A Control Strategy for High Quality of Hybrid DC Power Supply with Auto-correcting Ultracapacitor Voltage

Abstract

In this paper, a new control strategy is designed and evaluated for a Hybrid DC power supply that provides regulated DC bus voltage, and the fast transient response against load variation and source variations. The proposed DC bus is powered by a Solar photovoltaic source and supported with a battery and ultracapacitor storage. The averaged model is developed for the system under study and established its control strategy. The same model is used to determine compensator parameters used in various loops of the control strategy. After serving each transient, the perturb value of ultracapacitor voltage is brought back to nominal value using the proposed control strategy to prepare it for the future transient. Bi-directional converter associated with ultracapacitor is regulating DC bus voltage against load and source variations. The battery is providing a prolonged backup for the entire system. Analytically derived compensators for feedback and feedforward loops are verified by simulation results.