CN106849804A - A Permanent Magnet Synchronous Motor Rotor Position Observer Based on Random Frequency and High Frequency Square Wave Voltage Injection - Google Patents

Abstract

In order to solve the problem of noise generation in the existing sensorless control of a built-in permanent magnet synchronous motor based on a high-frequency signal injection method, a permanent magnet synchronous motor rotor position observer with random frequency and high-frequency square wave voltage injection is provided, and belongs to the field of motor control. The invention comprises the following steps: a random frequency signal generator for generating random frequency injection signals v with the same frequency and orthogonal phase_injAnd a random frequency demodulation signal v_dem(ii) a Envelope extraction means for demodulating the signal v from the random frequency_demα axis high frequency current i is extracted_αhAnd β Axis high frequency Current i_βhTo obtain α axis high-frequency current envelope signal i_α,puAnd β axis high frequency current envelope signal i_β,puA quadrature phase-locked loop 3 for generating a high-frequency current envelope signal i according to an α axis_α,puAnd β axis high frequency current envelope signal i_β,puThe position of the rotor is estimated. The invention can be widely applied to a built-in permanent magnet synchronous motor control system, does not need additional hardware and has obvious noise reduction effect.

Description

A view of permanent magnet synchronous motor rotor position with random frequency high frequency square wave voltage injection detector

technical field

The invention relates to a rotor position observer of a permanent magnet synchronous motor, in particular to a rotor position observer of a permanent magnet synchronous motor injected with random-frequency high-frequency square wave voltage, belonging to the field of motor control.

Background technique

In recent years, AC motors have played an important role in industrial products and household appliances. Compared with the traditional asynchronous motor, the permanent magnet synchronous motor has the advantages of high torque density and high power density, and thanks to the development of permanent magnet material preparation technology in recent years, it occupies an important position in modern industry. Currently, there are various types of permanent magnet synchronous motors used to drive various production equipment such as conveyor belts, robotic arms, cranes, paper mills and wastewater treatment. With the development and progress of power semiconductor devices, inverter topologies, and microprocessors, permanent magnet synchronous motors play an increasingly important role in variable speed motor control systems.

In order to obtain stable control performance, the rotor position and speed of the motor are essential links. The traditional method is to install a speed or position sensor on the rotor shaft. At present, there are mechanical speed and position sensors such as photoelectric code discs, rotary encoders and tachogenerators. Although these mechanical sensors have the advantages of high precision and high resolution, their installation brings many problems such as increased volume, increased system cost, increased complexity, and decreased reliability. Therefore, in the past 20 years, various position sensorless control methods have been proposed one after another. According to its scope of application, it can be divided into two categories: the back electromotive force model method suitable for medium and high speeds and the high frequency signal injection method for zero and low speeds. The former constructs a back EMF observer to calculate the back EMF signal related to the self-rotation position, and then obtains the self-rotation position. However, in the low-speed or even zero-speed region, this method cannot work effectively. The other type is based on high-frequency signal injection, by injecting high-frequency signals into the motor stator, tracking the salient poles of the rotor, and then obtaining the position of the motor rotor.

The high-frequency square wave voltage signal injection method tracks the salient poles of the motor to realize the zero-low speed position sensorless control method, which can ensure the control performance of the motor in the low speed range. However, this method has a defect, that is, the problem of noise generated by high-frequency current, which limits its application in industrial and household fields. The traditional high-frequency signal injection method uses a fixed frequency signal injection to concentrate the noise at a certain frequency, resulting in sharp and harsh noise.

Contents of the invention

The purpose of the present invention is to solve the problem of noise generation in the sensorless control of the existing built-in permanent magnet synchronous motor based on the high frequency signal injection method. The present invention provides a permanent magnet synchronous motor rotor with random frequency high frequency square wave voltage injection position observer.

