阅读说明：本技术 电子水泵永磁同步电机无传感器控制装置及方法 (Electronic water pump permanent magnet synchronous motor sensorless control device and method ) 是由 杨坤 李�浩 于 2021-01-13 设计创作，主要内容包括：本发明实施例公开了一种电子水泵永磁同步电机无传感器控制装置及方法,所述装置包括电流采样模块、磁链观测模块、锁相环模块、SVPWM调制模块、预定位模块、IF速度开环模块、无传感器速度闭环模块,预定位模块经过电流坐标变换得到同步旋转坐标系下直流的分量,将差值输入PI控制器调节,得到参考电压信号；IF速度开环模块：电流保持预定位电流不变,电流由PI控制器闭环控制,参数增强；无传感器速度闭环模块：经过坐标变换得到旋转坐标系下电流与电压分量,反正切计算得到转子角度,实时估算电机转速与转子位置。本发明可在无传感器条件下可靠启动电子水泵,低速稳定性与抗干扰能力强,高速动态性能佳,且对电机参数不敏感,提高电机控制鲁棒性。(The embodiment of the invention discloses a sensorless control device and a sensorless control method for a permanent magnet synchronous motor of an electronic water pump, wherein the device comprises a current sampling module, a flux linkage observation module, a phase-locked loop module, an SVPWM (space vector pulse width modulation) module, a pre-positioning module, an IF (intermediate frequency) speed open-loop module and a sensorless speed closed-loop module, wherein the pre-positioning module obtains a direct current component under a synchronous rotating coordinate system through current coordinate transformation, and inputs a difference value into a PI (proportional-integral) controller for regulation to obtain a reference voltage signal; an IF speed open loop module: the current keeps the preset bit current unchanged, the current is controlled by a PI controller in a closed loop mode, and the parameters are enhanced; sensorless speed closed loop module: and obtaining current and voltage components in a rotating coordinate system through coordinate transformation, performing arc tangent calculation to obtain a rotor angle, and estimating the rotating speed and the rotor position of the motor in real time. The invention can reliably start the electronic water pump under the condition of no sensor, has strong low-speed stability and anti-interference capability and good high-speed dynamic performance, is not sensitive to motor parameters, and improves the control robustness of the motor.)

1. A sensorless control device of an electronic water pump permanent magnet synchronous motor comprises a current sampling module, a flux linkage observation module, a phase-locked loop module and an SVPWM modulation module, and is characterized by also comprising a pre-positioning module, an IF speed open-loop module and a sensorless speed closed-loop module,

a pre-positioning module: after the motor is started, the three-phase current i of the motor is sampled and calculated in real time according to the current sampling module_a、i_b、i_cSetting the rotor position angleConverting the three-phase current through current coordinates to obtain a direct current component i under a synchronous rotating coordinate system_dAnd i_qLet give i^* _dEqual to a predetermined bit current I₀，i^* _qInputting the difference value of the given current value and the coordinate-transformed direct current component into a PI controller for regulation to obtain a reference voltage signal u_dAnd u_qAccording to u_dAnd u_qControlling a motor rotor to enter a pre-positioning mode;

an IF speed open loop module: after entering a preset position mode for preset time, entering an IF speed open-loop mode, keeping the preset position current constant, controlling the current in a closed-loop mode by a PI controller, and controlling the parameter enhancement kp1 to be 300 and ki1 to be 450; the frequency is continuously increased at a fixed acceleration of 1000 rpm/s;

sensorless speed closed loop module: when the rotating speed reaches 1/6 rated rotating speed, real-time sampling and calculating the three-phase current i of the motor through the current sampling module_a、i_b、i_cAnd three-phase voltage u_a、u_b、u_cObtaining the component i of the current under the rotating coordinate system through coordinate transformation_α、i_βAnd a voltage component u_α、u_βThe stator flux linkage psi is obtained by inputting the stator flux linkage psi into a flux linkage observation module_sαAnd psi_sβTransformed to obtain rotor flux linkage psi_rαAnd psi_rβAnd calculating the rotor angle by the arc tangentThe obtained rotor angleInput to a phase-locked loop module to estimate the rotating speed of the motor in real time_pllAnd rotor position; will give a given speed_refWith the estimated speed_pllThe difference is input into a PI controller, the PI controller parameters kp2 are 200, ki2 are 150, and a given torque current i is output^* _q(ii) a Let the flux linkage current give i^* _d＝0，i^* _d、i^* _qCurrent i detected in real time after coordinate transformation_d、i_qThe difference values pass through corresponding PI controllers respectively, the parameters are kept unchanged, and u is output_d、u_q(ii) a And then six paths of PWM driving signals are generated through an SVPWM modulation module, and an inverter circuit is driven to realize the sensorless control of the motor.

