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针对在电网三相电压不平衡时传统锁相环不能准确检测基波正序相位的问题,设计了一种双正弦幅值积分器解耦锁相环(decoupled double sinusoidal amplitude integrator phase-locked loop, DDSAI-PLL)。该锁相环利用正弦幅值积分器的频率选择特性,在αβ坐标系下采用正负序解耦结构实现了正序分量的完全提取。同时引入一阶负反馈系统作为频率自适应环节,使锁相环在电网频率发生偏移时仍然可以对基波正序频率进行准确估计。建立了DDSAI-PLL的数学模型,并对其关键参数进行了设计。最后使用DSP实现该锁相环,并在电压畸变条件下与传统的同步参考坐标系锁相环(SRF-PLL)进行了对比实验,结果证明了所提锁相方法的有效性。 相似文献
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对X3D进行简要介绍,具体分析与X3D场景交互的两种方式,其中重点探讨通过X3DSAI与外部程序进行信息通信的机制。以此为基础,研究并设计一种基于X3D场景进行三维信息查询定位的方法,并结合具体X3D场景编程予以实现,以证明该方法的简便性和实用性。 相似文献
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有源滤波器的谐波检测技术需要分离三相电流的基波分量。在电网非理想工况下,由于电流负序基波分量的影响,传统的谐波检测技术的性能受到一定的影响。文章通过在电网不对称工况下正弦幅值积分器的频域分析,提出一种在电网非理想工况下的谐波检测检测技术,该方法利用在αβ坐标下正弦幅值积分器(SAI)频率的选择作用,提取三相电流基波分量。文章详细介绍了基于正弦幅值积分器的谐波检测技术的工作原理、数学模型、频域分析,理论验证方案的可行性。搭建仿真模型,结果表明文章所提方法可以有效消除非理想工况对谐波检测的影响,准确快速检测到基波分量,给出补偿电流指令。 相似文献
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A sparse approximate inverse (SAI) preconditioning of deflated block‐generalized minimal residual (GMRES) algorithm is proposed to solve large dense linear systems with multiple right‐hand sides arising from monostatic radar cross section (RCS) calculations. The multilevel fast multipole method (MLFMM) is used to accelerate the matrix–vector product operations, and the SAI preconditioning technique is employed to speed up the convergence rate of block‐GMRES (BGMRES) iterations. The main purpose of this study is to show that the convergence rate of the SAI preconditioned BGMRES method can be significantly improved by deflating a few smallest eigenvalues. Numerical experiments indicate that the combined effect of the SAI preconditioning technique that clusters most of eigenvalues to one, coupled with the deflation technique that shifts the rest of the smallest eigenvalues in the spectrum, can be very beneficial in the MLFMM, thus reducing the overall simulation time substantially. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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提出了一个基于业务的传送网四元组故障测度方法(O,A,P,R)。为测度故障对网络造成的实际损失和潜在影响程度,提出了两个量化评价指标:业务中断指数和业务影响指数。通过连接离散的评价值,得到两个时变的连续评价函数。对该两个函数在故障时间上积分,得到量化的测度结果。四元组分别从实际损失、潜在影响、过程变化、相关信息等四个方面对结果进行描述。以某实际网络的一部分为样例环境,对该方法和其它方法的测度结果进行了对比。结果显示无论在单故障还是多故障场景下,该方法的效果都优于作对比的方法。 相似文献
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基于瞬时无功功率理论的ip-iq谐波检测法,环节繁多且结构复杂,同时低通滤波器(low pass filter,LPF)的存在又影响了谐波检测的快速性。为了准确且快速检测出电网谐波电流,实现对电网的补偿,该文提出一种基于正弦幅值积分器(sinusoidal amplitude integrator,SAI)的全电流谐波检测法,该方法在ip-iq谐波检测法的基础上省去负载电流有功分量和无功分量的计算环节,利用SAI的正序基波提取结构替换原来检测法中的LPF,提取出正序基波电流经过运算得到谐波指令电流,从而对电网进行补偿。在平衡电网下对所提方法进行仿真与实验,验证了该方法的可行性和有效性。 相似文献
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Synchronization with the grid voltage is critical in the control of grid-connected power converters. Under unbalanced grid condition, the conventional synchronous reference frame phase-locked loop (SRF-PLL) does not work well due to the effect of the fundamental negative sequence component. This paper proposes a new synchronization method, the sinusoidal amplitude integrator based phase locked loop (SAI-based PLL), to efficiently eradicate the effect of the fundamental negative sequence component. As a result, it can accurately and quickly estimate the amplitude and phase angle of the fundamental components of grid voltages in unbalanced grid conditions. In addition, when dc offset and harmonics are contained in the grid voltage, a multi-SAI-based PLL method is developed to extract the synchronization signal. The proposed SAI-based PLL incorporates the sinusoidal amplitude integrator into the conventional SRF-PLL. Its operation is analyzed using the complex-vector notation. Simulation and experimental results on the performance of the proposed SAI-based PLL and comparison with other synchronization methods are presented. 相似文献
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