Dual-loop Grid Current Control Technique for Grid-connected Inverter Using An LCL Filter 采用LCL滤波器的并网逆变器双闭环入网电流控制技术
Click to reformat the grid using current settings. 单击此处可使用当前设置重新设置网格格式。
A "1" suffix indicates no grid current flows, while a "2" suffix indicates grid current flows for some part of the cycle. 一个“1”后缀表明当前流动没有网格,而“2”后缀表明当前流动的网格部分的恶性循环。
The standard AC-coupled phase inverter or single-ended driver stages used in nearly all guitar amplifiers will not allow grid current flow, so they are class A1/ AB1/ B1 amplifiers. 标准的AC耦合三相逆变器或单端驱动阶段使用的几乎所有的吉他放大器将不允许电网电流的流动,所以级A1/AB1/B1放大器。
The numerical suffix appended to the class designation indicates whether or not grid current flows in any appreciable portion of the cycle. 数值后缀附加到指定表明阶级与否电网目前的流量在任何可观的一部分周期。
The series hybrid active power filter with fundamental current bypass channel provides a passive channel for the fundamental component of the grid current. Hence the required rating of the active filter can be greatly reduced. 带基波电流旁路通道的串联混合有源电力滤波器为电网电流中的基波成分提供了一个无源通道,因而可以大大降低有源部分的容量。
In order to reduce the background resulting from the dark current of the photomultiplier and the grid current of amplifer, a special design of auto-compensation circuit is provided. 为减小光电倍增管暗电流和放大器栅流产生的仪器自身本底,设计了随温度变化的自动补偿电路。
I designed a measuring system which can measure the anode current 、 anode voltage 、 grid current and grid voltage at one time. 根据要求,设计一个场发射参数的测量系统,此系统,工作在手动方式下可以测量出某一时刻点的场发射的阳极电流、阳极电压、栅极电流、栅极电压。
But rectifier type power electronic components may produce harmonic current and make contact grid's current distorting. 用于整流的电力电子器件会产生谐波,造成接触网电流畸变。
THD of the grid current is small and power factor is high at full range of loads or even in abnormal grid voltage. 全负载范围内或电网电压谐波含量大时,可实现高的输出功率因数和低的进网电流ηTHD。
In grid-tied mode, because of the effect of the output filter capacitor, the grid-connected inverter has high THD of the grid current and low power factor at light load. 可独立与并网双模式运行的逆变器在并网模式下,由于输出滤波电容的影响,在轻载时进网电流ηTHD高,输出功率因数低。
With more application of non-linear and time-varying power electronic devices, a great amount of harmonics is injected into the power grid, which results in serious distortion of grid current waveform. 随着各种非线性和时变性电力电子装置的大量应用,其产生的大量谐波注入到电网,导致电网电流波形严重畸变。
Although the grid current harmonics are much lower using PWM rectifier than that using diode rectifier, they can not be eliminated completely and are affected by many factors. 尽管与二极管整流相比,PWM整流器电网电流中的谐波含量大大降低,然而并不能完全消除,并受到各种因素的影响。
Three loop configuration for whole control system is built: the grid current loop, Z-Source capacitance voltage loop and PV array output voltage loop. 通过电路结构和控制目标将变换器控制系统分为三个闭环结构:并网交流电流环、Z源电容电压环、光伏阵列输入电压环。
PWM rectifier current-loop can be designed to guarantee stability. However, grids short-circuit impedance and distributed capacitance will affect the stability of PWM rectifier leading to grid current oscillation and a large amount of harmonics. 尽管单相PWM整流器设计时,能够保证电流环稳定,然而电网短路阻抗以及分布电容等参数将对PWM整流器的稳定性产生影响,导致电网电流振荡,产生大量的谐波。
This paper discusses this parameter from three parts: grid current total harmonic distortion, the dc component of the grid current and the power factor. Finally, factors affecting the electricity quality are analyzed. 供电电能质量是衡量并网逆变器性能的一个重要参数,本文主要对进网电流总的谐波畸变的影响因素进行了分析,此外也对电流直流分量、网侧功率因数进行了研究分析。
Grid current detection does not need load current detection and harmonic current extraction, is more simple and effective to solve the contradiction between the switch frequency and the width of hysteresis comparator in the traditional DPC ( Direct Power Control) method. 该控制结构无需进行负载电流检测和谐波电流提取,简单有效,同时也解决了传统的直接功率控制方法中开关频率与滞环宽度之间的矛盾。
