CN103281030A - Vector control method for mixed excitation motor no-position sensor - Google Patents

Abstract

The invention discloses a vector control method for a mixed excitation motor no-position sensor. The method mainly includes the steps that according to a vector control system of a mixed excitation synchronous motor, back electromotive force of an electric exciting winding is estimated through a sliding film observer according to current signals and voltage signals in the mixed excitation synchronous motor electric exciting winding, rotating speed information and rotor angle information are calculated through the back electromotive force, and finally rotating speed and an angle are brought into a driving system to achieve vector control of the mixed excitation synchronous motor. The sliding film observer is used for estimating the back electromotive force in the electric exciting winding, and the rotor position and the rotating speed information are obtained rapidly and accurately. Due to the fact that the current and the voltage in the electric exciting winding are direct current, in comparison with a traditional stator back electromotive force sliding film observer, the structure of the observer is simplified, links of integration and current feedback are reduced, accumulated errors and calculation of a processor can be effectively reduced, and therefore the vector control method has very good application prospects in the field of control over the mixed excitation synchronous motor.

Description

A kind of mixed excitation electric machine non-position sensor vector control method

Technical field

The present invention relates to a kind of mixed excitation electric machine non-position sensor vector control method, belong to the electric machines control technology field.

Background technology

Permagnetic synchronous motor is widely used in high accuracy transmission fields such as Digit Control Machine Tool, industrial robot, drive system of electric automobile because excitation source is thereby that permanent magnet has higher efficient and power density.But the inner excitation source of permagnetic synchronous motor is permanent magnet, and air-gap field is regulated difficulty, when the output torque can't promote with high speed when causing motor low speed a little less than the magnetic difficulty.The excitation source of hybrid exciting synchronous motor is permanent magnet and electric excitation winding, and this motor has been inherited permagnetic synchronous motor efficient and the high advantage of power density, and has stronger adjustable magnetic ability.

Synchronous machine adopts position transducers such as photoelectric encoder and Hall element to obtain rotating speed and rotor angle information more at present, the use of position transducer inevitably brings a series of problems, and for example: use cost height, installation difficulty and signal transmission are disturbed etc.For overcoming the variety of problems that position transducer brings, many scholars have carried out the research of position Sensorless Control.State observer has real-time and the good characteristics of robustness, and the synovial membrane observer has been subjected to attention as the outstanding person in the state observer in the position Sensorless Control field.

Current/voltage variable in the existing synovial membrane observation method is electric current and the voltage in the motor threephase armature winding.Mixed excitation electric machine is because the particularity of its structure, electric current in the electricity excitation winding and voltage have also comprised abundant rotor-position relevant information, electric current and voltage are DC quantity in the electric excitation winding on the other hand, this provides possibility for effectively simplifying computational process and reducing operand, and existing document does not all relate to research and the application of this respect.Therefore, utilize voltage and current in the electric excitation winding to realize position-sensor-free hybrid exciting synchronous motor vector control based on the synovial membrane observer most important theories research and practical value being arranged.

Summary of the invention

Goal of the invention: the present invention is directed to the deficiency of prior art, on the basis of analyzing existing non-position sensor vector control method based on the synovial membrane observer, proposed a kind of hybrid exciting synchronous motor drive system vector control method based on the synovial membrane observer,

Technical scheme: the present invention is realized by following technological means:

A kind of electric excitation winding back-emf estimation algorithm comprises the steps:

1) electric current and the voltage signal in the detection hybrid exciting synchronous motor electricity excitation winding;

2) structure synovial membrane observer is estimated electric excitation winding back-emf;

3) obtain the information of rotor speed and position according to the back-emf estimated value that obtains;

4) with rotating speed and the angle information substitution hybrid exciting synchronous motor vector control system asked for.

