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1、基于自适应逆控制的并联型有源电力滤波器的仿真研究吴言凤，吴正国（武汉海军工程大学 电气工程系，湖北 武汉 430033）摘 要：首次将自适应逆控制应用于并联型有源电力滤波器的控制，提出了一种新的并联型电力有源滤波器的控制方法。此方法把有源滤波器及主电路部分看作广义有源滤波器并利用其逆模型作为控制器对其进行控制。此控制算法对电路中的参数变化不敏感，不但简单易行，而且比较可靠有效，不但对理想三相电源电压能够产生较好的补偿效果，而且当电源电压出现畸变和不平衡时，仍能得到较好的补偿效果。仿真结果证实了所提出的算法的可行性。关键词：自适应逆控制；有源电力滤波器；广义有源滤波器中图分类号：TM74 文献标
2、识码：A1 引言 自适应逆控制在控制系统和调节器的设计中是一种很新颖的方法1 ，该方法用被控对象传递函数的逆作为串联控制器来对系统的动态特性做开环控制，系统动态特性控制和对象扰动控制被分为两个单独的过程2、3。自适应逆控制的控制器是自适应的，将其调节到既能使得对象及其控制器的总体动态响应达到最优；同时又能做到对系统动态特性的控制与对象扰动的控制分开处理而互不影响 自适应逆控制在消噪方面得到大量应用，已经成功解决了诸如空调管道中风扇噪声和汽车的马路噪声等许多噪声消除问题4，但目前国内外自适应逆控制在电力电子方面应用的报道较少，文献5将逆控制用于直流伺服电机的位置和速度的控制，文献6将其应用于一个
3、开关DC-DC升压电路，而用于有源滤波器的道尚未发现。 本文将自适应逆控制思想应用于并联型有源电力滤波器（active power filter，APF）的控制，将包括主电路与负载以及APF在内的电路结构看作广义的APF，通过求此广义APF的离线逆作为控制器实现对APF的控制。并分别对系统不同电压情况以及滤波电感和自适应参数改变对系统补偿效果的影响进行了仿真研究。仿真结果证明了所提出的控制算法不但算法简单，而且性能非常可靠。不仅在理想的电源电压情况下具有较好的补偿效果，而且当电源电压出现畸变与不对称情况下，仍能够得到较好的补偿效果。2 基于自适应逆控制的并联型有源电力滤波器21 有源滤波器的基
4、本原理图1所示的是传统并联型有源电力滤波器的基本原理图7。从图1可知： （1）其中为非线性负载产生的负载电流，将其进行傅氏分解：（2）式中 为基波电流的幅值；为n次谐波电流的幅值；为基波电流；为谐波电流。如果： （3）那么系统仅向负载提供基波电流，补偿后的系统电流将不再含有谐波成分。因此通过检测负荷产生的谐波电流，得到补偿电流的期望值，然后再控制脉宽调制（pulse width modulate，PWM）逆变器使之产生相应的补偿电流，然后将补偿电流注入到负荷节点以抵消负荷产生的谐波电流，达到滤波的目的。图1并联型有源电力滤波器Fig.1 Block diagram of shunt activ
5、e power filter图1所代表的有源电力滤波器的典型结构总是将滤波器的滤波电路和主电路分离开来，对有源滤波器的检测和控制要分别进行，而且由于直流端电容电压的储能功能，必须同时对直流端电容电压进行控制来减小扰动，而常规的控制方法如比例积分（proportion-integral，PI）控制总是存在参数难以调节而且对电路参数变化敏感的问题，而且常规的控制方法对由整流桥负载产生的谐波在跳变点处补偿时在补偿电流中总会因跟踪速度而产生尖峰。22 基于自适应逆控制的并联型有源电力滤波器 图2为所提出的基于自适应逆控制结构的并联型有源滤波器控制框图，将图1中包括主电路与负载以及APF在内的电路结构看
6、作广义的APF。根据文献9的分析，直流端电容电压的变化反映了主电路中电网电流的变化，通过控制电容电压为恒定参考值，即可达到控制谐波补偿的目的。因此我们可以定义如下方程： （4）图2 基于自适应逆控制的并联型有源电力滤波器Fig.2 Block diagram of shunt active power filter based on adaptive inverse control式中：V为有源滤波器直流端电容电压，而i则为期望的主电流幅值。根据式（4）所给出的关系我们对广义的APF进行自适应建模，得出其自适应模型后，那么通过离线建模可以得到自适应模型的逆模型，也即图中的。得到逆模型后，此逆模
7、型的复制作为控制器来实现对有源滤波器的控制。控制器的输出信号作为离线逆建模过程的指令信号。而控制器的输入信号可以设定为直流端电容电压的参考信号。 由于为APF模型的逆，因此在离线过程收敛的情况下，APF的模型与的级联传函即为1。在控制电路中，广义APF与的级联传函也为1，那么将控制器的输入指令给定为参考信号，广义的APF在完全收敛的情况下就跟踪这个输入信号。此控制方法中因为将广义的APF看作一个整体来控制，通过控制直流端电容电压的输出来控制整个APF，比起传统的控制方法来说，既不用再为直流端电容电压另设一套控制线路，又不存在任何参数调节困难的问题，而且因为是采用自适应滤波器，对滤波电路中参数的
8、改变不敏感，因此比较可靠。23 自适应滤波器及算法的设计 传统的无限冲击响应（infinity impulse response，IIR）滤波器虽然滤波器性能较好，但相位移大，无法引入入到APF的实时控制之中，而有限冲击响应FIR滤波器可做到较小相移10，在本算法中采用2阶有限冲击响应（finite impulse response，FIR）滤波器即可满足要求。最小均方算法（least-mean square，LMS）算法由于计算简单、计算量小、便于实现，算法的跟踪性能较好11，而且因为在本控制系统中不管是广义APF的自适应模型，还是由此模型得到的控制器，采用的FIR结构的滤波器只需2阶即可满
9、足要求，因此本文采用的自适应算法为LMS算法。3 在不同电源电压情况下补偿性能的仿真研究 针对所研究的算法，建立了基于自适应逆控制的并联型有源电力滤波器的仿真模型，仿真中的电路不变参数示于表格1。电源阻抗0.3Mh补偿支路电感5Mh电源电压220V自适应滤波参数N=2,=0.001直流侧电容2200F二极管整流桥负载50Mh, 30(串联) 表格1 仿真模型的电路参数 Tab.1 The parameters of the simulation model circuit31 电源电压为理想情况时的仿真研究 对理想电源电压情况可用如下方程表示： （5）其中： 为220V的峰值电压，而为基波频率
