Power control strategy for fixed-pitch PMSG-based hydrokinetic turbine

This paper presents a power control strategy for a fixed-pitch cross-flow hydrokinetic turbine (HKT) which operates at low rotational speed region (stall region) and maximum power point tracking. The suggested system uses a permanent magnet synchronous generator (PMSG), a diode rectifier, a boost DC-DC converter which is connected to a DC microgrid. Power control of the HKT is obtained by controlling the duty cycle of the boost DC-DC converter. This method employs an inner voltage loop to stabilize the system in the stall region and an outer power control loop to regulate the diode rectifier DC-link power. The suggested control strategy has the capability to adjust the HKT output power from zero to maximum available power for the complete operating range up to the cut-out water speed. The control system is designed and developed based on a linearized model of the system. The proposed strategy is experimentally verified with an electromechanical-based HKT emulator.