Efficient Voltage Profile Based Model-Predictive Control Strategy for Stand-Alone Wind-Integrated Hybrid Microgrid Systems

Future power system depends on penetrating more renewable energy to fulfill the drastic increase in energy demand with reduced carbon emission. Wind energy integration is increasing in worldwide each year. To efficiently investigate a quality voltage for AC loads under wind speed variations, a combined control strategy is proposed in this paper. It consists of PI and model predictive control (MPC) for the three-phase rectifier and interlinking inverter, respectively. The controlled rectifier ensures a constant DC-bus voltage under variable wind speed, while MPC is used to control output AC load voltage under abrupt load changes. Unlike traditional controllers, MPC does not require PI controllers for inner current and outer voltage loop or complex modulation steps. The discrete state-space model of VSI, LC filter, and load currents are used to predict future trends of load voltage for each of eight switching states. The control strategy selects the optimal switching state that reduces the error difference between reference and predicted load voltage. The proposed scheme is tested under perturbation of generation and load parameters. The proposed MPC strategy is compared with the conventional method-based PI controllers. The presented results ensure the effectiveness of the proposed approach with 0.67% THD for the AC output voltage.