Waveform control of fuel-cell inverter systems

Fuel-cell power systems comprising single-phase DC/AC inverters draw low-frequency AC ripple currents at twice the output frequency from the fuel cell. Such a 100/120 Hz ripple current may create instability in the fuel cell system, lowers its efficiency, and shortens the lifetime of fuel cell stack. This paper¹ presents a waveform control method that can mitigate such a low-frequency ripple current from being drawn from the fuel cell while the fuel-cell system delivers AC power to the load through a differential inverter. Theoretical analysis, simulation, and experimental results are provided to explain the operation and showcase the performance of the approach. Results validate that the proposed solution can achieve significant mitigation of the current ripple as well as high quality output voltage without the need for extra hardware.