Structure synovial membrane observer estimates rotating speed and rotor position information in the step 2, specifically comprises following steps:

1) voltage equation of hybrid exciting synchronous motor electricity excitation winding in α β rest frame is:

$\left[\begin{array}{c}{U}_{\mathrm{\&alpha;}}\\ U_{\mathrm{\&beta;}}\end{array}\right]=R_f\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}\end{array}\right]+\left[\begin{array}{cc}{\mathrm{<figure-callout\; id="0"\; label="L\; f"\; filenames="HDA00003283298100021.png,HDA00003283298100022.png"\; state="\{\{state\}\}">L</figure-callout>}}_f& 0\\ 0& L_f\end{array}\right]\left[\begin{array}{c}\frac{{\mathrm{di}}_{\mathrm{\&alpha;}}}{\mathrm{dt}}\\ \frac{{\mathrm{di}}_{\mathrm{\&beta;}}}{\mathrm{dt}}\end{array}\right]+\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]$

Wherein, U _αAnd U _βBe the component of electric excitation winding voltage in rest frame; R _fAnd L _fBe respectively electric excitation winding resistance and inductance; i _αAnd i _βBe the component of electric excitation winding electric current in rest frame; e _αAnd e _βThe component of the electric excitation winding back-emf of difference in rest frame.

Write voltage equation as the state equation form:

$\frac{{\mathrm{di}}_f}{\mathrm{dt}}={\mathrm{Ai}}_f+B(u_f-e_f)$

In the formula:

$i_f=\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}\end{array}\right],u_f=\left[\begin{array}{c}{U}_{\mathrm{\&alpha;}}\\ U_{\mathrm{\&beta;}}\end{array}\right],e_f=\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]$

$A=\left[\begin{array}{cc}-\frac{R_f}{L_f}& 0\\ 0& -\frac{R_f}{L_f}\end{array}\right],B=\left[\begin{array}{cc}\frac{1}{L_f}& 0\\ 0& \frac{1}{L_f}\end{array}\right]$

2) according to the state equation of step 1, be constructed as follows the synovial membrane observer:

" ^ " represents estimated value in the formula; K is the gain of observer, is tried to achieve by experiment; Sgn is sign function.

Drawing observation error is:

$\frac{{d\tilde{i}}_{\mathrm{\&alpha;}}}{\mathrm{dt}}=-\frac{R_s}{L_s}{\tilde{i}}_{\mathrm{\&alpha;}}+\frac{1}{L_s}{e}_{\mathrm{\&alpha;}}-\frac{k}{L_s}\mathrm{sgn}\left({\tilde{i}}_{\mathrm{\&alpha;}}\right)$

$\frac{{d\tilde{i}}_{\mathrm{\&beta;}}}{\mathrm{dt}}=-\frac{R_s}{L_s}{\tilde{i}}_{\mathrm{\&beta;}}+\frac{1}{L_s}{e}_{\mathrm{\&beta;}}-\frac{k}{L_s}\mathrm{sgn}\left({\tilde{i}}_{\mathrm{\&beta;}}\right)$

In the formula:

Definition sliding mode equivalent voltage equation is:

$\left\{\begin{array}{c}{u}_{\mathrm{eq\&alpha;}}={\left(\mathrm{ksng}\left({\tilde{i}}_{\mathrm{\&alpha;}}\right)\right)}_{\mathrm{eq}}=e_{\mathrm{\&alpha;}}\\ u_{\mathrm{eq\&beta;}}={\left(\mathrm{ksng}\left({\tilde{i}}_{\mathrm{\&beta;}}\right)\right)}_{\mathrm{eq}}=e_{\mathrm{\&beta;}}\end{array}\right.$

Switching characteristic on the definable sliding-mode surface is thus:

$\left\{\begin{array}{c}{Z}_{\mathrm{\&alpha;}}\left(t\right)=e_{\mathrm{\&alpha;}}\left(t\right)\\ Z_{\mathrm{\&beta;}}\left(t\right)=e_{\mathrm{\&beta;}}\left(t\right)\end{array}\right.$

In the formula: Z _α(t), Z _β(t) be respectively switching signal on α and the β axle; e _α(t), e _β(t) be back-emf; △ (t) is disturbing signal.

