A Compact Scherbius Drive Employing a Boost Chopper and a PWM Inverter

抄録

A compact Scherbius drive employing a boost chopper and a PWM inverter has been developed for general-purpose industrial uses. The latter provides a unity displacement factor and reduction of harmonics compared to the thyristor inverter, while the former ensures a small capacity for the inverter and dispenses with starting equipments. Thus, this Scherbius drive is much smaller in size and more efficient. Besides introducing this Scherbius drive, this paper gives an analysis of the transient rotor voltages followed by line voltage recovery just after an instantaneous power failure whether residual voltages of the wound-rotor induction motor exist or not. From the analysis it is confirmed that a dc reactor and a discharging resistor are effective to sup-press rotor transient voltages and they are applied to the commercial compact Scherbius drive which allows uninterrupted pumping operation of public utilities.