A permanent magnet synchronous motor rotor position observer with random frequency high-frequency square wave voltage injection of the present invention, said observer includes a random frequency signal generator 1, an envelope extraction device 2 and a quadrature phase-locked loop 3;

Random frequency signal generator 1, used to generate random frequency injection signal v _inj and random frequency demodulation signal v _dem , said random frequency injection signal v _inj and random frequency demodulation signal v _dem have the same frequency and phase quadrature; random frequency The injection signal v _inj is input to the estimated d-axis of the permanent magnet synchronous motor vector controller; the random frequency demodulation signal v _dem is input to the envelope extraction device 2;

The α-axis high-frequency current and the β-axis high-frequency current output by the permanent magnet synchronous motor vector controller are respectively input to the envelope extraction device 2;

The envelope extraction device 2 is used to extract the envelopes of the α-axis high-frequency current i _αh and the β-axis high-frequency current i _βh according to the random frequency demodulation signal v _dem , and obtain the α-axis high-frequency current envelope signal i _{α, Pu} and β-axis high-frequency current envelope signal i _β,pu ;

The quadrature phase-locked loop 3 is used to estimate the position of the rotor according to the α-axis high-frequency current envelope signal i _α,pu and the β-axis high-frequency current envelope signal i _β,pu .

Preferably, the random frequency signal generator 1 includes two fixed frequency signal generating units and a random selection unit;

The first fixed-frequency signal generation unit is used to generate an injected square wave signal v _inj1 and a demodulated square wave signal v _dem1 , the injected square wave signal v _inj1 and the demodulated square wave signal v _{dem1 have} the same frequency and phase quadrature ;

The second fixed-frequency signal generation unit is used to generate an injected square wave signal v _inj2 and a demodulated square wave signal v _dem2 , the injected square wave signal v _inj2 and the demodulated square wave signal v _{dem2 have} the same frequency and phase orthogonality ;

The frequency of the square wave signal generated by the two fixed frequency signal generating units is different;

The random selection unit randomly selects two fixed-frequency signal generating units once in each signal cycle, and the injected square wave signal and demodulated square-wave signal generated by the selected fixed-frequency signal generating unit are respectively used as random frequency injected signals v _inj and Random frequency demodulation signal v _dem output.

Preferably, the envelope extraction device 2 includes a double-cycle lag unit, a first multiplier, a second multiplier, a first first-order low-pass filter, a second first-order low-pass filter, and a first division unit , a second division unit and a computing unit;

The random frequency demodulation signal v _dem is input to the double cycle lag unit, and the output of the double cycle lag unit is input to the first multiplier and the second multiplier at the same time;

After the first multiplier multiplies the α-axis high-frequency current i _αh with the output of the double-period lag unit, it is input to the first first-order low-pass filter for filtering;

The second multiplier multiplies the β-axis high-frequency current i _βh with the output of the double-cycle lag unit, and then inputs it to the second first-order low-pass filter for filtering;

The first first-order low-pass filter inputs the output filtered signal to the first divider and computing unit;

The second first-order low-pass filter inputs the output wave signal to the first divider and the first divider respectively. computing unit;

said The calculation unit uses the output of the first first-order low-pass filter and the output of the second first-order low-pass filter as input a and input b respectively, The output of the calculation unit is respectively input to the first divider and the second divider;

The first divider takes the output of the first first-order low-pass filter as the dividend, and The output of the calculation unit is used as a divisor, and the α-axis high-frequency current envelope signal i _α,pu is output;

The second divider takes the output of the second first-order low-pass filter as the dividend, and The output of the calculation unit is used as a divisor to output the β-axis high-frequency current envelope signal i _β,pu .

Preferably, the quadrature phase-locked loop 3 includes a third multiplier, a fourth multiplier, a subtractor, a proportional-integral unit, an integral unit, a sine function calculation unit and a cosine function calculation unit;

The third multiplier multiplies the α-axis high-frequency current envelope signal i _{α, pu} by the output of the sine function calculation unit, and then inputs it to the subtrahend end of the subtractor;

The fourth multiplier multiplies the β-axis high-frequency current envelope signal i _{β, pu} with the output of the cosine function calculation unit, and then inputs it to the minuend end of the subtractor;

The subtractor outputs an error signal ε, and inputs the error signal ε to a proportional-integral unit;

The proportional-integral unit outputs an estimated rotational speed and the estimated speed input to the integrator;

The integrator outputs the estimated position and put the estimated position Simultaneously input to the sine function calculation unit and the cosine function calculation unit, the estimated position Estimated rotor position for quadrature phase locked loop.

