Development and implementation of novel paralleling methods for boost dc-dc converters used at the outputs of fuel cells

Typically, a boost dc-dc converter is utilized at the outputs of fuel cells that burn hydrogen which is considered by the experts to hold an important place in the future energy systems. Using several boost converters in parallel instead of a single unit is aimed in this work. Paralleling of converters yields more efficient, more reliable systems with high redundancy, and ease of maintenance, and paralleling can be achieved through methods that may or may not utilize a communication bus. Paralleling methods were investigated in detail, stability analysis for each of the methods was conducted, a novel method with communication and another novel method without communication were proposed for the parallel structure in this thesis. Each method was then implemented and successfully tested. Proposed communicative method uses input power information instead of the commonly used output current. It is believed that this property of the method makes it proper for renewable energy systems. A new characteristic transition system was also proposed and implemented for the droop method which is a non-communicative method. Simulation and experimental work showed that the proposed method yields a better sharing and voltage regulation at the same time.