An optimization approach to design decentralized load frequency controllers for generators in islanded microgrids

In this paper, an optimal decentralized controller is designed for the load frequency control of a microgrid with multiple synchronous generation systems and renewable energy sources in the islanded mode of operation. The decentralized controller includes multiple proportional-integral (PI) controllers designed and optimized simultaneously by using a classical descent-direction Quasi-Newton based optimization technique. The optimal decentralized PI controller accounts for the dynamic coupling among the areas of the microgrid without any communication links required among the PI controllers, and hence improves the frequency control performance as compared to a set of optimal linear-quadratic Gaussian (LQG) integral controllers of eighth order which are designed independently. Simulation results confirm the effectiveness of the proposed decentralized control approach.