A Fuel Cell Power Conditioning System With Low-Frequency Ripple-Free Input Current Using a Control-Oriented Power Pulsation Decoupling Strategy

This paper proposes a fuel cell power conditioning system based on the current-fed dual-half-bridge (CF-DHB) dc-dc converter that can achieve low-frequency ripple-free input current using a control-oriented power pulsation decoupling strategy when an inverter load is connected to the fuel cell system. Without adding any extra circuit components, the proposed power pulsation decoupling strategy can realize a smaller dc bus capacitor; a film capacitor, therefore, can be applied in this fuel cell power conditioning system to replace the bulky electrolytic capacitor. In order to eliminate the double-frequency ripple current disturbance introduced by the inverter load to the fuel cell stack, a proportional-resonant controller is developed to achieve an extra high control gain at a designed resonant frequency. The operation principles of the CF-DHB converter with a proposed power pulsation decoupling strategy are analyzed. In addition, the controller design guidelines are derived based on the system small-signal model. The experimental results of a 1-kW fuel cell power conditioning system are presented to validate the proposed technology.