Disturbance Rejection Control Strategy of Hybrid Battery/Super Capacitors Power System Based on a Single Converter

This paper proposes a robust control strategy for a hybrid battery/super capacitors power system with a single converter. In such systems, it is required to smooth the battery current considering the load power transient and the current oscillations of the DC bus delivered by the load in the context of a hybrid electric vehicle. Furthermore, constraints of all the system components, i.e. maximum current of the battery and super capacitors, state of the charge of the super capacitors and battery temperature should be taken into account. To deal with these demands, a novel cascaded voltage control loop is proposed. For the outer voltage loop, an anti-windup proportional integral controller is used to regulate the super capacitor voltage at its nominal value. On the other hand, for the inner voltage loop, an anti-windup super twisting controller is proposed to ensure the convergence of the DC bus voltage to its reference value while attenuating the external perturbation. Indeed, the specific feature of such controller is that it works like a low-pass filter which leads to attenuate the current oscillations in the DC bus.