CN101188398A - Online recognition method for asynchronous electromotor rotor resistance - Google Patents

Abstract

The invention relates to an online identification method on the rotor resistance of an asynchronous motor, and the method is used for optimizing resistance parameters in the vector control with a speed transducer. The invention includes the following procedures of collecting the electromagnetic torque Te and the psi 2parameter of the flux linkage of a rotor, identifying the rotor resistance according to the electromagnetic torque Te and the psi 2 parameter of the flux linkage of the rotor by the formula that r2 is equals to 3/2Pn omegas psi <2>2/Te, among which the p n is the number of the pole-pair of the motor, and the omega s is the slip angular frequency, taking the identified rotor resistance as the parameter to implement the vector control of the motor. The online identification method of the invention can identify the rotor resistance of the asynchronous motor on line on the vector control of the motor with the speed transducer by a voltage model method, thereby being simple and practical, and having higher precision. The invention can identify the resistance parameter of the rotor on line accurately under any condition that load exists, and the resistance parameter is stable. Experiments prove that the invention can obtain right resistance parameter of the motor rotor accurately whether the motor is in cold state or in hot state.

Description

The ONLINE RECOGNITION method of asynchronous electromotor rotor resistance

Technical field

The present invention relates to the recognition methods of a kind of rotor resistance, be specifically related to a kind of accuracy of identification height, can put forward the ONLINE RECOGNITION method of the asynchronous electromotor rotor resistance of motor vector control performance.

Background technology

Along with the progress at full speed of power electronic technology and deepening continuously of speed regualtion of AC motor theory.The application of asynchronous machine is increasingly extensive.The vector control of motor adopts the rotor flux linkage orientation strategy usually, and the directed order of accuarcy in magnetic field is subjected to the rotor-side parameter influence bigger.The parameter influence that mainly is rotor resistance is bigger, and this parameter changes bigger along with the temperature of motor, resistance may exceed more than 20% during the resistance value ratio cold conditions when motor is hot, can on-line identification for normal requirement of high-performance transducer to the rotor resistance parameter of motor, thus reach high control performance.

Because under the constant situation of motor-field, online rotor resistance and the rotating speed of identifying simultaneously, must on the excitation component of motor, inject AC signal for the Speedless sensor vector control, the magnetic field that makes motor is among changing, reach the lotus root of separating of rotor resistance and rotating speed, know speed sensor and the two kinds of situations of Speedless sensor of being divided into so the rotor resistance of stable state is debated.

At present, along with the precision and the efficient requirement of industrial production processing technology are more and more higher, adopt the vector control occasion of speed sensor more and more, and for the speed sensor vector control, rotor resistance is bigger to the accuracy influence of field orientation, if the rotor resistance parameter of controlling with rotor resistance parameter and reality differs bigger, can cause bigger weak magnetic and overexcitation effect, influence control performance, the rotor resistance on-line identification of research speed sensor is highly significant.

Can recognize that from document both domestic and external the rotor resistance on-line identification technology of many technical staff at the research speed sensor arranged, but the method more complicated that usually realizes, and precision is not high.

Summary of the invention

The purpose of this invention is to provide a kind of accuracy of identification height, can propose the recognition methods of the online asynchronous electromotor rotor resistance of motor vector control performance.

Another object of the present invention provides a kind of ONLINE RECOGNITION method that adopts the asynchronous electromotor rotor resistance of different resistance RMs in the rotor high and low frequency stage.

The technical scheme that realizes described purpose is: a kind of ONLINE RECOGNITION method of asynchronous electromotor rotor resistance, be used for optimizing the resistance parameter in the speed sensor vector control, and comprise the steps:

Gather electromagnetic torque T _eWith rotor flux ψ ₂Parameter;

Utilize described electromagnetic torque T _eWith rotor flux ψ ₂Parameter is discerned rotor resistance by following formula: $r_2=\frac{3}{2}{p}_n{\mathrm{\&omega;}}_s{{\mathrm{\&psi;}}_2}^2/T_e;$ Wherein, p _nBe motor number of pole-pairs, ω _sBe the slippage angular frequency;

As parameter, finish the motor vector control of speed sensor with the rotor resistance of described identification.

Preferably, described electromagnetic torque T _eMeet the following conditions: choose the static alpha-beta coordinate system of two-phase,

$T_e=\frac{3}{2}{p}_n[(u_{\mathrm{\&alpha;}}-i_{\mathrm{\&alpha;}}{r}_s)i_{\mathrm{\&alpha;}}+({\mathrm{\&mu;}}_{\mathrm{\&beta;}}-i_{\mathrm{\&beta;}}{r}_s)i_{\mathrm{\&beta;}}]/{\mathrm{\&omega;}}_1$

Wherein, ω ₁Be flux angle speed, p _nBe motor number of pole-pairs, r _sBe stator resistance.

