【作者】 张之梁；

【导师】 阮新波；

【作者基本信息】 南京航空航天大学 ， 电力电子与电力传动， 2005， 硕士

【摘要】 直流三电平(Three-level, TL)变换器可以降低开关管的电压应力,减小输出滤波器,非常适合高压输入的应用场合。全桥(Full-bridge, FB)变换器在大功率应用场合已经得到广泛的应用,而全桥三电平(Full-bridge Three Level, FB TL)变换器结合了 TL 变换器和 FB 变换器各自的优点,因此非常适合高压输入的大功率应用场合。但 FB TL 变换器的开关管数目较多,因而蕴涵着多种控制方式,为了寻求最优的软开关控制方案,需要对 FB TL 变换器的控制策略进行研究。 本文针对FB TL变换器提出斩波移相(Chopping plus phase-shift, CPS)控制,详 细 分 析 该 变 换 器 的 工 作 原 理 , 讨 论 开 关 管 实 现 零 电 压 开 关(Zero-voltage-switching, ZVS)的条件、谐振电感造成的占空比丢失、滤波电感的理论计算等,给出 FB TL 变换器的参数设计,并进行实验验证。 本文详细分析了 FB TL 变换器中飞跨电容和钳位二极管的工作原理,避免了开关管开通和关断差异造成的电压应力不均,为其工程应用提供理论依据。 为了减小 MOSFET 体二极管造成的导通损耗和反向恢复损耗,提高变换器效率,本文对全桥三电平变换器提出一种新的控制策略——双移相(Double phase-shift, DPS)控制,并进行实验验证。DPS 控制无需增加额外的元器件,保持 CPS 控制原有的优点,使 FB TL 变换器在宽输入电压范围内保持较高的变换效率。本文还将 DPS 控制推广为多移相控制,从而适合复合全桥多电平变换器和全桥多电平变换器。更多还原

【Abstract】 The most important advantage of the three-level (TL) converter is that the switches sustain only the half of the input voltage with the reduced output filter inductance, so it is very suitable for high voltage applications. Full-bridge (FB) converter is widely used in high power industrial applications. Thus,the FB TL converter will inherit the merits of both the TL converters and FB converters. However, due to the eight power switches in the FB TL converter, the efforts need to be concentrated on obtaining the optimal modulation strategy of the converter. This paper proposes a chopping plus phase-shift (CPS) control for the FB TL converter. The operation principle and characteristics of the FB TL converter are analyzed and verified experimentally. In order to avoid the unequal voltage stress of the switches due to the asymmetrical driving of the switches, the flying capacitor and the two clamping diodes are introduced and verified experimentally. In order to reduce the loss of MOSFETs’ body diodes, a novel double phase-shift (DPS) control for the FB TL converter is proposed, which improves efficiency by reducing loss of switches’ body diodes meanwhile maintains the converter’s original advantages without adding additional components compared to the CPS control. The operation principle is verified experimentally. In addition, the concept of the DPS control is extended to hybrid FB converter and FB multilevel converter.更多还原