阅读说明：本技术 基于高频注入法的永磁同步电机霍尔安装偏差补偿方法 (Hall installation deviation compensation method of permanent magnet synchronous motor based on high-frequency injection method ) 是由 苗奎星 魏海峰 张懿 李垣江 王浩陈 于 2020-11-23 设计创作，主要内容包括：本发明提供了一种基于高频注入法的永磁同步电机霍尔安装偏差补偿方法,电机技术领域,包括：分别获取预设时间范围内的三个霍尔传感器的数个开关量信息；根据开关量信息构造开关量状态排序表；通过缓慢匀速拖动永磁同步电机并注入高频脉振信号,实时计算转子角度位置信息；构造与转子角度位置信息所对应开关量状态排序表；通过比对霍尔输出的开关量状态排序表与构造的开关量状态排序表,计算角度点差值。根据平均角度点差值,对霍尔位置传感器输出信号翻转时间时刻进行补偿。有益效果为：可在电机零低速工况下,精确地获取转子位置信息,且脉振高频信号注入法可用于凸极率很小甚至隐极型的表贴式三项永磁同步电机转子位置的检测。(The invention provides a permanent magnet synchronous motor Hall installation deviation compensation method based on a high-frequency injection method, which belongs to the technical field of motors and comprises the following steps: respectively acquiring a plurality of switching value information of three Hall sensors within a preset time range; constructing a switching value state sequencing table according to the switching value information; the method comprises the steps of calculating the angle position information of a rotor in real time by dragging a permanent magnet synchronous motor slowly at a constant speed and injecting a high-frequency pulse vibration signal; constructing a switching value state sequencing table corresponding to the rotor angle position information; and calculating the difference value of the angle points by comparing the switching value state sequencing table output by the Hall with the constructed switching value state sequencing table. And compensating the turnover time moment of the output signal of the Hall position sensor according to the average angle point difference. The beneficial effects are that: the method can accurately acquire the position information of the rotor under the working condition of zero low speed of the motor, and the pulse vibration high-frequency signal injection method can be used for detecting the position of the rotor of the surface-mounted three-term permanent magnet synchronous motor with small salient pole rate and even a salient pole type.)

1. a permanent magnet synchronous motor Hall installation deviation compensation method based on a high-frequency injection method is characterized by comprising the following steps:

the method comprises the following steps: respectively acquiring a plurality of switching value information of three Hall sensors within a preset time range, and coding the switching value information to form a plurality of switching value information codes;

step two: a plurality of switching value information codes are converted into a switching state sorting table;

step three: dragging the permanent magnet synchronous motor slowly at a constant speed, injecting a high-frequency pulse vibration signal, and calculating the angular position information of the rotor in real time;

step four: constructing a Hall switching value information and switching state sequencing table corresponding to the rotor angle position information in the third step;

step five: and comparing the switching state sorting table in the second step with the switching value state sorting table in the fourth step, capturing an angle point of the difference of the first state value, capturing an angle point of the state value in a time interval after the angle point, recovering the unified angle point, and calculating the angle point difference. Repeating the above process within a preset time range, and calculating an average angle point difference value;

step six: and D, compensating the turnover time moment of the output signal of the Hall position sensor according to the average angle point difference obtained in the step five, and controlling the brushless direct current motor to normally operate.

2. The Hall installation deviation compensation method of the permanent magnet synchronous motor based on the high-frequency injection method as claimed in claim 1, wherein the preset time range is two periods; wherein, the change of the electrical angle by 360 degrees is a period; the specific method for coding the plurality of switching value information in the first step to form the plurality of switching value information codes is as follows:

firstly, arranging a plurality of switching value information according to a fixed sequence of three phases; and carrying out three-bit binary coding on the three switching value information of the three Hall sensors at the same moment, wherein each bit in the three-bit binary coding corresponds to the switching value information of one Hall sensor.