When the asynchronous machine rotor rotating speed reaches stable state, described rotor flux ψ ₂Obtain by the voltage model method integration:

$\frac{{\mathrm{d\&psi;}}_r}{\mathrm{dt}}=\frac{L_r}{L_m}(u_s-R_s{i}_s-\mathrm{\&sigma;}{L}_s\frac{{\mathrm{di}}_s}{\mathrm{dt}})$

Wherein, L _rBe the inductor rotor of asynchronous machine, L _sBe stator inductance, L _mBe mutual inductance, σ is the leakage inductance coefficient, R _sBe stator resistance, u _s, i _sIt is respectively the electric current and voltage value of stator; Choose the static alpha-beta coordinate system of two-phase.

Preferably, passing through voltage model method integration rotor flux ψ ₂The time, set up the high pass filter that prevents to introduce drift because of integration.

The parameter of described high pass filter is:

When asynchronous machine rotor low speed, described rotor flux ψ ₂Obtain by the current model method:

${\mathrm{\&psi;}}_2=\frac{L_m{i}_m}{T_{2}s+1},$ Wherein, choose the two-phase synchronous rotating frame, L _mBe mutual inductance, i _mBe the mutual inductance electric current, s is a revolutional slip, T ₂Be rotor time constant T ₂=L _r/ r ₂

The present invention adopts described technical scheme, its beneficial technical effects is: 1) the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance of the present invention, the motor vector control of speed sensor is passed through the rotor resistance of voltage model method ONLINE RECOGNITION asynchronous machine, simple and practical, precision is higher, under any loaded situation, all can realize on-line identification rotor resistance parameter exactly, and resistance parameter is stable, and ONLINE RECOGNITION method of the present invention all can accurately obtain correct rotor resistance parameter through experimental verification in the motor cold conditions with when hot; 2) the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance of the present invention in the rotor high and low frequency stage, that is greater than 5 hertz or during less than 5 hertz, selects voltage model method or current model method to gather rotor flux ψ respectively ₂, guarantee under any rotation status of rotor the resistance parameter of identification asynchronous machine rotor accurately; 3) the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance of the present invention is provided with high pass filter, at the described voltage model method integration rotor flux ψ that passes through ₂The time, can effectively prevent the drift that integration is introduced.

Description of drawings

Below by embodiment also in conjunction with the accompanying drawings, the present invention is described in further detail:

Fig. 1 is the FB(flow block) of first kind of execution mode of the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance of the present invention.

Fig. 2 is the FB(flow block) of second kind of execution mode of the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance of the present invention.

Embodiment

Please refer to Fig. 1, the present invention relates to a kind of ONLINE RECOGNITION method of asynchronous electromotor rotor resistance, the measured rotor resistance parameter of the ONLINE RECOGNITION method of described asynchronous electromotor rotor resistance is the motor vector control occasion that is used in speed sensor.ONLINE RECOGNITION method of the present invention is simple and practical, and the rotor resistance parameters precision height that records can improve the control performance of the motor vector control of speed sensor greatly.

ONLINE RECOGNITION method of the present invention is at first gathered electromagnetic torque T _eWith rotor flux ψ ₂Parameter.

When the asynchronous machine rotor rotating speed reaches stable state, the slippage angular frequency of speed sensor vector control _sBe accurately, can be used as definite value and treat.

Described rotor flux ψ ₂Obtain by the voltage model method integration: choose the static alpha-beta coordinate system of two-phase:

$\frac{{\mathrm{d\&psi;}}_r}{\mathrm{dt}}=\frac{L_r}{L_m}(u_s-R_s{i}_s-\mathrm{\&sigma;}{L}_s\frac{{\mathrm{di}}_s}{\mathrm{dt}})$ (formula 1)

Wherein, L _rBe the inductor rotor of asynchronous machine, L _sBe stator inductance, L _mBe mutual inductance, σ is the leakage inductance coefficient, R _sBe stator resistance, u _s, i _sIt is respectively the electric current and voltage value of stator.

Described electromagnetic torque T _eAdopt the back-emf method to calculate, calculate by formula 3: choose the static alpha-beta coordinate system of two-phase,

$T_e=\frac{3}{2}{p}_n[(u_{\mathrm{\&alpha;}}-i_{\mathrm{\&alpha;}}{r}_s)i_{\mathrm{\&alpha;}}+({\mathrm{\&mu;}}_{\mathrm{\&beta;}}-i_{\mathrm{\&beta;}}{r}_s)i_{\mathrm{\&beta;}}]/{\mathrm{\&omega;}}_1$ (formula 3)

Wherein, ω ₁Be flux angle speed, p _nBe motor number of pole-pairs, r _sBe stator resistance.

