Compared with continuous pulsewidth modulation (PWM), discontinuous PWM (DPWM) is a preferred solution in high-frequency Vienna-type rectifiers due to its inherent characteristics of less commutation number and higher efficiency. In this article, redundant clamping modes at the same subsector with opposite effects on the neutral point (NP) voltage are presented. Then, a modified DPWM (MDPWM) scheme is proposed to regulate the NP voltage by using redundant clamping modes. Thus, the NP voltage can be controlled in each switching period to lower the NP voltage fluctuation. The implementation of the proposed MDPWM is given with variable power factors analysis. Further, the switching loss comparison of conventional space vector PWM (SVPWM), hybrid DPWM (HDPWM), and proposed MDPWM is presented as well. A simulation model was built to verify the proposed NP voltage balance with different modulation indices and variable power factors. Finally, a 10-kW prototype is built to evaluate the proposed MDPWM scheme at conversion efficiency and current total harmonic distortion (THD). Experimental results and analysis show that comparing conventional SVPWM and HDPWM, the efficiency of MDPWM is the highest. The THD of DPWM is slightly higher than that of SVPWM, and it is only 2.5% at rated output power.

中文翻译：

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三相Vienna整流器具有中性点电压平衡能力的改进DPWM


与连续脉宽调制（PWM）相比，非连续脉宽调制（DPWM）因其换相次数少、效率高等固有特点，成为高频维也纳型整流器的首选解决方案。在本文中，提出了同一子扇区的冗余钳位模式，对中性点（NP）电压具有相反的影响。然后，提出了一种改进的DPWM（MDPWM）方案，通过使用冗余钳位模式来调节NP电压。这样，可以在每个开关周期控制NP电压，以降低NP电压波动。通过可变功率因数分析给出了所提出的 MDPWM 的实现。此外，还介绍了传统空间矢量 PWM (SVPWM)、混合 DPWM (HDPWM) 和所提出的 MDPWM 的开关损耗比较。建立了一个仿真模型来验证所提出的具有不同调制指数和可变功率因数的 NP 电压平衡。最后，构建了一个 10 kW 原型来评估所提出的 MDPWM 方案的转换效率和电流总谐波失真 (THD)。实验结果和分析表明，对比传统的SVPWM和HDPWM，MDPWM的效率最高。 DPWM的THD略高于SVPWM，在额定输出功率下仅为2.5%。