Comparison of Control Strategies for Maximizing Energy in a Supercapacitor Storage Subsystem

A storage supercapacitor subsystem is studied for insertion in a series hybrid electric vehicle (Fig. 1). This subsystem is composed of a supercapacitor bank and a braking resistor used when the supercapacitor voltage is at its maximum value. Generally, when the maximum voltage is reached by supercapacitor, a voltage drop occurs because of the current cancellation in the series resistance of the supercapacitor. Thus the stored energy is reduced compared to the maximum value that could be reached. To overcome this drawback, new control strategies are proposed by acting on the braking resistor. Energetic Macroscopic Representation (EMR) is used to organize the numerous blocks required for modelling and control. Experiment results are provided and highlight the increase of energy storage.