阅读说明：本技术 一种永磁同步电机的转子初始位置的估算方法及系统 (Estimation method and system for initial position of rotor of permanent magnet synchronous motor ) 是由 陈志杰 李云欢 于 2019-09-05 设计创作，主要内容包括：本发明提供了一种永磁同步电机的转子初始位置的估算方法及系统,其中估算方法包括：通过ADC电流采集模块对电机三相的电流进行采样,并计算得出高频旋转电流的模值<I>I</I><Sub><I>m</I></Sub><I>(n)</I>以及角度<I>θ</I><Sub><I>1</I></Sub><I>(n)</I>；其中,n代表拍数；通过高频电压注入发波模块在电机绕组中产生高频旋转电压；根据相邻三拍的高频旋转电流模值与相角组成的多边形的重心线来估算转子的初始位置。采用本发明的技术方案,估算的精度高,计算简单,避免了复杂的数字信号处理带来的固有延时。本发明可用于压缩机或者其他永磁电机的无位置传感控制。(The invention provides an estimation method and a system for an initial position of a rotor of a permanent magnet synchronous motor, wherein the estimation method comprises the following steps: sampling the three-phase current of the motor through an ADC current acquisition module, and calculating to obtain the modulus value of the high-frequency rotating current I m (n) And angle θ 1 (n) (ii) a Wherein n represents the number of beats; injecting high-frequency voltage into the wave-transmitting module to generate high-frequency rotating voltage in a motor winding; and estimating the initial position of the rotor according to the gravity center line of a polygon formed by the high-frequency rotating current mode values and the phase angles of the adjacent three beats. By adopting the technical scheme of the invention, the estimation precision is high, the calculation is simple, and the inherent time delay caused by complex digital signal processing is avoided. The invention can be used for the position-sensorless control of the compressor or other permanent magnet motors.)

1. A method for estimating an initial position of a rotor of a permanent magnet synchronous motor, comprising:

sampling the three-phase current of the motor through an ADC current acquisition module, and calculating to obtain a modulus I of the high-frequency rotating current_m(n) and an angle θ₁(n); wherein n represents the number of beats;

injecting high-frequency voltage into the wave-transmitting module to generate high-frequency rotating voltage in a motor winding;

and estimating the initial position of the rotor according to the gravity center line of a polygon formed by the high-frequency rotating current mode values and the phase angles of the adjacent three beats.

2. The permanent magnet of claim 1Method for estimating the initial position of the rotor of a step motor, characterized in that the modulus I of the high-frequency rotating current is_m(n) and an angle θ_I(n) is calculated by adopting the following steps:

step S101, collecting three-phase current value I_u(n)、I_v(n) and I_w(n)；

Step S102, converting three phases of current into two phases, and calculating the current I of the nth beat alpha and beta components by adopting the following formula_α(n) and I_β(n)：

Step S103, calculating the modulus I of the high-frequency rotating current by adopting the following formula_m(n) and angle θ_I(n)：

3. The method of estimating an initial position of a rotor of a permanent magnet synchronous motor according to claim 2, wherein the α and β components of the high frequency rotating voltage are calculated using the following equation:

wherein, U_mThe modulus of the high-frequency rotating voltage is shown, omega is the digital angular frequency of the high-frequency rotating voltage, and n is the beat number.

4. The method of claim 3, wherein the initial position of the rotor is estimated by using the following formula according to a gravity center line of a polygon formed by the modulus value and the phase angle of the high-frequency rotating current of three adjacent beats:

where x is the index of the maximum modulus of the vector of the high-frequency rotating current, θ (x) is the phase angle of the current at the maximum modulus of the vector of the current, I_m(x),I_m(x+1),I_m(x-1) is the modulus at the maximum current vector modulus and the current modulus for the next and previous beats, respectively.

