Distributed MPC-Based Frequency Control in Networked Microgrids With Voltage Constraints

The increasing penetration of renewables and growing number and multiple operating modes of microgrids (MGs) bring challenges to designing a frequency control scheme for the networked MG system (NMS) that can work in all possible scenarios. This paper proposes a distributed model predictive control-based controller to regulate the frequency while maintaining the voltage constraints of all buses in the NMS with different system topologies and operating modes. In the proposed scheme, the frequency is regulated by adjusting the voltage-sensitive load voltages through MPC. By applying a consensus version of the alternating direction method of multipliers algorithm, the proposed controller coordinates MGs in the NMS using limited communication between neighboring MGs to achieve better privacy and scalability. Simulation results on extensive scenarios show the proposed controller successfully mitigates the frequency deviation caused by renewables’ fluctuation with voltage constraints considered and performs comparably well with the centralized controller. General issues regarding frequency control of the NMS are also discussed.