一种三电平电压型逆娈器空间矢量调制方法研究

本文基于冗余电压矢量的不同处理，提出一种三电平空间电压矢量调制模式，这种调制模式较之常见的八段对称式SVPWM具有明显的谐波和控制优势。为解决三电平逆变器中点波动问题，基于这种调制方法提出了一种新的中点电压平衡控制方法，这种方法只需直流电容电压和负载三相电流的信息，控制算法简便易行，有利于计算机数字化实现。所提出控制方法的有效性通过仿真和实验研究得到了证实。     

声孔对耳机频响曲线的影响

利用集中参数系统的电-力-声类比方法,理论分析声孔对耳机频响曲线的影响,并用Micro-Cap软件进行仿真验证,从而指导耳机实际声学设计及调试.     

High efficiency bulk heterojunction organic solar cell by using high conductivity modified PEDOT: PSS as a buffer layer

In this paper,bulk heterojunction solar cells with poly-(3-hexylthiophene)(P3HT):[6,6]-phenyl-C61-butyric-acid-methylester(PCBM) as an active layer and modified poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) as a buffer layer are fabricated.The buffer layer is modified by adding 1% to 5% dimethyl sulfoxide(DMSO) into PEDOT:PSS solution before spin-coating.The conductivity of modified PEDOT:PSS and the performance of solar cells with modified PEDOT:PSS are measured.The highest conductivity of modified PEDOT:PSS with 4% DMSO can achieve 89.693 S/cm.The performance of organic solar cell with PEDOT:PSS modified by 4% DMSO is the best.The 4% DMSOmodified-PEDOT:PSS cell has a power conversion efficiency of 3.34%,V oc of 5.7 V,J sc of 14.56 mA/cm 2 and filling factor(FF) of 40.34%.