MULTIMODE-MULTILEVEL BIDIRECTIONAL TARGETED BATTERY VOLTAGE EQUALIZER FOR SERIES CONNECTED BATTERY UNITS

Abstract

With the government enacting several initiatives to reduce pollution and encourage green energy, the percentage of renewables in the nation's power capacity composition is certain to rise. However, numerous concerns and obstacles must be overcome before renewable energy can be seamlessly integrated into the Indian Power Grid. Energy storage is critical in such circumstances to balance the risks of renewables, enhancing overall system dependability and offering other ancillary services. To achieve voltage requirements, several lead acid battery cells are commonly linked in series. The voltages of all serially linked battery cells in a battery pack should be the same for optimum performance. However, such an outcome is unachievable in real life owing to inescapable factors. Unbalanced battery cell voltages can lower storage capacities and, in the worst-case scenario, produce explosions or fires, which is a severe impediment to safe and optimal battery operation. As a result, battery cell voltage equalizations have emerged as a critical study area. Battery equalizers improves battery life-cycle and safety. This research study proposes Multimode-Multilevel Bidirectional Converter (MMBE) and Multi-looped Current-controlled Bidirectional Bridge converter (MCBB), two new active voltage equalizers that can operate multiple legs at a time along with its auxiliary circuits for achieving faster and targeted balancing. Switching algorithm of the converter is effectively controlled by setting the thresholds of voltage difference and enabling multiple current loops to target the energy flow towards the weakest cells with customized gradients. The proposed topology and control are implemented on the MATLAB platform, and the results confirm the effectiveness and quick dynamics of the proposed equalization system.