Control of CLLC Resonant Converter in Grid Connected Electric Bus charging station

Battery Energy Storage System(BESS) is essential for a resilient microgrid. Electric vehicle charging stations operating in vehicle to grid(V2G) can act as a portable power source in the microgrid. To regulate the power flow for both BESS and electric vehicle charging stations, a bi-directional converter is necessary. This paper presents a test case where the BESS system and electric bus(EB) charging station are connected in parallel with the utility grid and loads. The Capacitor- Inductor-Capacitor (CLLC) converter is utilized as a bi-directional DC-DC converter. The CLLC converter is widely used due to its simple symmetrical design and ability to achieve soft switching. A novel dual hysteresis band logic along with variable frequency control method has been implemented for the CLLC converter. The DC link voltage, battery current, ZVS, and ZCS operations have all been examined in MATLAB/SIMULINK environment with an appropriate controller. Findings show that the BESS and EB charging station works satisfactorily in both forward and reverse modes.