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一种单相和三相基准正弦波发生器 总被引:6,自引:3,他引:3
1 前 言基准正弦波作为瞬时电压反馈控制逆变器的电压给定信号,波形质量直接影响到逆变器输出正弦波的幅值、频率及失真度,因此要求基准正弦波发生电路能提供稳定度高、失真度小并且幅值可调的正弦波形。现有的基准正弦波发生器多采用EPROM计数器生成,电路成本相对较高。本文研究了一种采用4018可预置1/N计数器构成的单相和三相基准正弦波发生器电路,讨论了电路工作原理和参数设计,给出了实验结果。2 单相基准正弦波发生器单相基准正弦波发生器电路由振荡分频、阶梯波合成和有源滤波电路三部分构成,如图1所示。振荡… 相似文献
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基于FPGA的高精度数字式三相基准正弦信号发生器的设计与实现 总被引:6,自引:0,他引:6
提出了一种采用数字合成与数字移相技术设计高精度数字式三相基准正弦波信号发生器的方法。系统由VHDL编制程序并下载至Xilinx公司的SpartanⅡ系列XC2S100E-6PQ208芯片上,加以简单的外围电路构成。实验表明采用该方法生成的三相基准正弦波具有频率精确度高、对称性好、波形失真小、频率和幅度均可数字式预置并可调节。 相似文献
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根据对单相不控整流电路直流侧接电阻负载时特性的研究,该文提出了一种单相半控整流电路,其交流侧电流波形为正弦波,直流侧输出电压含直流分量和倍频分量,当构成三相半控整流电路时,输出电压中二倍频分量便相互抵消了,只剩下稳定且可调的直流分量。基于半控整流电路,文中提出一种海上风电汇集与并网系统,该系统采用变流器直流侧串联升压的方式获得直流高电压,用于风电汇集和传输,省去了笨重而昂贵的海上换流站,大大节约了建造和维护成本。仿真及分析结果显示,文中所提方法能够满足海上风电并网的需求,且稳态和故障时的性能优异。 相似文献
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在瞬时无功功率理论的基础上,针对一般基于d-q变换的检测方法不能检测不对称三相电流的谐波的缺点,提出了一种新的电网谐波检测方法。此方法属于单相检测法,先提取电网电流中的某相基波幅值,再将基波幅值乘以与该相电流同相位的正弦波,从而得出该相的瞬时基波电流。该方法相对简化了结构,并且采用了改进的算法,能很好地运用于单相电路和三相电路的谐波检测。仿真结果表明,在电网三相电流对称和不对称的两种情况下,这种方法都能保证检测的实时性和精确性。 相似文献
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在瞬时无功功率理论的基础上,针对一般基于d-q变换的检测方法不能检测不对称三相电流的谐波的缺点,提出了一种新的电网谐波检测方法.此方法属于单相检测法,先提取电网电流中的某相基波幅值,再将基波幅值乘以与该相电流同相位的正弦波,从而得出该相的瞬时基波电流.该方法相对简化了结构,并且采用了改进的算法,能很好地运用于单相电路和三相电路的谐波检测.仿真结果表明,在电网三相电流对称和不对称的两种情况下,这种方法都能保证检测的实时性和精确性. 相似文献
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生产实践中常常遇到现场只有单相电网,而偏偏又是存有三相电动机,如何针对具体情况应用三相电动机是人们所关注的问题。一、三相电动机接入单相电网的联接线路要在单相电路电网电路中使用三相电动机,且又要求满载运行,需要采用两个相移元件:电容和电感元件。在这种运行情况下,电动机的定子绕组必须是三角形或星形接法。为了在单相电网电路中充分运用三相电动机,必须按图1所示线路接入三相电动 相似文献
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无正交虚拟信号生成的单相DQ锁相环研究 总被引:4,自引:0,他引:4
针对单相并网变流器的同步问题,为了在获得零稳态误差的同时消除对正交虚拟信号生成的需要,结合同步坐标变换的概念,提出一种用于同步单相电网信号的双派克变换锁相环(phase-locked loop,PLL).将单相信号等效为两相恒为零的三相信号,从而将对称正序分量、对称负序分量和对称零序分量的概念引入单相信号分析中.根据三相对称相量分解合成理论对单相信号进行分析,获得了单相信号正、负序同步变换结果之间的关系.通过自解耦,而非生成正交虚拟信号,获得单相信号与锁相结果之间的相位差,同时可获得单相输入信号的幅值.仿真和实验结果表明,所提出的单相锁相环可以准确获得输入信号的相位,消除锁相输出中的稳态误差;输入信号幅值、相位和频率阶跃条件下的仿真和实验证明了所提出锁相环的有效性和稳定性. 相似文献
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This paper is motivated to analyze the transient behavior of a single-phase self-excited induction generator (SEIG) using a three-phase machine due to switching of single-phase dynamic load like induction motors. The generator consists of a three-phase star connected induction machine excited with three-capacitors and a single-phase induction motor (IM) load. The developed dynamic models of the SEIG and the motor are based on stationary reference frame d–q axes theory incorporating the effect of cross-saturation in the magnetic circuit of the machine and the equations of excitation capacitors are described by three-phase abc model. The system suffers from heavy transients during switching of induction motor and becomes unstable. These problems may be due to resonance caused by series capacitors and the inductive motor load. The use of damping resistors across one series capacitor is proposed to damp out the starting transients for the stable operation. The motor can be started up successfully using the damping resistor. The variation of the damping resistance with the increase in load on the motor after successful starting to maintain constant terminal voltage has been presented. The eigenvalue technique is also employed to examine the transient conditions in the studied SEIG-IM system. The simulated and experimental results are presented for both the unsuccessful and successful starting of the motor. These results are in close agreement with each other, which show the effectiveness of the approach. 相似文献
