E.V. Bolovin, A.S. Glazyrin.

Department of Electric Drives and Equipment, National Research Tomsk Polytechnic University, Tomsk, Russia

Laboratory testing dynamic identification of the real induction motor parameters

Abstract

In this paper a laboratory testing dynamic identification of induction motor parameters is presented. The error of identification of the parameters is analyzed using the developed method.

Key words: induction motor, identification, difference schemes.

Introduction

Testing consisted of two phases. The first step - removing and receive visual transients of induction motor. The second step – the definition of induction motor parameters and calculation of error estimates of the parameters.

The test procedure

For the testing was used the real induction motor with the following specification:

- Rated power P_n = 22 kW;

- Nominal voltage U_n = 190/330 V;

- Rated frequency f_n = 50 Hz ;

- Stator resistance R₁= 0,106 ohms ;

- Reduced resistance of the rotor R¢₂ = 0.067 ohms ;

- Leakage inductance of the stator winding L_1σ = 0,684 mH ;

- Reduced to the stator leakage inductance of the rotor winding L¢_2σ = 0,667 mH ;

- The resulting inductance due to the magnetic flux in the air gap of the machine L_m = 24,711 mH;

- Number of pole pairs z_p = 2 ;

- Moment of inertia of the motor J = 0.5962 kg·m² ;

- Nominal speed ω_n = 157 rad/s ;

Processes for identification of parameters , (Fig. 1) and , , (Fig. 2) were build and compare them with the actual values.

Fig.1. Transients assessments , and identification models of asynchronous squirrel-cage motor .

Fig.2. Transients assessments , , identifying models of asynchronous squirrel-cage motor

Rms relative error of assessment given to the stator resistance of the rotor:

 Rms relative error of assessment equivalent inductance of the rotor winding:

Rms relative error of assessment equivalent inductance of the stator winding:

Rms relative error of assessment resulting inductance due to the magnetic flux in the air gap of the machine :

Rms relative error of assessment equivalent time constant of the rotor:

Conclusion

The difference between actual and estimated values are less than 5 percent, respectively, the identification of induction motor parameters based on difference schemes is effective.