Simple Integral Fuzzy Control for Converters with Highly Nonlinear Dynamics

A simple integral Takagi-Sugeno (T-S) fuzzy control scheme suitable for many types of converters is proposed in this paper. A converter with highly nonlinear characteristics, called active high power factor correction (AHPFC), is taken as an example to show the control scheme. Indeed, we can derive a linear controller to achieve zero output regulation error for the AHPFC converter. First, we include an integral error signal to form an augmented system. After translating the coordinate to the regulated point, we obtain the stabilization model. The model-based fuzzy approach is then used to handle the nonlinear system. The system stability is proven by Lyapunov theorem. The feedback gains are obtained by solving linear matrix inequalities (LMIs). A surprised property is that the gains are identical for every fuzzy control rule. This result greatly simplifies the controller to be a linear state feedback one. Finally, the simulation and experimental results show the satisfactory performance, which is better than the converter using a proportional integral (PI) controller.