两级高轻载效率数字功率变换器的研究

Research on two-stage power converter based on digital control with high light load efficiency

针对电源轻载效率低的问题,提出了一种数字(DSP)集成控制方法。该方法同时控制PFC级直流输出母线电压和全桥部分的开关时序,轻载时,通过调整母线电压并降低开关频率来减小开关损耗和环路电流损耗。实验结果表明,该变换器在10%额定负载下效率能达到90%,在5%额定负载下效率仍高于80%。

To solve the disadvantage of traditional- anlog power supply low and less efficiency under light load condition, the scheme of digital integrated control based on the DSP is proposed. The basic idea of the proposed control technique is to control both DC- link voltage of PFC stage and switching method of full- bridge stage. Under light load condition, the output voltage of PFC stage is adjusted dynamically and switch frequency to reduce the switching losses and circulating current losses. The results in-dicate, in 10 % load condition, the efficiency reaches 85 %, and in 5 % load condition, the efficiency is higher than 80 %. The integrated control scheme can improve efficiency.