《PWM整流器在自反馈串级调速系统的应用-毕业论文外文翻译.docx》由会员分享，可在线阅读，更多相关《PWM整流器在自反馈串级调速系统的应用-毕业论文外文翻译.docx（18页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、PWM整流器在自反馈串级调速系统的应用摘要： 本文分析了自反馈串级调速系统功率因数较低的原因，并提出了一种新的基于PWM技术的串级调速系统方案。在此系统中，用IGBT代替了可控硅。它可以提供电容式无功功率去补偿传统的串级调速系统产生的感应无功功率，因此，它可以提高功率因数。 文中介绍了PWM整流器和PWM电流控制方案。最后给出了仿真结果和结论，结果表明，新系统工作在单位功率因数。索引词 - 串级控制，功率因数，脉宽调制一 导言 在我们的日常生活和工业生产中，电力系统占相当大的比重，特别是这些载荷鼓风机和泵，使用多能量，因此节能的风机和水泵正在成为工业生产的主要问题之一。利用可控硅串级调速控制，
2、是风机和水泵节能的有效手段。比较变频调速控制，这种方法更好，更便宜，不仅能平滑调速还能节能2040。但是，传统的级联速度控制系统具有低谐波因素和多一些缺点。功率因数高负荷，高速低转速负荷0.4 0.6。它带来了巨大的浪费和污染。这个缺点阻碍了延伸和串级调速中的应用。在一种新的级联速度控制系统方案的基础上，提出了PWM整流器。在新的计划中，晶闸管逆变器被IGBT代带，并且系统具有高功率因数。二 CHOP内馈调速的原理 在电机中内反馈串级调速控制系统是异步电动机转子系列woundrotor抵抗速度的基础。一个新的三相对称绕组命名调整绕组定子绕组上，建立的初级绕组称为主绕组。额外的电动势绕组的调整是
3、由主绕组引起的。采用晶闸管逆变器，附加电动势serriedwound与转子绕组，其速度可以通过改变其规定。普通串级调速系统调速是通过改变反角，但无功功率提升，功率因数作为反角增加而减少。因此，斩波串级speedregulation系统如下： 1.对斩波串级调速系统中的整流桥输出电压 。逆变器的输出电压 转子回路方程是。因此，旋转速度公式可以显示为： 是调整相绕组电压，是斩波器脉冲持续时间比和对应的是转子额定电压。因此，电机的旋转速度可通过调节控制脉冲宽度的比例。 （1）三 功率因数的分析 对串级调速系统功率因数为：在公式中，P1是由电机吸收的有功功率; PT是有功功率给电网的反馈; Q1是由电
4、机从电网吸收的无功功率; QT是逆变器从电网吸收的无功功率。在斩波串级调速系统，逆角为固定的，因为，它是一般约 。因此，在系统中QT是不变的。但是，当电机在低速运行，增加，功率因数下降。四 PWM整流器的定性分析可控硅由PWM整流器 取代，新的级联速度控制系统方案原理图图2： PWM整流器是一个四象限变流器。其交流和直流侧可以控制的。当使用电网电测力矢量为参考，则PWM整流器的工作fourquadrant可以通过控制交流侧电压向量V。是固定的，所以也是固定的。在这种情况下，在PWM整流器交流侧电压矢量的运动轨迹是一个圆的半径的VL。当V的电压矢量端点的圆轨迹A点，电流矢量延迟电动势矢量 。PW
5、M整流器网侧电感为图3显示的特征。当V的电压矢量端点的圆轨迹B点，电流矢量I是平行，与电动势矢量E同一方向。在PWM整流器网侧图4显示为阻力特性。当电压矢量端点的圆V位点C点，电流矢量I是电动势矢量的PWM整流器网侧电容，图5显示的特征。当V的电压矢量端点的圆轨迹D点，电流矢量I是平行，与电动势矢量E相反的方向。在PWM整流器网侧显示为图6负阻特性。 （图3） (图4) （图5） （图6） 所以一定要确保输出端的直流电压，输入电流和交流侧电压可以 在负阻或电容特性恒定的情况下工作，因此或可以提高功率因数。五 PWM整流器控制系统的设计三相PWM整流器交流侧均为时变交流量，不利于控制系统设计。引
6、进电机矢量控制的思想，从交流侧看可以把电感电阻和交流侧看成一个交流电机的模型与三相逆变器相同, 我们更可以把三相交流电机的控制理论运用到三相PWM整流器中。把三相静止坐标变换成二相旋转坐标，在进行解耦控制，电压为外环，电压给定和实际的差值进行调节后经过PI后得到有功电流的给定，设定想要给定的无功电流，高功率因数系统中，功率因数为1，所以无功电流给定为0，在通过检测出来的实际的电流矢量变换和解耦后得到的实际的有功电流和无功电流与给定的有功电流和无功电流的比较来得到指令电压信号，从而我们得到如图所示的控制框图来实现系统的控制。这种直接通过检测实际电流，再进行矢量变换解耦控制的方法直接对电流进行控制
7、和上述的通过电压的关系来间接控制电流的方法更客观，而且控制更有效。因此根据坐标变换的关系，三相PWM整流器拓扑结构的两相旋转坐标系dq模型可描述为： （2） 上述方程中，是d和q轴的电动势矢量，矢量,是组件d和q轴的在AC端，电压矢量分量，是在交流侧电流向量d和q轴分量，p为微分算子。 在公式（2），因为D和q轴分量耦合，很难设计出控制系统。因此，一个控制策略的前馈解耦是给出的。 PI调节器，是层状的电流调节器，所以控制方程，矢量量化为： （3） ，是比例调节系数和积分调节回路的电流调节系数。 ，等价于，。 在电压环，所需的电流是三相对称正弦电流，它的电网电压同频。因此，在同步旋转坐标系 中，
8、是DC数量。因此，和可以顺利地调整PI调节器。方程式（4）。 （4） 介绍了在dq概念的瞬时功率，同步旋转坐标系，瞬时有功功率和PWM整流器无功功率可以显示为（5）： (5) 为了补偿 电机吸收无功功率 ，PWM整流器工程电容性质。因此，编号是： (6) 表格方程（3）（4）（6），对PWM整流器控制框图图7： (图7)六 PWM整流器串级调速系统的仿真结果 PWM整流器仿真串级调速控制的结构图和图7的直接电流控制策略系统的基础。模拟参数是电机额定功率为710kW，定子额定电压为6000V，额定电流为72A条，调整电压为510V，额定转速1487r/min。交流侧电感为0.001H，直流侧为0
9、.0033F电容，直流电压为1200V的。仿真结果图8，图9和图10。 （图8） （图9） （图10） 从图8可以看出直流电压为1200V，它有利于顺利调节速度。图9为A相电压和PWM整流器交流侧电流。结果表明，PWM整流器的电容特性运行。因此，有源电力输送到电网，同时产生的容性无功功率。因此，系统的工作原理功率因数，电压波形和电流如图10。在传统的斩波串级调速系统，因为晶闸管半控装置，逆变器上运行的特点和电感电流的波形不是正弦波。因此网侧电流延迟和系统的功率因数。电流和电压 晶闸管逆变器并网如图11图12所示。除了新的串级调速控制系统具有谐波少得多。从图13和图14，总谐波失真的新系统（TH
10、D）是5.56，是对传统的斩波串级调速系统，以12.28的一半。 （图11） （图12） （图13）| （图14）七 结论 本文提出了一种新的以级联速度控制系统为基础的PWM整流器。仿真验证了新的控制系统，新系统可以工作在单位功率因数。与传统的斩波串级调速系统相比，新的串级调速控制系统可节省无功补偿装置，降低谐波。因此，PWM整流器串级调速系统将广泛应用于未来。八 参考文献1马里乌什马林诺夫斯基，马立克Jasinski，“简单的三相PWM整流器直接功率控制采用空间矢量调制（DPC的支持向量机），工业电子，第一卷电机及电子学工程师联合会交易，51，2号，2004年4月。2蒋优化，宁宇，和龚优岷，
