共查询到20条相似文献，搜索用时 78 毫秒
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确定电力谐波测试仪的硬件系统和软件系统的设计方案,其中硬件系统包括STM32芯片、电流互感器、A/D电路、显示屏等器件;软件系统中,采用FFT和相位差校正法,对电力谐波参数进行测量并校正;将信号发生器产生的信号谐波测试结果和Matlab仿真结果对比。对比结果表明,此设计测量频率和幅值的准确度较高。 相似文献
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凌志峰 《湖州师范学院学报》2008,(Z1)
谐波测量在电力系统中有着重要的地位和作用.本文从谐波的特点出发,结合相关谐波标准,对写字楼的谐波进行实地测量,用MATLAB进行数据仿真,得出各谐波源的特性,并提出了相应的解决方案.进而对谐波的测量、监测与管理有一个全面的认识,以利于谐波的综合治理. 相似文献
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针对传统总谐波失真测量方法的局限性，设计了以快速傅里叶变换算法为核心的总谐波失真测量装置。该装置由电压偏置电路、自动增益控制电路、四阶滤波电路等组成，通过了单次时间、精度、数据对比等测试验证。结果表明：输入信号基波幅度在30～600 mV范围内，装置的总谐波失真测量值与理论计算值的相对误差小于5%;单次测量完成时间小于5 s。该装置具有高精度、可控增益、测量与运算速度快等优点，可用于分析和测量总谐波失真度，为信号的保持与还原提供了数据支撑。 相似文献
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针对谐波检测的现实重要性,在分析快速傅里叶变换算法在谐波检测中的应用原理以及谐波特征量的检测原理的基础上,利用LabVIEW编程软件,编写谐波检测分析软件,实现了对被测信号的基频、各次谐波频率和频谱、谐波含有率以及总畸变率等参数的测试分析,并通过仿真信号对软件系统进行验证。仿真的结果表明,基于FFT算法的虚拟谐波检测分析软件能够很好的实现对谐波参数的检测。 相似文献
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吴永明 《泉州师范学院学报》2004,22(6):45-49
在传统单开关三相DCM BOOST电路开关的理论基础上．利用软开关技术构成一种新型的三相BOOST低谐波高功率因数的ZVCT—PWM变流电路并分析其原理，进而设计一种离散控制方案来控制电路的工作状态．利用仿真软件Matlab进行仿真实验，并作谐波分析，通过实验得到加入软开关变换电路后，降低输入电流的总失真，电路工作在单位功率因数状态下，有效抑制谐波的产生． 相似文献
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彭显刚 《广东教育学院学报》2005,25(3):49-51
逆变器的谐波问题一直是困扰电气工程师的一大难题，也是衡量交流逆变器的一个重要指标．利用电气相角的偏差和电磁效应的叠加原理来实现控制策略，可以有效地消除或抑制谐波，使三相逆变器输出电压的质量得到提高．仿真结果表明，双桥路逆变器的电压输出波形比常规的三相逆变器的电压输出波形好． 相似文献
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根据四相整流电路的工作原理,分析并推导了不同负载情况下四相整流电路中交、直流侧谐波特性,建立了四相整流电路的仿真模型并对四相整流电路在不同负载情况下的谐波特性进行了仿真分析．研究结果表明四相整流电路直流侧只存在4的倍数次谐波,提高了整流电路中最低谐波次数．对于四相整流电路的进一步理论及应用研究具有重要的参考价值． 相似文献
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本文针对无线通信综测仪校测流程,提出一套基于GPIB接口的自动校测系统．系统基于虚拟仪器的设计思想,计算机通过SCPI语言对带有GPIB接口的无线通信综测仪及相关校准设备进行程控,并根据实际射频／音频信号的测试流程自动完成各种测试项目,包括功率、频率、谐波、相位噪声、调制质量等．系统在实际生产测试流程中的应用证明,较之传统的人工测试,自动化系统可以大幅提高测量效率与精确度．此外,系统结构模块化,扩展性强,具有很好的市场应用前景． 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献