Research On Photovoltaic And Storage Three-Port Converter Based On SiC Device

In recent years,along with the increasing global energy crisis and environmental pollution problems,the renewable energy distributed generation technology represented by photovoltaics and energy storage has been widely concerned by domestic and foreign researchers.Compared with the traditional Multi-Level Converter,the photovoltaics and energy storage combined Three-Port Converter realizes topology reconstruction through power device multiplexing,would reduces the system volume and power density.In this paper,Bidirectional Buck-Boost Converter and Dual-Active Bridge Converter are combined to a new Three-Port Converter toplogy,which has the advantages of flexible buck-boost and bidirectional power flow.The structure is simple and suitable for all kinds of new energy and energy storage independent power generation systems.Firstly,the working principle,power transmission characteristics and power loss model of the converter are analyzed.The PWM+ Phase Shift Modulation(PWM+PSM)strategy is adopted to improve the control freedom of the system.At the same time,the system energy control strategy is established to control the output voltage and improve the new energy utilization rate.The simulation is built in PSIM 9.1.0.The circuit model verifies the modulation strategy and energy control strategy.Aiming at the low threshold voltage,the weak negative voltage withstand capability of SiC MOSFET and the crosstalk problem in the toplogy application,a new designed type of drive circuit which can work stably is validated by the experimental setup.Finally,according to the theoretical guidance,the system architecture is designed,and the selection and parameters calculation of each component in the main power circuit are carried out,and the circuit design of SiC MOSFET driving,conditioning sampling and so on is realized.Then a experimental prototype with 500W power level SiC MOSFET-based Bidirectional Buck-Boost and Dual Active Bridge intergrated Three-Port Converter is completed.The main working mode of the TPC is tested and verified.The experimental results show that the prototype design of the converter is reasonable and effective,and meets the requirements of system verification.