On this basis, the neutral point non-effectively grounded grid current fault section location system designed and achieved has been put into the power grid after review and acceptance with favorable results. 在此基础上,设计实现的中性点非有效接地系统小电流故障区段定位系统已投入电网运行,经过评审验收,使用效果良好。
PR control enables better sinusoidal current control with zero steady-state error. The voltage feed forward control decouples the grid voltage with the grid current, so the gird voltage distortion and disturbance have no effect on grid current at all. 比例谐振控制在正弦电流跟踪控制中可以实现零稳态误差,电压前馈可以解除并网电流与电网电压之间的耦合关系,消除电网电压畸变或扰动对并网电流的影响。
In order to eliminate the negative sequence component of grid current, According to the relationship of the inverter output power and the positive and negative sequence component of grid current, suppression of negative sequence component of grid current control strategy is established. 为了消除并网电流的负序分量,根据逆变器输出功率与并网电流的正、负序分量的关系式建立了抑制网侧负序电流的控制策略。
The remote monitoring system is designed for oil well, which is based on two-way automatic communication system ( TWACS), and it is suitable for the grid of current oil field. 本论文设计了基于TWACS传输方式的油井远程监测系统,此系统比较适合油田电网的现状。
In control of the solar photovoltaic linking grid, use PI control and complex combination of repetitive control controller, effectively reduce error between linking grid current and the command current. 在光伏并网控制时,本文采用PI控制和重复控制结合的复合型控制器,有效减小并网电流与指令电流之间的误差。
According to the simulation results, it can be seen that composite control strategy based on PI, repetitive control and voltage feed-forward control could improve the quality of the grid current. And the power factor of the inverter output power could reach to 1. 通过仿真结果得出基于PI、重复控制和电压前馈控制的复合控制策略能够大大改善并网电流的质量,使逆变器能够以单位功率因数1向电网输送有功功率。
The dc-link voltage ripple can be filtered by notch filter in the sample loop to eliminate its affect on grid current. 对于直流电压脉动引起的谐波电流,可以通过设置直流电压采样陷波器的方法,滤除进入控制环路中的二次脉动分量,抑制对电流环的影响。
A fault takes place in a network, especially asymmetric fault, lead to the grid current imbalanced and DC side voltage instability, and feed into the grid power causing oscillation, even burned PV inverter, influence safe operation of grid-connected PV system and the grid. 电网发生故障,尤其是出现不对称故障时,会导致并网电流的不平衡和直流侧电压不稳定,造成馈入电网的功率发生振荡,甚至危及逆变器,影响光伏并网发电系统和电网的安全运行。
The result of test experiment show that the system can correctly implement the SVPWM control algorithm, and the grid current can keep the pace with grid voltage. 并通过实验证实该系统能正确执行SVPWM算法,实现三相交流并网,且并网电流与电网电压保持同步。
Distributed power generation systems consisted by a variety of new energy not only supply the local electrical loads, but also inject the surplus electricity into the power grid. It requires the grid current having good quality to reduce the pollution to the grid. 各种新能源所构成的分布式发电系统在满足本地供电之后,将多余的电能注入电网,这就要求分布式发电系统的进网电流具有较好的质量,从而减小对电网的污染。
The evaluation results verify that dual-loop current control strategy has the advantage of good damping performance, and the grid current phase can be controlled directly, moreover its stability is acceptable. The study for dual-loop current control scheme is present in this paper. 研究结果表明,电流双闭环控制策略具有谐振抑制能力强,入网电流相位直接可控的优点,且系统稳定性也较好。
Single-phase photovoltaic inverter current-loop has a wide-bandwidth and computation consumption of repetitive control is small. For these reasons, dead-beat control combined with repetitive control was proposed to eliminate grid current harmonic. 针对单相光伏并网逆变器电流环具有较宽的带宽,以及重复控制数据运算量较小的特点,提出了采用无差拍控制和重复控制相结合的方法抑制电压谐波对电网电流的影响。
Voltage oriented control scheme is used to realize the direct control of grid current. 利用基于电压定向的矢量控制策略,实现了直接电流控制。