Abstract A fuel cell‐based power systems emulator designed to test devices and loads intended to interact with real prototypes is presented. The emulator uses a digital processing device and electrical power systems, evaluating the impact of using either switching or linear power stages in the emulator capabilities. A real fuel cell prototype is emulated using a parameterized physical fuel cell model, which is computed online by a digital device. Also, several power stages not previously used specifically for this application, with different efficiencies and performances, were developed and analysed. One of the power stages was based on a two‐inductor step‐down DC/DC converter for a switching power stage instead of the classical buck structure that is more prone to duty cycle saturation in transients at low output voltages. The other ones used high‐power operational amplifiers for a linear power stage and linear regulators for a scalable linear power stage. Finally, the emulation system and the power stages were evaluated and validated using experimental data of a real fuel cell prototype. Copyright © 2010 John Wiley & Sons, Ltd.