2. The sensorless control device of the PMSM of electronic water pump as claimed in claim 1, wherein in the flux linkage observation module, the stator flux linkage ψ_sαThe low-pass filter is used for replacing a pure integral element for calculation, the filtering time is 2Ts, the Ts is the reciprocal of the switching frequency, and the stator flux linkage psi_sβThe filtering time of the middle low-pass filter is 4 Ts; when psi_sαIs greater thanCoefficient of time compensationWhen psi_sβGreater than psi_sCoefficient of time compensationThe expression of the compensated stator flux linkage is as follows:

where k is the filter coefficient, R is the stator resistance,. psi_sIs the stator flux linkage amplitude.

3. The sensorless control apparatus of an electric water pump pmsm according to claim 1, wherein the estimated rotational speed in the pll module Observing the angle of the rotor of the module for flux linkageRotor angle observed with the first 5 beatsDifference, estimated angle Rotor angle estimated for current beat of phase-locked loop moduleAnd taking a value of 100-300 as a phase-locked loop adjusting coefficient by taking a rotor angle difference value estimated in the first 5 beats.

4. The sensorless control device of an electronic water pump PMSM according to claim 1, wherein in the pre-positioning module, the current I is pre-positioned₀0.25In, In is motor ratingThe current, the preset bit current is closed-loop controlled by a PI controller, and is a parameter kp 0-200, and ki 0-300; predetermined bit time T₀＝0.1s。

5. A sensorless control method for an electronic water pump permanent magnet synchronous motor is characterized by comprising the following steps:

pre-positioning: real-time sampling and calculating three-phase current i of motor through current sampling module_a、i_b、i_cSetting the rotor position angleConverting the three-phase current through current coordinates to obtain a direct current component i under a synchronous rotating coordinate system_dAnd i_qLet give i^* _dEqual to a predetermined bit current I₀，i^* _qInputting the difference value of the given current value and the coordinate-transformed direct current component into a PI controller for regulation to obtain a reference voltage signal u_dAnd u_qAccording to u_dAnd u_qControlling a motor rotor, and entering an IF speed open loop step after a preset position time;

an IF speed open loop step: keeping the preset current constant, controlling the current in a closed loop mode by a PI controller, and increasing the parameters kp1 to 300 and ki1 to 450; the frequency is continuously increased at a fixed acceleration of 1000rpm/s, and when the rotating speed reaches 1/6 rated rotating speed, a sensorless speed closed loop step is carried out;

a sensorless speed closed loop step: real-time sampling and calculating three-phase current i of motor through current sampling module_a、i_b、i_cAnd three-phase voltage u_a、u_b、u_cObtaining the component i of the current under the rotating coordinate system through coordinate transformation_α、i_βAnd a voltage component u_α、u_βThe stator flux linkage psi is obtained by inputting the stator flux linkage psi into a flux linkage observation module_sαAnd psi_sβTransformed to obtain rotor flux linkage psi_rαAnd psi_rβAnd calculating the rotor angle by the arc tangentThe obtained rotor angleInput to a phase-locked loop module to estimate the rotating speed of the motor in real time_pllAnd rotor position; will give a given speed_refWith the estimated speed_pllThe difference is input into a PI controller, the PI controller parameters kp2 are 200, ki2 are 150, and a given torque current i is output^* _q(ii) a Let the flux linkage current give i^* _d＝0，i^* _d、i^* _qCurrent i detected in real time after coordinate transformation_d、i_qThe difference values pass through corresponding PI controllers respectively, the parameters are kept unchanged, and u is output_d、u_q(ii) a And then six paths of PWM driving signals are generated through an SVPWM modulation module, and an inverter circuit is driven to realize the sensorless control of the motor.

6. The sensorless control method of the PMSM of electronic water pump as claimed in claim 5, wherein in the sensorless speed closed loop step, the stator flux linkage ψ in the flux linkage observation module_sαThe low-pass filter is used for replacing a pure integral element for calculation, the filtering time is 2Ts, the Ts is the reciprocal of the switching frequency, and the stator flux linkage psi_sβThe filtering time of the middle low-pass filter is 4 Ts; when psi_sαIs greater thanCoefficient of time compensationWhen psi_sβGreater than psi_sCoefficient of time compensationThe expression of the compensated stator flux linkage is as follows:

where k is the filter coefficient, R is the stator resistance,. psi_sIs the stator flux linkage amplitude.

