| 摘要 |
PURPOSE:To detect a power regenerative current of an inverter without using a current detector which is expensive and has a large volume by selecting a current that flows through each switch of a switch group on the positive or negative side of the inverter to detect the current. CONSTITUTION:Positive main switch groups 3a-3c are connected in a direction for making a current flow the positive electrode of a DC power source 1 to an AC motor 2, and negative main switch groups 5a-5c are connected in a direction for making a current flow from an AC motor 2 to the negative electrode of the power source 1. Current detecting resistors 7a-7c are connected in series with the main switch groups 5a-5c. Current detecting resistors 7a-7c are connected in series with the switch groups 5a-5c. A current detector is formed of the resistors 7a-7c, current selecting switches 8a-8c and an inverting amplifier 9, and the output is fed back to a current control amplifier 11. |
