| 摘要 |
PURPOSE: To reduce the burden of a mechanical brake in the braking of a motor which is caused by the generation of the fault of an inverter main circuit, and to simplify the processing and circuit for sensing the short-circuit faults of the respective phases and arms of the inverter main circuit. CONSTITUTION: By the sensing signals fed from an overcurrent sensing circuit 6, a control circuit 3 forces the respective arms of an inverter main circuit 1 to be in OFF-states. Thereafter, by the sensing signals fed from a faulty phase sensing circuit 7, the control circuit 3 discriminates between a faulty phase or faulty arm and other sound phases, and by the ON-OFF controls of the arms of the sound phases, it feeds DC currents to a motor 2, and by the application of a DC brake to the motor 2, it stops the motor 2. By the utilization of the fact that the output terminal voltage of the faulty phase whose arm is shorted approximates to the level of the positive or negative electrode of the DC voltage of the inverter main circuit 1, the sensing of the faulty phase is performed while the change of this level is compared with a reference voltage. |
