Advanced Nonlinear Control Techniques for Wind Energy Conversions Systems

Abstract

This thesis presents control methods to improve the efficiency and dynamic response of wind turbines that use a permanent magnet synchronous generator operating under a wide input and load range. Two new nonlinear controllers are developed and tested. These controllers are designed to overcome the limitations of the conventional vector control methods which exhibit slow performance and uncertain stability. The first controller is based on a control Lyapunov function (CLF) which increases performance and guarantees stability under all operating conditions but is limited by its dependence on system parameters. A novel adaptive passivity based controller (APBC) is designed to overcome the parameter dependence of the CLF controller while, again, increasing performance and guaranteeing stability under all operating conditions. These controllers are simulated and their performance is compared to that of the conventional controller. The APBC controller exhibits the best performance of the three followed closely by the CLF based controller.