Control optimization of dual active bridge converter for DC microgrids with reduced DC-bus capacitance

• Main Author: Lee, Chun Meng
• Other Authors: Gooi Hoay Beng
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/145162
• Institution: Nanyang Technological University

Power electronic converters are widely used in common electronic devices such as computers, mobile phones, television, etc. Through conversion techniques, methods in the power electronic converters are programmed to process and control electrical energy by transforming it into various forms to fulfil the end-user requirements. A microgrid is a decentralized local energy source with control capabilities, enabling it to operate autonomously. These forms of electrical energy are generated from power grids to be transmitted and distributed to consumers. The power electronic converter plays an important role in monitoring, optimizing and controlling the output power (voltage and current). As such, the two-stage converter is being researched. It consists of a Dual Active Bridge (DAB) converter, a three-phase inverter and a DC bus capacitor of the DC microgrid. However, as there are problems with the stabilization of the DC bus voltage, the current solution utilizes large electrolytic capacitors to resolve the issue. These electrolytic capacitors are larger in size as compared to film capacitors. This results in the reduction of the stability and reliability of the system over time. As electrolytic capacitors are more expensive and larger in size as compared to film capacitors, the latter is preferred for its cost and space efficiency. However, the reduced capacitance value also affects the terminal impedance magnitude of the converters that could induce possible instability issues of the whole system. To address the above- mentioned instability issues, a novel technique has been proposed. The advantages of such a proposed method are no additional cost and power loss in both the DAB and buck converter.