A permanent magnet synchronous motor control method and system based on step-by-step multi-parameter identification

Abstract

The invention discloses a permanent magnet synchronous motor control method and system based on step-by-step multi-parameter identification, which detects and obtains three-phase stator current, obtains the actual value of the direct- and alternating-axis current at the current moment, obtains the stator inductance in real time, estimates the rotation speed and rotor position, and obtains the direct-axis current, the quadrature-axis current, the direct-axis reference voltage, the quadrature-axis reference voltage and the stator inductance. An online step-by-step parameter identification strategy is adopted based on a model reference adaptive observer to online identify and update the motor rotation speed, rotor position, stator resistance and air gap flux. The direct-axis reference voltage and the quadrature-axis reference voltage are input into a space vector pulse width modulation module after inverse transformation of rotating coordinates to generate a driving pulse signal, and a three-phase inverter is controlled to control the vector of the permanent magnet synchronous motor. The invention helps to solve the problem of under-rank in motor multi-parameter identification, reduce the convergence time of the observer, improve the estimation accuracy, and realize the reliable operation and higher performance control of the permanent magnet synchronous motor drive system.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and more particularly to a permanent magnet synchronous motor control method and system based on step-by-step multi-parameter identification. Background Art

[0002] At present, permanent magnet synchronous motors use permanent magnets to provide excitation, making the motor structure simpler, reducing processing and assembly costs, and eliminating collector rings and brushes that are prone to failure, improving the reliability of motor operation; because no excitation current is required and there is no excitation loss, the efficiency and power density of the motor are improved. In recent years, it has been widely used in high-performance control fields such as aerospace, electric vehicles, and robots. However, the installation of position sensors on permanent magnet synchronous motors for detecting position and measuring speed increases the system size and cost, and has problems such as low reliability. Especially in complex and special environments with high temperature, humidity, and strong radiation, the accuracy and reliability of the position sensor will be affected, thereby reducing the control performance of the motor. Therefore, position sensorless control has become a feasible solution to these problems.

[0003] In order to estimate the rotor speed and rotor position information, sliding mode observers and model reference adaptive observers are often used. However, due to the inherent jitter of the sliding mode observer, which reduces the estimation accuracy, its applicability in high-performance applications is not ideal. Relatively speaking, the model reference adaptive observer has the advantages of high steady-state accuracy and good convergence. However, the parameters of permanent magnet synchronous motors operating under complex and special working conditions are very easy to change, which leads to the deterioration of the estimation accuracy of the traditional model reference adaptive observer, thereby affecting the high-performance and reliable operation of the system.

[0004] Therefore, how to solve the lack-rank problem of multi-parameter identification of permanent magnet motors, improve the permanent magnet motor system in complex environments such as high temperature, humidity, strong radiation, etc. due to sensor reliability, and the decrease in speed control accuracy caused by motor parameter perturbations under complex and special working conditions are problems that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of this, the present invention provides a permanent magnet synchronous motor control method and system based on step-by-step multi-parameter identification to solve some of the problems mentioned in the background technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A permanent magnet synchronous motor control method based on step-by-step multi-parameter identification comprises the following steps:

[0008] S1. Detect and obtain the three-phase stator current, obtain the actual value of the AC and DC axis current at the current moment through coordinate transformation, and obtain the stator inductance according to the actual value of the AC and DC axis current;

[0009] S2. Obtain the estimated speed and rotor position at the current moment, obtain the quadrature-axis current reference value through the speed loop regulator according to the error with the reference speed, set the direct-axis current reference value to zero, obtain the quadrature-axis current error according to the quadrature-axis reference current and the actual current, and obtain the quadrature-axis reference voltage through the quadrature-axis current controller;

[0010] S3. Based on the direct-axis current, quadrature-axis current, direct-axis reference voltage, quadrature-axis reference voltage and stator inductance, an online step-by-step parameter identification strategy is adopted based on the model reference adaptive observer to online identify and update the motor speed, rotor position, stator resistance and air gap flux;

[0011] S4. After the rotating coordinates are inversely transformed, the direct-axis reference voltage and the quadrature-axis reference voltage are input into the space vector pulse width modulation module to generate a driving pulse signal to control the three-phase inverter to perform vector control on the permanent magnet synchronous motor.

