Recent years have seen significant popularity in the use of wind generators owing to the depletion of natural resources and growing concerns... Show moreRecent years have seen significant popularity in the use of wind generators owing to the depletion of natural resources and growing concerns about our environment. However, this development has raised issues concerning reliability of the wind turbine components. Among these faults, failure of current sensors is one of most common faults that can bring the wind generator to a standstill and lead to reduction in power yield. In addition, unscheduled maintenance often results in longer downtime and causes reduction of wind plant availability especially for those wind turbines located offshore or in remote areas. This dissertation proposes a survivable drive method to continue to operate the wind turbine in spite of current sensor failure. One of the common control strategies for the optimal of three-phase AC generators is vector control. Therefore, vector control method is implemented in this dissertation for both induction machine and Brushless PMSM. In order to achieve survivability when current sensor fault happens, a simple and effective method which doesn’t rely on current feedbacks is required as a backup control strategy. For this purpose, a digital control strategy is proposed for an induction machine and a Brushless PMSM. In addition, a current sensor failure detection method is designed to trigger the transition and a smooth transition method (only for induction machine) is implemented to ensure the smoothness of the control transition without stopping the system. Simulation and experimental results have been presented to prove feasibility and demonstrate the effectiveness of the proposed strategy. Ph.D. in Electrical Engineering, May 2012 Show less
