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受电网电压畸变等问题的影响,单相光伏并网逆变器输出电流中存在大量谐波,严重降低了该逆变器输出电能的质量。针对上述问题,提出一种基于扰动补偿器与矢量比例积分控制器的单相光伏并网逆变器谐波抑制方法。该方法借助扰动补偿器倍频次谐波的抑制能力实现高频谐波电流的有效补偿,利用矢量比例积分控制器实现工频交流电流的无静差跟踪。文章利用额定功率为5 kW的单相光伏并网逆变器样机进行稳态运行实验。实验结果表明,文章所提出的控制算法能够大幅度降低单相光伏并网逆变器输出电流的总谐波畸变率,从而提升该逆变器的并网电能质量。 相似文献
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随着光伏发电的占比迅速增大,光伏并网逆变器的控制器需要从锁相环中获取公共耦合电压点的幅值和相位,当其处于弱电网或电网电压传感器出现故障时,会造成锁相环不稳定,大大增加了逆变器的控制难度。提出一种基于内模原理的光伏逆变器电网电压估计与控制方法,该方法利用电流测量和滤波器参数的标称值,实现了公共耦合电压估计和单位矢量生成。在小型实验室样机上进行了实验,结果表明:与采用电压和电流传感器的传统电流控制相比,所提控制方案在理想和非理想电网电压条件下都能提供更好的瞬态响应能力,从而验证了所提方法的有效性。 相似文献
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基于电网电压前馈的光伏并网逆变器的仿真与实现 总被引:1,自引:0,他引:1
介绍了光伏并网逆变器的基本原理和拓扑结构;提出了一种基于电网电压前馈和电流跟踪控制技术的并网控制方法;建立了仿真模型;给出了系统控制的软件和硬件设计.在一台10kHz,3kW的实验样机上对该方案进行了实验,实验结果验证了该方法的有效性. 相似文献
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为提高弱电网下光伏接入的并网电流质量和系统的稳定裕度,提出一种基于公共耦合电压点的选频前馈结合相位超前校正的组合控制新策略,该策略设计选频环改善电网电压前馈函数,使其既保留对电网背景谐波的抑制,又避免稳定裕度的下降,同时提出在电流通路中设计超前补偿校正环节,补偿弱电网阻抗引起的系统相角裕度下降,增加稳定裕量,从而提高光伏并入弱电网的并网电流质量和系统的稳定裕度。通过仿真和实验验证该策略对谐波抑制和稳定裕度提高的有效性。 相似文献
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为限制光伏逆变器的并网电流直流分量注入电网,提高光伏发电电能质量,提出一种基于直流侧母线电压纹波分析的直流分量检测及补偿方法。该算法以LCL滤波的光伏并网逆变器数学模型为基础,推导分析直流母线电压纹波产生机理,得出直流母线工频纹波由并网电流直流分量产生的结论;通过对一个周期的母线电压分段积分可解析获得直流分量定量描述关系,并利用该解析值实时在线修正并网参考电流,结合电网电压前馈、并网电流外环、电容电流内环的复合控制算法设计电流控制器。仿真与实验结果表明,在不增加外围硬件电路的情况下,该算法可有效抑制并网电流直流分量。 相似文献
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为实现电网电压不平衡时对T型三电平光伏并网系统输出功率和电流质量的控制,以达到入网功率平稳或电流正弦为控制目标,结合光伏阵列输出功率前馈,在两相静止坐标系下提出一种直流母线电压外环PI控制、并网电流内环有限集模型预测控制的控制策略,并在电压外环中引入2倍频陷波器以获得平滑的入网功率参考值。仿真结果表明:当电网电压不对称时,采用所提控制策略能够实现对入网有功、无功功率2倍频脉动及负序电流的分别抑制或协调控制,且并网电流谐波畸变小、入网电能质量高,同时实现T型三电平逆变器的中点电位平衡。 相似文献
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针对传统的Z源逆变电路控制方式中需要独立分析升压电路控制因子和并网电路控制因子的问题,先在典型的Z源全桥逆变电路的拓扑结构中实现单桥臂上下管的直通相位控制方式下的开关时序,进而分析了Z源逆变电路的5种模态的工作原理,提出了一种适用于单相光伏逆变系统的Z源逆变电路直通控制方式,就是利用能量传递和傅里叶算法在直通零矢量和输出逆变电压之间建立直接联系。以一台3kW光伏并网逆变样机的测试结果表明,样机PV电压稳定,并网电压电流相位在50%输出功率下基本一致,其谐波含量和功率因数符合要求;同时,还具备一定的过压、欠压动态保护特性,反应时间迅速。结果表明,Z源逆变电路及其直通控制策略在光伏并网系统中的应用效果较好。 相似文献
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在离网模式下,微电网中虚拟同步发电机的输出电压易受不平衡负载影响。针对此问题,文章基于一阶全通滤波器(All-Pass Filter,APF)的电压电流正、负序分离方法,利用正序功率和正序电流建立了改进VSG控制模型,改善了VSG输出电压参考。采用比例积分(Proportional Integral,PI)+准比例谐振(Quasi Proportional Resonant,QPR)电压调节器对VSG输出负序电压分量进行控制,论证了PI+QPR调节器抑制负序电压分量的优良性能。最后,仿真结果验证了该控制策略的有效性,该方法有效地改善了三相微源逆变器输出电压的对称性。 相似文献
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定量分析计算电网电压暂降时DVR逆变单元与电网的功率交换情况,详细研究逆变单元在各种补偿策略下的输出电压和有功功率与故障前后电网电压、负载电压和参考相量的具体关系,并根据具体关系总结出5种补偿方法,通过Matlab平台对各种补偿方法进行仿真研究,最后根据不同的补偿方式进行单相DVR检测方法研究。 相似文献
