disturbance in step S2 is as follows: Let the voltage disturbance introduced by the inverter's nonlinearity be represented on the dq axis as follows: and Substituting this into the voltage equation of the motor, we obtain the voltage equation containing voltage disturbance as follows: ； in, and These are the voltages on the dq axes, respectively. and These represent the voltage perturbations on the dq axes, respectively. For stator resistance, Electric angular velocity, This refers to the quadrature-axis current component of the motor. This represents the direct-axis current component of the motor. For the quadrature axis inductance of the motor, It is a direct-axis inductor. It is a permanent magnet flux linkage. This refers to the electric angular velocity; as the motor's operating speed increases, the cross-coupling term... and The amplitude increases significantly, and its dynamic coupling effect will mask the real control quantity, leading to the accumulation of current tracking error; To reduce the impact of coupling terms, the current decoupling error caused by coupling terms and the voltage offset caused by inverter nonlinearity are both considered as disturbances in the system. ； make , , , Rewrite the above formula as: ； The voltage equations of a permanent magnet synchronous motor are first-order; therefore, the extended state observer for the dq-axis voltage is designed as follows: ； In the formula, It is the error between the estimated and measured values ​​of the d-axis current. and These are the dq-axis current values ​​output by the motor, respectively. and They represent and rate of change, It is the d-axis voltage value of the input motor. It is the d-axis current value estimated by the extended state observer. express rate of change, and These represent the total disturbances on the dq axes. and These are the control gains for the dq axes, respectively. It is the total d-axis perturbation estimated by the extended state observer. express The rate of change.

3. The method for full-frequency harmonic suppression of permanent magnet synchronous motors based on cooperative observation and spectrum spread according to claim 1, characterized in that: The random SVPWM modulation algorithm described in step S3 specifically involves: adjusting the carrier frequency... At the center frequency The variation within a random bandwidth in the vicinity is expressed as: ； In the formula, It is the center frequency; R is in Changing random numbers; It is the spread spectrum range of the RSF-PWM strategy.

4. The method for full-frequency harmonic suppression of permanent magnet synchronous motors based on cooperative observation and spectrum spread according to claim 1, characterized in that: The collaborative control logic for full-frequency domain harmonic suppression described in step S4 is as follows: The speed loop PI controller receives the motor speed feedback signal and outputs a torque reference value. The MTPA regulator generates a dq-axis current reference value based on the torque reference value. The current loop PI controller, in conjunction with the voltage compensation amount output by the extended state observer, corrects the initial voltage command of the current loop and outputs a compensated voltage command. The SVPWM modulation module converts the compensated voltage command into an inverter switching signal, driving the inverter to output three-phase voltage to the permanent magnet synchronous motor. At the same time, it collects the motor's dq-axis current signal in real time and feeds it back to the extended state observer, and collects the motor speed signal and feeds it back to the speed loop PI controller, forming a closed-loop control.

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