Diffusion-Based Distributed Coordination Control of Power Converters in MG for Efficiency Improvement

Abstract

The efficiency of the microgrid (MG) system is depended on converter and power line losses. The loss of converter relies on the load condition whereas the power line loss is affected by the line impedance. Improving the efficiency of the MG system should consider both types of losses. This paper proposed a distributed coordination control strategy of distributed generation (DGs) in the MG system for efficiency improvement considering the losses of the converter and power line. A cost function considering both types of losses is defined. The diffusion algorithm is used in the secondary control of each DG to optimize the cost function. The diffusion algorithm finds the output power of each DG that provides the highest efficiency. Considering the minimization of the converter and power line losses, the system efficiency could be improved by reducing not only converter loss but also power line loss. The proposed control method could achieve accurate power sharing at the heavy-load condition. The performance of the proposed method is similar to the conventional power-sharing control scheme at the heavy-load condition. However, at the light-load condition, the efficiency of the MG system with the proposed method could be improved. The feasibility of the proposed control strategy is validated by real-time simulation using OPAL-RT Technologies.

Keywords

• Microgrids
• power converter
• distributed control
• light-load efficiency improvement
• diffusion algorithm