3. The method for compensating the hall installation deviation of the permanent magnet synchronous motor based on the high-frequency injection method according to claim 1, wherein the maximum value v of the speed of the slow constant-speed dragging motor in the three steps is n/2000, where n is the rated rotation speed of the permanent magnet synchronous motor.

4. The Hall installation deviation compensation method of the permanent magnet synchronous motor based on the high-frequency injection method as claimed in claim 1, wherein the high-frequency pulsating signal is injected in the third step, and the specific method is as follows:

converting a three-phase stationary coordinate system into a two-phase dq synchronous rotating coordinate system through Clarke conversion and Park conversion; estimating two phasesSynchronous rotationInjecting a high-frequency cosine voltage signal on a d-axis of a coordinate system as follows:

wherein the content of the first and second substances,andfor injection ofHigh frequency voltages in the coordinate system are synchronously rotated.

5. The Hall installation deviation compensation method of the permanent magnet synchronous motor based on the high-frequency injection method as claimed in claim 4, wherein the rotor angle position information is calculated in the third step, and the specific method is as follows: by detecting the output of the permanent magnet synchronous motor after the injection of high-frequency pulse vibration signalsAnd performing amplitude modulation on the current response, obtaining an input signal based on a rotor position estimation method of the PLL after passing through a low-pass filter, and obtaining rotor position information after estimation.

6. The method for compensating the Hall installation deviation of the permanent magnet synchronous motor based on the high-frequency injection method according to claim 5, wherein the method for constructing the Hall switching value information and switching state sequencing table corresponding to the rotor angle position information in the step three in the step four comprises the following steps:

and converting the rotor angle position information estimated in the step three into the discrete switching value output by the Hall sensor according to the relation of the rotor angle information corresponding to the switching value information correctly output by the Hall sensor, and constructing a binary or decimal value of the switching value into an estimated switching value state sequencing table.

7. The method for compensating the hall installation deviation of the permanent magnet synchronous motor based on the high-frequency injection method as claimed in claim 6, wherein the switching value state sorting table in the second step is compared with the estimated switching value state sorting table constructed in the fourth step in the fifth step, and the method for capturing the angle point of the difference of the first switching value state is as follows:

the estimated switching value state sorting table constructed in the fourth step and the switching value state sorting table in the second step are arranged at the same time t_αComparing the state values; i.e. when the estimated switching value state sorting table is at t_αThe time state value is X_αWhen the switching value state sorting table in the step two is at t_αThe time state value is X_α′If X is_α≠X_α′Then the estimated rotor angular position θ at that time is captured_αRotor angular position θ from Hall output_α′。

8. The hall installation deviation compensation method of the permanent magnet synchronous motor based on the high frequency injection method according to claim 7, wherein the method for recovering the switching value state to the uniform angle point after capturing the angle point in the fifth step is as follows:

the estimated switching value state sorting table constructed in the fourth step and the switching value state sorting table in the second step are arranged at the same time t_α+ Δ t for state value comparison; i.e. when the estimated switching value state sorting table is at t_αThe state value at the time of + delta t is X_βWhen the switching value state sorting table in the step two is at t_αThe state value at the time of + delta t is X_β′If X is_β＝X_β′Then the estimated rotor angular position θ at that time is captured_βRotor angular position θ from Hall output_β′。

9. The method for compensating the hall installation deviation of the permanent magnet synchronous motor based on the high-frequency injection method as claimed in claim 8, wherein the method for compensating the turnover time of the output signal of the hall position sensor according to the average angle point difference obtained in the fifth step in the sixth step is as follows:

obtaining the average angle point difference value according to the fifth stepThe electrical angle quantity of the Hall position sensor offset can be obtainedMechanical angular amount of hall position sensor offset:

and reconstructing the switching sequence and the switching time information of the state values in the switching value state sequencing table according to the electrical angle offset and the running speed v of the permanent magnet synchronous motor by collecting, thereby realizing fault-tolerant control.

