Robust Hamiltonian Energy Control Based on Lyapunov Function for Four-Phase Parallel Fuel Cell Boost Converter for DC Microgrid Applications

Rapid developments in hydrogen fuel cell (FC) energy and DC microgrid systems have extended the applications of multiphase parallel interleaved step-up converters for stabilizing DC bus voltages. DC microgrid applications include vehicle systems, shipboard power systems, and more electric aircraft, which generate power at low voltage levels. The cascade architecture of a power converter in a DC microgrid may cause large oscillations and imbalance given that converters considered as loads have constant power load characteristics. In this work, output DC bus voltage stabilization and current sharing of a multiphase parallel-interleaved-FC boost converter is presented. The proposed robust controller with added integrator action is based on the Hamiltonian-Lyapunov function. The efficacy and robustness of the designed controller were successfully authenticated by experimental results obtained using a 2.5 kW prototype FC converter (via four-phase parallel-interleaved boost converters) and the dSPACE MicroLabBox platform. The main source of the FC is based on a fuel reformer engine that converts fuel methanol and water into H-2 gas in a polymer-electrolyte-membrane-FC stack (50 V, 2.5 kW).