LSM駆動用インバータの低速度域における出力電圧制御方式と出力電圧特性

抄録

A superconducting magnetic levitation (Maglev) system employs a linear synchronous motor (LSM) with primary side on ground. This system needs a VVVF inverter with large capacity to drive LSM. As such a inverter, a multiple pulse width modulation (PWM) inverter, which is formed by full bridge inverters connected in series through output transformer, has been developed. However, when output frequency is low, it is difficult for the inverter to generate a voltage required, because the inverter is multiplied by output transformer. So, when the output frequency is low, one of inverter units is switched to half bridge inverter without transformer, and the inverter is controlled by a special voltage assignment control method to reduce the burden on the output transformer of remaining full bridge inverters. This paper describes the voltage assignment control method to reduce the burden on the output transformer while output frequency is low. And the effects of the voltage assignment control method are investigated. And the characteristics of output voltage are discussed in detail.