Hardware Implementation and Characterization of SiC-Based Hybrid Three-Phase Rectifier Employing Third Harmonic Injection

A recently proposed third harmonic injection rectifier (two half-bridge legs) - serving as optional solution for passive three-phase diode bridge systems with LC output filter - is characterized by unity power factor (lambda approximate to 1) and low harmonic input currents (THD < 5 %). The rectifier at hand, furthermore sticks out of the crowd due to a very low number of active and passive switches compared to similar power electronic circuits based on the same (third harmonic injection) principle. Additionally, the more and more establishing and reliable SiC-MOSFET allows an optimized design for higher switching frequencies without seriously impairing the efficiency of the total system. A proper design of active and passive components of the optional circuit is therefore required and several operating modes and optimization possibilities are existing. Besides basic considerations of control structures and topology limitations, also various implementation issues are discussed. Finally, experimental results of a laboratory prototype based on a 10 kW/72 kHz rectifier system using SiC-MOSFETs verifies the proper behaviour of the proposed upgrade.