WO2009043279A1

WO2009043279A1 - Motor rotor position sensor and method for measuring position of motor rotor

Info

Publication number: WO2009043279A1
Application number: PCT/CN2008/072488
Authority: WO
Inventors: Meijuan Xie
Original assignee: Chery Automobile Co., Ltd.
Priority date: 2007-09-25
Filing date: 2008-09-24
Publication date: 2009-04-09
Also published as: CN101398313B; CN101398313A

Abstract

A motor rotor position sensor and a method for measuring the position of a motor rotor, said sensor comprises: a destination disk (1) installed on the motor rotor, an inductor (2) fixed in the motor case, and a DSP connected to the inductor (2). Said destination disk (1) is made of conducting materials, the edge of the destination disk (1) is of sine curve shape or cosine curve shape. The inductor (2) includes an ASIC circuit and a winding pair, which includes a sine planar winding and a cosine planar winding, and corresponding to the destination disk (1). The output terminal of the ASIC circuit is connected to a DSP, and the DSP sends out signals indicating the position of the rotor by calculation.

Description

The invention relates to a motor rotor position sensor and a method for measuring a rotor position of a motor. The application is submitted to the Chinese Patent Office on September 25, 2007, and the application number is 200710077323.0. The invention name is "a rotor position sensor of a motor and the motor rotor is measured by the sensor" The priority of the Chinese Patent Application, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor and a method of measuring the same using the same, and more particularly to a sensor for measuring a rotor position of a permanent magnet synchronous motor as a hybrid motor, and using the same in a hybrid vehicle A method of measuring the position of a rotor.

Background technique

In order to ensure smooth rotation of the motor and precise control of the motor, it is not only necessary to control the armature current, but also to detect the exact rotor position of the motor. Accurate rotor position detection can reflect whether the sinusoidal curve of the motor current is synchronized with the corresponding rotor position, which is beneficial to avoid fluctuations in the commutation torque. Currently, there are two main methods for detecting the rotor position of a motor: a position sensor measurement method and a position sensorless technique for measuring the rotor position. Among them, the method of detecting the position of the rotor of the motor by using the position sensor mainly involves applying an encoder, a resolver and a Hall position sensor device, and detecting the rotor position signal by using these devices; whether the encoder, the Hall position sensor or the resolver is attached The relevant circuit determines the rotor position, which is affected by the magnetic field of the stator winding of the motor during use, thus affecting the detection accuracy.

Summary of the invention

The technical problem to be solved by the present invention is to provide a rotor position sensor capable of eliminating the influence of the magnetic field of the stator winding of the motor, and to provide a method for accurately measuring the position of the rotor using the sensor.

In order to solve the above technical problem, the present invention provides a motor rotor position sensor comprising a target disk mounted on a rotor of the motor, an inductor fixed in the casing of the motor, and a DSP connected to the inductor, the target disk being made of a conductive material. Formed, the outer edge of which has a sinusoidal or cosine curve shape; the inductor comprises a pair of windings of an ASIC circuit, a sinusoidal plane winding and a cosine plane winding; the sinusoidal plane winding and the cosine plane winding correspond to a target disk; the ASIC circuit The output terminal is connected to the DSP, and the DSP outputs a rotor position signal at its data output port by operation. Further, in the inductive element of the present invention, there are four planar windings, two of which are sinusoidal windings, and the other two are cosine windings, the sinusoidal winding and the cosine winding are according to a first sinusoidal winding, a first cosine winding, and a second The sequential arrangement of the sinusoidal winding and the second cosine winding, and the subsequent winding senses that the sinusoidal angle of the vortex on the target disk is 90 degrees behind the angle of the previous winding.

In order to accurately measure the rotor position and rotational speed of the motor, it is another object of the present invention to provide a method of measuring the position of the rotor of the motor. The method utilizes a target disk made of a conductive material in a shape of a sine or a cosine curve on a target rotor; an inductive component corresponding to the target disk is disposed in the motor casing, and the output is connected to the DSP, and the output signal is in the DSP. Data processing is performed; data processing in the DSP includes at least the following steps:

(1) performing analog-to-digital conversion on the signal of the rotor position generated by the sensing element, and performing offset to obtain a bipolar position signal;

(2) Performing angular error and amplitude error compensation for the bipolar position signal;

(3) performing low-pass filtering;

(4) Check if the motor control is the torque control mode;

(5) If the result of the step (4) is affirmative, the DC link bus drift is subjected to band pass filter compensation and then the position signal is decoded;

(6) If the result of step (4) is negative, the position signal is directly decoded.