7. The sensorless control method of an electric water pump PMSM according to claim 5 wherein in the sensorless speed closed loop step, the PLL module estimates the speed of rotation Observing the angle of the rotor of the module for flux linkageRotor angle observed with the first 5 beatsDifference, estimated angle Rotor angle estimated for current beat of phase-locked loop moduleAnd taking a value of 100-300 as a phase-locked loop adjusting coefficient by taking a rotor angle difference value estimated in the first 5 beats.

8. The sensorless control method of an electronic water pump PMSM according to claim 5, wherein the predeterminationIn the bit step, the time T is predetermined₀0.1s, predetermined bit current I₀And 0.25In, In is the rated current of the motor, the preset bit current is controlled by a PI controller In a closed loop mode, the parameters kp0 are 200, and ki0 is 300.

Technical Field

The invention relates to the technical field of new energy automobiles, in particular to a sensorless control device and method for an electronic water pump permanent magnet synchronous motor.

Background

Modern automobiles also have most mechanical parts, which are not high in control precision and high in energy consumption. With the development of electric control technology, the demand for intellectualization and electromotion of an automobile system is continuously increased, and the overall performance of the automobile is more and more perfect. At present, most automobile cooling systems are still in a passive cooling mode, namely, a mechanical water pump driven by an engine crankshaft is adopted, so that the problems of difficulty in low-temperature starting, poor speed regulation effect, low efficiency and the like exist, and the performance of the cooling system is influenced. At present, an electronic water pump motor mainly comprises a permanent magnet brushless direct current motor (BLDC) and a Permanent Magnet Synchronous Motor (PMSM), and due to the defects of large noise, low efficiency, large torque ripple and the like of the BLDC, the PMSM has the characteristics of small volume, small noise, large power density and the like, so that the electronic water pump motor occupies higher and higher proportion. The PMSM for the electronic water pump needs to adapt to different working environments, and the electronic water pump for the automobile generally needs to keep normal and efficient operation at the ambient temperature of-40-60 degrees. And along with the continuous work of the motor, the temperature of the motor is continuously changed, and the internal resistance and inductance parameters of the motor are dynamically changed, so that the performance of a motor control system is influenced. How to compensate the influence of the motor parameters on the system and improve the performance of the control system is one of the technical problems which needs to be solved urgently by experts and scholars in the field.

In order to solve the problems, experts and scholars at home and abroad propose various sensorless control methods such as a sliding-mode observer method and a Kalman filtering method. The sliding mode observer method is a nonlinear control method, and the control principle is that a sliding mode switching surface is created in the state space of a system by taking the difference value between observed current and actual current, and a corresponding sliding mode control function is constructed. However, the sliding mode control function is discontinuous high-frequency switch control, which easily causes system buffeting and has poor performance at low speed. The Kalman filtering method is an optimal estimation method, the basic principle is that stator current, voltage and rotor flux linkage are used as input state variables, a motor nonlinear model is linearized, a rotor position-related motor state equation is established, recursive calculation of a linear Kalman filter is carried out, and an estimated value of required actual rotor position information can be obtained, so that sensorless control of the permanent magnet synchronous motor is realized.

Disclosure of Invention

The technical problem to be solved by the embodiment of the invention is to provide a sensorless control device and method for an electronic water pump permanent magnet synchronous motor, so as to improve the robustness of motor control.

In order to solve the above technical problems, an embodiment of the present invention provides a sensorless control device for a permanent magnet synchronous motor of an electronic water pump, including a current sampling module, a flux linkage observation module, a phase-locked loop module, an SVPWM modulation module, a pre-positioning module, an IF speed open-loop module, and a sensorless speed closed-loop module,

a pre-positioning module: after the motor is started, the three-phase current i of the motor is sampled and calculated in real time according to the current sampling module_a、i_b、i_cSetting the rotor position angleConverting the three-phase current through current coordinates to obtain a direct current component i under a synchronous rotating coordinate system_dAnd i_qLet give i^* _dEqual to a predetermined bit current I₀，i^* _qInputting the difference value of the given current value and the coordinate-transformed direct current component into a PI controller for regulation to obtain a reference voltage signal u_dAnd u_qAccording to u_dAnd u_qControlling a motor rotor to enter a pre-positioning mode;

