Ground Fault Detection for Flexible High Voltage Power Systems 2011-01-2252

Hybrid Electric Vehicles (HEV) in the consumer and commercial vehicle sectors have seen tremendous technological advancement in the last decade. The commercial vehicle industry in particular has benefited significantly from the hybridization of the propulsion system, and unlike the automotive segment, serves a wide variety of functions. This diversity in vehicle applications drives the necessity for high voltage power systems to be flexible in nature, allowing them to adapt to different vehicle architectures while performing the intended function. As a result, diagnostic modules within the high voltage power system, such as ground fault detection circuits, are being required to operate robustly in a high voltage power system that is exposed to electrical noise and significant variation in common mode impedance characteristics.

This paper explores four different ground fault detection methodologies that exist today in the industry, and evaluates their performance in a flexible high voltage power system. A thorough comparison of these technologies is performed based on results from seven distinct test cases, followed by a recommendation for the ideal ground fault detection system.