11、“研究单位功率因数的内馈斩波级联调速系统”，电力电子，第39卷第6号，2005年12月。 3章充维，张星，“PWM整流器及其控制策略”，北京：中国机械工业出版社，2003。 4陈白石“电力拖动自动控制系统”，北京：中国机械工业出版社，1997年论文 5宋桂英，“内反馈调速电机系统”，硕士论文，河北科技大学。九 履历马畅潇出生在1982年9月18日的中国。他于2005年加入中国北方电力大学。现在，他正在攻读电气和电子工程学院学士学位和他的专业是电力电子及电气传动设备。电子邮箱：machangxiao汪埃甍于1963年出生在中国。她是一名华中电力大学的副教授。是美国威斯康星大学麦迪逊分校学者从20
12、06年1月至Jun.2007。电子邮箱：aiming_068本文摘译自：R.Pena.J.C.Ctare.GM.Asher.Doubly fed induction generator using back-to back PWM converters and its application to variable-spced wind energy cration.IEEEProc-Electr.PowerAppl.Vol.143.NO.3.May1996:231-241 The Application of PWM Rectifier Used in SelfFeedback Cascad
13、e Speed Control System Ma Changxiao and Wang Aimeng Abstract-Analyzed the reason that the power factor of self feedback cascade speed control system is poor. A new cascaded speed-adjusting system scheme based on PWM technique is proposed in this paper. SCR is substituted with IGBT in the system. It
14、can provide capacitive reactive power to compensate inductive reactive power which the conventional cascaded speed adjusting system produces. So it can improve power factor. PWM rectifier and PWM direct current control strategy are introduced in the paper. At last, simulation result and conclusion a
15、re given. It shows that the new system works at unity power Factor. Index Terms- Cascade control, power factor, PWMI. INTRODUCTION IN our daily life and industrial production, electric drive accounts for a large proportion，especially these loads air blowers and pumps that use much energy, so the ene
16、rgy saving of fans and pumps is becoming one of the main issues in industry production. The use of SCR cascade speed control is an effective means of the energy conservation of fans and pumps. Compare with frequency control of motor speed, this method is better and cheaper, and not only bring about
17、smooth speed regulating but also save energy 20%40%. But the conventional cascaded speed control system has some disadvantages of low factor and much harmonic. The power factor is 0.6 with high-speed load and 0.4 with low-speed load. It brings great waste and pollution to the power. This disadvantag
18、e obstructs the extension and application of cascade speed regulation. A new cascaded speed control system scheme based on PWM rectifier is proposed in this paper. In the new scheme, thyristor inverter is substituted with IGBT, and the system works with high power factor.II. PRINCIPLE OF CHOP INNER
19、FEEDBACK SPEED REGULATION Cascade speed control system with internal feedback is base on the theory of rotor series resistance speed of woundrotor induction motor. In the motor, a new three-phase symmetrical winding named adjusting winding is founded on the stator winding and the primary winding cal
20、led main winding. The additional electromotive force is provided by adjusting winding which induced from main winding. Using thyristor inverter, the additional electromotive force is serriedwound with rotor winding, and the speed can be regulated by changing it. The speed regulation in ordinary casc
21、ade speed control system is by changing the inverse angle , however the reactive power enhanced and the power factor decreased as the increase of inverse angle. So chopping cascade speedregulation system is proposed. The system principle diagramis Fig.1. Fig.1 Fig. 1. Structure of chopping cascade s
