Design And Research Of SiC-based Energy Storage Charger

With the combination of high-speed railway station buildings and photovoltaic power generation systems,it has gradually become a masterpiece of the concept of green development.However,the photovoltaic power generation is affected by weather,day and night,which hinders the development of high-speed rail photovoltaic station buildings.Today’s combination of photovoltaic and energy storage has solved the limiting factors of photovoltaic power generation.However,the design theory of the energy storage charging of the new generation photovoltaic energy storage system is not perfect,resulting in large power consumption of the product and low efficiency.Therefore,this article mainly combines the current research status of energy storage chargers,and optimizes the design of energy storage chargers suitable for the new generation of optical storage systems.Front-to-back converter for energy storage charging.In the latter stage,a full-bridge LLC resonant converter is selected.Based on the energy storage load characteristics and charging curve,a new LLC resonant parameter optimization design method is proposed.Through the extended function description method,the open-loop characteristics of the converter are accurately obtained,and the compensator design is completed using MATLAB simulation software.Combined with PSIM simulation platform,the feasibility of the new design method is verified.The former stage PFC circuit compares and analyzes the characteristics of the SEPIC PFC and BOOST PFC circuits,and proposes an improved voltage tracking SEPIC PFC circuit,which satisfies the working condition of the latter stage full-bridge LLC resonant circuit always in the second region of the frequency gain curve.The improved SEPIC PFC circuit analyzes the control technology of BOOST PFC,and proposes a feedforward current control scheme for the circuit working in SEPIC PFC mode.Finally,the AC Sweep function of PSIM is used to verify the stability and feasibility of the proposed optimal control scheme.Designed for high efficiency and high frequency.Use Si C as the switchingcomponent of the circuit.Due to the large gap between Si C drivers and silicon-based devices,this article designed a driving circuit that complies with the characteristics through a power semiconductor test platform to make it more efficient to use the characteristics of Si C.For the system’s pre-and post-stage control,a voltage-tracking charging scheme was designed in combination with the four-stage charging method.The feasibility analysis of the overall control scheme was carried out using the PSIM simulation platform.Aiming at the flexibility and complexity of control,this paper uses a digital control circuit with TMS320F28035 as the control core.Finally,this paper sets up an experimental platform for Si C and Si energy storage chargers.For the full-bridge LLC resonant circuit,the experimental waveforms in the three states are tested and verified to verify the feasibility of the optimized design scheme.For the former circuit,the stability of the BOOST PFC circuit and the SEPIC PFC circuit is verified by the experimental data and waveforms obtained from the test.Through the experimental comparison of Si-type before and after stage circuits,the low loss characteristics of Si C are verified.Finally,it is concluded that the two circuits of the Si C type have a 4.2% and 5% increase in the pre-and post-stage circuits.By comparing and analyzing the loss regions of the Si C type and the Si type,the reason for the efficiency improvement of the SiC type circuit is obtained.