Further, the compensation for the position offset mainly includes an angle error and an amplitude error compensation. The compensation for angular error and amplitude error is performed as follows:

SensorA = G _A Sin6

SensorB = G _B Cos(0 + Αθ)

SensorA _x = SensorA = G _A Sin6 e _Ώ n ^G AD , Sensor ASinAO

SensorB, = r ,Los& = SensorB H

^{1 A} G _B CosA0 CosAO where: SensorA, SensorB is the uncompensated signal, Sensor, Semorm is the signal after compensation, (3⁄4, (3⁄4 and ^^ are constant, respectively uncompensated sinusoidal amplitude) , cosine phase amplitude and angular error.

The positive effect of the invention is that the proposed sensor meets automotive standards and is not affected by the magnetic field of the stator windings of the motor. The method for accurately measuring the rotor position and the rotational speed of the motor proposed by the present invention can be implemented by a DSP The device is uniformly completed, and the output rotor position angle signal is a digital signal, and the rotor speed value can be directly obtained by the signal. These results can be transmitted to the vehicle master controller through the car CAN bus, so the sensor and the use of the present invention are utilized. The method of the invention has a simple structure and low cost for accurately measuring the position and speed of the rotor of the motor. In addition, the preferred structure of the present invention utilizes two sine and cosine windings to collect signals generated by the rotation of the target disk, which eliminates the influence of target disk and detector distance changes and temperature changes on the measurement, through two sinusoidal windings and two The signal induced by the cosine winding can be subtracted.

The invention is further illustrated by the following examples and figures.

DRAWINGS

Figure 1 is a schematic view showing the installation of a rotor position sensor on a motor;

Figure 2 is a schematic view showing the relative position of the target disk in the rotor position sensor and the planar winding in the sensing element;

Figure 3 is a block diagram of the rotor position and speed determination method;

Figure 4 is a parallel resonant circuit diagram;

Figure 5 is a circuit diagram of the rotor sensor output and the DSP chip interface;

Figure 6 is a signal processing diagram of the rotor position sensor sensor;

Figure 7 shows the actual rotor position sensor output signal;

Figure 8 shows the absolute position angle of the rotor.

detailed description

1 is a schematic view showing the installation of a rotor position sensor according to an embodiment of the present invention. As shown in the figure: The rotor position sensor of the present invention comprises an inductor 2 and a target disk 1 installed at one end of the motor, and the target disk 1 is a ring shape. The disk has a thin portion with a rivet on the outside, and the inward portion is a convex portion having a certain thickness, and the outer shape of the disk is a sinusoidal or cosine curve, and the target disk 1 in FIG. . The target disk 1 is made of a metal material such as aluminum or iron, and the entire target disk 1 is fixed to the bracket 7 of the rotor 4 by rivets, and rotates around the rotor support shaft 6 together with the rotor 4, and the inductor 2 is mounted through the sensor mounting bracket 5. On one side of the stator 3, the inductor 2 includes an ASIC having a planar winding and a signal sensed by the planar winding (Application Specific Integrated Circuit, an ASIC circuit designed and manufactured by Chery Automobile Co., Ltd.). The output of the ASIC circuit is connected to the TMS320 808 DSP chip.

2 is a schematic view showing the relative position of the sensor 2 and the target disk 1. In the present embodiment, the inductor 2 has four planar windings, which are a first sinusoidal plane winding 21, a first cosine plane winding 22, and a second sinusoidal plane winding 23. The second cosine plane winding 24, the sinusoidal winding and the cosine winding are arranged in a word by word.

If the motor has 6 poles, the position sensor provides 6 cycles of signal rotation (the mechanical angle is 0 to 360 degrees), that is, one electrical angle period (360 degrees) corresponds to the mechanical angle of the motor 60 degrees, so the phase in Figure 2 The electrical angles between adjacent planar windings are 90 degrees out of each other. This 90 degree electrical angle difference can also be considered as the distance between adjacent planar windings. The target disk 1 is fixed to the rotor support together with the rotor and rotates together with the rotor support.

