Ballard Power Systems Corporation

Ecostar Electric Drive Systems L.l.c.

Orrin B West

Chingchi Chen

Douglas K Maly

A non-invasive, non-destructive method and system for determining power transistor peak die voltage utilizes values for each of a plurality of parameters determined by measurement of external terminal voltages for any number of switches, such as transistors of an inverter. Stray inductance values are calculated and used with measured current gradient to calculate the peak die voltages for the switches. A refinement of the method determines transistor peak die voltage without measuring current.

Method and system for non-invasive power transistor die voltage measurement

A device inserted between a grounded poly-phase external voltage source and a load providing low insertion loss for differential mode currents and high insertion loss for ground currents. The device receives voltages from the grounded poly-phase external voltage source over atone or more voltage lines. The voltages contain common mode voltages. A filter connected to each of the voltage lines reduces the ground current from the load. A summing block adds the voltages from each of the voltage lines to generate a total common mode voltage. A ground referenced controlled voltage source generates a cancellation voltage equal to the total common mode voltage in response to the generation of total common mode voltage. The total common mode voltage is injected into the filter and substantially reduces the common mode voltage on each voltage line thereby substantially reducing the ground currents associated with each common mode voltage on each voltage line.

Active ground current reduction device

An inverter circuit system for controlling the voltage level at the neutral point of a three-phase wye-connected load. A dc voltage source such as a pair of batteries in series and having first and second poles is connected by one pole to an inverter bus and connected by the other pole via an inductive impedance to the neutral point of a three-phase wye-connected load.

Growing community of inventors

Canton, MI, United States of America

Orrin B West