Input current-ripple reduction of a pulse-link DC-AC converter for fuel cells

This paper considers that the mechanism of input current-ripple on pulse-link DC-AC converter for fuel cells. And the reduction methods are shown. In general, fuel cells are weak about current ripple. The current-ripple damages to the fuel capacity and life span because the chemical reaction time when generates electricity is much slower than commercial frequency. Therefore, the input current-ripple reduction is essential factor in the DC-AC converter for fuel cells applications. In the conventional DC-AC converter topology, large smoothing capacitor is worked as the input current-ripple reduction. However, this large capacitor makes it difficult to reduce the size of DC-AC converter unit. Authors have proposed a novel topology called as pulse-link DC-AC converter. In this topology, a large capacitor for the smoothed DC power source is not needed because the first-stage boost converter provides boosted voltage pulse directly to PWM inverter. Instead, a series-connected LC circuit is inserted to reduce the input current-ripple. Furthermore, when duty ratio is controlled by sensing input current, input current-ripple is reduced less than 1Amp.