Taking a planar winding 21 as an example (the rest of the principle is the same), when the target disk 1 rotates with the rotor 4, the current in the planar winding generates an alternating magnetic field, as shown in Fig. 2, when the planar winding of the inductor is sweeping over the target disk. An eddy current will be generated in the target disk, which will generate an alternating magnetic field opposite to the direction of the planar winding of the inductor. The reaction of the alternating magnetic field to the planar winding causes the amplitude and phase of the high-frequency current to change (ie, the plane The inductance of the winding changes). This change is related to the geometry, conductivity, and permeability of the target disk. It is also related to the geometric parameters of the planar winding coil, the frequency of the current, and the distance from the coil to the conductor under test. The sensor measures the angle based on the change in the intensity of the eddy current effect caused by the change in the relative coverage area between the target disk and the planar winding of the inductor. The planar winding inductance is proportional to the area of the signal disk swept by the plane winding, and the target disk area S is the sine function of the absolute position angle (t) of the signal disk. Through the processing of the hardware circuit in the inductor, the inductance change of the planar winding, that is, the absolute position change of the signal plate e, t, is converted into the change of the output voltage of the inductor, so that S L o IJ.

Where (t) is the absolute position angle of the signal disk (motor rotor), S is the area of the planar winding sweeping the signal disk, and J is the planar winding inductance, which is the output voltage signal of the inductor.

The sensor detects the absolute position angle value by causing the sinusoidal voltage signal and the cosine voltage signal output by the two sensors to change the area of the two sets of planar windings whose electrical angles are different from each other by 90 degrees.

In this embodiment, there is a parallel resonant circuit in the ASIC circuit, and four planar windings are the sensing portions in the resonant circuit, and the resonant circuit is a component of the detector chip circuit. The target disk of this sensor is an aluminum disk with a sinusoidal outer edge, which is due to movement with the planar winding of the inductor. The eddy current effect will create a magnetic field on its surface that is proportional to the area of the aluminum disk. At this point, when the planar winding scans here will produce a varying inductance, the change in inductance causes the phase shift of the resonant circuit, so by determining the phase shift The position of the rotor can be accurately determined. The role of the four planar windings in the resonant circuit is to accurately determine the rotor position. In principle, two can be used. By obtaining the sine and cosine signals through the two, the absolute position of the rotor angle can be obtained. The effect of four is that the distance between the target disk and the detector changes and the influence of the temperature change on the measurement can be passed through the first sinusoidal plane winding 21 and the second sinusoidal plane winding.

23. The first cosine plane winding 22 and the second cosine plane winding 24 are subtracted to eliminate, so that the output signal is not affected by changes in the magnetic field and the electric field, otherwise only one sinusoidal plane winding and one cosine plane winding will be used. Affected by interference. The sensor implementation principle is briefly described by the following formula (1):

_Usm = P _h a(J ₂ l) - Pha(J ₂ 3) _{( 1} ) (the formula is not clear)

U _C0S = Pha(J22) - Pha(J24) where U _sm and U _∞s are the sine and cosine voltage signals of the two outputs of the sensor, Pha(J ² l), Pha(J23), Pha(J22), Ρ1ΐ3 (£24) represents the voltage output signal corresponding to the change in inductance of the planar windings 21, 23, 22, 24, respectively. Figure 6 is a schematic diagram of the internal implementation of the inductor. When measuring, when the planar winding is away from the target disk,

The LC loop is in a resonant state, the resonant frequency is the oscillation frequency of the quartz crystal oscillator, and the output voltage on the resonant loop is also the largest; when the sensor coil approaches the target disk, the equivalent inductance of the coil changes, causing the loop to be detuned and deviating from the resonant frequency. , causing the output voltage to drop. The output voltage is amplified, detected, filtered and output, realizing the transition from absolute position angle to voltage signal.

Figure 7 shows the actual two-channel voltage signal output. After the actual voltage signal is output, considering the influence of the error, etc., the absolute position of the rotor position needs to be obtained by the equation (2).