[0012] Preferably, the specific contents of S1 include: obtaining inductance and current data by offline measurement, and fitting the inductance and current relationship expression to achieve real-time acquisition and update of inductance parameters:

[0013]

[0014] Among them, i d with i q are the direct axis current and quadrature axis current, m s are the constant terms of the fitting formula, a1, a2 and a3 are the coefficients of the first-order, second-order and third-order terms of the direct-axis current, and b1, b2 and b3 are the coefficients of the first-order, second-order and third-order terms of the quadrature-axis current, respectively.

[0015] Preferably, the specific content of S2 is: the estimated speed is input into the speed outer loop and compared with the reference speed to obtain an error signal and given to the speed outer loop proportional integral regulator to obtain the quadrature-axis reference current, the estimated rotor position is input into the rotating coordinate transformation module and the rotating coordinate inverse transformation module, the reference value of the direct-axis reference current is 0, the error between the direct-axis reference current and the direct-axis actual current is input into the direct-axis proportional integral regulator to obtain the direct-axis reference voltage, and the error between the quadrature-axis reference current and the quadrature-axis actual current is input into the quadrature-axis proportional integral regulator to obtain the quadrature-axis reference voltage.

[0016] Preferably, the specific content of S3 includes:

[0017] The inductance parameters are updated in real time according to the stator inductance obtained in real time;

[0018] Based on the model reference adaptive observer, a multi-parameter identification strategy is designed to realize online parameter step-by-step identification of motor speed, stator resistance, and permanent magnet flux linkage.

[0019] A variable parameter PI regulator is designed to adaptively adjust the model reference adaptive observer.

[0020] Preferably, the variable parameter PI regulator is a function of the observation error, specifically:

[0021]

[0022] Among them, k p0 , k i0 is the initial PI parameter, k ps , k is is the adjustment range coefficient, d p d i To adjust the speed coefficient.

[0023] Preferably, the permanent magnet synchronous motor speed identification expression is:

[0024]

[0025] in, To identify the speed, and are the direct-axis current and quadrature-axis current identification values, L s is the stator inductance, ψ f is the air gap flux, k pω , k iω They are respectively the proportional coefficient and integral coefficient of the adaptive mechanism in the speed identification link.

[0026] Preferably, the permanent magnet synchronous motor stator resistance identification expression is:

[0027]

[0028] in, To identify the stator resistance, k pr , k ir are the proportional coefficient and integral coefficient of the adaptive mechanism in the stator resistance identification link, i′ d =i d +ψ f / L s , i′ q =i q , u′ d =u d +R s ψ f / L s , u′ q =u q .

[0029] Preferably, the permanent magnet flux identification expression of the permanent magnet synchronous motor is:

[0030]

[0031] in, is the air gap flux identification value, k pf , k if They are respectively the proportional coefficient and integral coefficient of the adaptive mechanism in the air gap flux identification link.

[0032] A permanent magnet synchronous motor control system based on step-by-step multi-parameter identification, including a permanent magnet synchronous motor position sensorless double closed-loop vector control model;

[0033] The permanent magnet synchronous motor position sensorless double closed-loop vector control model includes a speed outer loop module, a current inner loop module, a coordinate transformation module, a space vector pulse width modulation module, a power conversion module, and a speed and rotor position observation module based on step-by-step multi-parameter identification;

[0034] The speed and rotor position observation module based on step-by-step multi-parameter identification includes an inductance parameter real-time updating unit, a multi-parameter identification unit and a variable parameter PI regulator adaptive mechanism.

