Model predictive control to manage the hydrokinetic systems connected into grid by a back-to-back converter

The use of power converter devices in the integration of hydrokinetic turbine (HKT) systems is essential since these devices enable controlling the turbine rotation speed to manage the active power provided into grid, as well as, the reactive power compensation. This paper presents an advanced model predictive control (MPC) approach for the maximum power tracking and output frequency control of an HKT connected by a back-to-back converter. The system consists of a horizontal propeller turbine, permanent magnet synchronous generator, rectifier, and inverter. The systems were implemented in MATLAB with the proposed control, and verified through simulations where performance was evaluated based on state variables of the system. A comparison based on a classical proportional-integral (PI) control approach indicates that MPC can achieve superior transitory response and better settling time for high-efficiency implementations, while simultaneously maintaining easy-to-handle implementation. The MPC controller was four times faster than the PI controller in terms of setting time.