AC-DC Isolated Matrix Converter Charger: Topology and Modulation

This paper presents the modulation strategy for the 25 kW AC-DC isolated Matrix Charger three-phase rectifier (MCharger). The proposed topology allows current and voltage regulation for energy storage devices such as EVs batteries. Compared to a standard Dual-Active-Bridge topology, the Matrix converter allows to directly perform an AC-AC energy conversion thus eliminating the rectifying stage. A high frequency (HF) voltage waveform is generated to feed the isolation transformer, which is characterized by an almost negligible leakage inductance, allowing for the reduction of the transformer voltage drops. The rectification of the ac-waveform is achieved at the output stage, consisting of an H-bridge and an LC filter. The suggested topology powered with the proposed modulation is able to provide a wide output voltage range which can vary from 50 V to 500 V, providing up to a maximum power of 25 kW allowed for level I chargers.