| 摘要 |
<P>PROBLEM TO BE SOLVED: To control ripple current passing through a neutral wire in a neutral wire connecting-type uninterrupted power supply system where neutral points are mutually connected in an AC to DC/DC to AC conversion device constituted of a PWM rectifier and a PWM inverter. <P>SOLUTION: PWM controllers 11 to 14 of the PWM rectifier 1 generate three carrier signals obtained by shifting carrier phases of a triangular wave carrier signal generator 14 comparing respective phases U, V and W of AC input by 120°. A PWM waveform generator 13 generates a PWM waveform by comparing the carrier signals and sine wave signals of U, V and W phases by individual phase. Thus, a period is eliminated when three phases become ON. The controller of the PWM inverter is set to be the same. Controllers are applied to the controllers of the PWM rectifier and the PWM inverter. <P>COPYRIGHT: (C)2008,JPO&INPIT |
