Accurate voltage equalization of supercapacitors with online identification model

Voltage equalization scheme is used to solve the voltage imbalance problem between serial connected supercapacitors. The inner capacitor voltage instead of terminal voltage based balancing scheme has been proven to be more accurate. The inner capacitor voltage are traditionally deduced through offline identified model parameters, which are variable due to the effect of terminal voltage, interference, and temperature, which will cause undesirable balancing deviation. To address the problem, we propose an online identified model based voltage equalization scheme to improve the equalization accuracy. The scheme is achieved by identifying model parameters through recursive-least square (RLS) technique, which has the advantage of simplicity, easy practicability. Experimental results are given to verify the effectiveness and high accuracy of the proposed cell balancing method.