一种非线性控制的正弦波逆变器的研究

提出了一种基于ｏｎｅ－ｃｙｃｌｅ非线性控制的ＤＣ４８Ｖ／ＡＣ２２０Ｖ正弦波逆变器,详细阐明了控制原理,进行了谐波分析,仿真结果证明主出版社为器具有优良的抗线扰动性和限随性能。     

集值映射扰动多目标规划的稳定性

目的研究扰动集值映射多目标规划问题解集在上（下）半连续意义下的稳定性．方法依据拓扑、凸分析和泛函分析理论,对扰动集值映射多目标规划问题中特定的集值映射进行分析和研究．结果分别给出了锥有效解集和锥弱有效解集的上半连续和下半连续的充分性条件．结论进一步完善了多目标规划理论     

中弧线变形方式对扑翼能量吸收效率的影响

选用NACA0015翼型,在Re=1×10~4的条件下,采取正弦和分段函数两种不同的中弧线变形规律,通过对最大变形位置、变形幅值等参数的分析,揭示两种变形方式对于扑翼能量吸收效率的影响。研究表明:两种变形方式均能带来扑翼能量吸收效率的提升,且最大变形位置越靠后,扑翼能在更大的变形幅值范围内获得能量吸收效率的提升;随着最大变形位置的后移,正弦形式取代分段函数形式成为一种较优的变形方式;正弦的中弧线变形方式降低了输出功率系数曲线的第二个峰值,但其大幅提升第一、二峰值之间区域的数值,故正弦的中弧线变形方式仍是一种较优的变形方式。     

Rejection of narrow‐band disturbances subject to uncertain time delays

In this work, the problem of designing feedback contollers for the rejection of narrow‐band disturbances is considered. The design technique proposed herein is based on the overparametrization of a nominal minimum‐variance controller, which is designed by means of an ARMA model of a sinusoid in noise. The extra degrees of freedom so introduced are used to improve the robustness of the nominal controller, when the time delay of the plant is subject to uncertainties, by minimizing a minimum‐variance performance index along a one‐dimensional line. Copyright © 2000 John Wiley & Sons, Ltd.     

Some considerations on torque ripple suppression in reluctance motors

Although the reluctance motors are attractive from the standpoints of simple construction and drive electronics, the relatively high torque ripple and acoustic noise are major drawbacks. These drawbacks limit motor applications. In this paper, the torque ripple suppression of the reluctance motor under the sinusoidal current drive is examined. The analysis shows that the torque ripple is caused by the spatial harmonics of inductance. One approach is based on the compensation current generated with the spatial harmonics of inductance. Another is based on the modification of rotor tooth configuration to eliminate the spatial harmonics. According to the proposed strategies, torque ripple suppression characteristics can be evaluated at the design stage of the motor. Both approaches have been verified by experiments. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 118–128, 2000     

Large error recovery for a class of frequency tracking algorithms

The performance of a recently proposed high-order adaptive notch filter (HANF) for frequency estimation and tracking is studied. An analysis technique utilizing approximations with linear filters is employed to derive closed-form performance expressions for a noisy sinusoidal input signal. Important performance measures, such as stability, noise rejection, statistical efficiency, and tracking ability, are studied in detail, and rules for the design variables are given. A study is presented where the performance of HANF is compared with the performance of a minimal order adaptive notch filter (ANF), as well as with a frequency tracker based on least squares-modelling—the multiple frequency tracker (MFT). The study reveals that HANF is a competitive alternative to ANF, but also that, in general, the MFT is the method of choice. © 1998 John Wiley & Sons, Ltd.     

正弦力法动态力传感器灵敏度不确定度评定

随着汽车技术的日益发展,动态力传感器在汽车NVH、模态试验中用到的越来越多,一般采用动态法校准.本文依据振动与冲击传感器校准方法,以标准振动传感器为标准器,采用正弦力法校准动态力传感器灵敏度,并计算动态力传感器灵敏度测量值的不确定度,确保量准的准确一致和正确传递.     

药柱内孔分布的X射线在线检测方法研究

针对一类挤压成型的小型药柱,基于正弦投影和经验,通过重建多个视角下获取的X射线投影信息,在线检测药柱内孔的分布情况。实验结果表明,文中方法不仅减少了采集角度,降低了检测成本,同时还实现了在线检测的要求,能够更好地保证药柱内孔分布信息的准确性,当视角数目达到6个或以上时,精度可达到0.01 mm.     

Daubechies复小波的生成及其在短时电能质量扰动检测中的应用

在分析比较了现有用于短时电能质量扰动检测的方法后,研究了用正交紧支复小波进行检测与抑制噪声的原理,提出用Daubechies正交紧支实小波派生其复小波的实用方法,并结合复小波变换提供的相位信息构造了多种新型复合信息形式.仿真表明,采用本文方法派生的复小波及其复合信息形式进行电能质量扰动检测,具有良好的噪声鲁棒性且提高了应用Mallat算法的实时性.     

带地下室高层结构在地震作用下的时程分析

建立了带地下室高层结构在多支座干扰条件下的动力计算模型,编制了相应的时程分析程序,对地下室底板和顶板同时输入地震激励,考察了结构的动力反应并与惯常采用的单支座干扰时程分析结果进行了比较。