| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power converter comprising an open-phase detection circuit that can detect open phases of an input or an output by a relatively simple constitution. <P>SOLUTION: The power converter is constituted of: a rectifying circuit 1 that converts three-phase AC power to DC power; a DC circuit 2 that smoothes an output of the rectifying circuit; an inverter circuit 3 that converts an output of the DC circuit to an AC, and drives a motor 4; a current detector 9 that detects a DC current at the output side of the DC circuit; a current signal operator 8 that calculates a current ripple from a deference between the maximum value and the minimum value of the DC current in one cycle of an output of the inverter circuit; and an open-phase detection level setter 10 that sets an open-phase detection level proportional to a load-appropriate amount of the motor. When the current ripple exceeds the open-phase detection level, it is determined that the open-phase is generated at the inverter circuit or at the output side of the inverter circuit, and protective operation is applied to the converter. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
