High Step-Up Interleaved Stack DC-DC Converter with Zero Voltage Switching

• Main Authors: Ji-SyuanLi, 李紀儇
• Other Authors: Jiann-Fuh Chen
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/12746100868984877134

碩士 === 國立成功大學 === 電機工程學系 === 104 === ABSTRACT This thesis proposes a novel high step-up DC-DC converter with ZVS turn-on switches and ZCS turn-off diodes based on several existed techniques such as coupled-inductor, active clamping, stacked capacitor and interleaved technique. The proposed converter has a high conversion ratio, and high efficiency to meet the properties of renewable energy needs. Interleaved technique is used here in order to increase the capacity of circuit. The main objective of proposed circuit is soft-switching operation. The leakage inductance of coupled inductors resonates with two secondary-side capacitors during steady-state operating modes. When the converter is operated at different resonant frequencies, ZVS turn-on and ZCS turn-off can be respectively accomplished by some power switches and rectifying diodes. Then, the problems of switching loss and reverse recovery are mitigated and thus improve the efficiency of proposed converter. Besides, by applying interleaved technology, turns ratio of each coupled inductor can be reduced signifcantly, and current stress at primary-side winding is also decreased. Therefore, the capacity of circuit can be increased obviously. In the thesis, the steady-state characterisitcs, such as high step up voltage gain, voltage and current stress on the power components, and ripple ratio, are derived and compared with the conventional circuits. Border maps for different operating modes of soft-switching are also illustrated. Verification is done by software simulation. Lastly, by using controller TMDSDOCK28035, a circuit with 24V input voltage, 400V output voltage and 800W output power is implemented to prove the feasibility of proposed converter. The highest efficiency is around 95.6% when operating at 450W.