Hybrid electric vehicles (HEVs) offer many advantages, such as high fuel economy, low emissions, and possible silent operation. In the current HEV designs, there are usually two or more different DC voltage systems for different purposes of the vehicle operations. Galvanic isolation is often needed for safety concerns, especially in military vehicles. Bidirectional DC-DC converters are therefore used to interconnect different DC voltage bus and transfer energy between two different DC voltage buses. For example, in one of the developed military HEV systems, one DC-DC converter converts the high voltage (200 - 300 V) from HEV powertrain battery to low voltage (~14 V) for auxiliary needs in the vehicle, while the other converts 300 V powertrain battery voltage to 600 V to supply the powertrain motors. High efficiency, compact size, lightweight, and reliability are all essential requirements for DC-DC converters for HEVs. This paper details the development of an isolated bidirectional DC-DC converter for HEV energy management use, with focuses on the steady state operation analysis. A phase-shift controlled dual bridge topology is developed to achieve the requirements. The continuous and discontinuous operation modes are analyzed and the boundary for continuous operation was studied. The voltage ripple of the output was also derived. The proposed converter was simulated and a 10 kW prototype is built and tested. The experimental results of the converter's steady state operation and transient operation validated the design and simulation.
Isolated DC-DC converter for hybrid electric vehicle energy management applications
Isolierter Gleichspannungswandler für das Energiemanagement in Hybridfahrzeugen
2007
13 Seiten, 12 Bilder, 18 Quellen
Conference paper
English