DC bus shorting apparatus and method for polyphase AC inverter

摘要

An inverter for supplying electric alternating current (AC) to a load from a DC source of electric current has a DC bus. The DC bus has a positive conductor and a negative conductor. A plurality of switches are connected to the DC bus, and each of the switches has a conducting state and a nonconducting state. The switches are connected so that electric current may flow from the DC bus through at least one of the switches into the load. Means are provided for switching each of the switches from the nonconducting state into the conducting state at a predetermined time for each of the switches. Means are provided for switchably connecting the DC bus to the DC source of electric current. Means are provided for switchably shorting the positive conductor of the DC bus to the negative conductor of the DC bus in order to interrupt the current flow through the switches and thereby drive the switches into the nonconducting state. Gate turn off thyristors (GTO) such as silicon controlled rectifiers may serve to switchably connect the DC bus to the source of the DC current and also short the positive conductor of the DC bus to the negative conductor. Transistors may also serve as switches to switchably connect the DC bus and to short the bus.