The above technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

The beneficial effect of the present invention is that firstly, the random frequency signal generator 1 generates phase-orthogonal random frequency injection signals and random frequency demodulation signals. The random frequency injection signal is then injected into the estimated d-axis through the inverter in the PMSM vector controller. The envelope of the random high-frequency current in the two-phase stationary coordinate system is extracted by the envelope extraction device 2 to obtain a position-related sine and cosine signal. Finally, the position of the rotor will be estimated by quadrature phase-locked loop.

The random-frequency high-frequency signal injection method of the present invention switches the frequency of the injected signal randomly to disperse the frequency of the noise, thereby reducing the noise. And simple, reliable use. The practical application range of the high-frequency signal injection method is widened, and it can be widely used in the built-in permanent magnet synchronous motor control system without additional hardware, and the noise reduction effect is obvious.

Description of drawings

Fig. 1 is a schematic structural diagram of the principle structure of a permanent magnet synchronous motor rotor position observer injected with a random frequency high frequency square wave voltage in a specific embodiment; wherein the permanent magnet synchronous motor vector controller is an existing control scheme;

Fig. 2 is a schematic structural diagram of the random frequency signal generator described in the specific embodiment;

Fig. 3 is a schematic diagram of the principle structure of the envelope extraction device described in the specific embodiment;

Fig. 4 is a schematic diagram of the principle structure of the quadrature phase-locked loop described in the specific embodiment;

Figure 5 is a schematic diagram of the relationship between a two-phase stationary shaft system, a two-phase synchronous rotating shaft system and a three-phase stationary shaft system; where dq represents a two-phase synchronous rotating coordinate system, αβ represents a two-phase stationary coordinate system, and ABC represents a three-phase stationary coordinate system .

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention. This embodiment is described in conjunction with Fig. 1. A permanent magnet synchronous motor rotor position observer described in this embodiment is injected with a random frequency high frequency square wave voltage. This embodiment is based on the existing permanent magnet synchronous motor vector controller. , adding a random frequency signal generator 1, an envelope extraction device 2 and a quadrature phase-locked loop 3;

As shown in Figure 1, the permanent magnet synchronous motor vector controller includes a subtractor, a PI proportional-integral controller, an adder, (synchronous rotating axis to stationary axis coordinate transformation), (stationary axis to synchronous rotating axis coordinate transformation), space vector pulse width modulator SVPWM, low-pass filter LPF and high-pass filter HPF;

Indicates the stator current given value under the two-phase synchronous rotating shaft system;

Indicates the stator current feedback value under the two-phase synchronous rotating shaft system;

Indicates the high-frequency square wave voltage signal under the two-phase synchronous rotating shaft system;

v _{α, β} represent the voltage in the two-phase stationary coordinate system;

i _{α, β} represent the current in the two-phase stationary coordinate system;

A random frequency signal generator 1 is used to generate a random frequency injection signal v _inj and a random frequency demodulation signal v _dem , the random frequency injection signal v _inj and the random frequency demodulation signal v _{dem have} the same frequency and phase quadrature;

The random frequency injection signal v _inj is input to the estimated d-axis of the permanent magnet synchronous motor vector controller; the random frequency demodulation signal v _dem is input to the envelope extraction device 2;

In this embodiment, the random frequency injection signal is generated by the random frequency signal generator 1, and the random frequency high-frequency voltage signal is injected into the built-in permanent magnet synchronous motor IPMSM by the inverter of the permanent magnet synchronous motor vector controller; the current of the motor Contains fundamental wave components and random frequency components. The random high-frequency current of the motor is extracted through the high-pass filter HPF, and the α-axis high-frequency current i _αh and the β-axis high-frequency current i _βh are obtained.

