| 摘要 |
PURPOSE:To reduce voltage stress by partially mounting a DC short-circuit mode in the PWM control of an inverter and conducting step-up chopper operation. CONSTITUTION:A power convertor is composed of an AC power 1, a reactor 2, a first diode rectifier 3, an inverter 5, an insulating transformer 6, a second diode rectifier 7, a capacitor, etc., and supplies load connected to said capacitor 8 with power. The inverter 5 is constituted in single-phase bridge connection at that time, and switches S1-S4 as arm elements for the inverter 5 are organized of the antiparallel connection circuits of transistors and diodes. Regarding the operation of the switches S1-S4 for the inverter 5, S1 and S3 are turned ON for a specified period, DC output terminals P and N for the first diode rectifier 3 are short-circuited, and the DC output currents of the diode rectifier 3 are increased and the operation of a step-up chopper is conducted. Inverter operation is performed after a short-circuit mode is released, and DC-AC power conversion is executed.
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