In step 3, add low pass filter

Be used for filtering the high fdrequency component of switching signal to reduce the error that high-frequency interferencing signal causes.

Described rotor angle

Spinner velocity

Beneficial effect: the present invention is directed to mixed excitation electric machine self structure characteristics, electric current and the voltage measured in the electric excitation winding are estimated rotor speed and angle by the synovial membrane observer.Because the voltage and current in the electric excitation winding is DC quantity, and is simple relatively than traditional synovial membrane observation method structure.Owing in the process of finding the solution the electric current estimated value, save integration and current feedback link, can effectively reduce accumulated error and operand simultaneously.

Description of drawings

Fig. 1 is synovial membrane observer structure chart;

Fig. 2 is hybrid exciting synchronous motor position-sensor-free vector control main circuit structure figure;

Fig. 3 is rotor angle simulation result figure;

Fig. 4 is motor speed simulation result figure.

Embodiment

Below in conjunction with Figure of description the present invention is described in further detail:

The present invention relates to a kind of electric excitation winding back-emf estimation algorithm, specifically, comprise the steps:

1. gather electric current and the voltage signal of electric excitation winding by transducer, obtain the component U of voltage and current in α β coordinate system by changes in coordinates again _α, U _β, i _αAnd i _β

2. referring to Fig. 1, the voltage status equation of hybrid exciting synchronous motor electricity excitation winding in α β rest frame:

$\frac{{\mathrm{di}}_f}{\mathrm{dt}}={\mathrm{Ai}}_f+B(u_f-e_f)$

Because electric current is DC quantity in the electric excitation winding, that is:

$\frac{{\mathrm{di}}_f}{\mathrm{dt}}=0$

Then the voltage status equation can be reduced to following formula:

$\frac{{\mathrm{di}}_f}{\mathrm{dt}}={\mathrm{Ai}}_f+B(u_f-e_f)=0$

That is:

i _f=-A ^-1·B(u _f-e _f)

According to following formula, bring electric excitation winding resistance and back-emf switch function into equation simultaneously and can draw the electric current estimated value:

The electric current estimated value that calculates according to following formula can get switch function and be:

The k that wherein gains is specifically recorded by experiment.

Owing to contain a large amount of high order harmonic components among the following formula result, add low pass filter as follows, can draw the back-emf estimated value:

Finally can obtain rotor angle and speed:

3. referring to Fig. 2, bring top calculating gained result into hybrid exciting synchronous motor vector control drive system, obtain switching signal and drive main power inverter and electric exciting power converter through overdrive circuit.

Embodiment: by structure shown in Figure 2, build simulation model under the MATLAB/SIMULINK environment, parameter is as follows: motor rated power P _N=750w, number of pole-pairs p=4, busbar voltage Udc=300V, excitation winding voltage U f=35V, armature winding and excitation winding mutual inductance Msf=0.05207H, rated speed 1500rpm.When given rotating speed was 400rpm, simulation result as shown in Figure 3 and Figure 4.By Fig. 3 and Fig. 4 as can be known, when motor stabilizing moved, this method can accurately be asked for rotor angle and the rotating speed of hybrid exciting synchronous motor.

Claims (4)

1. a mixed excitation electric machine non-position sensor vector control method is characterized in that: comprise the steps:

1) electric current and the voltage signal in the detection hybrid exciting synchronous motor electricity excitation winding;

2) structure synovial membrane observer is estimated electric excitation winding back-emf;

3) obtain the information of rotor speed and position according to the back-emf estimated value that obtains;

4) with rotating speed and the angle information substitution hybrid exciting synchronous motor vector control system asked for.

