インバータ駆動回転機の固定子コイル電界緩和システムにおけるPWM波形印加時の発熱および電界分布

抄録

Inverter-fed drives of form-wound motors become essential for the high efficiency operation in the industrial field. It has been revealed that the high frequency repetitive pulses cause the local heating and electric field enhancement at the end-turn stress grading (SG) system, however, few paper deals with the stresses under the pulse width modulation (PWM) waveforms. In this research, potential distributions, electric field and time-averaged power densities under the PWM waveforms are numerically investigated, as functions of the carrier and the fundamental frequency. As a result, the power densities increase with the fundamental and the carrier frequency, whereas the field at the SG system is almost constant, regardless of the both frequency component. The estimation method of the power density and resulting temperature rise under the PWM is also proposed.