5. The method of estimating an initial position of a rotor of a permanent magnet synchronous motor according to claim 4, wherein the estimating of the initial position of the rotor comprises the steps of:

step S301, determining the analog angular frequency omega and the switching period T of the high-frequency voltage vector_sCalculating the digital angular frequency ω 2 pi Ω T_sAnd the total number of beats of hair requiredSetting n to be 0;

step S302, calculating the wave generation voltage U of the nth beat_a(n),U_β(n) wave sending is carried out, an ADC current acquisition module carries out phase current acquisition and calculation to obtain a module value I of the phase current vector of the ith beat_m(n) and phase angle theta_m(n) adding 1 to the number of beats n<Repeating the step to calculate the module value and the phase angle of the phase current vector of the N +1 th beat, otherwise jumping to the next step;

step S301, determining the maximum beat number x of the modulus value of the phase current vector, and estimating the initial position of the rotor

6. An estimation system of an initial position of a rotor of a permanent magnet synchronous motor, comprising:

the ADC current acquisition module samples the current of three phases of the motor and calculates the module value I of the high-frequency rotating current_m(n) and an angle θ₁(n); wherein n represents the number of beats;

the high-frequency voltage injection wave-transmitting module is used for generating high-frequency rotating voltage in the motor winding; and the rotor initial position estimation module estimates the initial position of the rotor according to the gravity center line of a polygon formed by the high-frequency rotating current mode values and the phase angles of the adjacent three beats.

7. The system of claim 6, wherein the modulus I of the high frequency rotating current is larger than the modulus I of the high frequency rotating current_m(n) and an angle θ_I(n) is calculated by adopting the following steps:

step S101, collecting three-phase current value I_u(n)、I_v(n) and I_w(n)；

Step S102, converting three phases of current into two phases, and calculating the current I of the nth beat alpha and beta components by adopting the following formula_α(n) and I_β(n)：

Step S103, calculating the modulus I of the high-frequency rotating current by adopting the following formula_m(n) and angle θ_I(n)：

8. The system for estimating an initial position of a rotor of a permanent magnet synchronous motor according to claim 7, wherein the α and β components of the high-frequency rotating voltage are calculated by using the following formula:

wherein, U_mThe modulus of the high-frequency rotating voltage is shown, omega is the digital angular frequency of the high-frequency rotating voltage, and n is the beat number.

9. The system for estimating the initial position of the rotor of the permanent magnet synchronous motor according to claim 8, wherein the rotor initial position estimation module estimates the initial position of the rotor according to a gravity center line of a polygon formed by the modulus value and the phase angle of the high-frequency rotating current of the adjacent three beats by adopting the following formula:

where x is the index of the maximum modulus of the vector of the high-frequency rotating current, θ (x) is the phase angle of the current at the maximum modulus of the vector of the current, I_m(x),I_m(x+1),I_m(x-1) is the modulus at the maximum current vector modulus and the current modulus for the next and previous beats, respectively.

10. The system of claim 9, wherein the estimating of the initial position of the rotor comprises:

step S301, determining the analog angular frequency omega and the switching period T of the high-frequency voltage vector_sCalculating the digital angular frequency ω 2 pi Ω T_sAnd the total number of beats of hair requiredSetting n to be 0;

step S302, calculating the wave generation voltage U of the nth beat_a(n),U_β(n) wave sending is carried out, an ADC current acquisition module carries out phase current acquisition and calculation to obtain a module value I of the phase current vector of the ith beat_m(n) and phase angle theta_m(n) adding 1 to the number of beats n<Repeating the step to calculate the module value and the phase angle of the phase current vector of the N +1 th beat, otherwise jumping to the next step;

step S301, determining the maximum beat number x of the modulus value of the phase current vector, and estimating the initial position of the rotor

Technical Field

The invention belongs to the technical field of motor control, and particularly relates to a method and a system for estimating an initial position of a rotor of a permanent magnet synchronous motor.

Background

The initial position of the rotor needs to be accurately obtained when the permanent magnet motor is started, reverse rotation can be avoided, starting torque can be improved, starting impact is reduced, and the like. Typically, the rotor position information is derived from mechanical sensors, and the presence of mechanical sensors not only adds to the hardware cost of the system, but also reduces the robustness and reliability of the system.

