| Summary: | 碩士 === 建國科技大學 === 電機工程系暨研究所 === 101 === Abstract
Traditional metal streetlights are too energy-consuming and require to work in the conditions of high temperature, therefore the service life is short and does not match the energy-saving trend of the times, they have been gradually replaced by white LED lights. According to the current white LED luminous efficacy(cool white: 254 lm/W, warm white: 216 lm/W), much larger than the metal lamps 60 lm/W luminous efficiency, white LED lights can save about 1/3 to 1/2 of energy. To achieve the energy-saving purpose, it is also required to take into account the efficiency and power factor problems when installed LED streetlights. According to the CNS LED Streetlight Standard CNS15233, which specifies the input power factor and overall conversion efficiency must be greater than 90%, this thesis proposes a new design of 200W high-performance LED streetlight drive circuits. It is composed of four parts of circuits: (1) power factor correction, (2) LLC resonant converter, (3) synchronous rectification, (4) constant current control circuit. The experimental results show that its power factor at full load under 220V input is up to 0.97, and the conversion efficiency of PFC stage is up to 97.8%; the maximum and full load conversion efficiencies of LLC resonant converter stage are as high as 96% and 95.5% respectively. The whole circuit conversion efficiency at full load is as high as 93%, power factor is also up to 0.99, either power factor or conversion efficiency is much superior to the values specified by the CNS Standards.
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