10、，此处为50Hz。此时电源电压为理想三相对称情况。32 电源电压畸变情况时的仿真研究当电源电压发生畸变时，用如下方程式表示：（6）其中：、定义同（5）式。而=22V。此时电源电压发生了五次畸变。33 电源电压不平衡时的仿真研究 电源电压不平衡时的情况用如下的方程式来表示： （7）其中：、及的定义如同（6）式。此时因为电源电压中含有负序电压，所以电压不再是平衡的。（a）负载电流及谐波含量图 (b)理想电源电压补偿后主电流及谐波含量图(c)电源电压畸变时补偿后主电流及谐波含量图(d)电源电压不平衡时补偿后主电流及谐波含量图图3 仿真结果Fig.3 The simulation results图3所
11、示以上几种情况的仿真结果。图3中（a）为负载电流的波形，在几种电源电压情况下负载电流基本不变，从其谐波含量图可以看出，在补偿前电源电流畸变严重，单次谐波如5、7次谐波含量都非常高。图3中（b）、（c）、（d）分别为三种仿真情况时补偿后的电网电流波形及谐波含量。从图中可以看出，无论是对理想的电源还是当电源电压发生畸变或者不平衡，补偿后的电网电流中单次谐波含量都比较低，而且在负载电流跳变点处不存在任何尖峰，这说明基于自适应逆控制的有源滤波器具有较好的动态跟踪补偿性能，而不管电网情况是否理想。表格2定量的描述了补偿前后的电网电流中最高次谐波及其含量，从表中我们也可以看出对于三种电源电压情况来说，补偿
12、后的单次谐波含量都得以大大降低，说明所提出的控制方式具有较好的补偿性能。负载电流最高次谐波含量（%）714.222510.921补偿后电网电流理想电源72.16151.976畸变52.081 131.908不平衡271.599151.586表格2 补偿前后主电流中最高次谐波含量对照表Tab.2 The percents contrast of the highest harmonic in the main supply currents before and after compensation 5 滤波电感和自适应参数对滤波性能影响的仿真 在表格1其它参数不变的情况下，对理想电源电压情况，
13、分别改变补偿支路的滤波电感和自适应步长参数，仿真研究滤波器相应的补偿性能，表格3、4分别为相应参数改变时所对应的补偿后主电流中所含的最高次谐波。滤波电感L(mh)最高次谐波含量（%）175.904385.2892372.951132.30931.252.01018.751.9074231.641351.612551.635171.4546231.562111.3817111.54071.4708112.17672.088953.683113.497表格3 滤波电感变化时的补偿效果对照表Tab.3 Contrast of the compensation performance while th
14、e filter inductor changing当主电路滤波电感在一定范围内变化时，APF的滤波性能并没有受到明显的影响。对于选定的负载，滤波电感的选取有一个最佳值，在本仿真中从表格4可以看出，当滤波电感值为6时主电流的谐波含量最低，当电感值在其附近变化时，滤波性能逐渐变差，但是总体来说，所提出的并联型有源电力滤波器对电路参数的变化不是很敏感。自适应步长参数（）最高次谐波含量（%）2(发散)22.921231.4271（收敛）112.02451.3690.551.488351.4410.151.581171.1740.051.51.7092.51.6150.00151.520111.495
15、0.0001171.52671.350表格4 自适应参数变化时的补偿效果对照表Tab.4 Contrast of the compensation performance while the adaptive parameter changing而对于建模和离线建模过程自适应参数来说，为简化起见，在本仿真中取相同的值。从表格4可以看出，本算法中的自适应参数可以在一个较大的范围内取值，只要保证建模以及离线建模过程是收敛的，APF都能取得较好的滤波效果。相对来说，稍微大些的自适应参数具有较好的滤波效果。4 结论 本文首次将自适应逆控制的思想，应用于有源电力滤波器的研究，提出了基于自适应逆控制的并联
16、型有源电力滤波器，并且对所提出的控制方法进行了仿真研究，本方法不仅简单易行，而且具有可靠的性能，因为算法本身的自适应性能，因此在较大的范围内对电路参数的变化不敏感。仿真结果表明，将自适应逆控制用于有源电力滤波器的控制，不但理想电源情况下可以产生较好的补偿效果，而且当电网中电源发生畸变和不平衡时仍然可以取得非常好的控制效果，仿真结果表明了所提出的控制方法的有效性。参考文献：1 B Widrow, E Walach. adaptive inverse controlJ. Control engineering practice. 1997,5(1):146147.2 B.威德罗，E.瓦莱斯(B W
17、idrow ，E Walach)著，刘树棠，韩崇昭(Liu Shutang ，Han Chongzhao)译. 自适应逆控制(Adaptive inverse control)M. 西安(Xian)：西安交通大学出版社(Xian Jiaotong University Press)，20003 B Widrow, M Bilello, Adaptive inverse controlC. Proceeding of the 1993 international symposium on intelligent control. Chicago, USA, 1993.164 赵斌，张如辉，齐占庆
18、(Zhao Bin，Zhang Ruhui， Qi Zhanqing). 基于自适应逆控制的飞机客舱消噪系统(System of Eliminating Airplan Cabin Noise Based on Adaptive Inverse Control)J. 控制工程（Control Engineering of China）.2002,9(6):84865 Jianming Lu, Muhammad Shafiq, Takashi Yahagi. Model reference adaptive control for nonminimum phase system and its