At present, research is disclosed for estimating the initial position of a rotor of a permanent magnet synchronous motor, a high-frequency current vector is generated in a stator winding by injecting a rotating high-frequency voltage signal into a motor winding, a negative sequence current containing rotor information in a high-frequency current component is generated, and a high-frequency injection position estimation value is obtained by adopting an arc tangent algorithm. The method is complex in calculation, a large amount of sine and cosine trigonometric operation and digital filtering are needed for extracting negative sequence current, engineering implementation is complex, signal phase delay is brought, position estimation accuracy is affected, and a method which can be simply implemented is needed.

Disclosure of Invention

Aiming at the technical problems, the invention discloses a method and a system for estimating the initial position of a rotor of a permanent magnet synchronous motor, which have high estimation precision and simple calculation.

In contrast, the technical scheme adopted by the invention is as follows:

a method for estimating an initial position of a rotor of a permanent magnet synchronous motor includes:

sampling the three-phase current of the motor through an ADC current acquisition module, and calculating to obtain a modulus I of the high-frequency rotating current_m(n) and an angle θ₁(n); wherein n represents the number of beats;

injecting high-frequency voltage into the wave-transmitting module to generate high-frequency rotating voltage in a motor winding;

and estimating the initial position of the rotor according to the gravity center line of a polygon formed by the high-frequency rotating current mode values and the phase angles of the adjacent three beats.

The technical scheme of the invention adopts auxiliary mathematical geometry, estimates the direction of the long axis of the ellipse by calculating the gravity center line of a polygon formed by the modulus value and the phase angle of the high-frequency rotating current of three adjacent beats, and can quickly and accurately estimate the position of the rotor by simple geometric operation.

As a further improvement of the invention, the modulus I of the high-frequency rotating current_m(n) and an angle θ_I(n) is calculated by adopting the following steps:

step S101, collecting three-phase current value I_u(n)、I_v(n) and I_w(n)；

Step S102, converting three phases of current into two phases, and calculating the current I of the nth beat alpha and beta components by adopting the following formula_α(n) and I_β(n)：

Step S103, calculating the modulus I of the high-frequency rotating current by adopting the following formula_m(n) and angle θ_I(n)：

As a further improvement of the present invention, α and β components of the high-frequency rotating voltage are calculated by using the following formula:

wherein, U_mThe modulus of the high-frequency rotating voltage is shown, omega is the digital angular frequency of the high-frequency rotating voltage, and n is the beat number.

As a further improvement of the invention, the initial position of the rotor is estimated by adopting the following formula according to the gravity center line of a polygon formed by the modulus value and the phase angle of the high-frequency rotating current of adjacent three beats:

where x is the index of the maximum modulus of the vector of the high-frequency rotating current, θ (x) is the phase angle of the current at the maximum modulus of the vector of the current, I_m(x),I_m(x+1),I_m(x-1) is the modulus at the maximum current vector modulus and the current modulus for the next and previous beats, respectively.

As a further development of the invention, the estimation of the initial position of the rotor comprises the following steps:

step S301, determining the analog angular frequency omega and the switching period T of the high-frequency voltage vector_sCalculating the digital angular frequency ω 2 pi Ω T_sAnd the total number of beats of hair requiredSetting n to be 0;

step S302, calculating the wave generation voltage U of the nth beat_a(n),U_β(n) wave sending is carried out, an ADC current acquisition module carries out phase current acquisition and calculation to obtain a module value I of the phase current vector of the ith beat_m(n) and phase angle theta_m(n) adding 1 to the number of beats n<Repeating the step to calculate the module value and the phase angle of the phase current vector of the N +1 th beat, otherwise jumping to the next step;

step S301, determining the maximum beat number x of the modulus value of the phase current vector, and estimating the initial position of the rotor

The invention also discloses an estimation system for the initial position of the rotor of the permanent magnet synchronous motor, which comprises the following steps:

the ADC current acquisition module samples the current of three phases of the motor and calculates the module value I of the high-frequency rotating current_m(n) and an angle θ₁(n); wherein n represents the number of beats;

the high-frequency voltage injection wave-transmitting module is used for generating high-frequency rotating voltage in the motor winding;

and the rotor initial position estimation module estimates the initial position of the rotor according to the gravity center line of a polygon formed by the high-frequency rotating current mode values and the phase angles of the adjacent three beats.

