Novel Bidirectional Three Port Converter and Its Control Strategy for DC Microgrid System
Adding an energy storage device as the third port in the traditional distributed new energy grid connection interface can effectively improve the output power fluctuations caused by the strong uncertainty and randomness of distributed new energy.In this article a novel non-isolated bidirectional thre-port converter and its control method suitable for high rise to drop ratio DC microgrid systems was proposed and studied.By integrating a dual active half bridge converter and a non-isolated bidirectional Buck/Boost converter,bidirectional power transmission between any two of the three ports was achieved.A detailed analysis was conducted on the working principle,output characteristics,and control strategy of the proposed new converter.Through phase shifting plus pulse width modulation control methods,a wide range of voltage regulation and smooth power switching between various ports were achieved.A 1 kW experimental prototype was built to verify the feasibility and effectiveness of the proposed new three port converter and its control method.The research results obtained in this article have theoretical guidance and engineering practical reference significance for improving the stability of distributed new energy access.
non-isolated bidirectional three-port converterPWM+phase-shiftingsoft switchhybrid control strategyoperation mode analysis
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