10. The utility model provides a fault-tolerant control system of single-phase hall trouble of brushless DC motor which characterized in that includes: the invention provides a permanent magnet synchronous motor Hall installation deviation compensation method based on a high-frequency injection method, and an optional system structure comprises the following steps: the device comprises a high-frequency signal injection unit, a motor driving unit, a sampling current decoupling unit, a permanent magnet synchronous motor unit, a band-pass filter unit, a local carrier unit, a PLL rotor position estimation unit and a speed regulation unit;

the high-frequency signal injection unit is connected with the motor driving unit and is used for injecting a high-frequency pulse vibration signal into the motor; the sampling current decoupling unit is connected with the motor driving unit and is used for carrying out coordinate transformation and decoupling on the sampling current; the motor driving unit is connected with the permanent magnet synchronous motor unit and is used for driving the permanent magnet synchronous motor to operate; the band-pass filter unit is connected with the sampling current decoupling unit and is used for extracting a high-frequency current component containing rotor position information in quadrature axis current; the local carrier injection unit is connected with the band-pass filter unit and is used for injecting common-frequency signals to facilitate demodulation; the PLL rotor position estimation unit is connected with the local carrier injection unit and used for demodulating high-frequency current components containing rotor position information and estimating the rotor position; the speed adjusting unit is connected with the PLL rotor position estimating unit and used for adjusting the torque and the rotating speed of the motor.

Technical Field

The invention relates to the technical field of permanent magnet synchronous motors, in particular to a permanent magnet synchronous motor Hall installation deviation compensation method based on a high-frequency injection method

Background

The permanent magnet synchronous motor has the advantages of simple structure, small volume, light weight, small loss, high efficiency, high power factor and the like, and is mainly used for replacing motors of high-performance servo transmission systems and direct current motors which require quick response, wide speed regulation range and accurate positioning.

The switch type Hall sensor has small volume, low price, stable operation and more convenient installation and maintenance. The locking type switch Hall sensor can output square wave signals according to the change of the magnetic field intensity, and the rising edge and the falling edge in the square wave correspond to the zero crossing point of the magnetic field, so that the operation interval and the position of the rotor can be positioned according to the switch Hall signals.

The permanent magnet synchronous motor has numerous Hall position sensor starting methods, the method is easy to realize, the precision required by the permanent magnet synchronous motor on the position information of a rotor is high under the starting working condition, and if the deviation degree of the initial installation position of the Hall position sensor is too large, the starting and the operation of the permanent magnet synchronous motor flutter, the noise is large, and even the permanent magnet synchronous motor cannot normally operate. A compensation method for the excessive deviation degree of the initial installation position of the hall position sensor is needed, so that the motor can normally operate under the working condition.

Disclosure of Invention

The invention provides a Hall installation deviation compensation method of a permanent magnet synchronous motor based on a high-frequency injection method, which aims to solve the problem that the permanent magnet synchronous motor operates abnormally under the working condition that the deviation degree of the initial installation position of a Hall position sensor is overlarge in the prior art.

The invention provides a permanent magnet synchronous motor Hall installation deviation compensation method based on a high-frequency injection method, and an optional system structure comprises the following steps: the device comprises a current regulator module, an inverse Park conversion module, an SVPWM modulation module, a three-phase inverter, a Park conversion module, a Clark module, a PLL rotor position estimation module, a low-pass filter, a band-pass filter and a speed regulator module. And a high-frequency signal is injected behind the current regulator module, and the low-pass filter is connected with the PI regulator to form a PLL sub-position estimation module.

The invention provides a permanent magnet synchronous motor Hall installation deviation compensation method based on a high-frequency injection method, which comprises the following steps:

the method comprises the following steps: respectively acquiring a plurality of switching value information of three Hall sensors within a preset time range, and coding the switching value information to form a plurality of switching value information codes;

step two: a plurality of switching value information codes are converted into a switching state sorting table;

step three: and slowly dragging the permanent magnet synchronous motor at a constant speed, injecting a high-frequency pulse vibration signal, and calculating the angular position information of the rotor in real time.

