三电平直流变换器的交错式PWM方法  

Interleaved PWM Method for Three-level DC/DC Converter

作　　者：刘威[1] 吕征宇[1] LIU Wei;LYU Zhengyu(College of Electrical Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学电气工程学院,杭州310027

出　　处：《电源学报》2018年第2期11-17,共7页Journal of Power Supply

摘　　要：三电平结构可将开关管的电压应力箝位于输入电压的一半,因此在高输入电压场合得到了广泛应用。为保证三电平变换器的正常运行,输入分压电容和隔直电容上的电压必须基本平衡,而实际电路中驱动电路延时不一致等问题可能导致电压失衡。本文提出了一种具有更强均压能力的脉冲宽度调制PWM(pulse width modulation)方法 ,该方法通过交错使用两种传统的PWM方法实现。交错式PWM方法将隔直电容电压与输入分压电容电压解耦,同时保证前者一直维持在理想值附近,大大简化了采样电路和均压策略,因此只需要调节驱动信号间的相位差便可以实现电压平衡。实验结果验证了所提调制方法和均压策略的有效性。Since the voltage stress on power switches is only half of the input voltage through the utilization of a three-level(TL)structure,TL converters have been widely used in high-voltage applications.To ensure the normal operation of TL converters,the voltages on the input-divided capacitors and the blocking capacitor must be balanced basically,whereas the asymmetry of time-delay in the drive circuit may result in voltage unbalance in practice.In this paper,a novel pulse width modulation(PWM)method with better voltage-balancing ability is proposed,which is implemented by interleaving two traditional PWM methods.The new PWM method decouples the blocking capacitor voltage from the voltages of input-divided capacitors,and ensures that the former voltage is always kept around its ideal value,which greatly simplifies the sampling circuit and the voltage-balancing strategy.In this way,only the phase shift between driving signals need to be adjusted to achieve voltage balance.Experimental results verified the effectiveness of the proposed modulation method and voltage-balancing strategy.

关 键 词：脉冲宽度调制 三电平 均压 

分 类 号：TM46[电气工程—电器]