N sine (t) = (U _sm - UxofFs) I Uxamp ₍ ^ )

N cosine (t) = (U cos "Uyoffs) I Uyamp wherein Uxoff _S, Uyoffs sinusoidal output voltage signal respectively, the output voltage signal waveform of the cosine offset neutral line and zero voltage, Uxamp, Uyamp sinusoidal output voltage signal respectively, The amplitude of the cosine output voltage signal waveform, N sine (t), N cosine (t) is the value of the voltage signal normalized. According to the obtained N _S ine (t), N _C0S in _e (t) and considering the sign change of the value to determine the quadrant of the absolute rotor position angle, refer to Figure 8 and find the absolute rotor position angle. The solution is represented by the following equation: if (abs(Nsine(t))< abs(Ncosine(t)))

{ if (Ncosine(t) < 0)

{ if(Nsine(t) < 0) { 6»(t) = atan(Nsine(t)/Ncosine(t)) - pi; }

Else { ^(t) = atan(nsine/Ncosine(t)) + pi; } }

Else { θ = atan(Nsine(t)/Ncosine(t)); } }

Else

{ if(nsine < 0) { 6»(t) = - pi/2 - atan(Nco sine(t)/Nsine(t)); }

Else { 6»(t) = pi/2 - atan(Nco sine(t)/Nsine(t)); } }

^(t) = ^(t)* 180° / pi;

Where abs is the absolute value function, pi is ^ "value," tan is the inverse tangent function

As shown in Fig. 5, the sensor output of the rotor position sensor is two paths, one is a sinusoidal voltage signal, and the other is a cosine voltage signal. The two signals are output to the DSP chip through the A/D conversion module in the chip to realize the analog signal. The transition to the digital signal is such that the motor is controlled by the above solution in the motor control to obtain the absolute position angle of the motor rotor.

In this embodiment, the material of the target disk 1 is aluminum or other metal materials such as copper, iron, etc., the target disk is mounted on the rotor support, and the sensor sensor 2 is fixedly mounted on the motor casing through the sensor bracket portion 5. Inside, the guarantee is installed as shown in Figure 1. The target disk 1 rotates together with the motor rotor 4, and the target disk 1 is in an alternating electromagnetic field. Since the target disk 1 is a metal conductor, an induced current is generated, which is called an eddy current effect, so the sensor is also called a vortex-based rotor. sensor. The conductive material of the target disk 1 generates eddy current loss, and the four planar windings of the first sinusoidal plane winding 21, the first cosine plane winding 22, the second sinusoidal plane winding 23, and the second cosine plane winding 24 are all four in the inductor 2. As part of the resonant circuit, as shown in Figure 4, the eddy current effect of the conductive material of the target disk 1 can result in a reduction in inductance in the planar winding. The area of the target disk 1 scanned by the planar winding of this sensor is proportional to the change in inductance, and the change in inductance causes the phase shift of the resonant circuit, so the position of the rotor can be accurately determined by determining the phase shift. The output signal repeats its own waveform for each pole pair. For example, this motor has 6 pairs of poles.

IPM (Interior Permanent Magnet Machine) motor, the waveform of the output signal is repeated 6 times for each mechanical rotation period. The two output signals of the sensor are input into the DSP chip for decoding to obtain a rotor position signal. The specific process is shown in Figure 3: (1) ADC (analog-to-digital conversion) is performed on two output signals of the rotor position sensor through two 12-bit AD channels of the TMS320 808 DSP chip. This signal is a voltage signal and is a positive value, and is performed by performing a sine and cosine output voltage signal. The zero offset of the line converts the signal into a bipolar (positive and negative) position signal.

(2) Orthogonal two-phase signals may have errors in amplitude and angle due to installation restrictions and errors. According to the following formula, Semor _A , ^«3⁄4 is the digital signal of the sinusoidal signal and the cosine signal with the target disc position information outputted by the ASIC circuit and stored in the DSP memory through the ADC. The signal is not compensated, Se _Ra0 , Se o are the signals after compensation in the DSP, GA, (3⁄4 is the uncompensated sinusoidal amplitude, the cosine phase amplitude, its value and the motor rotor speed, the number of winding coils in the rotor position sensor sensor and The shape of the target disk is related to the angle error, which is obtained by comparing the actual measured rotor position angle with the angular position measured by the sensor. The actual measured rotor position angle can be obtained by observing the back electromotive force or the like.