[0035] Preferably, the speed outer loop module and the current inner loop module both use proportional-integral regulators to achieve zero-static-error tracking of speed and current, the coordinate transformation module includes stationary coordinate transformation, rotating coordinate transformation and rotating coordinate inverse transformation, and the power transformation module uses a three-phase two-level inverter to provide three-phase alternating current to the permanent magnet synchronous motor.

[0036] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a permanent magnet synchronous motor control method and system based on step-by-step multi-parameter identification, which fits the polynomial relationship expression between inductance and current offline, and applies it to the real-time update of online inductance parameters, thereby ensuring the accuracy of the inductance parameters used by the subsequent model reference adaptive observer, and improving the speed of online determination of real-time inductance parameters, thereby eliminating the disadvantage of significantly increasing the complexity of the algorithm when using other forms of observers or introducing inductance identification in the subsequent model reference adaptive observer;

[0037] Based on the model reference adaptive observer, the motor speed, stator resistance and air gap flux are identified online step by step, solving the problems of large estimation error and easy falling into local optimal solution caused by the lack of rank when multiple parameters are identified at the same time.

[0038] In order to further reduce the adjustment time of the model reference adaptive observer and improve the estimation accuracy, the proportional coefficient and integral coefficient of the adaptive mechanism PI regulator are defined as functions of the estimation error respectively, so as to realize dynamic adjustment of parameters within a certain range and improve the overall performance of the model reference adaptive observer. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0040] Figure 1 The accompanying drawing is a schematic diagram of the principle of a permanent magnet synchronous motor control method based on step-by-step multi-parameter identification provided by the present invention;

[0041] Figure 2 The accompanying drawing is a schematic diagram of the control principle of the online step-by-step parameter identification strategy of the model reference adaptive observer provided by the present invention;

[0042] Figure 3 The accompanying drawing is a schematic diagram of the principle of the improved model reference adaptive observer provided by the present invention;

[0043] Figure 4 The accompanying drawing is a schematic diagram of the stator resistance offline measurement principle provided by the present invention;

[0044] Figure 5 The accompanying drawing is a topological diagram of a two-level three-phase inverter provided by the present invention;

[0045] Figure 6 The accompanying drawing is a schematic diagram of the model reference adaptive observer control structure provided by the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The embodiment of the present invention discloses a permanent magnet synchronous motor control method based on step-by-step multi-parameter identification, such as Figure 1 , including the following steps:

[0048] S1. Detect and obtain the three-phase stator current, obtain the actual value of the AC and DC axis current at the current moment through coordinate transformation, and obtain the stator inductance according to the actual value of the AC and DC axis current;

[0049] S2. Obtain the estimated speed and rotor position at the current moment, obtain the quadrature-axis current reference value through the speed loop regulator according to the error with the reference speed, set the direct-axis current reference value to zero, obtain the quadrature-axis current error according to the quadrature-axis reference current and the actual current, and obtain the quadrature-axis reference voltage through the quadrature-axis current controller;

[0050] S3. Based on the direct-axis current, quadrature-axis current, direct-axis reference voltage, quadrature-axis reference voltage and stator inductance, an online step-by-step parameter identification strategy is adopted based on the model reference adaptive observer to online identify and update the motor speed, rotor position, stator resistance and air gap flux;

[0051] S4. After the rotating coordinate inverse transformation, the direct-axis reference voltage and the quadrature-axis reference voltage are input into the space vector pulse width modulation module to generate a driving pulse signal to control the three-phase inverter to perform vector control on the permanent magnet synchronous motor.

[0052] In order to further implement the above technical solution, the specific contents of S1 include: offline measurement to obtain inductance and current data, and fitting the inductance and current relationship expression to achieve real-time acquisition and update of inductance parameters:

[0053]

[0054] Among them, i d with i q are the direct axis current and quadrature axis current, m s are the constant terms of the fitting formula, a1, a2 and a3 are the coefficients of the first-order, second-order and third-order terms of the direct-axis current, and b1, b2 and b3 are the coefficients of the first-order, second-order and third-order terms of the quadrature-axis current, respectively.

