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The Scientific World Journal
Volume 2013, Article ID 815280, 13 pages
http://dx.doi.org/10.1155/2013/815280
Research Article

PSO Based PI Controller Design for a Solar Charger System

1Department of Electrical Engineering, National Chin-Yi University of Technology, Taichung 41170, Taiwan
2Graduate Institute of Automation and Technology, National Taipei University of Technology, Taipei 10608, Taiwan

Received 2 March 2013; Accepted 11 April 2013

Academic Editors: C.-F. Juang and J. Zhang

Copyright © 2013 Her-Terng Yau et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Due to global energy crisis and severe environmental pollution, the photovoltaic (PV) system has become one of the most important renewable energy sources. Many previous studies on solar charger integrated system only focus on load charge control or switching Maximum Power Point Tracking (MPPT) and charge control modes. This study used two-stage system, which allows the overall portable solar energy charging system to implement MPPT and optimal charge control of Li-ion battery simultaneously. First, this study designs a DC/DC boost converter of solar power generation, which uses variable step size incremental conductance method (VSINC) to enable the solar cell to track the maximum power point at any time. The voltage was exported from the DC/DC boost converter to the DC/DC buck converter, so that the voltage dropped to proper voltage for charging the battery. The charging system uses constant current/constant voltage (CC/CV) method to charge the lithium battery. In order to obtain the optimum PI charge controller parameters, this study used intelligent algorithm to determine the optimum parameters. According to the simulation and experimental results, the control parameters resulted from PSO have better performance than genetic algorithms (GAs).