| 摘要 |
<P>PROBLEM TO BE SOLVED: To resolve a problem that, in a conventional circuit, a step-down ratio and a step-up ratio of a step-up/step-down chopper become large when an AC input voltage is high, which causes that a generated loss is biased to a specific semiconductor element, and as a result, the element and a cooling device become large in size and high in cost. <P>SOLUTION: When an AC power supply voltage is high (e.g. 400 V), a regenerative power from an electric motor is discharged once to a DC input of a CVCF (Constant-Voltage Constant-Frequency) inverter by a second step-up/step-down chopper, and the discharged power is charged in power storage means by a first step-up/step-down chopper. In addition, at the time of interruption of the AC power supply or voltage reduction, discharge from the power storage means to the DC input of the CVCF inverter is performed by the first step-up/step-down chopper, and the DC power is discharged to a DC intermediate capacitor by the second step-up/step-down chopper. <P>COPYRIGHT: (C)2012,JPO&INPIT |
