Autonomous Decentralized DC Bus Voltage Control using DC Multi Power Units in DC Microgrid Applications

A bidirectional onboard DC/DC converter that can be used to rapidly charge an electric vehicle (EV) or feed EV battery power to a DC microgrid based on application requirements is proposed. This system concept is labeled as an onboard fast battery charging EV (cEV). Interestingly, owing to the presence of the inbuilt quick EV charger, external high power chargers are not required for fast charging applications. The proposed autonomous control strategy may also aid in DC grid voltage stabilization within the permissible range of 360 V to 400 V when power is being transferred from a PV to DC bus by controlling the DC/DC converter for PV and the DC multi power unit (DCMPU) independently. The DCMPU can also control both the power or DC bus voltage based on system requirements. Next, a droop-based control is implemented in the DCMPU to avoid mutual interference in the controllers. Detailed simulation studies are performed in MATLAB/Simulink to demonstrate the effectiveness of the proposed system. Overall, the proposed system helps maintain DC bus voltage fluctuations within a permissible range.