Step four: and constructing a Hall switching value information and switching state sequencing table corresponding to the rotor angle position information in the third step.

Step five: and comparing the switch state sorting table in the second step with the switch state sorting table in the fourth step, capturing an angle point of the difference of the first state value, capturing an angle point of the state value in a time interval after the angle point, recovering the unified angle point, and calculating the angle point difference. And repeating the process within a preset time range, and calculating the average angle point difference.

Step six: according to the average angle point difference obtained in the fifth step, compensating the turnover time of the output signal of the Hall position sensor, and controlling the brushless direct current motor to normally operate;

optionally, the preset time range is two periods; wherein, the electrical angle change of 360 degrees is a period.

Optionally, in the first step, the m pieces of switching value information are encoded, and a specific method for forming m pieces of switching value information codes is as follows: firstly, arranging m pieces of switching value information according to a fixed sequence of three phases; and carrying out three-bit binary coding on the three switching value information of the three Hall sensors at the same moment, wherein each bit in the three-bit binary coding corresponds to the switching value information of one Hall sensor.

Optionally, the specific method for converting m switching value information codes into the switching value state sorting table in the second step is as follows:

firstly, coding each switching value information into decimal numbers, and then tabulating the decimal numbers obtained after coding and converting the switching value information into the decimal numbers according to the acquired time sequence to form a switching state sequencing table.

Optionally, the maximum value v of the speed of the slow constant-speed traction motor in the illustrated step three is n/2000, where n is the rated rotation speed of the permanent magnet synchronous motor.

Optionally, the high-frequency pulse oscillation signal is injected in step three, and the specific method is as follows:

and transforming the three-phase stationary coordinate system into a two-phase dq synchronous rotating coordinate system through Clarke transformation and Park transformation.

Estimating two phasesInjecting a high-frequency cosine voltage signal into a d axis of a synchronous rotating coordinate system:

wherein the content of the first and second substances,andfor injection ofHigh frequency voltages in the coordinate system are synchronously rotated.

Optionally, the method for calculating the rotor angle position information in step three includes:

by detecting the output of the permanent magnet synchronous motor after the injection of high-frequency pulse vibration signalsShaft high frequencyAnd current response, amplitude modulation is carried out on the current response, an input signal of a rotor position estimation method based on PLL is obtained after the input signal is processed by a low-pass filter, and rotor position information can be obtained after estimation.

Optionally, the method for constructing hall switching value information corresponding to the information on the angular position of the rotor estimated in step four includes the following steps:

and converting the rotor angle position information estimated in the step three into the discrete switching value output by the Hall sensor according to the relation of the rotor angle information corresponding to the switching value information correctly output by the Hall sensor, and constructing a binary or decimal value of the switching value into an estimated switching value state sequencing table.

Optionally, the step five of comparing the switching value state sorting table in the step two with the estimated switching value state sorting table in the step four, and the method of capturing the angle point at which the first switching value state is different is as follows:

the estimated switching value state sorting table constructed in the fourth step and the switching value state sorting table in the second step are arranged at the same time t_αA comparison of the state values is performed. I.e. when the estimated switching value state sorting table is at t_αThe time state value is X_αWhen the switching value state sorting table in the step two is at t_αThe time state value is X_α′If X is_α≠X_α′Then the estimated rotor angular position θ at that time is captured_αRotor angular position θ from Hall output_α′。

Optionally, the method for recovering the switching value state to the uniform angle point after capturing the angle point in the fifth step is as follows:

the estimated switching value state sorting table constructed in the fourth step and the switching value state sorting table in the second step are arranged at the same time t_α+ Δ t the state value comparison. I.e. when the estimated switching value state sorting table is at t_αThe state value at the time of + delta t is X_βWhen the switching value state sorting table in the step two is at t_αThe state value at the time of + delta t is X_β′If X is_β＝X_β′Then the estimated rotor angular position θ at that time is captured_βRotor angular position θ from Hall output_β′。