As shown in Figure 1, the envelope extraction device 2 of this embodiment is provided with an input port of α-axis high-frequency current i _αh , an input port of β-axis high-frequency current i _βh , an input port of random frequency demodulation signal v _dem , and an input port of α-axis high frequency High frequency current envelope signal i _{α, pu} output port and β axis high frequency current envelope signal i _{β, pu} output port;

The envelope extraction device 2 is used to extract the envelopes of the α-axis high-frequency current i _αh and the β-axis high-frequency current i _βh in the stationary two-phase coordinate system according to the random frequency demodulation signal v _dem , and obtain the α-axis high-frequency current Envelope signal i _α,pu and β-axis high-frequency current envelope signal i _β,pu ;

As shown in Figure 1, the quadrature phase-locked loop 3 of this embodiment is provided with an α-axis high-frequency current envelope signal i _{α, pu} input port, a β-axis high-frequency current envelope signal i _{β, pu} input port, an estimated rotational speed Output port and estimated location output port;

The quadrature phase-locked loop 3 is used to estimate the position of the rotor according to the α-axis high-frequency current envelope signal i _α,pu and the β-axis high-frequency current envelope signal i _β,pu .

In this embodiment, the rotor position is extracted from the α-axis high-frequency current envelope signal i _α,pu and the β-axis high-frequency current envelope signal i _β,pu Then estimate the position of the rotor.

In a preferred embodiment, as shown in FIG. 2 , the random frequency signal generator 1 of this embodiment includes two fixed frequency signal generation units and a random selection unit;

The first fixed-frequency signal generating unit is configured to generate an injected square wave signal v _inj1 and a demodulated square wave signal v _dem1 , the injected square wave signal v _inj1 and the demodulated square wave signal v _{dem1 have} the same frequency and phase orthogonality;

The second fixed-frequency signal generating unit is used to generate an injected square wave signal v _inj2 and a demodulated square wave signal v _dem2 , the injected square wave signal v _inj2 and the demodulated square wave signal v _{dem2 have} the same frequency and phase quadrature;

The frequency of the square wave signal generated by the two fixed frequency signal generating units is different;

The random selection unit in this embodiment randomly selects two fixed-frequency signal generating units once in each signal cycle, and the injected square wave signal and demodulated square wave signal generated by the selected fixed-frequency signal generating unit are respectively used as random frequency injected signals v _inj and random frequency demodulation signal v _dem output.

The random frequency signal generator 1 in this embodiment randomly selects the random frequency injection signal v _inj and the random frequency demodulation signal v _dem once in each signal cycle, and randomly switches the frequency of the injection signal v _inj , so that the high frequency current of the motor generates The frequency of the noise is dispersed, thereby reducing the noise.

In a preferred embodiment, as shown in FIG. 3 , the envelope extraction device 2 of this embodiment includes a double-cycle lag unit 2-1, a first multiplier 2-2, a second multiplier 2-3, a first first-order Low-pass filter 2-4, second first-order low-pass filter 2-5, first division unit 2-6, second division unit 2-7 and a Computing units 2-8;

The random frequency demodulation signal v _dem is input to the double cycle lag unit 2-1, and the output of the double cycle lag unit 2-1 is simultaneously input to the first multiplier 2-2 and the second multiplier 2-3;

After the first multiplier 2-2 multiplies the α-axis high-frequency current i _αh with the output of the double-cycle lag unit 2-1, it is input to the first first-order low-pass filter 2-4 for filtering;

After the second multiplier 2-3 multiplies the β-axis high-frequency current i _βh with the output of the double-cycle lag unit 2-1, it is input to the second first-order low-pass filter 2-5 for filtering;

The first first-order low-pass filter 2-4 inputs the filtered signal of the output to the first divider 2-6 and the first divider respectively. Computing units 2-8;

The second first-order low-pass filter 2-5 inputs the output wave signal to the first divider 2-7 and the first divider respectively. Computing units 2-8;

of this embodiment Computing unit 2-8 uses the output of the first first-order low-pass filter 2-4 and the output of the second first-order low-pass filter 2-5 as input a and input b respectively, The output of the computing unit 2-8 is input to the first divider 2-6 and the second divider 2-7 respectively;

The first divider 2-6 uses the output of the first first-order low-pass filter 2-4 as the dividend, and The output of the calculation unit 2-8 is used as a divisor, and the α-axis high-frequency current envelope signal i _α,pu is output;

The second divider 2-7 takes the output of the second first-order low-pass filter 2-5 as the dividend, and The output of the calculation unit 2-8 is used as a divisor to output the β-axis high-frequency current envelope signal i _β,pu .