Because, $T_e=\frac{3}{2}{p}_n\frac{L_m}{L_r}{i}_{t1}{\mathrm{\&psi;}}_2$ (formula 4)

Simultaneously, the slippage angular frequency of electrode _sFormula is:

${\mathrm{\&omega;}}_s=\frac{L_m{i}_{t1}}{T_2{\mathrm{\&psi;}}_2}$ (formula 5)

So, can release the asynchronous electromotor rotor resistance parameter according to (formula 4) and (formula 5) and be:

$r_2=\frac{3}{2}{p}_n{\mathrm{\&omega;}}_s{{\mathrm{\&psi;}}_2}^2/T_e$ (formula 6)

Then, utilize described electromagnetic torque T _eWith rotor flux ψ ₂Parameter is by formula 6 identification rotor resistances.

At last, as parameter, finish the motor vector control of speed sensor with the rotor resistance of described identification.

Consider integral and calculating rotor flux ψ ₂May introduce drift, therefore calculate rotor flux ψ at voltage model method ₂The Shi Zengjia high pass filter.Owing to increased high pass filter, magnetic linkage amplitude and phase place when low speed have moderate finite deformation, and the stator back electromotive force is very little during low speed, and virtual voltage and voltage instruction are also inconsistent, error is big, so the method for this increase high pass filter is not suitable for using under the rotor low speed.

In the present embodiment, the parameter of described high pass filter is:

For the speed sensor vector control, slip-frequency ω _sBe accurately, so as long as accurately obtain rotor flux ψ ₂With electromagnetic torque T _eJust can obtain rotor resistance r accurately ₂ONLINE RECOGNITION method of the present invention is actual to be the magnetic linkage that utilizes voltage model the to calculate rotor resistance parameter that is optimized.Voltage model is subjected to the influence of stator resistance parameter, dead area compensation etc. inaccurate owing to calculate magnetic linkage in the rotor low frequency, is being more accurately more than 5 hertz.And since load hour, the ω of calculating _sAnd T _eAll smaller, both are divided by very big to the precision influence of rotor resistance, usually can the accurate recognition rotor resistance value greater than 20% nominal load the time.In order to improve the accuracy that makes calculating, calculate T _eAnd ψ ₂Need to add high pass filter, so this method effect when rotating speed reaches stable state is relatively good.

Usually in load during greater than 20% nominal load, it is more accurate that described rotor is discerned, but the method for ONLINE RECOGNITION asynchronous electromotor rotor resistance of the present invention is having under the loading condition all effectively, only is not limited to also to be not limited to only greater than 5 hertz of occasions greater than 20% nominal load.

Please refer to Fig. 1, be depicted as the FB(flow block) of first kind of execution mode of the method for ONLINE RECOGNITION asynchronous electromotor rotor resistance of the present invention.Execution mode shown in Figure 1 only is in order to clearly demonstrate technical scheme of the present invention, and ONLINE RECOGNITION method of the present invention is having under the loading condition all effectively, only is not limited to also to be not limited to only greater than 5 hertz of occasions greater than 20% nominal load.

It at first is the step 10 that starts the rotor resistance ONLINE RECOGNITION.

Be then judge asynchronous machine rotor output frequency whether greater than 5 hertz step 20; Calculate electromagnetic torque rotor flux ψ greater than 5 hertz employing voltage model methods ₂ONLINE RECOGNITION less than 5 hertz end resistance.

The rotor output frequency greater than 5 hertz of prerequisites under, adopt the back-emf method to calculate electromagnetic torque T _eStep 30.

Next be determining step 30 calculate electromagnetic torque T _eWhether greater than the step 40 of 20% rated power.Adopt voltage model method to calculate rotor flux ψ greater than entering of 20% rated power ₂Step 51.ONLINE RECOGNITION less than the end resistance of 20% rated power.

Calculate the step 52 of rotor resistance by formula 6.

The step 53 of utilizing high pass filter that the rotor resistance that calculates is carried out high-pass filtering.

Upgrade the rotor resistance parameter that Vector Control System of Induction Motor is used, optimize the step 44 of Vector Control System of Induction Motor performance.This method all can accurately obtain correct rotor resistance through experimental verification in the motor cold conditions with when hot.

Please refer to Fig. 2, as second execution mode of ONLINE RECOGNITION asynchronous electromotor rotor resistance of the present invention, the rotor ONLINE RECOGNITION process when having increased asynchronous machine rotor low speed.

In the present embodiment, described asynchronous machine rotor low speed is meant the rotor output frequency smaller or equal to 5 hertz situation, and no longer adopt voltage model method to calculate rotor flux ψ this moment ₂, but calculate the step of magnetic linkage 22 by setting up the current model method.

