Design challenges of industrial high-power converters with low pulse-ratios

This paper presents the design challenges of highpower converters with low pulse-ratios from an industry point of view. Some standard design concepts to improve the power capability, power quality and the dynamic performance of the converter are reviewed. The novelty of this work is that it provides an insight of concepts with extremely low pulse-ratios (e.g. 5 pulses per 180 ° fundamental). A comparative performance evaluation of these concepts is presented for highpulse-ratio and low-pulse-ratio applications, respectively. It is concluded that the performance/effectiveness of some design concepts is strongly degraded due to the low pulse-ratio, where special attention needs to be drawn. In contrast, some other concepts bring only real benefit for low pulse-ratio applications and are not attractive for high pulse-ratio converters. Some special and interesting phenomena of these concepts are explored. At the end, the design recommendations for low pulse-ratio converters are summarized.