スイッチング素子数を削減した無瞬断巻線切り替えが可能なPWM整流器

抄録

This paper proposes a PWM rectifier with a seamless winding changeover capability. The proposed PWM rectifier can be operated in the star connection mode as well as in the delta connection mode, for which the output voltage is equivalent to a generator with delta winding. The proposed topology is used for open-end winding generators. One of the ports of the generator is connected to a PWM rectifier. Another port is connected to a diode bridge rectifier, which has a switch to short the dc-link of the diode bridge rectifier. The PWM rectifier and the diode bridge rectifier are connected via diodes. The proposed configuration allows seamless winding changeover with reduced number of switches in comparison with a conventional winding changeover circuit. When the delta connection is used, a new control method for achieving low current THD has to be used. The proposed circuit and control are assessed through experiments. The generator current THD of the star connection and the delta connection are 4.0% and 4.7%, respectively. In addition, the transient response is analyzed. In spite of the winding changeover in both the directions, power is continuously supplied to the load.