Voltage Regulation using a Novel LLC Bidirectional DC-DC Converter with Load-Source Swapping Mechanism /

Abstract

Due to limited availability of energy reserves, the current world trends are shifting towards fulfilling most of their energy needs from the readily available renewable energy resources (RERs) such as solar, wind etc. This raw energy needs to be converted into useful form. With increase in distributive energy sources (DES) on distribution side, many issues have been raised, among which voltage regulation is of great significance because of the fluctuating nature of the renewable energy resources. For voltage regulation, different devices are being used such as inverters, storage capacitors and DC-DC converters, for smooth power flow operation between load and energy storage systems. Applications involving two-directional power flow, use bidirectional DC-DC converters. A new topology based on LLC bidirectional DC-DC resonant tank converters is presented here, having a novel design consisting of a by-pass resonant tank technique, along with an adaptive load-source swapping mechanism, which is the key feature of the project. The proposed converter design is derived from conventional LLC and DAB topologies. This enables the converter to efficiently switch between two operational modes: buck and boost efficiently, by continuously monitoring the fluctuating DC input voltage. The modelling equations for both modes have been shown for output current and voltage along with the timing diagram of the topology. The simulation results show that the voltage regulation is efficiently achieved in both buck and boost modes with different variations in input voltage, reference voltage and load. The research emphasizes towards efficient ways of energy generation using renewable energy resources with minimal losses and cost.