| dc.description.abstract | The main objective of this dissertation is to design and implement high performance shunt active power filter (APF) systems. In the past, most shunt active power filters used proportional integral (PI) controller. However, it may be necessary to retune the PI parameters for different operation conditions. Therefore, this dissertation proposes two kinds of controllers, which are robust and adaptive, for a single-phase shunt APF to improve line power factor (PF) and mitigate line current harmonics. The APF systems respectively include a Takagi-Sugeno (T-S) fuzzy and model reference adaptive controllers (MRAC). Because APF is a bilinear system, it is not easy to design the controller. Hence, this dissertation firstly employs the linearization method to approach the nonlinearity of the system and solve the stability problem.
In the T-S fuzzy controller design, the parallel distributed compensation (PDC) is employed with the T-S models. To find stable feedback gains and a common positive-definite matrix for the designed fuzzy control system, it is based on Lyapunov’s stability theory and solved via MATLAB’s linear matrix inequality (LMI) tool. In the MRAC design, Lyapunov’s stability theory and Barbalat’s Lemma are used to design an adaptive law which guarantees asymptotic output tracking for the system. While compared with the conventional proportional-integral (PI) control, the advantages of the T-S fuzzy and MRAC are more flexible, adaptive and robust. Moreover, MRAC can self-tune the controller gains to assure the system stability.
To verify the proposed systems, a digital signal microcontroller (dsPIC30F4012) is utilized to implement the control algorithms. And an 1-kVA laboratory prototype of the active power filter is built to test the feasibility. Both simulation and experimental results are provided to verify the effectiveness of the proposed active power filter systems which increase the power factor, reduce the current harmonics and enhance the robustness of the transient response.
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