|Author:||Chu, Miu-lai Grace|
|Title:||Modeling and design of power-factor-correction power supplies|
|Subject:||Hong Kong Polytechnic University -- Dissertations.|
Electric current regulators.
Switching power supplies.
Electric power factor.
Electric current converters.
|Department:||Department of Electronic and Information Engineering|
|Pages:||xxii, 179 p. : ill. ; 30 cm.|
|Abstract:||Nowadays, with the increasing concern in environmental protection and energy conservation, more emphasis has been put in maintaining the power quality of AC power lines and further boosting the efficiency of end-user devices. This demands a high power factor in the end-user device. Following this worldwide trend, the tightening of international standards and regulations on current harmonics limits further increases such demands in the off-line devices' market. Power factor correction (PFC) is an inevitable solution to address these ever-increasing demands for high power quality in the delivery of electric power from the generating ends to the end users. In medium to high power off-line applications, PFC has even become a mandatory feature in order to comply with the tightened regulatory standards. Typically a PFC power supply consists of two stages. The first stage is the boost PFC pre-regulator which is responsible for providing PFC function. The cascading second stage is a dc-dc converter which is responsible for providing tight output regulation and fast transient response. The purpose of this thesis is to address the stability and performance issues of such a system. A simple yet effective modeling solution will be introduced to analyze and predict the occurrence of the line-frequency instability phenomenon. The criteria for the onset of this phenomenon and its effect on the power factor will be illustrated. Experimental results will be provided to verify the theoretical analysis. In addition, the thesis will cover stability analysis of PFC pre-regulators terminated with other load terminations for completeness and relevance of the study. After that, we will focus on control design methodologies for improving system performances. A unified and systematic approach will be introduced to generate robust control rules for boost PFC converters. Under this approach, the control parameters can be designed according to the desired steady-state and transient-response performances. Experiments are conducted and simulations are performed to evaluate the performances of the resulting control solutions. Furthermore, the current loop control will be re-examined from a sliding mode viewpoint. This approach results in additional constraints for the design of control parameters and leads to a better understanding of the relationship between the sliding-mode approach and other common derivation approaches. This thesis contains eight chapters. The first two chapters provide an introduction of the boost PFC converter and an overview of the development of PFC technologies. The rest of the thesis reports the tasks accomplished in this research project. These tasks share a common objective, which is to provide useful guidelines to facilitate the control design of boost PFC power systems for ensuring stability and at the same time embracing performance improvement. For each task, theoretical derivation, analysis and practical implementation methods will be detailed. Simulation and experimental results will also be presented to verify the theoretical analysis. It is hoped that this thesis can serve as a useful reference for practicing engineers to design high-performance PFC converters.|
|Rights:||All rights reserved|
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