This embodiment provides the specific structure of the envelope extracting device 2, the envelope extracting device 2 first passes through the double cycle lag unit 2-1, the first multiplier 2-2, the second multiplier 2-3 and the first one The first-order low-pass filter 2-4 and the second first-order low-pass filter 2-5 preliminarily obtain the envelope current signal. In order to further improve the rotor position accuracy, the first divider 2-6, the second divider 2-7 and The calculation unit 2-8 calculates and obtains envelope signals i _α,pu and i _β,pu with high precision. Not only that, the double-period hysteresis unit 2-1 included in this embodiment can effectively suppress the delay effect of the digital system. In general, the device can demodulate the sine-cosine envelope signal from the random high-frequency current signal in the α-β axis stationary coordinate system. Make it do preliminary processing for the following quadrature phase-locked loop 3 device.

In a preferred embodiment, as shown in FIG. 4 , the quadrature phase-locked loop 3 in this embodiment includes a third multiplier 3-1, a fourth multiplier 3-2, a subtractor 3-3, and a proportional-integral unit 3- 6. An integral unit 3-7, a sine function calculation unit 3-4 and a cosine function calculation unit 3-5;

The third multiplier 3-1 multiplies the α-axis high-frequency current envelope signal i _{α, pu} by the output of the sine function calculation unit 3-4, and then inputs it to the subtrahend end of the subtractor 3-3;

The fourth multiplier 3-2 multiplies the β-axis high-frequency current envelope signal i _{β, pu} with the output of the cosine function calculation unit 3-5, and then inputs it to the minuend end of the subtractor 3-3;

The subtractor 3-3 outputs the error signal ε, and inputs the error signal ε to the proportional integral unit 3-6;

The proportional integral unit 3-6 outputs the estimated rotational speed and the estimated speed Input to the integrator 3-7;

Integrator 3-7 outputs estimated position and put the estimated position Simultaneously input to the sine function calculation unit 3-4 and the cosine function calculation unit 3-5, the estimated position and estimated speed Indicates the position of the rotor estimated by the quadrature phase-locked loop 3 .

This embodiment provides the specific structure of the quadrature phase-locked loop 3, the input signal of the quadrature phase-locked loop 3 is the α-axis high-frequency current envelope signal and the β-axis high-frequency current envelope signal, and the output signal is the estimated position and estimated speed First, the rotor position error signal ε is extracted by multiplying the third multiplier 3-1, the fourth multiplier 3-2, the subtractor 3-3, the sine function calculation unit 3-4 and the cosine function calculation unit 3-5. Adjust the rotor position error signal ε to 0 using the proportional integral unit 3-6 and the integral unit 3-7, then estimate the position will converge to the actual rotor position, achieving an estimate of the rotor position. The quadrature phase-locked loop has a simple structure and strong robustness, and can realize the estimation of the rotor position.

Although the invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It is therefore to be understood that numerous modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the invention as defined by the appended claims. It shall be understood that different dependent claims and features described herein may be combined in a different way than that described in the original claims. It will also be appreciated that features described in connection with individual embodiments can be used in other described embodiments.

Claims (4)

1. a kind of permanent-magnet synchronous motor rotor position observer that random frequency high frequency square wave voltage is injected, it is characterised in that institute Stating observer includes random frequency signal generator, envelope extraction device and an orthogonal phaselocked loop；

Random frequency signal generator, for producing random frequency Injection Signal v_injWith random frequency demodulated signal v_dem, it is described Random frequency Injection Signal v_injWith random frequency demodulated signal v_demFrequency is identical and quadrature in phase；Random frequency Injection Signal v_injIn input to the estimation d axles of vector controller of permanent-magnet synchronous motor；Random frequency demodulated signal v_demIt is input into envelope extraction Device；

The α axles high frequency electric and β axle high frequency electrics of vector controller of permanent-magnet synchronous motor output are separately input into envelope extraction dress Put；

Envelope extraction device, for according to random frequency demodulated signal v_dem, extract α axle high frequency electrics i_αhWith β axle high frequency electrics i_βh Envelope, obtain α axle high frequency electric envelope signals i_α,puWith β axle high frequency electric envelope signals i_β,pu；

Orthogonal phaselocked loop, for according to α axle high frequency electric envelope signals i_α,puWith β axle high frequency electric envelope signals i_β,pu, estimate The position of rotor.

