Yosuke Harada

Input Current-Ripple Consideration for the Pulse-link DC-AC Converter for Fuel Cells by Small Series LC Circuit

This paper mentions the input current ripple reduction method of the Pulse-link DC-AC Converter for Fuel Cells. The conventional DC-AC converter for fuel cells is interpolated large capacitor between boost converter stage and PWM inverter stage. That capacitor disturbs the size reduction of this unit. To overcome this problem, authors have proposed a novel topology called as Pulse-link DC-AC converter. The proposed topology provides boosted-voltage pulse directly to PWM inverter. This topology does not require large capacitor between two stages. Instead, small values of inductor and capacitor are connected series and inserted between two stages in parallel. This paper examines the relationship between the inductor and capacitor values and input current-ripple. As the result, inductor value has the relationship with current-ripple.

Steady-state characteristics of a novel DC-AC converter for fuel cells

Clean energy system is demanded because of global warming and energy issues. Fuel cells are one of the clean energy sources, and they may be replaced from the fossil fuels. And now, the specifications of DC-AC converter for fuel cells are demanded high efficiency and reduction of the size. This paper proposes a novel DC to AC converter topology for fuel cells. The proposed topology provides the boosted voltage pulse directly to the PWM inverter. As the result, this topology has no large smoothing capacitor. Moreover, this topology is able to achieve zero-voltage-switching (ZVS) of PWM inverter automatically. This paper firstly analyzes the each states of the proposed topology. Secondary, steady-state characteristics of proposed topology are shown by some experience. From the results, the advantage of the proposed topology is mentioned.

Characteristics of a pulse-link inverter for fuel cells

This paper proposes a novel DC-AC converter topology for fuel cells. This topology provides pulsed voltage to PWM inverter directly. As the results, it will be possible to reduce the size of this component because of no need for smoothing circuit between boost converter and PWM inverter. Furthermore, this topology is expected to achieve ZVS of the PWM switches because pulsed voltage has certainly zero voltage period in the switching period. This paper analyzes the novel topology called Pulse-link inverter. And it is shown the advantage the converter by the experimental results.

Consideration for input current-ripple reduction on a novel pulse-link DC-AC converter for fuel cells

Authors have proposed a novel DC-AC converter topology for fuel cells, which includes a novel method for the reduction of input current-ripple. In general, the current- ripple in fuel cells give s damage to the fuel cell consumption and life span because the chemical reaction time is much slower than the commercial power source frequency. Therefore, the input current-ripple should be reduced in the DC-AC converter for fuel cells. In the conventional DC-AC converter, a large capacitor is inserted between the boost converter stage and the PWM inverter stage for the current- ripple reduction. This capacitor disturbs the size reduction of the converter unit. In the proposed topology, the first- stage boost converter provides a series of boosted voltage pulses directly to the second-stage PWM inverter. Therefore, a large capacitor for the smoothed DC power source is not needed. Instead, a series-connected LC circuit is inserted for the current-ripple reduction. This paper focuses the mechanism of current-ripple reduction. Moreover, an active method for the current-ripple reduction is proposed, which reduces the input current-ripple less than 1 Amp.

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 1 Amp.

Consideration for input current-ripple of pulse-link DC-AC converter for fuel cells

This paper mentions the static characteristics of pulse-link DC-AC converter for fuel cells, and considers the input current-ripple reduction method. Fuel cells have weakness about current-ripple because the chemical reaction time is much slower than commercial frequency. Therefore, the input current-ripple reduction is essential factor in the DC-AC converter for fuel cells applications. Input current-ripple from fuel cells gives damage the fuel consumption and life time. The conventional DC-AC converter has large smoothing capacitor between boost converter stage and PWM converter stage, in order to reduce input current-ripple. That capacitor prevents from reduction the size of unit. Authors have proposed a novel topology called as pulse-link DC-AC converter. The pulse-link DC-AC converter topology is no need to insert large capacitor. Furthermore, the series-connected LC circuit between two stages connected in parallel works as ripple canceling. This paper shows the mechanism of current-ripple reduction.

Input current-ripple reduction on Pulse-link DC-AC converter for fuel cell applications operated by zero-current-slope mode

This paper considers input current-ripple reduction on Pulse-link DC-AC converter for fuel cells applications operated by zero-current-slope mode. For reducing the input current-ripple, series LC circuit has been connected in parallel at the Pulse-link DC-AC converter. The input current-ripple characteristics have two main domains with combination of series LC parameters. The current-ripple level depends on inductance values. Input current-ripple is reduced when the inductor current flown at series LC circuit has zero-slopes in one switching period. At that time, small parameters values can be achieved.

Analysis of pulse-link DC-AC converter for fuel cells applications operated in zero-current-slope mode

In fuel cells applications, current-ripple reduction is essential for conversion efficiency and life span. This paper analyzes the pulse-link DC-AC converter for fuel cells applications operated in zero-current-slope mode. As the result, in zero-current-slope operation mode, input-current-ripple is reduced. Furthermore, in this operation mode, the parameters of series LC circuit which is worked as ripple canceling are less values.

The effect of series LC circuit parameters on current-ripple reduction in Pulse-link DC-AC converter for fuel cell applications

This paper examines the effect of input current-ripple reduction on Pulse-link DC-AC converter for fuel cells applications. For reducing the input current-ripple, series LC circuit has been connected in parallel at the Pulse-link DC-AC converter. The input current-ripple characteristics have two main domains with combination of series LC parameters. The current-ripple level depends on inductance values. Input current-ripple is reduced when the inductor current flown at series LC circuit has zero-slopes in one switching period. At that time, small parameters values can be reached.

Input current-ripple reduction method on a novel pulse-link DC-AC converter for fuel cells applications

This paper proposes a novel DC-AC converter topology for fuel cells applications, and mentions the reduction methods of input current-ripple. Fuel cells are generated electricity by chemical reaction. Chemical reaction time is much slower than commercial frequency. So, input current-ripple may damage the fuel consumption and life span. The conventional DC-AC converter for fuel cells has large capacitor between boost converter stage and PWM inverter stage, in order to reduce the input current-ripple. That capacitor prevent from reducing the size of its unit. The proposed DC-AC converter, called pulse-link DCAC converter provides boosted-voltage pulse directly to PWM inverter. This topology is no need to insert large capacitor. Furthermore, the series LC circuit which is inserted on proposed topology works as ripple canceling. This paper shows the mechanism of current-ripple reduction. Moreover, active input current-ripple reduction method is shown.