A level-shifted pulse width modulation strategy for hybrid cascaded multilevel converters

作者：Chen Zhong; Xu Yaming; Liu Yayun; Na Xianlong

来源：Proceedings of the CSEE, 2016, 36(23): 6490-6500.

DOI：10.13334/j.0258-8013.pcsee.152724

• Hybrid cascaded
• Modulation strategy
• Multilevel converter
• Reverse power
• Unipolar

The hybrid cascaded multilevel converters, compared with the traditional cascaded ones, can generate more output levels with less switch devices and isolated sources, which have obvious advantages of increasing power density, reducing the size and cost of the system. However, with the general hybrid modulation, it appears that the high-voltage cell feeds power into the low-voltage cell in some modulation ratio interval, making the dc-bus voltage boost of the low-voltage cell. To avoid the problem, a bidirectional controlled rectifier is employed, increasing the complexity of the equipment and limiting its applications. A unipolar level-shifted pulse width modulation (LS-PWM) strategy was presented. With this strategy, the problem of reverse power can be avoided at any modulation ratio, and the diode rectifier is also available. Computer simulations and experimental verification based on this strategy were presented.

• 出版日期2016
• 单位南京航空航天大学