DC-DC converters Energy industries & utilities History of engineering & technology Non-minimum phase systems PEMFC NEXA 1200 PV generation PV systems Technology: general issues boost converter comparative study constant power load core losses methods dc-dc power electronic converters discontinuous conduction mode energy efficiency experimental validation fabrication ferromagnetic material fractional-order PID controller fuel cell gallium trioxide grid connection hybridization inductors inverter leakage ground current low voltage ride-through (LVRT) multilevel inverter neutral point clamped new equivalent electrical model of fuel cell