半桥三电平直流变换器的电容电压控制策略  

Capacitor Voltage Control Strategy for Half-Bridge Three-Level Converter

作　　者：周玮阳 虞晓阳[1] 金科[1] 刘志军[1] 

机构地区：[1]南京航空航天大学江苏省新能源发电与电能变换重点实验室,南京210016

出　　处：《电工技术学报》2015年第16期56-62,共7页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51007038;51377080);江苏省自然科学基金杰出青年基金(BK20130036);霍英东教育基金会基础性研究课题(131056);江苏省产学研联合创新资金-前瞻性联合研究项目(BY2012016);光宝电力电子技术科研基金项目资助

摘　　要：三电平(TL)直流变换器具有主开关管电压应力为输入电压一半的优点,适用于高压输入场合。本文所研究的四开关半桥TL直流变换器可以实现一次侧开关管的宽范围软开关,而且避免了钳位二极管和飞跨电容带来的可靠性问题。但是主电路以及控制电路的不对称可能造成输入分压电容以及隔直电容的偏压,从而导致主功率管以及整流二极管电压应力增加。本文提出了一种电容电压控制策略,通过调节正负半周占空比以及相位差,实现输入分压电容和隔直电容的电压控制,提高变换器运行的可靠性。最后研制了一台输入800V、输出28V/2k W的原理样机,实验结果验证了偏压理论分析的正确性以及电容电压控制策略的有效性。Three-level（TL） DC/DC converters apply especially to nlgn-vottage input occasions for the reason that the voltage stress across the power switches is only half of the input voltage. The four switches half-bridge TL converter studied in this paper can achieve wide range soft switching of the primary switches. Besides, it removes the clamped diodes and flying capacitor to ensure high reliability. However, the asymmetry of the main circuit and control circuit result in voltage unbalance among the input capacitors and blocking capacitor, which can result in high voltage stress of the power switches and the rectifier diodes. A novel capacitor voltage control strategy is proposed to realize voltage control and improve the reliability of the converter by regulating duty cycle and phase shift of the positive and negative half-cycles. Finally, an input 800V output 28V/2kW prototype was built and tested in the lab. The experimental results validate the theoretical analysis of voltage unbalance and capacitor voltage control strategy.

关 键 词：半桥三电平 偏压 电容电压控制 占空比 相位差 

分 类 号：TM46[电气工程—电器]