| 摘要 |
PURPOSE: To obtain a control method in which a power supply to a load can be continued without momentary interruption by a method wherein, when a failure is occurred in a semiconductor switch during a power supply from a commercial power supply, the power supply is changed over to a power supply from a multifunctional inverter without momentary interruption so as to be returned to the power supply from the commertial power supply via a bypass contactor when a commercial voltage exists. CONSTITUTION: When a failure is occurred in a semiconductor switch 3 during a power supply to a load 23 from a commercial power supply 21, a semiconductor-switch-failure detection means 31 detects the failure of the semiconductor switch 3 so as to output a failure signal 61. A changeover control circuit 31, on the basis of the failure signal, changes over to a power supply from a battery 22 by a multifunctional inverter 5 without momentary interruption, and it judges whether the commercial voltage of the commercial power supply 21 exists or not. When the voltage exists, a bypass contactor 4 is turned on so as to be returned to the power supply from the commerical power supply 21 via the bypass contactor 4. Thereby, it is possible to continue the power supply to the load 23 without momentary interruption. |
