双馈风力发电机模型-翻译完毕.docVIP

Vector Controlled Doubly Fed Induction Generator for Wind Applications矢量控制的双馈感应风力发电机的应用程序Dr. Ani Gole, Dept. of Electrical and Computer Eng.,University of Manitoba.This document discusses the theory of operation behind the doubly fed generator case developed by Ani Gole (Univ. of Manitoba, Canada) and Om Nayak (Nayak Corporation, Princeton, NJ). The controller concept is based on the paper by Pena et al 1.Description of Rotor Current Generation Circuit (Generator PWM Converter and Controls) 转子电流产生电路的描述（发电机脉宽调制转换器及其控制）双馈感应发电机ABCIsaIsbINDUCTION GENERATOR13.8 kV, 500 HPIscVbVcCTRLSTLCABI M b cW a& Controls& ControlsGRIDPWM ConverterPWM ConverterbabcacGENERATORVaira,irb,ircFig 1: Doubly Fed Induction Generator The Doubly fed induction generator/motor allows power output/input into the stator winding as well as the rotor winding of an induction machine with a wound rotor winding.双馈式感应发电机/电动机通过绕线转子绕组将功率输出/输入感应电机的定子绕组和转子绕组。Using such a generator it is possible to get a good power factor even when the machine speed is quite different from synchronous speed. 使用这样发电机即使在机器转速完全不同于同步速度时也可以得到一个好的功率因数。 Such machines can therefore operate without the need for excessive shunt compensation.这种发电机不需要过度的并联补偿。The rotor currents (ira,irb,irc) of the machine can be resolved into the well known direct and quadrature components id and iq. 双馈感应发电机的转子电流(ira,irb,irc)可以分解为直接和正交分量id 和 iq。 The component id produces a flux in the air gap which is aligned with the rotating flux vector linking the stator; id部分在空气间隙处产生磁通，这与连结定子的旋转磁通量是一致的。whereas the component iq produces flux at right angles to this vector. 而iq产生的磁通与id产生的垂直。The torque in the machine is the vector cross product of these two vectors, and hence only the component iq is contributes to the machine torque and hence to the power. 机器的转矩是这两个向量的向量积，因此，只有iq与机械转矩变化有关，进而导致功率的变化。The component id then controls the reactive power entering the machine. id控制输入机器的无功功率。If id and iq can be controlled precisely, then so can the stator side real and reactive powers. 如果iq和id能被精准控制，于是定子侧的实际功率和无功功率就能被准确控制。The procedure for ensuring that the correct values of id and iq flow in the rotor is achieved by generating the corresponding phase currents references ira_ref, irb_ref and irc_ref, and then using a suitable voltage sourced converter (VSC) based current source to force these currents into the rotor. 确保id和iq正确的值流入转子侧的方法是产生相电流参考值 ira_ref, irb_ref和irc_ref，然后用一个基于电流源的合适的电压转换器促使这些电流流入转子侧。The latter action is straightforward and can be achieved using current-reference pulse width modulation (CRPWM) or other technique. 后面的过程就很直接了，用当前参考脉冲宽度调制(CRPWM)或者其他的相应的装置就可以实现。The crucial step is to obtain the instantaneous position of the rotating flux vector in space in order to obtain the rotating reference frame. 最关键的一步是获得空间里旋转磁通向量的瞬时位置，从而确定旋转参考系。This can be achieved by realizing that on account of Lenzs law of electromagnetism, the stator voltage (after subtracting rotor resistive drop) is simply the derivative of the stator flux linkage la as in eqn. (1) which is written for phase a. 这点可以这样获得:根据楞次定律，定子电压（减去转子电阻上压降后）是定子磁链 la的导数，如下式所写：.(1)The control structure shown in Fig. 2 can thus be used to determine the location (fs) of the rotating flux vector.因而图2所示的控制结构能够决定旋转磁通的位置。Fig 2: Determination of rotating mag. Flux vector locationlalbRaIn Fig. 2, the three phase stator voltages (after removal of resistive voltage drop) are converted into the Clarke (aandb) components va and vb , which are orthogonal in the balanced steady state. 在图2中，三项定子电压Va、Vb、Vc（已去除电阻电压降）被转换成 va 和 vb ， va 和 vb处于正交平衡的稳定状态。This transformation is given by:转换公式如下:(2)Integrating va and vb , we obtain la and llbb , the Clarke components of stator flux.给va 和 vbb积分,我们得到 la 和 lb以及定子磁通 Converting to polar form转化为极坐标形式(3)The angle fs gives the instantaneous location of the stators rotating magnetic field. 角fs 给出了定子磁场的瞬时位置.In practical control circuits, as in Fig. 2, some filtering is required in order to rid the quantities la and lb of any residual dc component introduced in the integration process.在实际电路中，如图2所示，为了减少集成过程中引入的残余直流分量( la 和 lb)，需要对其进行一些过滤。Now the rotor itself is rotating and is instantaneously located at angle fr (labeled “rotor angle” in the figure).既然，转子本身旋转，且瞬时位置由角fr（标记为转角图）体现。Thus, with a reference frame attached to the rotor, the stators magnetic field vector is at location ffs-fr , which we refer to the “slip angle” fslip. 