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The overall efficiency of photovoltaic (PV) systems connected to the grid depends on the efficiency of direct current (DC) of the solar modules to alternate current (AC) inverter conversion. The requirements for inverter connection include: maximum power point, high efficiency, control power injected into the grid, high power factor and low total harmonic distortion of the currents injected into the grid. An approach to power factor control and reactive power regulation for PV systems connected to the grid using field programmable gate array (FPGA) is proposed. According to the grid demands; both the injected active and reactive powers are controlled.In this paper, a new digital control strategy for a single-phase inverter is carried out. This control strategy is based on the phase shift between the inverter output voltage and the grid voltage, and the digital sinusoidal pulse width modulation (DSPWM) patterns, in order to control the power factor for a wide range of the inverter output current and consequently the control and the regulation of the reactive power will be achieved. The advantage of the proposed control strategy is its implementation around simple digital circuits.In this work, a simulation study of this strategy has been realized using Matlab/Simulink and PSIM. In order to validate its performance, this control has been implemented in a FPGA. Experimental tests have been carried out demonstrating the viability of this control in order to control the power factor and the injected power into the grid. 相似文献
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A grid-connected photovoltaic power conversion system with single-phase multilevel inverter 总被引:1,自引:0,他引:1
This paper presents a grid-connected photovoltaic (PV) power conversion system based on a single-phase multilevel inverter. The proposed system fundamentally consists of PV arrays and a single-phase multilevel inverter structure. First, configuration and structural parts of the PV assisted inverter system are introduced in detail. To produce reference output voltage waves, a simple switching strategy based on calculating switching angles is improved. By calculated switching angles, the reference signal is produced as a multilevel shaped output voltage wave. The control algorithm and operational principles of the proposed system are explained. Operating PV arrays in the same load condition is a considerable point; therefore a simulation study is performed to arrange the PV arrays. After determining the number and connection types of the PV arrays, the system is configured through the arrangement of the PV arrays. The validity of the proposed system is verified through simulations and experimental study. The results demonstrate that the system can achieve lower total harmonic distortion (THD) on the output voltage and load current, and it is capable of operating synchronous and transferring power values having different characteristic to the grid. Hence, it is suitable to use the proposed configuration as a PV power conversion system in various applications. 相似文献