Design of a model predictive controller for grid connected microgrids

Power electronics converter and inverter systems for microgrid operations are always stochastic in nature. When the system operates in grid tied mode the user always faces a steady state residual problem as the load connected to the grid varies and so the amount of current drawn from the microgrid varies which leads to a mismatch between the actual current and desired current. As a result, input current changes which create a significant amount of voltage drop at the input. All the converters and inverters used in our system are controlled using model predictive controller (MPC) except the boost converter for solar PV system which is operating in incremental conductance method (INC) and for the bi-directional converter a two-loop continuous current control is implemented for controlling the output voltage as well as the inductor current reference. The inner loop forms the core of MPC whereas the outer loop keeps track of the voltage. The proposed control strategy gives very fast dynamics when subjected to different stochastic conditions and certainly the control strategy does not allow the DC voltage to fall below a certain voltage level. The presented simulation results justify the effectiveness of proposed strategy. Copyright © 2021 Inderscience Enterprises Ltd.