Performance Comparison of Optimised and Non-Optimised Yaw Control for a Multi Rotor System

This paper presents an optimised yaw algorithm for the novel yaw system whereby the thrust of individual rotors of a Multi Rotor System (MRS) are varied in order achieve yaw torque. The control system is built upon a previous paper where a non-optimised yaw algorithm is shown to be capable of providing stable yaw control for an MRS. The optimised yaw algorithm provides increased energy capture and improved performance compared to that of the non-optimised system. The MRS model is also developed further from the previous paper which simplifies the MRS by clustering together groups of rotor and power conversion (RPC) systems. All 45 RPC systems are modelled to more accurately represent the MRS and to allow feedback from each RPC system. Both an estimated wind speed and system of flags are fed back to the optimised yaw algorithm to calculate the RPC systems with greatest potential change in yaw torque and to ensure that each RPC system does not operate outside a defined safe operational envelope. The performance of the energy capture for the optimised yaw controller is analysed and compared to the basic non-optimised controller. The optimised controller shows improved yaw control at each wind speed. The reduction in energy capture for the non-optimised controller is 0.61 %, 1.9% and 0.89% of the total energy captured for 8m/s, 11m/s and 15m/s respectively. This compares to 0.45%, 0.67% and 0.66% for the optimised controller.