2. vector control method according to claim 1 is characterized in that: structure synovial membrane observer estimates rotating speed and rotor position information in the step 2, specifically comprises following steps:

1) voltage equation of hybrid exciting synchronous motor electricity excitation winding in α β rest frame is:

$\left[\begin{array}{c}{U}_{\mathrm{\&alpha;}}\\ U_{\mathrm{\&beta;}}\end{array}\right]=R_f\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}\end{array}\right]+\left[\begin{array}{cc}{L}_f& 0\\ 0& L_f\end{array}\right]\left[\begin{array}{c}\frac{{\mathrm{di}}_{\mathrm{\&alpha;}}}{\mathrm{dt}}\\ \frac{{\mathrm{di}}_{\mathrm{\&beta;}}}{\mathrm{dt}}\end{array}\right]+\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]$

Wherein, U _αAnd U _βBe the component of electric excitation winding voltage in rest frame; R _fAnd L _fBe respectively electric excitation winding resistance and inductance; i _αAnd i _βBe the component of electric excitation winding electric current in rest frame; e _αAnd e _βThe component of the electric excitation winding back-emf of difference in rest frame.

Write voltage equation as the state equation form:

$\frac{{\mathrm{di}}_f}{\mathrm{dt}}={\mathrm{Ai}}_f+B(u_f-e_f)$

In the formula:

$i_f=\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}\end{array}\right],u_f=\left[\begin{array}{c}{U}_{\mathrm{\&alpha;}}\\ U_{\mathrm{\&beta;}}\end{array}\right],e_f=\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]$

$A=\left[\begin{array}{cc}-\frac{R_f}{L_f}& 0\\ 0& -\frac{R_f}{L_f}\end{array}\right],B=\left[\begin{array}{cc}\frac{1}{L_f}& 0\\ 0& \frac{1}{L_f}\end{array}\right]$

2) according to the state equation of step 1, be constructed as follows the synovial membrane observer:

" ^ " represents estimated value in the formula; K is the gain of observer, is tried to achieve by experiment; Sgn is sign function.

Drawing observation error is:

$\frac{{d\tilde{i}}_{\mathrm{\&alpha;}}}{\mathrm{dt}}=-\frac{R_s}{L_s}{\tilde{i}}_{\mathrm{\&alpha;}}+\frac{1}{L_s}{e}_{\mathrm{\&alpha;}}-\frac{k}{L_s}\mathrm{sgn}\left({\tilde{i}}_{\mathrm{\&alpha;}}\right)$

$\frac{{d\tilde{i}}_{\mathrm{\&beta;}}}{\mathrm{dt}}=-\frac{R_s}{L_s}{\tilde{i}}_{\mathrm{\&beta;}}+\frac{1}{L_s}{e}_{\mathrm{\&beta;}}-\frac{k}{L_s}\mathrm{sgn}\left({\tilde{i}}_{\mathrm{\&beta;}}\right)$

In the formula:

Definition sliding mode equivalent voltage equation is:

$\left\{\begin{array}{c}{u}_{\mathrm{eq\&alpha;}}={\left(\mathrm{ksng}\left({\tilde{i}}_{\mathrm{\&alpha;}}\right)\right)}_{\mathrm{eq}}=e_{\mathrm{\&alpha;}}\\ u_{\mathrm{eeq\&beta;}}={\left(\mathrm{ksng}\left({\tilde{i}}_{\mathrm{\&beta;}}\right)\right)}_{\mathrm{eq}}=e_{\mathrm{\&beta;}}\end{array}\right.$

Switching characteristic on the definable sliding-mode surface is thus:

$\left\{\begin{array}{c}{Z}_{\mathrm{\&alpha;}}\left(t\right)=e_{\mathrm{\&alpha;}}\left(t\right)\\ Z_{\mathrm{\&beta;}}\left(t\right)=e_{\mathrm{\&beta;}}\left(t\right)\end{array}\right.$

In the formula: Z _α(t), Z _β(t) be respectively switching signal on α and the β axle; e _α(t), e _β(t) be back-emf; △ (t) is disturbing signal.

3. vector control method according to claim 1 is characterized in that: add low pass filter in step 3

Be used for filtering the high fdrequency component of switching signal to reduce the error that high-frequency interferencing signal causes.

4. vector control method according to claim 1 is characterized in that: described rotor angle

Spinner velocity

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