[0055] Under light load or no-load conditions, the inductance changes approximately linearly with the current, and the higher-order terms can be ignored to reduce the computational burden. After the inductance parameters are obtained through online calculation, they are updated and used in the model reference adaptive observer of the subsequent stage.

[0056] In order to further implement the above technical solution, Figure 1 The specific content of S2 is: the estimated speed is input into the speed outer loop and compared with the reference speed to obtain an error signal and given to the speed outer loop proportional integral regulator to obtain the quadrature-axis reference current; the estimated rotor position is input into the rotating coordinate transformation module and the rotating coordinate inverse transformation module; the reference value of the direct-axis reference current is 0; the error between the direct-axis reference current and the actual direct-axis current is input into the direct-axis proportional integral regulator to obtain the direct-axis reference voltage; the error between the quadrature-axis reference current and the actual quadrature-axis current is input into the quadrature-axis proportional integral regulator to obtain the quadrature-axis reference voltage.

[0057] In order to further implement the above technical solution, Figure 2 and Figure 3 , the specific contents of S3 include:

[0058] The inductance parameters are updated in real time according to the stator inductance obtained in real time;

[0059] Based on the model reference adaptive observer, a multi-parameter identification strategy is designed to realize online parameter step-by-step identification of motor speed, stator resistance, and permanent magnet flux linkage.

[0060] A variable parameter PI regulator is designed to adaptively adjust the model reference adaptive observer.

[0061] In this embodiment, the stator resistance and air gap flux value need to be measured offline when calculating the inductance parameter offline to ensure the accuracy of the offline calculation as much as possible. The present invention uses the DC volt-ampere method to measure the stator resistance of the permanent magnet synchronous motor offline; the offline identification of the air gap flux adopts the motor pair dragging method to drag the permanent magnet synchronous motor to a stable speed, and the motor winding remains open-circuited. At this time, the flux value can be calculated by the measured back electromotive force value and the speed value; in the offline inductance measurement, in order to improve the measurement accuracy, the motor is stably operated in the high-speed area so that the back electromotive force is much larger than the resistance voltage drop, and the inductance parameters under different currents are measured, and multiple sets of data are collected to ensure the measurement accuracy and reduce the error. Then, the inductance and current are fitted to obtain the inductance and current expressions for online inductance parameter update.

[0062] Specific: such as Figure 4 , the permanent magnet synchronous motor starts running and waits for the current to stabilize before starting to measure and calculate the stator resistance R s The calculation formula is like Figure 5 , the switch state of the three-phase bridge arm of the inverter is set as follows: VT1 and VT4 are high-frequency complementary signals, VT3 and VT5 are always turned off, and VT6 and VT2 are always turned on. According to the duty cycle, the calculation formula of the stator resistance is further expressed as Where d represents the duty cycle. During the measurement process, two duty cycles d1 and d2 are used to obtain the corresponding currents I1 and I2 respectively, and the stator resistance value can be calculated as

[0063] When the permanent magnet synchronous motor is driven by the coaxial prime mover to rotate to a stable speed and the motor winding remains open, the corresponding direct axis current and quadrature axis current should both be 0. At this time, the voltage equation under the stable operation state of the motor can be used. Get u s =ω e ψ f The voltage vector amplitude is U Am is the voltage amplitude of phase A, U ABm is the motor line voltage amplitude, U AB is the effective value of the motor line voltage. The final offline calculation formula for the air gap flux is: Where n is the motor mechanical speed, p n is the number of motor pole pairs.

