China Merchants Cruise Shipbuilding CO., Ltd.
Through research on power electronics converters and energy storage technology, DC-grid hybrid propulsion plants are becoming an optimal alternative for vessel owners seeking ways to improve fuel efficiency, reduce emissions as well as enhanced redundancy. Firstly, introduce the basic structure and operation principle of electric propulsion converter sys-tem for a DC-grid hybrid ship; Secondly, aiming at multi-operation mode and control strategy of the onboard daily load power supply converter, a positive and negative sequence-dividing control under dq synchronous rotating coordi-nate is proposed which can ensure that the output voltage of the three-phase power supply converter is balanced even with single-phase load, the negative sequence reference is constructed through coordinate transformation without digi-tal low-pass filter. Finally, the correctness and effectiveness of the proposed control strategy is verified by building the simulation model. The experimental shows that compared with the traditional single positive sequence-dividing control voltage waveform, the unbalance is about 12%, and the unbalance of the positive and negative sequence-dividing control waveform is less than 0.5%, which shows the strategy is more effective.