To detect breakdown of an H bridge circuit while avoiding unnecessary operation of a motor of an electric power steering device.
In order to carry out breakdown detection of first to fourth switching elements 46a-46d of the H bridge circuit 41, the first and second switching elements 46a, 46b are firstly and simultaneously turned ON at a first step to confirm that every third and fourth switching elements 46c, 46d is not ON-damaged. The third and fourth switching elements 46c, 46d are simultaneously turned ON at a subsequent second step to confirm that every first and second switching elements is not ON-damaged. Thereafter, the first to fourth switching elements 46a to 46d are turned ON in this order at the third step to detect whether or not they are OFF-damaged. Thereby, even when a power relay 43 and a fail-safe relay 47 are interlocked and turned ON, the unnecessary operation of the motor M at the third step can be certainly prevented.
COPYRIGHT: (C)2005,JPO&NCIPI
Masato Yuda
Hiroaki Ishigaki
Showa Corporation
| JP63168162U | ||||
| JP8084494A | ||||
| JP10020001A |
Kazuaki Niki