Neutral point voltage control for three-level fuel cell power conversion system

A three-level Power Conversion System (PCS) for fuel cell (FC) is investigated. The three-level PCS is composed of a diode clamped three-level inverter and a three-level DC/DC converter, which have the common neutral point. To suppress variation of the neutral point voltage of three-level PCS, a novel control strategy is presented by the three-level DC/DC converter. Through modeling of fuel cell power conversion system, the neutral point voltage control is derived. The control loops are designed. The control strategy is verified by simulation and experiments. The neutral point voltage and DC-bus voltage control are achieved excellently both on static and dynamic conditions.