Study of a multiphase interleaved step-up converter for fuel cell high power applications

This paper presents a study of a high power dc distributed system supplied by a fuel cell generator. A proposed parallel power converter with interleaving algorithm is chosen to boost a low dc voltage of fuel cell to a dc bus utility level. The present interleaved step-up converters are composed of two and four identical boost converters connected in parallel. Converters are controlled by interleaved switching signals, which have the same switching frequency and the same phase shift. By virtue of paralleling the converters, the input current can be shared among the cells or phases, so that high reliability and efficiency in power electronic systems can be obtained. In addition, it is possible to improve the system characteristics such as maintenance, repair, fault tolerance, and low heat dissipation. During the past decade, power electronics research has focused on the development of interleaved parallel converters. For an interleaving technique with a real fuel cell source, this work is the first presentation; it is not just a fuel cell simulation. So, the design and experimental verification of 1.2-kW prototype converters at a switching frequency of 25 kHz connected with a NexaTM PEM fuel cell system (1.2-kW, 46-A) in a laboratory is presented. Experimental results corroborate the excellent system performances. The fuel cell ripple current can be virtually reduced to zero. As a result, the fuel cell mean current is nearly equal to the fuel cell rms current.