| 摘要 |
A method of and apparatus for directing the power of a d.c. voltage source between a three-phase mains and a d.c. circuit employ a diode bridge comprising a plurality of first diodes to rectify a three-phase mains voltage to a d.c. voltage when power is flowing from the three-phase mains to the d.c. circuit, converting the d.c. voltage to a three-phase a.c. voltage, when power is flowing from the d.c. circuit to the three-phase mains, by means of transistors in parallel with the diodes, employ control devices for controlling the transistors, form control voltages for the control means by a plurality of second diodes from the three-phase mains in such manner that each the transistor is conductive during the conduction time of the respective diode in parallel therewith, and shorten the conduction times of the transistors, in order to reduce the power circulating in the d.c. circuit, by connecting Zener diodes in series with respective ones of the transistors. |