[0064] In order to further implement the above technical solution, Figure 3 As shown, the proportional coefficient and integral coefficient of the original adaptive mechanism are defined as functions of the observation error, and the variable parameter PI regulator is a function of the observation error, specifically:

[0065]

[0066] Among them, k p0 , k i0 is the initial PI parameter, k ps , k is is the adjustment range coefficient, d p d i To adjust the speed coefficient.

[0067] In this embodiment, an online step-by-step parameter identification strategy based on a model reference adaptive observer has better parameter robustness and parameter identification accuracy. Specifically: the first step completes the identification of the permanent magnet synchronous motor speed, and the rotor position can be obtained by integrating the speed. The stator resistance and the permanent magnet flux are identified in the second and third steps respectively after the identified speed is stable. The identified values ​​of the stator resistance and the permanent magnet flux are used to update the corresponding parameter values. The parameter robustness lies in that the stator resistance and the permanent magnet flux will change due to the change of the motor operating temperature, and the change is nonlinear, and the identification of the speed is a method based on the motor parameter model. Therefore, the real-time observation of the stator resistance and the permanent magnet flux is realized and updated in the model through the step-by-step parameter identification method based on model reference adaptation, which ensures the accurate identification of the motor speed, and the rotor position is obtained through the speed through the integration link.

[0068] In order to further implement the above technical solution, the permanent magnet synchronous motor speed identification expression is:

[0069]

[0070] in, To identify the speed, and are the direct-axis current and quadrature-axis current identification values, L s is the stator inductance, ψ f is the air gap flux, k pω , k iω They are respectively the proportional coefficient and integral coefficient of the adaptive mechanism in the speed identification link.

[0071] Specifically: The stator current state equation of the permanent magnet synchronous motor is:

[0072]

[0073] make:

[0074]

[0075] We can get:

[0076] p[i′]=[A][i′]+[B][u′]

[0077] As a reference model equation, the adjustable model can be constructed according to the structural form:

[0078]

[0079] Among them, the first two items are adjustable models when resistance and flux are not considered, and the last three items are model compensation items when resistance and flux changes are considered;

[0080] The equation can be further expressed as:

[0081]

[0082] By comparing the reference model and the adjustable model, the estimated error equation is:

[0083]

[0084] Considering that the resistance estimation error and the flux estimation error are zero, we can get:

[0085]

[0086] That is, the first step is to estimate the motor speed only, and its error equation is:

[0087]

[0088] make:

[0089]

[0090] The above formula can be expressed as:

[0091] p[g ω ]=[A][ε ω ]-[D]

[0092] From the motor speed error equation, it can be seen that the estimated speed depends on the current error, given by Figure 6 It can be seen that it is a nonlinear control system, the forward channel is a linear constant link, and the feedback channel is a nonlinear time-varying link. According to the system superstability theory, it is necessary to ensure that the transfer function matrix of the forward channel link is strictly positive and real, so that the nonlinear time-varying link of the corresponding feedback channel can meet Popov's superstability criterion.

[0093] Therefore, the standard relationship can be obtained:

[0094]

[0095] By combining it with the motor speed error equation, the adaptive law of the motor speed can be obtained:

[0096]

[0097] In order to further implement the above technical solution, the identification expression of the stator resistance of the permanent magnet synchronous motor is:

[0098]

[0099] in, To identify the stator resistance, k pr , k ir They are respectively the proportional coefficient and integral coefficient of the adaptive mechanism in the stator resistance identification link.

[0100] Specific:

[0101] Used to estimate the stator resistance of the motor, considering that the speed estimation error and the flux estimation error are both zero, we can get:

[0102]

[0103] The stator resistance estimation error is defined as:

[0104]

[0105] Further, the stator resistance estimation error equation can be obtained:

[0106]

[0107] This can be expressed as:

[0108]

[0109] make:

[0110]

[0111] but:

[0112]

[0113] Still represents a nonlinear feedback system. If the current channel transfer function matrix satisfies strict positive real, then the feedback link satisfies the superstability criterion, that is:

[0114]

[0115] By combining it with the motor stator resistance error equation, the adaptive law of the motor stator resistance can be obtained:

[0116]

[0117] In order to further implement the above technical solution, the permanent magnet flux identification expression of the permanent magnet synchronous motor is:

[0118]

[0119] in, is the air gap flux identification value, k pf , k if They are respectively the proportional coefficient and integral coefficient of the adaptive mechanism in the air gap flux identification link.