The specific method for constructing a new switching state sorting table according to the average angle point difference obtained in the step five in the step six is as follows:

obtaining the average angle point difference value according to the fifth stepThe electrical angle quantity of the Hall position sensor offset can be obtainedMechanical angular amount of hall position sensor offset:

according to the electric angle offset, the switching sequence and the switching time information of the state values in the switch state sequencing table can be constructed by collecting the running speed v of the permanent magnet synchronous motor, so that the fault-tolerant control is realized.

The invention has the beneficial effects that:

1. the method for compensating the Hall installation deviation of the permanent magnet synchronous motor based on the high-frequency injection method has the advantages of simple system structure and easiness in implementation. The high-frequency pulse vibration signal injection method and the feedback signal demodulation are utilized, the rotor position information can be accurately acquired under the zero-low-speed working condition of the motor, and the pulse vibration high-frequency signal injection method can be used for detecting the rotor position of the surface-mounted three-term permanent magnet synchronous motor with small salient pole rate or even hidden pole type.

2. The rotor position information acquired by a high-frequency pulse vibration signal injection method constructs a switch state sequencing table, the switch state sequencing table is compared with a switch state sequencing table constructed by Hall signal output switch information, if the state values are different, the deviation of the initial installation position of the Hall sensor can be detected, the deviation angle can be further calculated, a compensation strategy is realized, the system improves the adaptability and stability of the control system, the normal operation of the permanent magnet synchronous motor can still be ensured under the condition that the deviation occurs in the initial installation position of the Hall sensor, and the adverse effect of the deviation of the initial installation position of the Hall sensor on the control system is reduced.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:

FIG. 1 is a control flow chart of Hall installation deviation compensation of a permanent magnet synchronous motor based on a high-frequency injection method in the invention;

FIG. 2 is a structural block diagram of a control system of a Hall installation deviation compensation method of a permanent magnet synchronous motor based on a high-frequency injection method in the invention;

FIG. 3 is a diagram illustrating an ideal Hall position sensor switch state ordering according to the present invention;

FIG. 4 is a diagram showing the relationship between the stationary coordinate system, the synchronous rotating coordinate system and the estimated synchronous rotating coordinate system according to the present invention;

FIG. 5 is a control block diagram of the present invention based on PLL rotor position estimation;

FIG. 6 is a diagram showing sector detection results after the Hall position sensor is shifted and sector estimation results based on a pulse-taking high-frequency injection method.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a permanent magnet synchronous motor Hall installation deviation compensation method based on a high-frequency injection method, and as shown in figure 2, an optional system structure comprises a high-frequency signal injection unit, a motor driving unit, a sampling current decoupling unit, a permanent magnet synchronous motor unit, a band-pass filter unit, a local carrier unit, a PLL rotor position estimation unit and a speed regulation unit.

The high-frequency signal injection unit is connected with the motor driving unit and is used for injecting a high-frequency pulse vibration signal into the motor; the sampling current decoupling unit is connected with the motor driving unit and is used for carrying out coordinate transformation and decoupling on the sampling current; the motor driving unit is connected with the permanent magnet synchronous motor unit and is used for driving the permanent magnet synchronous motor to operate; the band-pass filter unit is connected with the sampling current decoupling unit and is used for extracting a high-frequency current component containing rotor position information in quadrature axis current; the local carrier injection unit is connected with the band-pass filter unit and is used for injecting common-frequency signals to facilitate demodulation; the PLL rotor position estimation unit is connected with the local carrier injection unit and used for demodulating high-frequency current components containing rotor position information and estimating the rotor position; the speed adjusting unit is connected with the PLL rotor position estimating unit and used for adjusting the torque and the rotating speed of the motor.