19、application to DC servo motor systemsC. AMC96.208-2126 Rafael Ramos, Antonio Mnuel; Francesc Guinjoan. Sinusoidal signal generation in a switching DC-DC boost converter by means of inverse adaptive controlJ. IMTC 2000. Proceedings of the 17th IEEE, Vol 2,2000:9319347 王群，姚为正，刘进军，等（Wang Qun, Yao Weizh
20、eng, Liu Jinjun, et al）.电压型谐波源与串联型有源电力滤波器（Voltage Type Harmonic Source and Series Active Power Filter）.电力系统自动化（Automation of Electric Power Systems）.2000,24(7):30358 Shyh-Jier Huang，Jinn-Chang Wu. A Control Algorithm for Three-Phase Three-Wired Active Power Filters Under Nonideal Mains VoltagesJ. IE
21、EE Transactions on power electronics，Vol.14，1999(4)：7537609 舒双焰，丁洪发，段献忠(Shu Shuangyan, Ding Hongfa, Duan Xianzhong). 基于自适应数字滤波的谐波检测（Harmonic Detection Based on Adaptive Digital Filtering）J. 电力自动化设备(Electric Power Automation Equipment). 2000，20（6）：131610Simon Haykin. Adaptive filter theory (Fourth ed
22、ition) M. Xian: Publishing house of electronics industry. 2002.The Simulation Research of the Shunt Active Power Filter Based on Adaptive Inverse ControlWu Yanfeng, Wu Zhengguo(Deparment of Electrical Engineering, Naval University of Engineering, HubeiWuhan 430033)Abstract: The algorithm of the adap
23、tive inverse control is first used in the control of the shunt active power filter, a novel control algorithm of the shunt active power filter is proposed. The active filter and the main circuit are look as the generalized active filter and the inverse of its model is used as the controller to contr
24、ol the active filter. It has the advantage that the compensation effect is senseless to the change of the other parameters of the circuit. This algorithm is reliable and easy to be implemented. It not only has good performance under ideal supply voltage, but works well when the supply voltage is dis
25、torted or unbalanced. Simulation results verified the feasibility of the proposed algorithm.Index terms: adaptive inverse control; active power filter; generalized active filter 作者简介：吴言凤，女，博士研究生，1974年6月生，研究方向：电力电子技术，自适应滤波吴正国，男，博士生导师，1943年12月生，研究方向：电力电子技术，自适应滤波与小波分析电 话：13554319026，（027）83443425email:
26、 wu_y_f2003通讯地址： 武汉海军工程大学407教研室 邮编 430033Editors note: Judson Jones is a meteorologist, journalist and photographer. He has freelanced with CNN for four years, covering severe weather from tornadoes to typhoons. Follow him on Twitter: jnjonesjr (CNN) - I will always wonder what it was like to huddle
27、 around a shortwave radio and through the crackling static from space hear the faint beeps of the worlds first satellite - Sputnik. I also missed watching Neil Armstrong step foot on the moon and the first space shuttle take off for the stars. Those events were way before my time.As a kid, I was fas
28、cinated with what goes on in the sky, and when NASA pulled the plug on the shuttle program I was heartbroken. Yet the privatized space race has renewed my childhood dreams to reach for the stars.As a meteorologist, Ive still seen many important weather and space events, but right now, if you were si
