Optimal power dispatch and control of a wind turbine and battery hybrid system

In this paper, a new power dispatch and control methodology is proposed for a hybridized wind turbine and battery system to supply consistent power within each 30min. First, the desired battery state of charge (SOC) is determined as a function of wind speed offline using an probabilistic analysis of historical wind data. With this information, a one-step ahead model predictive optimization approach is developed for scheduling the hybrid system power output for the next 30min. Compared to conventional multi-step-ahead model predictive optimizations, the proposed one-step ahead optimization with offline-obtained desired SOC obviates calculations with inaccurate multi-step-ahead wind predictions, hence it is more reliable and computational efficient. Second, a real-time controller is developed to make the actual hybrid system power output match the scheduled target. It determines the reference power set point for wind turbine by a steady state optimization approach and subsequently applies an active power controller to track this set point. Simulation results show that, compared to the conventional heuristic scheduling approach and standard real-time control, implementing the new methodology significantly reduces the ramp rate, generator torque changing rate, battery charging rate and the power output deviation from the scheduled target.