An investigation of variable speed horizontal-axis wind turbines using direct model-reference adaptive control

Pitch-controlled variable-speed horizontal-axis wind turbines (HAWTs) are increasingly being investigated for use in electrical power production. The governing equations of HAWTs are expensive to calculate and test, change substantially over time, and are extremely non-linear. Therefore, adaptive methods are a suitable approach for control of HAWTs. Direct model-reference adaptive control is shown to perform well as a pitchregulated control scheme. The adaptive controller shows performance comparable to previous work in steady speed operation (Region 3), and shows model-tracking with errors of less than 1% during varying speed operation (Region 2). Simulations of the transition from Region 2 to Region 3 indicate an average overshoot of six percent. The controller is tested using MATLAEYSIMULINK simulations based on a computer generated and experimentally verified non-linear plant model of a Grumman WindstreamHAWT. An appropriate reference model that operates in Region 2 without knowledge of windspeed and plant parameters has yet to be found.