| 摘要 |
PURPOSE: To miniaturize a device, by connecting a reactor for protecting a GTO, just to the GTO of a lower side arm. CONSTITUTION:Each phase U'-W' of an inverter is organized in the same manner with a three-phase inverter circuit, and upper and lower side arms UA', LA' are respectively composed of a gate turn-off thyristor(GTO)1, a fly- wheel diode 2, and a snubber circuit 3, and current is fed to the induction motor IM of a load 6. In this case, from the upper side arm UA', a reactor for protecting the GTO is removed, and just on the lower side arm LA', the reactor 4L for protecting the GTO is set. Then, from the protecting reactor 4L of the lower side arm LA', voltage equal to the overcharge voltage component of a condenser in the snubber circuit is generated on commutation. As a result, the cathode voltage of the GTO/U of the upper side arm UA' can be contrived not to come to power voltage or more.
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