Patent ID: 7684217
Filing Date: 2010-03-23
Classification: H02M

Abstract:
1. A polyphase inverter, comprising: a switching circuit having: a plurality of serial connections of high arm switching devices and low arm switching devices provided for each phase; and a plurality of diodes parallelly connected to each of said high arm switching devices and said low arm switching devices for applying a current only in a direction opposite to a direction in which said high arm switching devices and said low arm switching devices apply the current, ends of a plurality of said high arm switching devices opposite to said low arm switching devices being commonly connected, ends of a plurality of said low arm switching devices opposite to said high arm switching devices being commonly connected, and outputting an output current from a connection point of said high arm switching device and said low arm switching device toward a polyphase load for each phase; a plurality of capacitors charged by conduction of said low arm switching devices, provided for each phase, one end of each being connected to said connection point for each phase; a plurality of high side control circuits provided for each phase for controlling opening and closing of said high arm switching devices by receiving an operation power from corresponding said capacitor; and a low side control circuit for allowing said low arm switching device provided at a phase corresponding to said output current that gives the largest value compared between phases to conduct, when said output current of any phase is smaller than a predetermined value, a direction from said connection point to said polyphase load being set to positive, in a period in which all of said high arm switching devices are non-conductive.