Patent ID: 6078173
Filing Date: 2000-06-20
Classification: G01R

Abstract:
A method for simultaneously testing a plurality of inverters for failure of individual components said inverters being connected to a common source of direct current electric power, each of the inverters comprising at least three phases with each phase comprising at least two switching devices serially connected between a relatively positive voltage bus and a relatively negative voltage bus, each of the inverters being coupled to supply power to a respective one of a plurality of three phase loads via a connection from respective junctions mediate each pair of switching devices to a corresponding phase terminal of the respective load, comprising simultaneously testing said plurality of inverters by:monitoring voltage between the positive and negative voltage busses and monitoring current at each phase terminal of each load;gating each switching device in each inverter momentarily into conduction in sequence from a first switching device in a first phase to a second switching device in a third phase until detection of a voltage drop or a load current;interrupting, in response to a detected voltage drop, the sequence of gating and advancing the step of gating to the next occurring phase; andinhibiting operation of any inverter in which phase current is detected in any phase during the step of gating.