Recent Improvements of Efficiency and Power Density of DC—DC Converters for Automotive Applications

摘要

Automotive industry is considered to be one ofthe main contributors to environmental pollution and globalwarming. Therefore, many car manufacturers are in nearfuture planning to introduce hybrid electric vehicles (HEV),fuel cell electric vehicles (FCEV) and pure electric vehicles(EV) to make our cars more environmentally friendly.These new vehicles require highly efficient and small powerconverters. In recent years, considerable improvementswere made in designing such converters. In this paper, anapproach based on so called Snubber Assisted Zero Voltageand Zero Current Switching topology otherwise also knowas SAll is presented. This topology has evolved to be one ofthe leaders in the field of highly efficient converters withhigh power densities. Evolution and main features of thistopology are briefly discussed. Capabilities of the topologyare demonstrated on two case study prototypes based ondifferent design approaches. The prototypes are designed tobe fully bi-directional for peak power output of 30 kW. Bothdesigns reached efficiencies close to 99 % in wide load range.Power densities over 40 kW/litre are attainable in the sametime. Combination of MOSFET technology and SAlltopology is shown to be very beneficial to convertersdesigned for EV applications.