Cascaded H-Bridge MLI based Grid Connected Cell Level Battery Energy Storage System

This paper proposes a combination of cell-level energy processing and a Cascaded H-Bridge Multilevel Inverter (CHBMLI) for medium voltage, grid connected, battery energy storage systems. One isolated converter (Dual Active Bridge DC-DC Converter) manages each cell in the Battery Module, and the combination of Battery module and converter modules are cascaded to get the multi-level ac output voltage. The operating principle and control design of cell level isolated converter with double frequency ripple power, and the control strategy of the CHBMLI are presented. The performance of the battery cell level CHBMLI system with a 9-level inverter at small scale power level is validated through the simulations in MATLAB
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software. The configuration holds promise for improving the performance and reliability of the battery modules at the cell level while also providing cell level galvanic isolation and high ac voltage.