29、tting next to me, youd hear my foot tapping rapidly under my desk. Im anxious for the next one: a space capsule hanging from a crane in the New Mexico desert.Its like the set for a George Lucas movie floating to the edge of space.You and I will have the chance to watch a man take a leap into an unim
30、aginable free fall from the edge of space - live.The (lack of) air up there Watch man jump from 96,000 feet Tuesday, I sat at work glued to the live stream of the Red Bull Stratos Mission. I watched the balloons positioned at different altitudes in the sky to test the winds, knowing that if they wou
31、ld just line up in a vertical straight line we would be go for launch.I feel this mission was created for me because I am also a journalist and a photographer, but above all I live for taking a leap of faith - the feeling of pushing the envelope into uncharted territory.The guy who is going to do th
32、is, Felix Baumgartner, must have that same feeling, at a level I will never reach. However, it did not stop me from feeling his pain when a gust of swirling wind kicked up and twisted the partially filled balloon that would take him to the upper end of our atmosphere. As soon as the 40-acre balloon,
33、 with skin no thicker than a dry cleaning bag, scraped the ground I knew it was over.How claustrophobia almost grounded supersonic skydiverWith each twist, you could see the wrinkles of disappointment on the face of the current record holder and capcom (capsule communications), Col. Joe Kittinger. H
34、e hung his head low in mission control as he told Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunday.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no p
35、recipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than th
36、e cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause), he can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet (22.7 miles/36.53 kilometers). Here, Fearl
37、ess Felix will unclip. He will roll back the door.Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite t
38、he distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end.Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will
39、begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 27
40、0-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everythi
41、ng goes as planned, it wont. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).It might not be the moon, but Kittinger free fell from 102,800 feet in 1960 - at the dawn of an infamous space race that captured the hearts of many. Baumgartner will attempt to break that record, a feat that boggles the mind. This is one of those monumental moments I will always remember, because there is no way Id miss this.