[0120] Specific:

[0121] Used to estimate the air gap flux of the motor, considering that the speed estimation error and the stator resistance estimation error are both zero, we can get:

[0122]

[0123] Define the permanent magnet flux estimation error:

[0124]

[0125] Further, the permanent magnet flux estimation error equation can be obtained as:

[0126]

[0127] The Popov superstability relation that must be satisfied when estimating the permanent magnet flux is:

[0128]

[0129] It can be expressed as:

[0130]

[0131] By combining the permanent magnet flux error equation of the motor, the adaptive law of the permanent magnet flux of the motor can be obtained as follows:

[0132]

[0133] A permanent magnet synchronous motor control system based on step-by-step multi-parameter identification, such as Figure 1 , including a position sensorless double closed-loop vector control model for permanent magnet synchronous motor;

[0134] The permanent magnet synchronous motor position sensorless double closed-loop vector control model includes a speed outer loop module, a current inner loop module, a coordinate transformation module, a space vector pulse width modulation module, a power conversion module, and a speed and rotor position observation module based on step-by-step multi-parameter identification;

[0135] The speed and rotor position observation module based on step-by-step multi-parameter identification includes an inductance parameter real-time update unit, a multi-parameter identification unit and a variable parameter PI regulator.

[0136] In order to further implement the above technical scheme, both the speed outer loop module and the current inner loop module adopt proportional-integral regulator to realize zero-static-error tracking of speed and current. The coordinate transformation module includes stationary coordinate transformation, rotating coordinate transformation and rotating coordinate inverse transformation. The power conversion module adopts a three-phase two-level inverter to provide three-phase alternating current to the permanent magnet synchronous motor.

[0137] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0138] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A permanent magnet synchronous motor control method based on step-by-step multi-parameter identification, characterized in that: The following steps are involved: S1. Detect and obtain the three-phase stator current, obtain the actual value of the AC and DC axis current at the current moment through coordinate transformation, and obtain the stator inductance in real time according to the actual value of the AC and DC axis current; S2. Obtain the estimated speed and rotor position at the current moment, obtain the quadrature-axis current reference value through the speed loop regulator according to the error with the reference speed, set the direct-axis current reference value to zero, obtain the quadrature-axis current error according to the quadrature-axis reference current and the actual current, and obtain the quadrature-axis reference voltage through the quadrature-axis current controller; S3. According to the direct-axis current, quadrature-axis current, direct-axis reference voltage, quadrature-axis reference voltage and stator inductance, an online step-by-step parameter identification strategy is adopted based on the model reference adaptive observer to perform online identification and update of the motor speed, rotor position, stator resistance and air gap flux; S4. The direct-axis reference voltage and the quadrature-axis reference voltage are input into the space vector pulse width modulation module after the rotating coordinate inverse transformation to generate a drive pulse signal to control the three-phase inverter to control the permanent magnet synchronous motor vector; The specific contents of S1 include: offline measurement to obtain inductance and current data, and fitting the inductance and current relationship expression to achieve real-time acquisition and update of inductance parameters: Among them, i d with i q are the direct axis current and quadrature axis current, m s is the constant term of the fitting formula, a1, a2 and a3 are the coefficients of the first-order, second-order and third-order terms of the direct-axis current, b1, b2 and b3 are the coefficients of the first-order, second-order and third-order terms of the quadrature-axis current, respectively; The specific contents of S3 include: The inductance parameters are updated in real time according to the stator inductance obtained in real time; Based on the model reference adaptive observer, a multi-parameter identification strategy is designed to realize online parameter step-by-step identification of motor speed, stator resistance and air gap flux. A variable parameter PI regulator is designed to improve the adaptive mechanism of the model reference adaptive observer and improve its parameter identification convergence speed and accuracy.

