This paper studys a multi-phase boost converter for fuel cell (FC) applications. An original control law based on the Hamiltonian energy control principle for dc microgrid is considered. Using the port-controlled Hamiltonian property, we propose simple solutions to the system performance and stabilization problems when the interaction between power sources and constant power loads (CPLs). To corroborate the proposed control law, a prototype FC power converter (2.5-kW two-phase boost converter) is implemented in the laboratory. The Methanol FC system includes a fuel reformer that converts methanol and water liquid fuel into hydrogen gas to polymer electrolyte membrane FC (PEMFC) stack (2.5-kW, 50 V). The proposed control approach is realized with a digital estimate in a dSPACE MicroLabBox controller card. The experimental and simulation results verify that this is a good control scheme during constant power load cycles.