The invention provides a control algorithm for Hall installation deviation compensation of a permanent magnet synchronous motor based on a high-frequency injection method, which comprises the following steps of:

step S10: respectively acquiring a plurality of switching value information of three Hall sensors within a preset time range, and coding the switching value information to form a plurality of switching value information codes;

in the embodiment, the three-phase hall sensors are installed in a 120-degree distributed manner, and the preset time range is preferably two periods; wherein, the electrical angle change of 360 degrees is a period.

The switching value state of one Hall sensor is only two, the corresponding switching value state is 0 when the Hall signal is at low level, and the corresponding switching value state is 1 when the Hall signal is at high level. The switching value information comprises the switching value states of three Hall sensors, and each bit corresponds to the switching value state of one Hall sensor. Under the normal state of the Hall sensor, the state information coding of the switching value is as follows: 001. 010, 011, 100, 101, 110;

step S20: a plurality of switching value information codes are converted into a switching state sorting table;

the output of the ideal hall position sensor is as shown in fig. 3, all the switching value information of the hall sensor collected in the preset time range is converted, the switching value state information codes are regarded as binary values, all possible situations are between '000' and '111' in the form of binary codes, the states can be simplified into 6 decimal values, and simplified replacement is performed according to actual needs. And finally, converting the switching value information into a switching state sequencing table according to the sequence of the switching value information. For example: the switching value information of the three Hall sensors at the first moment is respectively 1, 0 and 1, the binary coding is carried out to obtain 101, the binary coding is converted into decimal in place 5, the switching value information of the three Hall sensors at the second moment is respectively 1, 1 and 0, the binary coding is carried out to obtain 110, the binary coding is converted into decimal in place 6, and the binary coding is converted into a switching state sequencing table 56.

Step S30: dragging the permanent magnet synchronous motor slowly at a constant speed, injecting a high-frequency pulse vibration signal, and calculating the angular position information of the rotor in real time;

the maximum speed value of the slow constant-speed dragging motor is preset preferentially: and v is n/2000, wherein n is the rated rotating speed of the permanent magnet synchronous motor. Injecting a high-frequency pulse vibration signal, wherein the specific method comprises the following steps:

the three-phase stationary coordinate system is transformed to the two-phase dq rotating coordinate system by Clarke transformation and Park transformation as shown in fig. 4, wherein the dq coordinate system is the actual two-phase rotating coordinate system,the coordinate system is an estimated two-phase rotational coordinate system. Theta is the actual rotor position and theta is,to estimate the rotor position, Δ θ is the position estimation error, which is given by:

estimating two phasesInjecting a high-frequency cosine voltage signal on a d axis of a rotating coordinate system:

wherein the content of the first and second substances,andfor injection ofHigh frequency voltages in the rotating coordinate system.

In step S30, the method for calculating the rotor angle position information includes:

firstly, according to a permanent magnet synchronous motor model, the model of the permanent magnet synchronous motor under the excitation of a high-frequency signal can be equivalent to a pure inductance model, wherein a voltage equation is simplified as follows:

in the formula u_dh、u_qhFor high-frequency voltage components on the dq axis of the motor, i_dh、i_qhIs a high-frequency current component on the dq axis of the motor, L_dhAnd L_qhIs the dq axis inductance under the excitation of high frequency signals.

The following relation equation can be obtained according to the coordinate transformation relation:

in the formula:andrespectively estimated rotationThe voltage and current components of the quadrature-direct axis under the coordinate system.

