Modelling of Battery Management System based on Switching Capacitors

In this paper, a simulation model of a voltage balancing system for series connected cells of a supercapacitor battery is made. The Battery Management System (BMS) is based on switched capacitors used to actively balance the series connected cells of the battery. The semiconductor switch losses were investigated using the model. Based on the analysis of switching transients and energy transfer between individual cells, element selection requirements for these switches are defined. Typical waveforms for the currents and voltages are presented to define the requirements for the semiconductor structures. The simulation model has been developed with PLECS software. The losses in the transistor switches are investigated for several BMS operating modes.