High Efficient Hybrid Cascaded Multilevel Inverter for Battery Energy Management

In electric vehicle energy storage systems, a large number of battery cells are usually connected in series to enhance the output voltage for motor driving. In our project, a hybrid cascaded multilevel converter with H-bridge inverter is designed. In the proposed system, eveif any one of the battery cell is damaged, the backup battery which is added in the circuit comes into action at the event of fault which enhances the life of the battery. Where-in in the existing system when any one of battery cell is damaged, the whole battery cell has to be replaced. Each battery cell can be controlled to be connected into the circuit or to be bypassed by a half-bridge converter. The H-bridge inverter is used to control voltage balance of the battery cell. Each half bridge can make the battery cell to be involved into the voltage producing or to be operated in bypassed mode. All half-bridges are cascaded to output a staircase shape dc voltage and an H-bridge converter is used to change the direction of the dc bus voltages to make up ac voltages. Here space vector pulse width modulation technique is used to generate pulse to the thyristors. The proposed design reduces switching loss and Total Harmonic Distortion (THD) compared to the existing system.