Secondly, calculating the estimation under the excitation of the pulse vibration high-frequency voltage signalThe shaft current high frequency response is:

the high-frequency cosine voltage signal injected on the d axis is substituted into the formula to obtain:

therefore, the high frequency current response value on the q-axisAs follows:

finally, the current is respondedAnd modulated sin (ω)_ht) multiplying, processing by a low pass filter LPF to obtain corresponding signals, sending the signals to a PI regulator, and outputting the corresponding PI regulator as an estimated value of the position of the motor rotorThe specific method is as follows:

obtaining an input signal based on a PLL rotor position estimation system after passing through a low-pass filter:

when the rotor position estimation error is sufficiently small, the error signal can be linearized, i.e.:

wherein:

as shown in fig. 5, in order to obtain the rotor position angle θ of the motor, as known from the control block diagram of the PI regulator, the LPF filter takes the form of a first-order low-pass filter with a desired bandwidth σ, and its transfer function can be expressed as:

the transfer function of the PI regulator adopts the following form:

wherein: gamma ray_P，γ_iProportional and integral gains of the PI regulator are respectively, and the closed loop transfer function of the PI regulator is as follows:

in order to set the parameters of the PI regulator, the 3 poles of the above equation are configured to be δ — 3 α, and the parameters of the PI regulator may be defined as:

therefore, the rotor position information functional relation under the S domain can be obtained according to the process, and the rotor angle position information can be accurately estimated.

Step S40: and constructing a Hall switching value information and switching value state sequencing table corresponding to the rotor angle position information in the step S30.

Similarly, in step S20, hall switching value information corresponding to the estimated rotor angular position information is constructed, the rotor angular position information estimated in step S30 is converted into switching values output by discrete hall sensors, and binary or decimal values of the switching values are constructed as an estimated switching value state ordering table.

Step S50: and comparing the switching value state sorting table in the step S20 with the switching value state sorting table in the step S40, capturing an angle point at which the first switching value state is different, capturing an angle point at which the switching value state is recovered to be uniform in a time interval after the angle point, and calculating an angle point difference. And repeating the process within a preset time range, and calculating the average angle point difference.

Comparing the switching state sorting table in the second step with the estimated switching value state sorting table in the fourth step, and capturing the angle point of the first switching value state difference as follows:

the estimated switching value state ranking table constructed in the step S40 and the switching value state ranking table in the step S20 are at the same time t_αA comparison of the state values is performed. I.e. when the estimated switching value state sorting table is at t_αThe time state value is X_αWhen the switching value state sorting table in the step two is at t_αThe time state value is X_α′If X is_α≠X_α′Then the estimated rotor angular position at that time is capturedSet theta_αRotor angular position θ from Hall output_α′。

The method for recovering the switch state to the uniform angle point after capturing the angle point comprises the following steps:

the estimated switching value state sorting table constructed in the step S40 and the switching value state sorting table in the step S are at the same time t_α+ Δ t the state value comparison. I.e. when the estimated switching value state sorting table is at t_αThe state value at the time of + delta t is X_βWhen the switching value state sorting table in the step two is at t_αThe state value at the time of + delta t is X_β′If X is_β＝X_β′Then the estimated rotor angular position θ at that time is captured_βRotor angular position θ from Hall output_β′。

Calculating the angular point difference theta_ΔThe equation of (a) is as follows:

θ_Δ＝θ_β-θ_α′

calculated average angle point differenceThe equation of (a) is as follows:

wherein T is the number of the periods output by the Hall position sensor within the preset time range.

Step S60: and D, compensating the turnover time moment of the output signal of the Hall position sensor according to the average angle point difference obtained in the step five, and controlling the brushless direct current motor to normally operate.

As shown in fig. 6, the average angle point difference obtained according to the step S50The electrical angle quantity of the Hall position sensor offset can be obtainedMechanical angular amount of Hall position sensor offsetWherein N is the pole pair number of the permanent magnet synchronous motor.

T can be acquired according to electrical angle offset_αThe average running speed V of the permanent magnet synchronous motor in the interval of + delta t is calculated according to the switching sequence of the state values in the switch state sequencing table constructed in the step S40 and the overturning time moment of the output signal of the Hall position sensorAnd finishing the angle compensation of the installation position of the Hall position sensor. The concrete method of +/-is related to the running direction of the motor and the installation deviation direction of the Hall position sensor.

For example, when the motor runs clockwise and the installation deviation of the central axis of the Hall position sensor is advanced,