In this paper, we present a novel method for designing a controller with good rubustness for variable-speed wind energy conversion systems based on a characteristic model. Due to the stochastic operating conditions and the inevitable nonlinear characteristics inherent in the system, the dynamic model is usually too complex for the system analysis and controller design. Therefore, we first develop a detailed plant characteristic model of a variable-speed wind energy conversion system, which simplifies significantly the engineering implementation. Then the sliding mode incorporating fuzzy tuning schemes is applied to design a controller that optimizes the converter system efficiency and robustness. Analysis and experimentation show that the method achieves satisfactory wind energy tracking.