In this paper, a high power factor LED driver with hot swap, smart output voltage regulation and dimming control is proposed. The dimming control is used to change LED brightness. During converter is working, the hot ...In this paper, a high power factor LED driver with hot swap, smart output voltage regulation and dimming control is proposed. The dimming control is used to change LED brightness. During converter is working, the hot swap function supply users to remove and insert LED module. The smart output voltage can regulate quickly and rightly output voltage in different number of LED series connection. The system consists two stages, one is 50 W flyback converter which is used as power factor corrector, it is input source is 110-220 V, PF （power factor） is about 0,994. The other is Boost DC/DC converter, it can offer 35-60 V of output voltage. Finally, a prototype has been built and tested. The simulation and experimental results are shown to verify the feasibility of the proposed method.展开更多
In this paper, the peak-to-average power ratio(PAPR) of orthogonal frequency division multiplexing(OFDM) signal is reduced by combining the discrete cosine transform(DCT) with clipping in optical intensity-modulated d...In this paper, the peak-to-average power ratio(PAPR) of orthogonal frequency division multiplexing(OFDM) signal is reduced by combining the discrete cosine transform(DCT) with clipping in optical intensity-modulated direct-detection(IM/DD) OFDM systems. First, the data are transformed into new modified data by DCT. Second, the proposed scheme utilizes the clipping technique to further reduce the PAPR of OFDM signal. We experimentally demonstrate that the optical OFDM transmission system with this proposed scheme can achieve significant performance improvement in terms of PAPR and bit error rate(BER) compared with the original optical OFDM systems.展开更多
文摘In this paper, a high power factor LED driver with hot swap, smart output voltage regulation and dimming control is proposed. The dimming control is used to change LED brightness. During converter is working, the hot swap function supply users to remove and insert LED module. The smart output voltage can regulate quickly and rightly output voltage in different number of LED series connection. The system consists two stages, one is 50 W flyback converter which is used as power factor corrector, it is input source is 110-220 V, PF （power factor） is about 0,994. The other is Boost DC/DC converter, it can offer 35-60 V of output voltage. Finally, a prototype has been built and tested. The simulation and experimental results are shown to verify the feasibility of the proposed method.
基金supported by the National Natural Science Foundation of China(No.51376162)the Open Fund of the State Key Laboratory of Millimeter Waves(Southeast University,Ministry of Education,China)(No.K201214)+1 种基金the Zhejiang Provincial Natural Science Foundation of China(No.LY13F050005)the Key Industrial Project of Special Major Science and Technology of Zhejiang Province(No.2012C11016-2)
文摘In this paper, the peak-to-average power ratio(PAPR) of orthogonal frequency division multiplexing(OFDM) signal is reduced by combining the discrete cosine transform(DCT) with clipping in optical intensity-modulated direct-detection(IM/DD) OFDM systems. First, the data are transformed into new modified data by DCT. Second, the proposed scheme utilizes the clipping technique to further reduce the PAPR of OFDM signal. We experimentally demonstrate that the optical OFDM transmission system with this proposed scheme can achieve significant performance improvement in terms of PAPR and bit error rate(BER) compared with the original optical OFDM systems.
