| 摘要 |
PROBLEM TO BE SOLVED: To prevent the breakdown of a switching circuit due to the fault of a short protecting circuit by monitoring the level of the short protecting circuit by a micrcomputer after the stop of an inverter and by counting the abnormal level of the short protecting circuit within a constant time based on a PWM period. SOLUTION: When a microcomputer has detected the abnormal level of the short protecting signal from a short protecting circuit of a switching element for a constant time, an inverter is stopped. The level of the short protecting signal by the microcomputer after the inverter is stopped is confirmed. When the level is the normal level, the control is returned to the ordinary control. When the level is the abnormal level for the constant time, conversely, the inverter is stopped as the abnormal short protection, and the abnormal level is counted within the constant time based on a PWM period. Thus, the breakdown of the switching element caused by the fault of the short protecting circuit, can be prevented. |
