Research Projects

Battery storage is a critical component in green energy applications, providing power when renewable energy sources cannot meet the demand. They have also proved to be an additional source of power that can be supplied to the grid at peak load instant and charge themselves at light load conditions. For this purpose, a highly efficient bidirectional converter topology has to be developed to interface such a battery bank to the grid. The bidirectional capability of the converter will enable the charging and discharging of the battery bank. A phase-modulated bidirectional, high-frequency isolated converter that would meet the above-mentioned requirement is presented in this project. The key features of the converter are: • The converter would allow bidirectional power transfer between a 400V, 50Ah battery storage and a 3-phase (415V,50Hz) utility grid that is also connected to a renewable energy source in an ac-coupled configuration. • This high-frequency (100 kHz) isolated, soft-switched, single-stage power converter will have a rating of 20kW and an efficiency of more than 94%. • This will be a topologically novel phase-shift converter with a lossless voltage clamp across secondary-side devices. Therefore, voltage stress will be reduced and reliability will be more. • It would be modular in structure. Series/parallel connections of multiple such units would be possible for high-power applications • A closed-loop control strategy for grid synchronization and constant current/ constant voltage charging of the battery will be implemented. • The grid-connected modular battery storage system will be integrated with renewable energy sources like PV through an ac-coupling configuration. The work methodology will initially involve designing the topology mentioned above. The topology will then be theoretically analyzed rigorously and simulated in simulation platforms like PLECS and MATLAB for verification of the same. After this, the closed-loop control strategy will be devised by using a digital controller like FPGA. Grid Synchronization and control power flow to the grid will be implemented in order to maintain the safe operation of the converter and enhance the battery life. The topology being bidirectional can be used along with the PV module for similar applications. The single-phase version of this topology has already been developed and a hardware prototype of the same has been tested at our lab facility under grid-connected conditions. The project's successful development will lead to a highly efficient grid-interfaced battery storage solution and will be an invaluable step toward achieving the goal of green energy.