22、peed regulation system Output voltage of the rectifier bridge is . Output voltage of the inverter is . Equation of the rotor loop is So the formula of the rotation speed can shows as: UT 2 is the phase voltage of the adjusting winding, is the pulse duration ratio of the chopper and E20 is rotor rate
23、d voltage. So the rotation speed of the motor can be controlled by regulating the pulse duration ratio.III. ANALYSE OF POWER FACTOR The power factor of cascade speed control system is:(1) In the equation, P1 is the active power absorbed from grid by motor；PT is the active power feedback to grid form
24、 the system; Q1 is the inductive reactive power which is absorbed by motor from grid; QT is the inductive reactive power absorbed from grid by inverter. In the chopping cascade speed regulation system, the inverse angle is fixed, because of the margin, it is generally about 300. So QT is changeless
25、in the system. But when the motor runs at a low speed, PT increased, and the power factor decreased.IV. ANALYSE OF PWM RECTIFIER Substituted SCR by PWM rectifier, the principle diagram of the new cascaded speed control system scheme is Fig.2. The Application of PWM Rectifier Used in Self- Feedback C
26、ascade Speed Control System Ma Changxiao and Wang Aimeng Fig. 2. Structure of PWM rectifier cascade speed regulation system PWM rectifier is a four-quadrant converter. Its AC and DC sides can be controlled. When using the grid electromotive force vector as reference, the PWM rectifier can work in fo
27、urquadrant by controlling the AC side voltage vector V . I hypothesis fixedness, so the is fixedness too. In this situation, the motion trajectory of the PWM rectifier AC side voltage vector is a round with the radius of VL . When the endpoint of voltage vector V on the circle locus A point, current
28、 vector I delays electromotive force vector and the net side of the PWM rectifier shows inductance characteristic as Fig.3. When the endpoint of voltage vector V on the circle locus B point, current vector I is parallel and the same direction with electromotive force vector E . The net side of the P
29、WM rectifier shows positive resistancecharacteristic as Fig.4. When the endpoint of voltage vector V on the circle locus C point, current vector I is lead electromotive force vector and the net side of the PWM rectifier shows capacitance characteristic as Fig.5. When the endpoint of voltage vector V
30、 on the circle locus D point, current vector I is parallel and the opposite direction with electromotive force vector E . The net side of the PWM rectifier shows negative resistance characteristic as Fig.6. （3） （4） （5） （6） So make sure the output voltage of the DC side isinvariableness, the input cu
31、rrent and voltage of the AC side can work on negative resistance or capacitance characteristic, hence QT =0or QT=Q1 . The power factor is increased.V. DESIGN OF THE PWM RECTIFIER CONTROL SYSTEMAs the AC side of three-phase PWM rectifier is timevarying, it is difficulty to design the control system.
