Study and Implementation of a Hybrid Three-Level Converter

• Main Authors: Chen,Kuan-Hao, 陳冠豪
• Other Authors: 林伯仁
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/e7mxa7

碩士 === 國立雲林科技大學 === 電機工程系 === 103 === This paper presents a hybrid three-level ZVS converter for high input voltage and high output current applications. The primary side of the converter consists of three-level PWM converter and LLC converter that can achieve the functions of wide range ZVS turn-on for the power switches, less circulating current loss and low output inductance. Three-level ZVS converter can reduce the voltage stress of power switches at half of input voltage. The flying capacitor is adopted in the circuit in order to balance two input capacitor voltages. The half-bridge LLC converter, shared the same active switches at lagging leg of the conventional three-level PWM converter, can extend the ZVS range of lagging-leg switches. This topology can promote the efficiency of the converter at light load. In the circuit configuration, the output sides of LLC converter and three-level PWM converter are connected in parallel with a low cost diode to provide a positive rectified voltage in order to reduce the primary circulating current. Finally, the effectiveness of the proposed converter is verified by the circuit analysis, simulated results and experimented waveforms with input DC voltage 750V~800V, output DC voltage 24V and load current 60A.