Multi-Rotor Wind Turbine Control: Strategies for Pitch Replacement and Mechanical Load Mitigation

This paper presents a two-level control scheme for multi-rotor wind turbines. The first subordinate decentralized controller replaces the active pitch control with oversized generators that achieve the power limitation objective. In combination with this, the second higher-level controller mitigates the mechanical load on the main tower by adjusting the thrust forces acting on the side turbines through coordinated local torque control. The results proved that the decentralized controller managed to replace the pitch control by achieving the same power curve, and the load mitigation controller tended to equate the thrusts on both turbines, which mitigates the mechanical loads on the turbine tower. A high-fidelity QBlade model was developed and showed consistent results to the simplified model in SIMULINK.