基于瞬时无功理论的APF谐波检测算法研究

发布时间：2018-03-11 19:12

本文选题：谐波检测　切入点：有源电力滤波器　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着非线性负载的使用,其产生的谐波电流对电网的污染越来越严重。有源电力滤波器(APF)作为治理谐波改善电能质量的电子设备,在电力系统谐波治理中起到了关键作用,而其谐波检测环节的性能直接影响整个系统的补偿效果。因此,论文以并联有源滤波器为研究对象,围绕如何提高有源滤波器谐波检测环节的性能做了深入研究。首先,论文从瞬时无功功率的角度对p-q和ip-iq算法进行谐波检测的理论基础进行分析,并对p-q和ip-iq算法在电网电压畸变下的谐波检测性能进行了对比,结果表明:对于ip-iq算法来讲,其谐波检测性能受电网电压中谐波的影响较小,因此,当电网电压存在畸变的工况下应优先选择ip-iq谐波检测算法。此外,论文对低通滤波类型、截止频率、阶数对其性能的影响进行了分析,并与均值滤波对比表明,在稳态情况下,均值滤波不仅可以提高动态响应速度,而且可以改善谐波检测精度。其次,锁相环实时准确的锁定电网电压频率是谐波电流检测的重要一环。因此,论文对基于同步旋转坐标下dq变换的锁相环进行分析,结果表明当电网电压中含有谐波时,同步旋转坐标系下产生的二倍工频波动会影响锁相环的性能,从而影响谐波电流检测的性能。为了提高锁相环在电网电压含有谐波时的性能,文中采用了基于广义二阶积分器的锁相环,利用广义二阶积分器的带通特性实现对基波分量的提取和对谐波电压的抑制,从而降低电网电压畸变对锁相环的影响。此外,文中详细分析了二阶广义积分器的主要参数对锁相环性能的影响,并通过仿真验证了基于广义二阶积分器锁相环的ip-iq谐波检测算法可以得到总谐波畸变率较小的电流。最后,为了验证基于广义二阶积分器的锁相环与均值滤波结合的ip-iq算法的可行性与有效性,通过搭建的并联有源电力滤波器系统模型与实验样机,采用基于广义二阶积分器的锁相环与均值滤波结合的ip-iq谐波检测算法进行系统仿真与实验验证,结果表明:补偿后的网侧电流波形满足相关要求。
[Abstract]:With the use of nonlinear load, the harmonic current produced by APFF is becoming more and more serious to the power network. APFF (active Power filter), as an electronic device for harmonic control and improvement of power quality, plays a key role in harmonic control of power system. The performance of harmonic detection directly affects the compensation effect of the whole system. Therefore, the thesis takes shunt active power filter as the research object, and makes a deep research on how to improve the performance of harmonic detection link of active power filter. In this paper, the theoretical basis of harmonic detection based on p-q and ip-iq algorithm is analyzed from the angle of instantaneous reactive power, and the harmonic detection performance of p-q and ip-iq algorithm under voltage distortion is compared. The results show that: for ip-iq algorithm, The harmonic detection performance is less affected by the harmonics in the grid voltage. Therefore, the ip-iq harmonic detection algorithm should be preferred when the voltage is distorted. In addition, the low pass filter type, cut-off frequency, cut-off frequency should be selected in this paper. The effect of order number on its performance is analyzed, and the comparison with mean filter shows that mean filter can not only improve the dynamic response speed but also improve the accuracy of harmonic detection in steady state. The phase-locked loop (PLL) is an important link in harmonic current detection. Therefore, the phase-locked loop based on DQ transformation in synchronous rotation coordinates is analyzed in this paper. The results show that when the voltage of the power system contains harmonics, The double power frequency fluctuation in synchronous rotating coordinate system will affect the performance of phase-locked loop, thus affecting the performance of harmonic current detection. In order to improve the performance of phase-locked loop when the voltage of power network contains harmonics, In this paper, a phase-locked loop based on generalized second-order integrator is used to extract the fundamental component and suppress the harmonic voltage by using the band-pass characteristic of the generalized second-order integrator, so as to reduce the influence of the voltage distortion on the phase-locked loop. In this paper, the influence of the main parameters of the second order generalized integrator on the performance of the PLL is analyzed in detail, and the simulation results show that the ip-iq harmonic detection algorithm based on the generalized second-order integrator PLL can obtain the current with low total harmonic distortion. In order to verify the feasibility and validity of the ip-iq algorithm based on the generalized second-order integrator PLL and mean filter, the model of shunt active power filter system and the experimental prototype are built. The ip-iq harmonic detection algorithm based on the generalized second-order integrator combined with phase-locked loop and mean filter is simulated and verified by experiments. The results show that the compensated current waveform meets the related requirements.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM935

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