The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using po...The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using power converters they can be strongly non-harmonic, sometimes piecewise constants with zero spaces between them. Then, one deals with power series of time pulses. The impulse switching functions which are orthogonal ones can be derived from these series. The new impulse switching functions are created using Z-transform, inverse Z-transform and numerical series/sequences. The impulse switching functions created this way can be used for both steady- and transient state investigation of converters.展开更多
Polymer solar cells(PSCs) were fabricated by combining a diketopyrrolopyrrole-based terpolymer(PTBT-HTID-DPP) as the electron donor, and [6,6]-phenyl C_(61) butyric acid methyl ester(PC_(61)BM) as the electron accepto...Polymer solar cells(PSCs) were fabricated by combining a diketopyrrolopyrrole-based terpolymer(PTBT-HTID-DPP) as the electron donor, and [6,6]-phenyl C_(61) butyric acid methyl ester(PC_(61)BM) as the electron acceptor, and the power conversion efficiency(PCE) of 4.31% has been achieved under AM 1.5 G(100 m W cm^(-2)) illumination condition via optimizing the polymer/PC_(61)BM ratio, the variety of solvent and the spin-coating speed. The impact of the spin-coating speed on the photovoltaic performance of the PSCs has been investigated by revealing the effects of the spin-coating speed on the morphology and the absorption spectra of the polymer/PC_(61)BM blend films. When the thickness of the blend films are adjusted by spin-coating a fixed concentration with different spin-coating speeds, the blend film prepared at a lower spin-coating speed shows a stronger absorption per unit thickness, and the correspond device shows higher IPCE value in the longer-wavelength region. Under the conditions of similar thickness, the blend film prepared at a lower spin-coating speed forms a more uniform microphase separation and smaller domain size which leads to a higher absorption intensity per unit thickness of the blend film in long wavenumber band, a larger short-circuit current density(J_(sc)) and a higher power conversion efficiency(PCE) of the PSC device. Noteworthily, it was found that spin-coating speed is not only a way to control the thickness of active layer but also an influencing factor on morphology and photovoltaic performance for the diketopyrrolopyrrole-based terpolymer.展开更多
文摘The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using power converters they can be strongly non-harmonic, sometimes piecewise constants with zero spaces between them. Then, one deals with power series of time pulses. The impulse switching functions which are orthogonal ones can be derived from these series. The new impulse switching functions are created using Z-transform, inverse Z-transform and numerical series/sequences. The impulse switching functions created this way can be used for both steady- and transient state investigation of converters.
基金supported by the National Natural Science Foundation of China (51573153)the Natural Science Foundation of Hunan Province of China (2015JJ2141)+1 种基金the Scientific Research Foundation of the State Education Ministry for the Returned Overseas Chinese Scholars (2014–1685)the Scientific Research Fund of Hunan Provincial Education Department (15A180)
文摘Polymer solar cells(PSCs) were fabricated by combining a diketopyrrolopyrrole-based terpolymer(PTBT-HTID-DPP) as the electron donor, and [6,6]-phenyl C_(61) butyric acid methyl ester(PC_(61)BM) as the electron acceptor, and the power conversion efficiency(PCE) of 4.31% has been achieved under AM 1.5 G(100 m W cm^(-2)) illumination condition via optimizing the polymer/PC_(61)BM ratio, the variety of solvent and the spin-coating speed. The impact of the spin-coating speed on the photovoltaic performance of the PSCs has been investigated by revealing the effects of the spin-coating speed on the morphology and the absorption spectra of the polymer/PC_(61)BM blend films. When the thickness of the blend films are adjusted by spin-coating a fixed concentration with different spin-coating speeds, the blend film prepared at a lower spin-coating speed shows a stronger absorption per unit thickness, and the correspond device shows higher IPCE value in the longer-wavelength region. Under the conditions of similar thickness, the blend film prepared at a lower spin-coating speed forms a more uniform microphase separation and smaller domain size which leads to a higher absorption intensity per unit thickness of the blend film in long wavenumber band, a larger short-circuit current density(J_(sc)) and a higher power conversion efficiency(PCE) of the PSC device. Noteworthily, it was found that spin-coating speed is not only a way to control the thickness of active layer but also an influencing factor on morphology and photovoltaic performance for the diketopyrrolopyrrole-based terpolymer.
