Diesel Generator DC Power System Current Harmonic Suppression

The dc microgrid consisting of a diesel generator (DG) and energy storage system (ESS) is becoming a popular concept for power distribution in transportation, such as vessels. In this article, a DG dc power system composed of a three-phase diode rectifier and an interleaved converter is designed. However, the front-end diode leads to a sixth harmonic component (6HC) in the dc-side voltage and current, which reduces the efficiency and lifetime of the converter and ESS. Therefore, a 6HC suppression strategy based on a passive high-pass filter (HPF) is proposed. The proposed HPF configuration extracts high-frequency harmonics directly on the dc-link for building a compensation component, which allows the reconstruction of the duty cycle. This approach provides lower noise and higher accuracy. Then, the effectiveness of the proposed method is analyzed from the perspective of the ac small-signal model. Finally, an experimental prototype is built and tested, and the results show that the proposed method can effectively suppress 6HC and improve the system efficiency.