New unidirectional hybrid delta-switch rectifier

This paper introduces a novel 3-phase hybrid rectifier assembled by the parallel connection of a 3-phase diode bridge boost rectifier with a 2-level unidirectional delta-switch rectifier. This system aims to take advantage of the commonly low power losses and high reliability of a diode based rectifier and also to benefit from the delta-rectifier capability of processing reactive power. Therefore, a highly efficient and reliable high power factor rectifier system with controlled dc-link voltage is constructed. Additionally, this work presents an efficiency comparison between the proposed hybrid delta-switch rectifier and other concepts such as the new 3-level unidirectional hybrid T-type or VIENNA 6-switch rectifiers and the single self-commuted converters, including the VIENNA 6-switch, delta-switch and T-type rectifiers for 10 kW 50 Hz operation. It is shown that the hybrid systems can achieve higher efficiency than the single self-commuted rectifier they are based on. Finally, experimental results obtained with an assembled unidirectional hybrid delta-switch rectifier prototype are presented in order to demonstrate the performance and feasibility of this solution.