Evaluation of ultra-compact rectifiers for low power, high-speed, permanent-magnet generators

Literature reports several future portable and distributed power supplies in the watt to kilowatt range based on rotating machinery equipped with a variable-speed permanent-magnet generator. In order to generate a constant dc voltage, an ultra-compact, highly efficient, low power rectifier is required. In this paper, different topologies are compared concerning losses, volume and control complexity. The most suitable, the half controlled three-phase PWM boost rectifier (HCBR) is selected and evaluated, and a novel modulation scheme enhancing the power electronics efficiency is proposed. The integration into a compressed-air-to-electric-power-system with a generator rotating at 350 000 rpm is presented including measurement results.