an IF speed open loop module: after entering a preset position mode for preset time, entering an IF speed open-loop mode, keeping the preset position current constant, controlling the current in a closed-loop mode by a PI controller, and controlling the parameter enhancement kp1 to be 300 and ki1 to be 450; the frequency is continuously increased at a fixed acceleration of 1000 rpm/s;

sensorless speed closed loop module: when the rotating speed reaches 1/6 rated rotating speed, real-time sampling and calculating the three-phase current i of the motor through the current sampling module_a、i_b、i_cAnd three-phase voltage u_a、u_b、u_cPassing through the coordinateConverting to obtain a component i of the current under a rotating coordinate system_α、i_βAnd a voltage component u_α、u_βThe stator flux linkage psi is obtained by inputting the stator flux linkage psi into a flux linkage observation module_sαAnd psi_sBeta, transformation to obtain rotor flux linkage psi_rαAnd psi_rCalculating beta, arctangent to obtain rotor angleThe obtained rotor angleInput to a phase-locked loop module to estimate the rotating speed of the motor in real time_pllAnd rotor position; will give a given speed_refWith the estimated speed_pllThe difference is input into a PI controller, the PI controller parameters kp2 are 200, ki2 are 150, and a given torque current i is output^* _q(ii) a Let the flux linkage current give i^* _d＝0，i^* _d、i^* _qCurrent i detected in real time after coordinate transformation_d、i_qThe difference values pass through corresponding PI controllers respectively, the parameters are kept unchanged, and u is output_d、u_q(ii) a And then six paths of PWM driving signals are generated through an SVPWM modulation module, and an inverter circuit is driven to realize the sensorless control of the motor.

Correspondingly, the embodiment of the invention also provides a sensorless control method of the permanent magnet synchronous motor of the electronic water pump, which comprises the following steps:

pre-positioning: real-time sampling and calculating three-phase current i of motor through current sampling module_a、i_b、i_cSetting the rotor position angleConverting the three-phase current through current coordinates to obtain a direct current component i under a synchronous rotating coordinate system_dAnd i_qLet give i^* _dEqual to a predetermined bit current I₀，i^* _qThe difference value of the given current value and the DC component after coordinate transformation is input into a PI controller to be regulated to obtain a reference voltageSignal u_dAnd u_qAccording to u_dAnd u_qControlling a motor rotor, and entering an IF speed open loop step after a preset position time;

an IF speed open loop step: keeping the preset current constant, controlling the current in a closed loop mode by a PI controller, and increasing the parameters kp1 to 300 and ki1 to 450; the frequency is continuously increased at a fixed acceleration of 1000rpm/s, and when the rotating speed reaches 1/6 rated rotating speed, a sensorless speed closed loop step is carried out;

a sensorless speed closed loop step: real-time sampling and calculating three-phase current i of motor through current sampling module_a、i_b、i_cAnd three-phase voltage u_a、u_b、u_cObtaining the component i of the current under the rotating coordinate system through coordinate transformation_α、i_βAnd a voltage component u_α、u_βThe stator flux linkage psi is obtained by inputting the stator flux linkage psi into a flux linkage observation module_sαAnd psi_sβTransformed to obtain rotor flux linkage psi_rαAnd psi_rβAnd calculating the rotor angle by the arc tangentThe obtained rotor angleInput to a phase-locked loop module to estimate the rotating speed of the motor in real time_pllAnd rotor position; will give a given speed_refWith the estimated speed_pllThe difference is input into a PI controller, the PI controller parameters kp2 are 200, ki2 are 150, and a given torque current i is output^* _q(ii) a Let the flux linkage current give i^* _d＝0，i^* _d、i^* _qCurrent i detected in real time after coordinate transformation_d、i_qThe difference values pass through corresponding PI controllers respectively, the parameters are kept unchanged, and u is output_d、u_q(ii) a And then six paths of PWM driving signals are generated through an SVPWM modulation module, and an inverter circuit is driven to realize the sensorless control of the motor.

The invention has the beneficial effects that: the invention can reliably start the electronic water pump through the motor rotor pre-positioning mode, the IF speed open-loop mode and the sensorless speed closed-loop mode under the sensorless condition, has strong low-speed stability and anti-interference capability and good high-speed dynamic performance, is not sensitive to motor parameters, and improves the motor control robustness.

Drawings

FIG. 1 is a control block diagram of a predetermined bit pattern of an embodiment of the present invention.

