MATHEMATICAL MODEL OF A SIX-PHASE ASYNCHRONOUS MOTOR WITH FREQUENCY CONTROL

MATHEMATICAL MODEL OF A SIX-PHASE ASYNCHRONOUS MOTOR WITH FREQUENCY CONTROL

 

  1. Petrushin1, Y. Plotkin2, A. Yakimets1,
  2. Yenoktaiev1, V. Horoshko1, A. Kirilenko1

1State University «Odessa Polytechnic»

 2Berlin School of Economics and Law

 

Abstract. A mathematical model of a six-phase asynchronous electric motor is proposed, which allows to determine the operational characteristics at speed control. The model excludes higher spatial harmonics 5, 7 and a multiple of them from consideration. The results of mathematical modeling were confirmed by experimental studies. The experimental mechanical characteristics of a six-phase motor have a different slope than a three-phase. Consideration of the family of mechanical characteristics (at different frequencies of supply voltage and values of this voltage according to volts per hz speed control U/f=const) and the load characteristics makes it possible to move to the control characteristics, which are the dependence of currents and power consumption on speeds, both at the drive input and at the motor input. A comparison of the control characteristics of three and six-phase motors, which showed a significant difference in currents and the proximity of the values of power consumption at the input of the motor. Also, close values of currents and power consumption at the input of the drive. The relative error of the theoretically calculated by means of mathematical model of the corresponding parameters concerning results of experimental researches is defined. The error increases significantly during the transition to the unsaturated state of the motor. Using the obtained errors, it is possible to adjust the mathematical model, in particular the take to account losses from higher time harmonics that will improve the theoretical analysis of work frequency-controlled electric drives. Experimental studies have confirmed that the values of the currents at the input of a six-phase motor comparatively to the currents at the input of a three-phase motor have decreased approximately in twice.

Keywords: six-phase asynchronous motor, mathematical modeling, experimental research, control characteristics, relative error.