摘要
随着现代工业技术的发展,电力系统中非线性负荷大量增加。各种非线性和时性电子装置大规模地应用,造成电能质量恶化。电力有源滤波器以其优越的补偿性能,已成为电力电子技术领域的研究热点之一。而其中并联型有源电力滤波器过去和将来都将占据重要地位。
本文重点研究三相三线制并联电压型有源电力滤波器。有源电力滤波器的两大关键技术是谐波与无功电流的检测和补偿电流控制。实时、准确地检测出电网中瞬态变化的谐波与无功电流是有源电力滤波器进行精确补偿的前提。目前有多种谐波与无功电流检测方法,其中,基于瞬时无功功率理论的检测法是三相系统中应用最为广泛的一种方法,包括适用于对称无畸变电网的p-q法及适用于不对称有畸变电网的ip-iq法和d-q法。补偿电流的控制方法是实现有源电力滤波器功能的核心环节,它负责控制有源电力滤波器产生预期的补偿电流。本文详细分析了并联型有源电力滤波器的控制策略,包括补偿电流跟踪控制和直流侧电压控制。通过分析和比较滞环控制、三角波控制和基于空间矢量的电压控制方法,最后确定补偿电流跟踪控制选用三角波比较控制法和滞环控制方法。 最后,为了验证所提出的检测方法和控制方法的正确性,本论文用MATLAB6.5/SIMULNIK下的电力系统模块Simpowersystems Blockset对整个三相三线制并联电压型有源电力滤波器系统进行了仿真研究。仿真结果表明本文所设计的滤波器可以很好的滤除谐波,完成抑制谐波的作用。
关键词:有源电力滤波器;谐波与无功电流检测:补偿电流控制;三角波比较和滞环控制;仿真
The design and research of Three-phase and three-wire System Shunt Active Power Filter
Abstract
With the development of modern industrial technology,a large number of nonlinear loads in power systems to increase. Various nonlinear and time-scale application of electronic devices, caused power quality deterioration . Active power filter with its superior compensation performance. has become one of hot Research focus on power electronics technology area.
The thesis mainly considers three-Phases and three-wire system shunt active. power f活动装置ilter. The two key technologies are harmonic and reactive currents detection ,and compensation currents control玻璃退火炉.Exact and real-time detection of the instantaneous variable harmonic and reactive current in power system is the premise for compensation of active power filter. At present,there are many detection methods concerning harmonic and reactive current,in which,the method based on instantaneous reactive power theory is used widely in three-phase system than others,and it consists of p-q detection method applied to symmetry power system without distortion,ip- iq detection method and d-q detection method applied to asymmetry distortion power System. Control method for compensation current is the key tache to accomplish the various functions of active power filter to establish the anticipative
compared current. This paper analyzes the parallel active power filter control strategy, Including the compensation current tracking control and DC voltage control. Through analysis and comparison of hysteresis control, triangular wave control and space vector-based voltage control. Finalize the compensation current tracking control method used an
d the triangular wave comparison control method of hysteresis control.
Finally, to verify the proposed detection method and control method is correct. Under this thesis, the power system with MATLAB6.5/SIMULNIK Simpowersystems Blockset blocks on the whole three-phase three-wire shunt active power filter system voltage conducted a simulation study. Simulation results show that the designed filter can filter out harmonic well, the completion of the role of harmonic suppression.
Key word: Active Power Filter; Harmonic and reactive current detection; Compensation current control; Triangular wave comparison and hysteresis control; Simulation
第一章 电网谐波的实际问题
电力系统中三相桥式整流器的使用极为广泛,由此引起的谐波电流也成了人们日益关注的问题。安置滤波器是减小谐波电流的有效措施 , 然而多数滤波器的设计要求对整流器所产生的谐波电流进行计算。三相不可控整流器的电路图如下图所示:
图1.1 三相不可控整流电路
上述电路中取相关参数如下表所示:
表1.1 三相不可控整流电路的相关器件参数
器件名称 | Xs | XL | Xd | Xc | Rd | Id |
参数值 | 0.1161 | 0.1472 | 1.1918 | 4.1108 | 0.5119 | 0.1306 |
| | | | | | |
对上表所取的参数,下面对谐波电流进行计算。为表达方便 , 采用了标幺值数据形式,基波电流与电抗分别定义为:
(1.1)
式中P0为整流器额定输出功率。
直流侧 n 次谐波电流以其有效值与平均电流 Id0的比值表示; 交流侧ν次谐波电流以其幅值与基波电流幅值的比值表示。交流侧电流波形畸变率计算到v=25
(1.2)
其中直流侧电流计算公式为:
(1.3)
式中 Id0 —直流分量
Id n , δn —n 次谐波电流的幅值及相角
(1.4)
Ed0 —整流输出电压的直流分量:(1.5)
交流侧谐波电流的计算公式可由直流侧导出,。由于三相电流对称 , 所以只需计算 a 相电流。
(1.6)
式中: (1.7)
公式1.7中:
(1.8)
式中ξ为换流起始角偏移量,μ换流重叠角,可由下式计算得到:
(1.9)
ν次谐波电流幅值及相角分别为:
(1.8)
结合上述相关公式和表中相关数据可得整流电路的整流谐波电流的计算值,如下表所示:
表1.2 整流谐波电流的计算值
谐波次数 | K5=0,K7=0,双导程蜗杆Kv=0 a5=0°, a7=0°; (v≧11) | K5=0.0248,K5=0.0066, Kv=0°;a5=24.9°, a7=24.39°;(v≧11) | K5=0.0679,K5=0.0272, Kv=0;a5=22.9°, a7=20.13°;(v≧11) |
计算结果 |
直流侧 | 6 | 1.64 | 1.91 | 2.23 |
12 | 0.23 | 0.28 | 0.38 |
18 | 0.07 | 0.08 | 0.10 |
交流侧 | 5 | 20.03 | 20.19 | 20.34 |
7 | 12.02 | 12.12 | 12.52 |
11 | 6.91 | 7.10 | 7.76 |
13 | 5.57 | 5.82 | 5.83 |
pgd-47617 | 3.32 | 3.57 | 蔬菜保鲜柜3.88 |
19 | 2.59 | 2.85 | 2.22 |
2327.5g bt | 1.55 | 1.77 | 2.13 |
THD | 25.42 | 25.79 | 26.40 |
| | | | |
针对上述整流器产生的谐波电流,本文设计了下文所介绍的三相三线制有源电力滤波器用于补偿该整流器产生的谐波电流,提高公用电网的电能质量。
第二章 绪论
2.1有源电力滤波的产生、发展及现状
随着现代工业技术的发展,电力系统中非线性负荷大量增加。各种非线性和时性电子装置如逆变器、整流器及各种开关电源等大规模地应用,其负面效应也日益明显。电力电子装置的开关动作向电网中注入了大量的谐波和次谐波分量,导致了交流电网中电压和电流波形的严重失真,从而替代了传统的变压器等铁磁材料的非线性引起的谐波,成为主要的谐波源。电能质量的下降严重影响着供、用电设备的安全经济运行,降低了人们的生活质量。世界各国已经十分重视电能的质量的管理。谐波治理是电能问题的核心内容之一,也是现代电力发展的迫切要求。