32、So the method of vector control of asynchronous motor is introduced. The ABC reference frame changes to d-q synchronously rotating reference frame bases on the grid voltage frequency. So the sinusoidal variables in ABC reference frame become DC variables in d-q synchronously rotating reference frame
33、. It is easy to design the control system. In the d-q synchronously rotating reference frame, the q coordinate axis is coincides with the grid electromotive force vector Edq , so the d axis component of the electromotive force vector ed is zero. In the synchronously rotating reference frame, the q a
34、xis component shows the active power and the d axis shows the reactive power. In d-q synchronously rotating reference frame, the model of three-phase PWM rectifier is: （2） In the equation mentioned above, ed ,eq is the d and q axis component of the electromotive force vector Edq , vd ,vq is the d an
35、d q axis component of the voltage vector in the AC side, id ,iq is the d and q axis component of the current vector in the AC side, and p is the differential operator. In the equation (2), because the d and q axis component is coupled, it is difficult to design the control system. So a control strat
36、egy based on the feed-forward decoupling isapplied. The PI regulator is bedded in the current regulators, so the control equation of vd ,vq is: (3) KiP,KiI is the proportion adjustment coefficient and the integral regulation coefficient of the current regulating loop. *, * iq id is the appointed val
37、ue of iq ,id . In the voltage loop, the needed current is the three phase symmetrical sine current, and its the same frequency of grid voltage. So in d-q synchronously rotating reference frame,and are DC quantity. Hence iq and id can be adjusted smoothly by PI regulator. The equation is (4). (4)Intr
38、oduced the conception of instantaneous power, in the dq synchronously rotating reference frame, the instantaneous active power and reactive power of the PWM rectifier net side can shows as （5）: (5) In order to compensate the inductive reactive power absorbed by motor, the PWM rectifier works in capa
39、citive character. So id is: (6) Form the equation (3) (4) (6), the control block diagram of PWM rectifier is Fig.7. VI. SIMULATION RESULTS OF THE PWM RECTIFIER CASCADE SPEED CONTROL SYSTEMSimulate the PWM rectifier cascade speed control system base on the structure of Fig.1 and the direct current co
40、ntrol strategy of Fig.7. The simulation parameters are: the rated power of inner-feeding motor is 710kW, the stator rated voltage is 6000V, the rated current is 72A, the voltage of adjusting winding is 510V, the rated speed is 1487r/min. The inductance in AC side is 0.001H, the capacitance in DC sid
41、e is0.0033F, the DC voltage is 1200V. The results of simulation are Fig.8, Fig.9 and Fig.10. Fig.8 Fig.9 Fig.10 From Fig.8, the DC voltage works on 1200V, it is beneficial to regulate the speed smoothly. Fig.9 is the A phase voltage and current of PWM rectifier AC side. It shows that PWM rectifier r
42、uns on capacitance characteristic. So it transports active power to the grid meanwhile produces capacitive reactive power. Hence the system works on unity power factor, as the waveform of voltage and current in Fig.10. In conventional chopping cascade speed regulation system, because thyristor is ha
43、lf-controlled device, the inverter runs on inductance characteristic and the current waveform is not sine wave. Hence current delays voltage in net side and the power factor of the system is poor. The current and voltage of thyristor-inverter and grid is shown in Fig.11 and Fig.12 Fig.11 Fig.12 Besides the new cascade speed control system has much less harmonic. From Fig.13 and Fig.14, the total harmonic distortion（THD）of the new system is 5.56%, it is about half of the conventional chopping cascade speed regulation system which is 12.28%. Fig.13 Fig.14VII. CONCLUSION This paper propo