Fig. 2 is a control block diagram of the IF speed open loop mode of an embodiment of the present invention.

FIG. 3 is a control block diagram of a sensorless speed closed loop mode of an embodiment of the present invention.

Fig. 4 is a control block diagram of the flux linkage observer module of the embodiment of the present invention.

Fig. 5 is a control block diagram of a phase-locked loop module of an embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict, and the present invention is further described in detail with reference to the drawings and specific embodiments.

If directional indications (such as up, down, left, right, front, and rear … …) are provided in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the movement, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are only used for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

The sensorless control device of the permanent magnet synchronous motor of the electronic water pump comprises a current sampling module, a flux linkage observation module, a phase-locked loop module, an SVPWM (space vector pulse width modulation) module, a pre-positioning module, an IF (intermediate frequency) speed open-loop module and a sensorless speed closed-loop module.

Motor starterBefore the motor is started, the pre-positioning module samples and calculates the three-phase current i of the motor in real time according to the current sampling module, referring to fig. 1, because the position of the rotor cannot be determined due to the absence of the position sensor, and the working mode of the electronic water pump allows the low-speed slow rotation_a、i_b、i_cSetting the rotor position angleConverting the three-phase current through current coordinates to obtain a direct current component i under a synchronous rotating coordinate system_dAnd i_qLet give i^* _d(in the art, the letters are given values and not actual values) equal to the predetermined bit current I₀，i^* _qInputting the difference value of the given current value and the coordinate-transformed direct current component into a PI controller for regulation to obtain a reference voltage signal u_dAnd u_qAccording to u_dAnd u_qAnd controlling the motor rotor to enter a pre-positioning mode.

An IF speed open loop module: after entering the pre-positioning mode for the pre-positioning time, entering an IF speed open-loop mode, referring to fig. 2, the current keeps the pre-positioning current unchanged, the current is closed-loop controlled by a PI controller, the parameter enhancement kp1 is 300, and ki1 is 450; the frequency is continuously increased at a fixed acceleration of 1000 rpm/s. When the rotating speed reaches 1/6 rated rotating speed, the motor back electromotive force is established, the motor voltage and current are proper, and the mode is switched to the sensorless speed closed loop mode.

Sensorless speed closed loop module: when the rotating speed reaches 1/6 rated rotating speed, a sensorless speed closed loop mode is entered, please refer to fig. 3-5, and the current sampling module samples and calculates the three-phase current i of the motor in real time_a、i_b、i_cAnd three-phase voltage u_a、u_b、u_cObtaining the component i of the current under the rotating coordinate system through coordinate transformation_α、i_βAnd a voltage component u_α、u_βThe stator flux linkage psi is obtained by inputting the stator flux linkage psi into a flux linkage observation module_sαAnd psi_sβTransformed to obtain rotor flux linkage psi_rαAnd psi_rBeta, arc tangent calculation to obtainRotor angleIn order to improve the accuracy of the estimated rotating speed and the rotor position, the obtained rotor angleInput to a phase-locked loop module to estimate the rotating speed of the motor in real time_pllAnd rotor position; setting the given (upper computer or automobile control system) rotating speed_refWith the estimated speed_pllThe difference is input into a PI controller, the PI controller parameters kp2 are 200, ki2 are 150, and a given torque current i is output^* _q(ii) a Let the flux linkage current give i^* _d＝0，i^* _d、i^* _qCurrent i detected in real time after coordinate transformation_d、i_qDifference (i.e. i)^* _dAnd i_dDifference of (i)^* _qAnd i_qDifference of) are respectively passed through correspondent PI controllers, the parameters are retained and u is outputted_d、u_q(ii) a And then six paths of PWM driving signals are generated through an SVPWM modulation module, and an inverter circuit is driven to realize the sensorless control of the motor.

In the flux linkage observation module, the stator flux linkage psi_sαThe low-pass filter is used for replacing a pure integral element for calculation, the filtering time is 2Ts, the Ts is the reciprocal of the switching frequency, and the stator flux linkage psi_sβThe filtering time of the middle low-pass filter is 4 Ts; when psi is used to reduce the influence of the low pass filter on the phase lag and amplitude attenuation of the system_sαIs greater thanCoefficient of time compensationWhen psi_sβGreater than psi_sCoefficient of time compensationThe expression of the compensated stator flux linkage is as follows:

where k is the filter coefficient, R is the stator resistance,. psi_sIs the stator flux linkage amplitude.