As a further improvement of the invention, the modulus I of the high-frequency rotating current_m(n) and an angle θ_I(n) is calculated by adopting the following steps:

step S101, collecting three-phase current value I_u(n)、I_v(n) and I_w(n)；

Step S102, converting three phases of current into two phases, and calculating the current I of the nth beat alpha and beta components by adopting the following formula_α(n) and I_β(n)：

Step S103, calculating the modulus I of the high-frequency rotating current by adopting the following formula_m(n) and angle θ_I(n)：

As a further improvement of the present invention, α and β components of the high-frequency rotating voltage are calculated by using the following formula:

wherein, U_mThe modulus of the high-frequency rotating voltage is shown, omega is the digital angular frequency of the high-frequency rotating voltage, and n is the beat number.

As a further improvement of the invention, the initial position of the rotor is estimated by adopting the following formula according to the gravity center line of a polygon formed by the modulus value and the phase angle of the high-frequency rotating current of adjacent three beats:

where x is the index of the maximum modulus of the vector of the high-frequency rotating current, θ (x) is the phase angle of the current at the maximum modulus of the vector of the current, I_m(x),I_m(x+1),I_m(x-1) is the modulus at the maximum current vector modulus and the current modulus for the next and previous beats, respectively.

As a further development of the invention, the estimation of the initial position of the rotor comprises the following steps:

step S301, determining the analog angular frequency omega and the switching period T of the high-frequency voltage vector_sCalculating the digital angular frequency ω 2 pi Ω T_sAnd the total number of beats of hair requiredSetting n to be 0; the calculation of step S302 is started from n — 0;

step S302, calculating the wave generation voltage U of the nth beat_a(n),U_β(n) and are subjected toWave generation, the ADC current acquisition module acquires phase current and calculates to obtain a modulus im (n) and a phase angle theta m (n) of the phase current vector of the ith beat, and if the beat number n is added with 1<Repeating the step to calculate the module value and the phase angle of the phase current vector of the N +1 th beat, otherwise jumping to the next step;

step S301, determining the maximum beat number x of the modulus value of the phase current vector, and estimating the initial position of the rotor according to the above formula (4)

Compared with the prior art, the invention has the beneficial effects that:

according to the technical scheme, the rotor position can be solved into the direction of the long axis of the current elliptic track, the direction of the long axis of the ellipse is estimated by calculating the gravity center line of a polygon formed by the high-frequency rotating current module values and the phase angles of the adjacent three beats by means of mathematical geometry, and the rotor position can be quickly and accurately estimated by simple geometric operation. The estimation precision is high, the calculation is simple, and the inherent time delay caused by complex digital signal processing is avoided. The invention can be used for the position-sensorless control of the compressor or other permanent magnet motors.

Detailed Description

Preferred embodiments of the present invention are described in further detail below.

A method for estimating an initial position of a rotor of a permanent magnet synchronous motor includes:

(1) sampling the three-phase current of the motor through an ADC current acquisition module, and calculating to obtain a modulus I of the high-frequency rotating current_m(n) and an angle θ₁(n); wherein n represents the number of beats; the method comprises the following specific steps:

step S101, collecting three-phase current value I_u(n)、I_v(n) and I_w(n)；

Step S102, converting three phases of current into two phases, and calculating the current I of the nth beat alpha and beta components by adopting the following formula_α(n) and I_β(n)：

Step S103, calculating the modulus I of the high-frequency rotating current by adopting the following formula_m(n) and angle θ_I(n)：

(2) Injecting high-frequency voltage into the wave-transmitting module to generate high-frequency rotating voltage in a motor winding; the alpha and beta components of the high-frequency rotating voltage are calculated by adopting the following formula:

wherein, U_mThe modulus of the high-frequency rotating voltage is shown, omega is the digital angular frequency of the high-frequency rotating voltage, and n is the beat number.

