| 摘要 |
<P>PROBLEM TO BE SOLVED: To avoid power swing by determining a power running state or a regenerating state to control electric conduction when controlling a motor by detecting a current using a detection element embedded in a switching element that can detect only a current of one polarity. <P>SOLUTION: An inverter circuit 3 is configured by using IGBT4X-4Z having a current detecting function in a semiconductor switching element of each phase connected to a ground side. A polarity detecting unit turns on all the IGBTs to detect zero-cross timing of a current between a U phase and a V phase based on a current flowing through sense IGBT7X, 7Y, and 7Z when each phase winding 2U, 2V, and 2W of a motor 1 is short-circuited. A change polarity detecting unit detects zero-cross timing of a change in the amount of a current between the U phase and the V phase. When a current polarity detecting circuit 11 determines the polarity of a W phase current, a power-running/regenerating determination unit determines whether a motor is in a power running state or regenerating state according to the polarity of the W phase current. An activation processing unit stops switching control when the motor is determined to be in a regenerating state. <P>COPYRIGHT: (C)2013,JPO&INPIT |
