| 摘要 |
<P>PROBLEM TO BE SOLVED: To simultaneously perform regenerative current absorption and direct AC power conversion in a power conversion device. <P>SOLUTION: A converter 4 is connected to an inverter 6 via a cramp circuit 5. The converter 4 performs commutation in a first commutation mode which compares a trapezoidal wave with a carrier or in a 120-degree electrical connection mode. A diode Dcl of the cramp circuit 5 is short-circuited by a short-circuiting switch Qcl. When a power factor and a power supply voltage are lowered, the short-circuiting switch Qcl goes conductive, so that capacitors 51, 52 of the cramp circuit (5) are connected in series between DC power supply lines LL, LH. While the short-circuiting switch Qcl remains conductive, the converter 4 performs communication in the 120-degree electrical connection mode instead of the first commutation mode. <P>COPYRIGHT: (C)2010,JPO&INPIT |