2. a kind of permanent-magnet synchronous motor rotor position of random frequency high frequency square wave voltage injection according to claim 1 is seen Survey device, it is characterised in that the random frequency signal generator is random including two fixed frequency signal generating units and one Select unit；

First fixed frequency signal generating unit, for producing an injection square-wave signal v_inj1With a demodulation square-wave signal v_dem1, the injection square-wave signal v_inj1With demodulation square-wave signal v_dem1Frequency is identical and quadrature in phase；

The second fixed frequency signal generating unit, for producing an injection square-wave signal v_inj2Believe with a demodulation square wave Number v_dem2, injection square-wave signal v_inj2With demodulation square-wave signal v_dem2Frequency is identical and quadrature in phase；

The square-wave signal frequency difference that two fixed frequency signal generating units are produced；

The random selection unit is randomly choosed once in each signal period to two fixed frequency signal generating units, choosing The injection square-wave signal and demodulation square-wave signal that the fixed frequency signal generating unit selected is produced inject respectively as random frequency Signal v_injWith random frequency demodulated signal v_demOutput.

3. the permanent-magnetic synchronous motor rotor position that a kind of random frequency high frequency square wave voltage according to claim 1 and 2 is injected Put observer, it is characterised in that the envelope extraction device multiplies including binary cycle hysteresis unit, the first multiplier, second Musical instruments used in a Buddhist or Taoist mass, the first low-pass first order filter, the second low-pass first order filter, the first divider, the second divider and oneComputing unit；

Random frequency demodulated signal v_demTo binary cycle hysteresis unit, the output of binary cycle hysteresis unit is input into the simultaneously for input One multiplier and the second multiplier；

First multiplier is by α axle high frequency electrics i_αhAfter being multiplied with the output of binary cycle hysteresis unit, input to the first single order Low pass filter is filtered；

Second multiplier is by β axle high frequency electrics i_βhAfter being multiplied with the output of binary cycle hysteresis unit, input to the second single order Low pass filter is filtered；

First low-pass first order filter by the filtering signal of output be separately input into the first divider andCalculate single Unit；

Second low-pass first order filter by the ripple signal of output be separately input into the first divider andCalculate single Unit；

It is describedComputing unit divides the output of the first low-pass first order filter and the output of the second low-pass first order filter Not as input a and input b,The output of computing unit is separately input into the first divider and the second divider；

First divider, will using the output of the first low-pass first order filter as dividendThe output of computing unit is made It is divisor, output α axle high frequency electric envelope signals i_α,pu；

Second divider, will using the output of the second low-pass first order filter as dividendThe output of computing unit is made It is divisor, output β axle high frequency electric envelope signals i_β,pu。

4. a kind of permanent-magnet synchronous motor rotor position of random frequency high frequency square wave voltage injection according to claim 3 is seen Survey device, it is characterised in that the orthogonal phaselocked loop includes the 3rd multiplier, the 4th multiplier, subtracter, a ratio product Subdivision, integral unit, a SIN function computing unit and a cosine function computing unit；

3rd multiplier is by α axle high frequency electric envelope signals i_α,puAfter being multiplied with the output of SIN function computing unit, input is to subtracting The subtrahend end of musical instruments used in a Buddhist or Taoist mass；

4th multiplier is by β axle high frequency electric envelope signals i_β,puAfter being multiplied with the output of cosine function computing unit, input is to subtracting The minuend end of musical instruments used in a Buddhist or Taoist mass；

The subtracter output error signal ε, and the error signal is input into pi element；

The pi element output estimation rotating speedAnd by the estimation rotating speedIt is input into integrator；

The integrator output estimation positionAnd by the estimated locationIt is input into simultaneously to SIN function computing unit and cosine Function calculating unit, the estimated locationIt is the position of the rotor that orthogonal phaselocked loop is estimated.