(3) Estimating the initial position of the rotor according to the gravity center line of a polygon formed by the high-frequency rotating current mode values and the phase angles of the adjacent three beats, wherein the specific algorithm comprises the following steps:

step S301, determining the analog angular frequency omega and the switching period T of the high-frequency voltage vector_sCalculating the digital angular frequency ω 2 pi Ω T_sAnd the total number of beats of hair requiredSetting n to be 0;

step S302, calculating the wave generation voltage U of the nth beat_a(n),U_β(n) wave sending is carried out, an ADC current acquisition module carries out phase current acquisition and calculation to obtain a module value I of the phase current vector of the ith beat_m(n) and phase angle theta_m(n) adding 1 to the number of beats n<Repeating the step to calculate the module value and the phase angle of the phase current vector of the N +1 th beat, otherwise jumping to the next step;

step S301, determining the maximum beat number x of the modulus value of the phase current vector, and estimating the initial position of the rotor according to the following formula (4)

Where x is the index of the maximum modulus of the vector of the high-frequency rotating current, θ (x) is the phase angle of the current at the maximum modulus of the vector of the current, I_m(x),I_m(x+1),I_m(x-1) is the modulus at the maximum current vector modulus and the current modulus for the next and previous beats, respectively.

The rotation track of the high-frequency current vector is an ellipse, and the direction of the major axis is coincident with the rotor position, so that the rotor position can be solved by converting into the direction of the major axis of the current elliptic track. The technical scheme of the invention adopts auxiliary mathematical geometry, estimates the direction of the long axis of the ellipse by calculating the gravity center line of a polygon formed by the modulus value and the phase angle of the high-frequency rotating current of three adjacent beats, and can quickly and accurately estimate the position of the rotor by simple geometric operation.

In addition, the invention also discloses an estimation system of the initial position of the rotor of the permanent magnet synchronous motor, which comprises the following steps:

the ADC current acquisition module samples the current of three phases of the motor and calculates the module value I of the high-frequency rotating current_m(n) and an angle θ₁(n); wherein n represents the number of beats;

the high-frequency voltage injection wave-transmitting module is used for generating high-frequency rotating voltage in the motor winding;

and the rotor initial position estimation module estimates the initial position of the rotor according to the gravity center line of a polygon formed by the high-frequency rotating current mode values and the phase angles of the adjacent three beats.

Modulus I of the high-frequency rotating current_m(n) and an angle θ_I(n) is calculated by adopting the following steps:

step S101, collecting three-phase current value I_u(n)、I_v(n) and I_w(n)；

Step S102, converting three phases of current into two phases, and collectingThe current I of the n-th beat alpha and beta components is calculated by the following formula_α(n) and I_β(n)：

Step S103, calculating the modulus I of the high-frequency rotating current by adopting the following formula_m(n) and angle θ_I(n)：

The alpha and beta components of the high-frequency rotating voltage are calculated by adopting the following formula:

wherein, U_mThe modulus of the high-frequency rotating voltage is shown, omega is the digital angular frequency of the high-frequency rotating voltage, and n is the beat number.

The rotor initial position estimation module estimates the initial position of the rotor according to the gravity center line of a polygon formed by the high-frequency rotating current module values and the phase angles of the adjacent three beats by adopting the following steps:

step S301, determining the analog angular frequency omega and the switching period T of the high-frequency voltage vector_sCalculating the digital angular frequency ω 2 pi Ω T_sAnd the total number of beats of hair requiredSetting n to be 0;

step S302, calculating the wave generation voltage U of the nth beat_a(n),U_β(n) wave sending is carried out, an ADC current acquisition module carries out phase current acquisition and calculation to obtain a module value I of the phase current vector of the ith beat_m(n) and phase angle theta_m(n) adding 1 to the number of beats n<Repeating the step to calculate the module value and the phase angle of the phase current vector of the N +1 th beat, otherwise jumping to the next step;

step S301, determining the maximum beat number x of the modulus value of the phase current vector, and according to a formula(4) Estimating initial position of rotor

Where x is the index of the maximum modulus of the vector of the high-frequency rotating current, θ (x) is the phase angle of the current at the maximum modulus of the vector of the current, I_m(x),I_m(x+1),I_m(x-1) is the modulus at the maximum current vector modulus and the current modulus for the next and previous beats, respectively.

The method and the system of the embodiment are simple, and the rotor position can be estimated quickly and accurately through simple geometric operation. The estimation precision is high, the calculation is simple, and the inherent time delay caused by complex digital signal processing is avoided.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.