Described rotor flux ψ ₂The current model method specifically:

${\mathrm{\&psi;}}_2=\frac{L_m{i}_m}{T_{2}s+1}$ (formula 2) wherein, chooses the two-phase synchronous rotating frame, L _mBe mutual inductance, i _mBe the mutual inductance electric current, s is a revolutional slip, T ₂Be rotor time constant T ₂=L _r/ r ₂

Electromagnetic torque T _eThe same with voltage model method also is to adopt the back-emf method.

Use described electromagnetic torque T then _eWith rotor flux ψ ₂, utilize formula 6 to calculate the resistance parameter of asynchronous machine rotor.

Please refer to Fig. 2, the difference of the present embodiment and first execution mode is: being lower than 5 hertz at the motor output frequency is, adopts the current model method to gather rotor flux ψ ₂Below only narrate difference with first execution mode.

It at first is the step 10 that starts the rotor resistance ONLINE RECOGNITION.

Be then judge asynchronous machine rotor output frequency whether greater than 5 hertz step 20; Calculate electromagnetic torque rotor flux ψ less than 5 hertz employing current model methods ₂Calculate electromagnetic torque rotor flux ψ 2 greater than 5 hertz employing voltage model methods.

The rotor output frequency less than 5 hertz of prerequisites under, adopt the back-emf method to calculate electromagnetic torque T _eStep 22.

Next be to adopt the current model method to calculate rotor flux ψ ₂Step 24.

Calculate the step 26 of rotor resistance by formula 6.

Upgrade the rotor resistance parameter that Vector Control System of Induction Motor is used, optimize the step 28 of Vector Control System of Induction Motor performance.

Above content be in conjunction with concrete preferred implementation to further describing that the present invention did, can not assert that concrete enforcement of the present invention is confined to these explanations.For the general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, can also make some simple deduction or replace, all should be considered as belonging to protection scope of the present invention.

Claims (6)

1. the ONLINE RECOGNITION method of an asynchronous electromotor rotor resistance is used for optimizing the resistance parameter in the speed sensor vector control, it is characterized in that: comprise the steps:

Gather electromagnetic torque T _eWith rotor flux ψ ₂Parameter;

Utilize described electromagnetic torque T _eWith rotor flux ψ ₂Parameter is discerned rotor resistance by following formula: $r_2=\frac{3}{2}{p}_n{\mathrm{\&omega;}}_s{{\mathrm{\&psi;}}_2}^2/T_e;$ Wherein, p _nBe motor number of pole-pairs, ω _sBe the slippage angular frequency;

As parameter, finish the motor vector control of speed sensor with the rotor resistance of described identification.

2. the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance according to claim 1 is characterized in that: described electromagnetic torque T _eMeet the following conditions: choose the static alpha-beta coordinate system of two-phase,

$T_e=\frac{3}{2}{p}_n[(u_{\mathrm{\&alpha;}}-i_{\mathrm{\&alpha;}}{r}_s)i_{\mathrm{\&alpha;}}+({\mathrm{\&mu;}}_{\mathrm{\&beta;}}-i_{\mathrm{\&beta;}}{r}_s)i_{\mathrm{\&beta;}}]/{\mathrm{\&omega;}}_1$

Wherein, ω ₁Be flux angle speed, p _nBe motor number of pole-pairs, r _sBe stator resistance.

3. the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance according to claim 2 is characterized in that: when the asynchronous machine rotor rotating speed reaches stable state, and described rotor flux ψ ₂Obtain by the voltage model method integration:

$\frac{{\mathrm{d\&psi;}}_r}{\mathrm{dt}}=\frac{L_r}{L_m}(u_s-R_s{i}_s-\mathrm{\&sigma;}{L}_s\frac{{\mathrm{di}}_s}{\mathrm{dt}})$

Wherein, L _rBe the inductor rotor of asynchronous machine, L _sBe stator inductance, L _mBe mutual inductance, σ is the leakage inductance coefficient, R _sBe stator resistance, u _s, i _sIt is respectively the electric current and voltage value of stator; Choose the static alpha-beta coordinate system of two-phase.

4. the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance according to claim 3 is characterized in that: passing through voltage model method integration rotor flux ψ ₂The time, set up the high pass filter that prevents to introduce drift because of integration.

5. the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance according to claim 4, it is characterized in that: the parameter of described high pass filter is

6. the ONLINE RECOGNITION method of asynchronous electromotor rotor resistance according to claim 2 is characterized in that: when asynchronous machine rotor low speed, and described rotor flux ψ ₂Obtain by the current model method: ${\mathrm{\&psi;}}_2=\frac{L_m{i}_m}{T_{2}s+1},$ Wherein, choose the two-phase synchronous rotating frame, L _mBe mutual inductance, i _mBe the mutual inductance electric current, s is a revolutional slip, T ₂Be rotor time constant T ₂=L _r/ r ₂

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