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详细分析了三相Buck型脉宽调制AC/AC交流斩波器的电路结构、工作原理及其控制策略。通过比较三相输入电压值的大小,并结合输出电压误差放大信号与三角载波的比较结果,可确定该斩波器各开关管的工作状态。本文以传统的单相输出电压反馈控制策略为基础,提出了一种新颖的三相输出电压反馈控制策略。分别采用两种控制策略,对三相Buck型脉宽调制AC/AC交流斩波器进行了仿真比较研究,并研制了一台原理样机。仿真和实验结果表明:在相同工作条件下,该斩波器采用三相输出电压反馈控制比采用单相输出电压反馈控制具有更好的控制效果。 相似文献
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This paper is aimed at presenting a novel system topology and control scheme of a selective dual-mode pulse-modulated high-efficiency single-phase sinewave power-conversion circuit for the new energy generation and storage applications. This power-conversion system is composed of a time-sharing-operated sinewave-absolute-modulation boost chopper with a bypass diode in the first power conditioning and processing stage and time-sharing sinewave partially pulse-modulated full-bridge inverter in the second stage. The proposed power conditioner is operated by a selective time-sharing dual-mode pulse pattern signal processing control scheme without electrolytic capacitor dc link. The unique operating principle of the two-power conditioning and processing stages with sectional time-sharing dual-mode partial sinewave-modulation scheme is described and discussed with a design example. In addition, this paper proposes also a sinewave tracking voltage controlled soft switching pulsewidth-modulation boost chopper with a bypass-diode loop, which includes a passive auxiliary edge-resonant snubber. The new conceptual operating principle and the control implementation of this novel power conditioner are presented and evaluated through experimental and simulation results 相似文献
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设计了一种新型单相与三相输入兼容的特定消谐式变频器.提出了一种单相与三相输入兼容的变频器主电路,深入研究了离线计算与在线计算相结合实现特定消谐的方法.实验结果表明,该变频器具有消除谐波次数多,残余谐波含量小,电压利用率高,直流母线电压高,输出稳压特性好,开关角数据存储空间小的特点,有很好的应用前景. 相似文献
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A new control scheme for the hybrid photovoltaic-diesel single-phase autonomous power system is proposed. The main advantage of this scheme is that the voltage control is accomplished by the interface inverter without need to the automatic voltage regulator of the diesel-driven generator. Unlike three-phase systems, frequency and voltage control in single-phase autonomous power systems imposes additional complexity. This is due to the pulsating nature of the single-phase loads instantaneous power at twice the rated frequency that may degrade the control efficacy. This obstacle is addressed in this paper and a new scheme is presented. The approach includes three control loops for maximum power tracking, voltage control and frequency control. The generator field current is held constant at its nominal value avoiding the saturation in the field circuit. A robust fuzzy logic controller is adopted for the speed control loop of the diesel engine. The dynamic performance of the system is investigated under different operating conditions. 相似文献
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为进一步降低铁路功率调节器在大功率补偿过程的开关频率,采用开关频率较低的混合级联81电平变换器作为电压源、开关频率较高的单相全桥变换器作为电流源,将两个电压源背靠背连接,提出一种81电平铁路功率调节器。由于系统中承担85%的补偿功率的开关器件的开关频率在250 Hz及以下,开关频率高的电流源仅承担1%的功率,因此系统开关损耗小且对补偿电流参考信号的跟踪性能好。研究了系统的基本结构及其等效电路,通过构建等效对称三相电压源建立等效三相电路,采用有功功率平均分配法,使得补偿后的系统等效为Y-Y型对称三相电路,从而实现不平衡电流补偿,并提出一种新的补偿电流检测方法。仿真结果证明所提系统及其补偿方法的有效性和可行性。 相似文献