Design and Implementation of PWM Control Techniques for the Full-Bridge DC/DC Converter

• Main Authors: Bo-Yuan Chen, 陳柏元
• Other Authors: 賴炎生
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/2s4z9c

博士 === 國立臺北科技大學 === 電機工程系博士班 === 101 === The main theme of this dissertation is to develop PWM control techniques for full-bridge DC/DC converter. A new switching control technique that can improve light load and standby power losses of phase-shift controlled full-bridge DC/DC converter is proposed. Furthermore, a new random PWM control technique is proposed to reduce the harmonics intensity while considering the efficiency. First, the continuous time-domain model of full-bridge DC/DC converter is established by state space average method. Based on the converter model, the digital controller is designed and implemented by an FPGA system. After that, ZVS condition for phase-shift control method and power losses for full-bridge DC/DC converter with PWM and phase-shift control are analyzed. According to the analyzed results, a switching control technique is developed to improve light load and stand by power losses. The results are verified by experimental results. Finally, a new random PWM technique is presented. The proposed technique can reduce the harmonic intensity of full-bridge DC/DC converter while considering the efficiency. The proposed method uses pseudo random binary sequence generator to generate random bits to change switching frequencies to effectively spread the dominate harmonics. The effectiveness of the proposed techniques is verified by both simulation and experimental results.