| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technology of detecting a ground fault that occurs to a motor, using an existing inverter. <P>SOLUTION: If a ground fault occurs to a three-phase motor 10, a voltage across the terminals of a smoothing capacitor 1 rises, every time any one of high-arm side transistors Q21-Q23 and low-arm side transistors Q24-Q26 constituting an inverter circuit 20 changes from ON to OFF. By detecting a voltage across the terminals of the smoothing capacitor 1 from a ground fault detection portion 3 and by calculating an increment during a first prescribed period and another increment during a second prescribed period, a sudden power failure is separated so that a ground fault can be detected. <P>COPYRIGHT: (C)2007,JPO&INPIT |
