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ABSTRACT: 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.
Applied Power Electronics Conference and Exposition (APEC), 2010 Twenty-Fifth Annual IEEE; 03/2010
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ABSTRACT: 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.
Telecommunications Energy Conference, 2009. INTELEC 2009. 31st International; 11/2009
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ABSTRACT: 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.
Applied Power Electronics Conference and Exposition, 2009. APEC 2009. Twenty-Fourth Annual IEEE; 03/2009
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ABSTRACT: 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.
Power Electronics and Motion Control Conference, 2008. EPE-PEMC 2008. 13th; 10/2008
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ABSTRACT: 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.
Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
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ABSTRACT: This paper proposes a novel topology of DC-AC converter for fuel cells application, and considers the input- current reduction method. The conventional DC-AC converter for Fuel Cells has large capacitor between boost converter stage and PWM converter stage, in order to reduce input-current ripple. That capacitor disturbs to reduce the size of unit. The proposed DC-AC converter provides boosted-voltage pulse directly to PWM inverter. So, this topology is no need to insert large capacitor. Furthermore, the series LC circuit which is inserted on proposed circuit topology works as ripple canceling. This paper shows the mechanism of current-ripple reduction. Moreover, active input current-ripple reduction method is shown. Using this method, input current ripple becomes 1[A].
Applied Power Electronics Conference and Exposition, 2008. APEC 2008. Twenty-Third Annual IEEE; 03/2008
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ABSTRACT: 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.
Power Electronics, 2007. ICPE '07. 7th Internatonal Conference on; 11/2007
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ABSTRACT: 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.
Telecommunications Energy Conference, 2007. INTELEC 2007. 29th International; 11/2007
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ABSTRACT: Fixed-frequency PWM (pulse-width modulation) zero-voltage
switching (ZVS) conversion was realized by applying partial resonance to
the forward converter. The advantages of this technique are less EMI
(electromagnetic interference) and power dissipation in the switching
transistor, the ability to utilize a conventional PWM control method,
ease of suppression of the EMI influence due to fixed-frequency
operation, and suppressed voltage-stress on the switching transistor.
The hybrid converter has the advantages of both ZVS resonant and PWM
converters. The converter achieves excellent efficiency: 86% at 5 V 20 A
output, DC 48 V input. A wide input voltage range (18-60 DC, 85-265 V
AC) and a high level of responsiveness are also achieved
Telecommunications Energy Conference, 1989. INTELEC '89. Conference Proceedings., Eleventh International; 11/1989
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ABSTRACT: The operation of a push-pull converter constructed using a self-excited inverter (a multivibrator) is described. While the switching losses of FETs in the inverter were small, turn-on and turn-off slopes changed depending on the load conditions, so that the oscillating frequency varied slightly. Two types of magnetic cores were used in experiments; power conversion efficiencies reached 76 percent or more for load currents from 5 to 10 A, and the oscillating frequency changed by about 10 percent in the 0 to 10 A range. Use of a core with good frequency characteristics should enable operation at up to 1 MHz.
IEEE Translation Journal on Magnetics in Japan 11/1985; 1(7):849-850.
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ABSTRACT: Novel zero-voltage-switched (ZVS) quasiresonant converters (QRCs)
utilizing partial resonance are presented. The partial-resonance
technique overcomes high-voltage stress in the ZVS resonant converter by
adding a clamp mode between resonant modes while the power transistor is
off. A novel self-running converter whose frequency is determined by the
saturable inductor is proposed. The self-running converter uses partial
resonance that has interesting characteristics and is able to control
output voltage easily. Experimental results show that zero cross
switching and low EMI (electromagnetic interference) are achieved using
this approach
Telecommunications Energy Conference, 1988. INTELEC '88., 10th International;
