三相四线制有源电力滤波器控制策略的研究

发布时间：2019-02-16 12:08

【摘要】：近年来,谐波源负载大量使用造成了系统电能质量在很多情况下难以满足要求,电网被迫接入了越来越多的各类补偿装置。有源电力滤波器(active power filter,APF)被认为是治理谐波问题有效手段,它克服了传统PPF固有缺陷。在电网中,相当一部分谐波源负载是通过三相四线制的接线形式接入电网。随着智能微电网的应用,中低压谐波污染问题越来越严重,普通的三线制APF的使用越发具有局限性。论文研究内容如下:1、建立了abc坐标下三相输出电流开关状态的数学模型,引入dq0坐标变换对相关数学表达式进行了有效处理。2、三相四线APF直流侧上下电容中点电位偏移是一直存在的问题,定义表示中线电流与中点偏移量的影响因子,把上均压电容电压和下均压电容电压之间的差值作为算出注入谐波指令电流中的中线电流的依据。定义合适的采样周期,根据逆变载波比较信号来计算一定周期内的影响因子大小。并做了仿真验证。3、以dq0坐标下数学模型为背景设置一阶LADRC补偿电流控制核心算法。运用线性ADRC中LESO的对扰动综合估计的优势,对dq轴数学模型上的耦合进行了解耦,并给出参数整定方法。仿真波形说明LADRC在控制输出补偿电流方面优于同条件下PID效果,证明LADRC能够代替传统PI的应用场合。4、进行了系统综合仿真,分别对负载平衡、突加负载和负载不平衡下,APF系统滤波效果进行分析。结果表明,三相四线制APF具有良好的谐波治理效果,同时负载不平衡下中线电流也在可控范围内,本文的研究对象能够治理复杂的谐波问题。
[Abstract]:In recent years, the heavy use of harmonic source load makes the power quality of the system difficult to meet the requirements in many cases, and the power network has been forced to access more and more kinds of compensators. Active Power filter (active power filter,APF) is considered to be an effective method to solve harmonic problems. It overcomes the inherent defects of traditional PPF. In the power network, a considerable part of the harmonic source load is connected to the power network through three-phase four-wire connection. With the application of smart microgrid, the problem of medium and low voltage harmonic pollution is becoming more and more serious, and the use of common three-wire APF is becoming more and more limited. The main contents of this paper are as follows: 1. The mathematical model of three-phase output current switching state in abc coordinates is established, and the related mathematical expressions are effectively processed by introducing dq0 coordinate transformation. The midpoint potential shift of the DC side of three-phase four-wire APF capacitor is always a problem. The definition of the influence factor of midline current and midpoint offset is defined. The difference between the upper-voltage and the down-voltage is used as the basis for calculating the midline current injected into the harmonic instruction current. The appropriate sampling period is defined and the influence factor is calculated according to the contravariant carrier comparison signal. Finally, the first order LADRC compensation current control core algorithm is set up based on the mathematical model in dq0 coordinates. Using the advantage of LESO in linear ADRC to estimate disturbance synthetically, the coupling of dq axis mathematical model is decoupled, and the method of parameter tuning is given. The simulation waveform shows that LADRC is superior to PID in controlling the output compensation current. It is proved that LADRC can replace the application of traditional PI. 4. The filtering effect of APF system is analyzed. The results show that the three-phase four-wire APF has good harmonic control effect and the midline current is controllable under the unbalanced load. The object of this paper can deal with complex harmonic problems.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM761;TN713.8

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