Distributed Control Scheme Based on Model Predictive Control for Supplying Power in an Isolated DC Microgrid

In this paper, a control scheme is presented for an isolated DC microgrid including wind turbine connected to permanent magnet synchronous generator, electrical energy storage unit, and variable electrical loads. Energy sources are connected to a common bus through DC buck and buck-boost converters. The local distributed controllers are located in the first control layer. These controllers are designed based on a Lyapunov stability analysis and thereby its stability is guaranteed. Moreover, the current and voltage, injected to the network, are adjusted by controlling the switching functions of the converters. The decentralized secondary controllers determine the contribution of the local units for supplying the local loads. In this control layer, a model predictive controller for the wind generation unit as well as a proportional-integral controller for preserving the bus voltage are proposed to determine the reference currents for the local controllers. In addition to the practical simplicity, complete isolation of the secondary controllers, minimum requirements to data transfer, and providing a control structure without any need to change in development plan are the important advantages of the proposed control scheme. The performance of the controllers is investigated and verified using the simulations in MATLAB software performed for different cases.