Single-Stage Multi-Function Converters for PV Power Supply Systems

• Main Authors: Chien-Hsuan Chang, 張健軒
• Other Authors: Tsai-Fu Wu, Ph.D.
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/33408785414293896440

博士 === 國立中正大學 === 電機工程研究所 === 90 === The objective of this dissertation is to develop stand-alone or grid-connection photovoltaic (PV) power supply systems, of which each consists of only one single-stage converter and can fulfill multiple features. In these systems, reduction of switch counts and driving circuits can achieve the advantages of compact size, low cost and high efficiency. For the stand-alone systems, several single-stage converters (SSCs) for PV powered lighting system (PPLS) applications are generated through the synchronous switch technique. One of the proposed SSCs, integrated from a buck-boost charger/discharger and a class-D series resonant parallel loaded inverter, is analyzed and designed into a PPLS. The proposed system has a simple configuration, as well as a zero voltage switching (ZVS) feature, and can achieve the same functions as those in conventional systems. Due to the nonlinear and time-variant nature of switches and the resonant behavior of inverters, a fuzzy logic controller (FLC) is designed to control both the charging and discharging current, and to improve its dynamic and steady state performance. A prototype has been built and successfully demonstrated the feasibility, adaptivity and robustness of PPLS applications with the SSCs controlled by the FLC. For the grid-connection systems which can fully utilize the existing components, there are two single-stage and multi-feature systems proposed in this dissertation. First, a PV power supply system with grid-connection, power factor correction and lamp driving features is presented. This system can suppress the peak power supplied from utility line during daytime, and can draw power from utility line to drive fluorescent lamps with near unity power factor during nighttime or low insolation. Secondly, this research presents a grid-connection PV power supply system with a feature of dynamic power conditioning, which can not only draw maximum real power from PV arrays but can filter harmonic currents and improve power factor. Once maximum PV power varies, the proposed inverter system can dynamically condition its corresponding reactive power and distortion power, while still can process the maximum real power and utilize its utmost installation capacity. Simulated and experimental results of these two systems have verified their validity and feasibility.