| 摘要 |
PROBLEM TO BE SOLVED: To prevent a useless overcurrent detecting operation caused by reverse recovery current of a diode.SOLUTION: There are provided an inverter circuit 25 for driving a motor 26, a driving circuit 28 for supplying a switching signal to a switching element of the inverter circuit 25, DC current detecting means 31 for detecting DC input current of an inverter portion, and an over-current detector 29 for stopping the switching signal of the switching element when the current value detected by the DC current detecting means 31 exceeds a threshold value. The threshold value for stopping the switching element is set to be variable at the switching time of the switching element. Accordingly, when a diode connected to the switching element in reverse parallel or a parasitic diode formed in the switching element is used and reverse recovery current of the diode occurs under driving of a motor, the threshold value for stopping the switching element is made variable, whereby a useless over-current detecting operation can be prevented. |
