Modeling and Control of a Switching Regulator with a Fuel-Cell Stack as Input Source for Power Generation

The input voltage of a switch-mode converter is usually assumed to be constant; however, this is not valid if a fuel cell stack (FCS) is used as an input source. A FCS is an unregulated voltage source due to the nonlinear relationship between the output voltage and the demanded current; then, an effective controller is needed to deal with this issue. A controller design of an energy processing system is discussed in this work. This system consists of a FCS and a power boost converter that delivers energy to a load despite input voltage variations and significant load changes. The designed controller should ensure voltage regulation, good dynamic performance, and system stability. Experimental validation is carried out with a FCS and a 900 W boost converter prototype.