無感測器風力再生能源系統之功率追蹤控制:以T-S模糊方法為基礎

Abstract

Among the fastest-growing renewable energy technologies, wind power is gaining much more attention then ever before. This thesis deals with the maximum power tracking control for the permanent magnet synchronous generator (PMSG) of a wind energy conversion system (WECS). This thesis discuses how to exactly represent the (WECS) nonlinear system as a T-S fuzzy model, and uses intelligent control to achieve maximum power tracking, moreover, the stability, exponential convergence property, fast transient response, and properties like robustness are taken into considerations. First of all, a systematic method is given to represent a nonlinear system exactly as a T-S fuzzy model which can accurately represent the nonlinear system under a certain region with a few fuzzy rules. A brand new control idea is brought up: Using virtual desired variables (VDVs) to deal with the tracking control problems, on the other hand, BP-learning algorithm of neural network is used to adjust the grade function of the fuzzy controller to achieve faster transient responses. Tracking control is technically transformed into a much simple stabilization problem. Then the design procedure is split into two independent steps: i) Determine the VDVs from the desired output equation and the generalized kinematic constraint; ii) Determine the control feedback gains by solving a set of LMIs. Lyapnunov’s method is used to obtain the stability conditions which insure the stability of the closed loop system, these adequate conditions can be transformed as LMIs and solved using powerful numerical methods to obtain the control gains. Since sensorless controller design of PSMG is a trend, we focus on observer-based controller design in the second part of the thesis. When observers are implemented to re-establish the immeasurable states, some disturbing terms will arise on stability analysis. However, we discovered that the membership functions of fuzzy model still satisfy a Lipschitz-like property; therefore, observer gain and controller gain can be obtained separately. To this point, sensorless controller design process is solved in less complicated and satisfactory way. Above controlling techniques are verified under the actual parameters of a certain type of WECS and result in very nice performance.