In this paper, a multiphysical proton exchange membrane fuel cell stack model, which is suitable for real-time emulation is presented. The model covers three physical domains: electrical, fluidic, and thermal. A Ballard 1.2 kW 47 cells fuel cell stack model is introduced. The corresponding fuel cell system auxiliary models are given based on experimental tests. Based on the modeling equations, the fuel cell dynamic phenomena in different physical domains are analyzed and the corresponding time constant expressions are given. Using the real-time stack model, a fuel cell stack emulator based on a buck converter is used to emulate the fuel cell stack electrical part. The experimental results show that the emulator can reproduce the real-stack behavior with a great agreement. Such a fuel cell stack emulator can be used for hardware-in-the-loop applications, in order to test and validate the fuel cell system design.