As an embodiment, the estimated rotation speed in the phase-locked loop module Observing the angle of the rotor of the module for flux linkageRotor angle observed with the first 5 beatsDifference, estimated angle Rotor angle estimated for current beat of phase-locked loop moduleAnd taking a value of 100-300 as a phase-locked loop adjusting coefficient by taking a rotor angle difference value estimated in the first 5 beats.

As an implementation mode, in the pre-positioning module, the current I is pre-positioned₀The rated current of the motor is In 0.25In, the preset bit current is controlled by a PI controller In a closed loop mode, and parameters kp0 are 200, and ki0 is 300; predetermined bit time T₀0.1s, which is often related to the mechanical time of the water pump motor.

Referring to fig. 1 to 5, a sensorless control method for a permanent magnet synchronous motor of an electronic water pump according to an embodiment of the present invention includes a pre-positioning step, an IF speed open-loop step, and a sensorless speed closed-loop step.

Pre-positioning: real-time sampling and calculating three-phase current i of motor through current sampling module_a、i_b、i_cSetting the rotor position angleConverting the three-phase current through current coordinates to obtain a direct current component i under a synchronous rotating coordinate system_dAnd i_qLet give i^* _dEqual to a predetermined bit current I₀，i^* _qInputting the difference value of the given current value and the coordinate-transformed direct current component into a PI controller for regulation to obtain a reference voltage signal u_dAnd u_qAccording to u_dAnd u_qAnd controlling a motor rotor, and entering an IF speed open loop step after the preset position time.

An IF speed open loop step: keeping the preset current constant, controlling the current in a closed loop mode by a PI controller, and increasing the parameters kp1 to 300 and ki1 to 450; the frequency is continuously increased at a fixed acceleration of 1000rpm/s, and when the rotating speed reaches 1/6 rated rotating speed, a sensorless speed closed loop step is carried out.

A sensorless speed closed loop step: real-time sampling and calculating three-phase current i of motor through current sampling module_a、i_b、i_cAnd three-phase voltage u_a、u_b、u_cObtaining the component i of the current under the rotating coordinate system through coordinate transformation_α、i_βAnd a voltage component u_α、u_βThe stator flux linkage psi is obtained by inputting the stator flux linkage psi into a flux linkage observation module_sαAnd psi_sβTransformed to obtain rotor flux linkage psi_rαAnd psi_rβAnd calculating the rotor angle by the arc tangentThe obtained rotor angleInput to a phase-locked loop module to estimate the rotating speed of the motor in real time_pllAnd rotor position; will give a given speed_refWith the estimated speed_pllThe difference is input into a PI controller, the PI controller parameters kp2 are 200, ki2 are 150, and a given torque current i is output^* _q(ii) a Let the flux linkage current give i^* _d＝0，i^* _d、i^* _qCurrent i detected in real time after coordinate transformation_d、i_qThe difference values pass through corresponding PI controllers respectively, the parameters are kept unchanged, and u is output_d、u_q(ii) a And then six paths of PWM driving signals are generated through an SVPWM modulation module, and an inverter circuit is driven to realize the sensorless control of the motor.

In one embodiment, the stator flux linkage psi in the flux linkage observation module is used in the sensorless velocity closed loop step_sαThe low-pass filter is used for replacing a pure integral element for calculation, the filtering time is 2Ts, the Ts is the reciprocal of the switching frequency, and the stator flux linkage psi_sThe filtering time of the beta low-pass filter is 4 Ts; when psi_sαIs greater thanCoefficient of time compensationWhen psi_sBeta is greater than psi_sCoefficient of time compensationThe expression of the compensated stator flux linkage is as follows:

where k is the filter coefficient, R is the stator resistance,. psi_sIs the stator flux linkage amplitude.

In one embodiment, the phase-locked loop module estimates the rotational speed during the sensorless speed closed loop step Observing the angle of the rotor of the module for flux linkageRotor angle observed with the first 5 beatsDifference, estimated angle Rotor angle estimated for current beat of phase-locked loop moduleAnd taking a value of 100-300 as a phase-locked loop adjusting coefficient by taking a rotor angle difference value estimated in the first 5 beats.

In one embodiment, the pre-positioning step pre-positions the time T₀0.1s, which is related to the mechanical time constant of the permanent magnet synchronous motor of the electronic water pump. Predetermined bit current I₀And 0.25In, In is the rated current of the motor, the preset bit current is controlled by a PI controller In a closed loop mode, the parameters kp0 are 200, and ki0 is 300.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.