MIMO H∞ control for power source coordination – application to energy management systems of electric vehicles

This paper deals with a control strategy used for designing energy management systems within average-power electric vehicles. The power supply system is composed of three sources, namely a fuel cell, a battery and an ultracapacitor – specialized within distinct frequency ranges – which must be coordinated in order to satisfy power demand of the vehicle’s electrical motor. The three sources with their associated DC-DC converters are paralleled on a common DC-bus supplying the electrical motor. The DC-bus is required to be constant regardless of the load state thanks to the fuel cell which provides the mean power and to the other two sources – auxiliary sources – which are controlled to supply the high-frequency variations of power demand according to an H∞ optimization strategy. MATLAB R ©/SimulinkR © numerical simulation is used to validate the proposed strategy under real driving cycle condition proposed by IFSTTAR (Institut Français des Sciences et Technologies des Transports, de l’Aménagement et des Réseaux), and this approach is assessed against another optimal strategy that uses LQR as control design.