SemorA = GA sin θ

Sensors = GBCOS(6 + ΑΘ)

Sens or A\ = SemorA = GA sin Θ

(3) Perform 200Hz low-pass filtering on the compensated signal.

(4) If the motor speed exceeds a certain value a and is currently in the torque mode, the influence of the DC bus drift needs to be considered. Therefore, the filtering result of (3) is further subjected to 67 Hz low-pass filtering, and the two filtering results are different to obtain a band-pass filtering result. , Eliminate the influence of DC bus drift on the position signal.

(5) By calculating the inverse tangent of the result value of the sine cosine signal and considering the influence of the rotor position offset, the rotor position angle is defined at [0, 2], and the value is ak, and ak-l is the last time. Find the value and find the difference: ek=ak-ak-l

(6) According to the AD channel, the minimum number of sampling times is 2, if ek<- π, it means that the motor is rotating forward, at this time the actual ek=ek+2r, if ek>r, then Indicates that the motor is reversing, the actual ek = ek-2r, according to = -! + to find the rotor position angle at time k. There are 6 output waveforms in one mechanical cycle, so it is limited to [0, 6*2 ] (7) If the velocity sampling starts, the velocity sampling instant is the mechanical angular velocity ω = ^θ " ^θ " , where A is the value of the previous velocity sample time

(8) Low-pass filtering of the speed of lOOhz to filter out noise.

Here, the calculation result is first subjected to low-pass filtering of 200 Hz to obtain a 0-200 Hz passband. If DC bus drift is applied, 67HZ low-pass filtering is performed to obtain a 0-67hz passband. If the two filtering results are different, 67HZ is obtained. -200HZ passband.

Claims

Rights request

A motor rotor position sensor comprising a target disk (1) mounted on a rotor of the motor, a sensor (2) fixed in the motor casing, and a DSP connected to the sensor, wherein: the target disk (1) made of a conductive material, the outer edge of which has a sinusoidal or cosine curve shape; the inductor (2) comprises an ASIC circuit and a winding pair comprising a sinusoidal plane winding and a cosine plane winding; the sinusoidal plane winding and the cosine plane winding Corresponding to the target disk (1); the output end of the ASIC circuit is connected to the DSP, and the DSP outputs a rotor position signal at its data output port by operation.

2. A rotor position sensor for an electric machine according to claim 1, wherein: said winding pair in said inductor (2) comprises four planar windings, respectively a first sinusoidal winding (21), a second a sinusoidal winding (23), a first cosine winding (22), and a second cosine winding (24), according to a first sinusoidal winding (21), a first cosine winding (22), a second sinusoidal winding (23), The second cosine windings (24) are arranged in sequence, and the subsequent windings sense that the sinusoidal angle of the vortex on the target disk is 90 degrees behind the angle of the previous winding.

3 . The motor rotor position sensor according to claim 1 , wherein: the target disk ( 1 ) has an annular band shape, and both sides of the outer edge thereof are sinusoidal shapes symmetric with respect to a center line of the target disk. The material is made of metal aluminum.

4. A motor rotor position sensor according to claim 1, wherein: said motor is an in-line permanent magnet motor.

5. A method for measuring the position of a rotor of a motor, using a target disk made of a conductive material with a sinusoidal or cosine curve shape on the target rotor; and an output component corresponding to the target disk in the motor casing, the output signal of which is connected to the DSP Perform data processing; characterized in that: performing data processing in the DSP includes the following steps:

(3) performing low-pass filtering; (4) Check if the motor control is the torque control mode;

6. A method of measuring a rotor position of a motor according to claim 5, wherein the compensation of the angular error and the amplitude error in said step (2) is performed as follows:

SensorA = G _A Sin6

SensorB = G _B Cos(0 + Αθ)

SensorA _x = SensorA = G _A Sin6

e _Ώ n ^G AD , Sensor ASinAO

SensorB, = r ,Los& = SensorB H

^{1 A} G _B CosA0 CosAO where: SmsorA, SensorB is the uncompensated signal, Sensor, Smsor is the signal after compensation, GA, (3⁄4 and ^^ are constant, respectively, uncompensated sinusoidal amplitude, Cosine phase amplitude and angular error.