| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 98 === For years, power supplies have been designed using analog circuit design techniques. "Digital" power supplies have been designed over the last decade as well, and they have gradually gained more and more acceptance. In this thesis, two PI-controlled digital power converters have been presented. The hardware and firmware parts of the proposed system are described in detail. The power converter utilized in this thesis is a simple buck converter, and the digital controller is implemented using a dsPIC micro-controller from Microchip Corp.
In order to improve the performance of the digital power converter, two kinds of digital controller are discussed in this thesis: classical Proportional-Integral (PI) controllers and fuzzy PI controllers. Conventional PI controllers are perhaps the most well-known and most widely used controllers in modern industries. Generally speaking, PI controllers have the merits of being simple, reliable, and effective.
However, their performance will deteriorate if the system under control becomes nonlinear. Fuzzy PI controllers are generally superior to the conventional ones, particularly for higher-order, time-delayed, and nonlinear systems. However, their design methods are slightly more advanced and their resulting formulas are somewhat more complicated. In this paper, a formula-type fuzzy PI controller is presented. It will be seen that although the presented fuzzy PI controllers are designed by fuzzy mathematics, their final form as controllers are conventional controllers. Therefore, they can be used to directly replace the conventional ones in applications and can be easily implemented using
low cost microcontrollers. In this thesis, we will compare these two classes of PI controllers and discuss their advantages as well as III limitations. Simulation and experimental results will also be provided to verify the correctness of the proposed system.
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