A Low-Harmonic Front-End Rectifier for EV Chargers with Dual Single-Phase Auxiliary Rectifier Pulse-Tripling Circuit

To effectively reduce the input current harmonics of the front-end rectifier for high-power electric vehicle chargers, this paper proposes a low-harmonic 36-pulse front-end rectifier equipped with a dual single-phase auxiliary rectifier pulse-tripling circuit (DSPAR-PTC). The proposed 36-pulse rectifier consists of a 12-pulse rectifier based on a medium-frequency power electronic transformer and the aforementioned DSPAR-PTC. According to the relationship between input and output voltages, the DSPAR-PTC operates in multiple conduction states to modulate and increase the number of output levels of the rectifier bridge. Based on the current characteristics of the AC and DC sides, the 12-pulse rectifier is upgraded to a 36-pulse topology. Thereby, the total harmonic distortion (THD) of the input current is reduced to one-third of the original value, and an approximately sinusoidal input current is achieved. The equivalent capacity of the DSPAR-PTC is only 3.7% of the rated output power, and no active power devices are required. It features a simple circuit structure, easy engineering implementation, and low cost. A 50 kW rectifier model is established on the Starsim HIL hardware-in-the-loop platform of Modeling Tech. The corresponding results verify the correctness of the theoretical analysis and demonstrate the harmonic suppression performance of the proposed topology.