2. A permanent magnet synchronous motor control method based on step-by-step multi-parameter identification according to claim 1, characterized in that: The specific content of S2 is: the estimated speed is input into the speed outer loop, compared with the reference speed to obtain a speed error signal and input into the speed outer loop proportional integral regulator to obtain the quadrature-axis reference current; the estimated rotor position is input into the rotating coordinate transformation module and the rotating coordinate inverse transformation module; the reference value of the direct-axis reference current is 0; the error between the direct-axis reference current and the actual direct-axis current is input into the direct-axis proportional integral regulator to obtain the direct-axis reference voltage; the error between the quadrature-axis reference current and the actual quadrature-axis current is input into the quadrature-axis proportional integral regulator to obtain the quadrature-axis reference voltage.

3. The permanent magnet synchronous motor control method based on step-by-step multi-parameter identification according to claim 1 is characterized in that: The variable parameter PI regulator is a function of the observation error, specifically: Among them, k p0 , k i0 is the initial PI parameter, k ps , k is is the adjustment range coefficient, d p ,d i To adjust the speed coefficient.

4. The permanent magnet synchronous motor control method based on step-by-step multi-parameter identification according to claim 1 is characterized in that: The speed identification expression of permanent magnet synchronous motor is: in, To identify the speed, and are the direct-axis current and quadrature-axis current identification values, L s is the stator inductance, ψ f is the air gap flux, k pω , k iω They are respectively the proportional coefficient and integral coefficient of the adaptive mechanism in the speed identification link.

5. The permanent magnet synchronous motor control method based on step-by-step multi-parameter identification according to claim 1 is characterized in that: The identification expression of the stator resistance of permanent magnet synchronous motor is: in, To identify the stator resistance, k pr , k ir are the proportional coefficient and integral coefficient of the adaptive mechanism in the stator resistance identification link, i d ′=i d +ψ f / L s ,i q ′=i q , u′ d =u d +R s ψ f / L s , u′ q =u q .

6. A permanent magnet synchronous motor control method based on step-by-step multi-parameter identification according to claim 1, characterized in that: The identification expression of permanent magnet flux linkage of permanent magnet synchronous motor is: in, is the air gap flux identification value, k pf , k if They are respectively the proportional coefficient and integral coefficient of the adaptive mechanism in the air gap flux identification link.

7. A permanent magnet synchronous motor control system based on step-by-step multi-parameter identification, based on a permanent magnet synchronous motor control method based on step-by-step multi-parameter identification according to any one of claims 1 to 6, characterized in that: Including permanent magnet synchronous motor position sensorless double closed-loop vector control model; The permanent magnet synchronous motor position sensorless double closed-loop vector control model includes a speed outer loop module, a current inner loop module, a coordinate transformation module, a space vector pulse width modulation module, a power conversion module, and a speed and rotor position observation module based on step-by-step multi-parameter identification; The speed and rotor position observation module based on step-by-step multi-parameter identification includes an inductance parameter real-time updating unit, a multi-parameter identification unit and a variable parameter PI regulator adaptive mechanism.

8. A permanent magnet synchronous motor control system based on step-by-step multi-parameter identification according to claim 7, characterized in that: The speed outer loop module and the current inner loop module both use proportional-integral regulators to achieve zero-static-error tracking of speed and current. The coordinate transformation module includes stationary coordinate transformation, rotating coordinate transformation, and rotating coordinate inverse transformation. The power conversion module uses a three-phase two-level inverter to provide three-phase AC power to the permanent magnet synchronous motor.

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