因此，给转子加一个参考系，定子磁场磁通在位置ffs-fr处，这就是所谓的偏离角fslip.。The instantaneous values for the desired rotor currents can then be readily calculated using the inverse dq transformation, with respect to the slip angle, as shown in Fig. 4. 对于偏离角,如图4所示，使用逆dq变换可以很容易计算出所需的转子电流的瞬时值。The equations for all transformations are shown in the appendix.所有转换方程见文档末尾附录部分。IraaIrbbIrccIra_refIrb_refIrc_refslpangto StatorDQRotoralfabetaABC2 to 3TransformalfabetaD and Q reference currentsGeneration of current referencesFig. 4: Final step in generation of rotor phase reference currentsOnce the reference currents are determined, they can be generated using a voltage sourced converter operated with a technique such as current reference pulse width modulation (CRPWM) as shown in Fig. 5. 一旦参考电流确定，他们使用图5所示的参考电流脉冲调制控制的电压转换器产生。The Appendix gives a short introduction to CRPWM.附录部分对参考电流脉冲调制（CRPWM）作了简要说明。hynhyT1T4Ira_refC-E+C-E+C-E+T3T6T5T2Irb_refIrc_refhyira_refira_refhyT1CPanelhysband0100.1C+E+C+E-Current-Reference PWM Controls. Hysteresis band can be adjustedIraIrbIrc*-1Fig. 5: CRPWM Converter and Controller for rotor currentsGrid PWM Converter and Controls:电网脉冲调制转换控制：As can be seen from Fig. 5, the rotor side VSC converter requires a dc power supply. 如图5所示，转子侧VSC转换器需要直流供电。The dc voltage is usually generated using another voltage sourced converter connected to the ac grid at the generator stator terminals. 用连接到交流电网的电压源换流器产生直流电压，电压源换流器位于发电机定子终端。A dc capacitor is used in order to remove ripple and keep the dc bus voltage relatively smooth.用直流电容器来滤波且保证直流母线电压相对稳定。 This grid PWM Converter is operated so as to keep the dc voltage on the capacitor at a constant value.电网脉冲调制转换器保障了电容器两端直流电压的稳定。 In effect, this means that the Grid side converter is supplying the real power demands of the rotor side converter.事实上，这意味着网侧变流器提供的有用功率由转子侧变流器控制。It is possible to operate this converter using a current reference approach used for the rotor side converter.用针对转子侧变流器的参考电流法是可以来控制网侧变流器的。 However, as mentioned earlier, CRPWM has the drawback that the switching frequency and hence the losses are not predictable.然而，如前面所提到的那样，参考电流脉冲调制有如下缺点：开关频率的损失是无法预估的。Therefore, a feedback controller is used in which the error between the desired and ordered currents is passed through a proportional-integral controller which controls the output voltage of a conventional Sinusoidal PWM Converter. 因此，需要运用一个反馈控制器 让故障电流通过比例积分控制器。比例积分控制器是用来控制传统的正弦脉冲调制转换器的。The advantage of the SPWM controller is that the number of switchings in a cycle is fixed, and so the losses can be easily estimated a-priori.正弦脉宽调制控制器的好处是一个周期的开关次数是固定的，因此损耗易被估算。It is possible to control the d axis current by controlling the d-component of the SPWM output waveform and the q axis current via the q component. 通过控制正弦脉宽调制的d部分输出波形 进而控制d轴的电流，同理q轴电流由q部分控制。However, this leads to a poor control system response, because attempting to change id also causes iq to change transiently. 然而这会导致不良的控制系统响应，因为试图改变id时也会导致iq暂时改变。Hence, modifications have to be made to the basic P-I controller structure so that a decoupled response is possible, and a request to change id changes id and not iq; and vice-versa.因此，需要对导出控制器作出修改，进而产生解耦响应。并且改变id的请求改变id而不是iq,反之亦然。If a voltage sourced converter with constant dc bus voltage is connected to an ac grid through a (transformer) inductance L and resistance R, it can be shown that that:如果电压源转换器和恒定直流总线电压，通过电阻（R）和电感(L)连接到交流电网中，那么可以如下表示： .(4)Here v=vd is the voltage of the ac grid, and because this is chosen as the reference, vq is by definition, zero.这里v=vd 指的是交流电网的电压，因为这里的V被选为参考值，vq被定义为0. Ed and eq are the d and q components of the generated VSC voltage. Ed和eq是VSC电压的dq部分。Eqn. 4 clearly shows that attempting to change id using ed will also cause a transient change in iq. 从等式4中不难看出，用ed改变id的值的同时也会导致iq值的瞬间变化。If instead, we use the quantities Lx1 and Lx2 to control the currents, the resulting equations are decoupled. 如果换个说法，我们用Lx1和 Lx2的数量来控制电流，最终的方程式是解耦的。Using feedback PI control, we let the error in the id loop affect L x1 and in the iq loop, L x2 as shown in Fig. 6.如图6所示，用反馈PI控制，我们可以让id部分的故障影响Lx1,iq部分的影响 Lx2。图6：解耦控制器D-F-IPi1d*1.6i1qB+D-F+3.266Vdref1Vqref1D+F-IPD+F-idrefiqrefwLwLVd=3.22 kVLx1Lx2Fig 6: Decoupled Controller.1.6In the selected circuit, the grid transformer rating is 4 kV (secondary) , 1 MVA with 10% leakage, giving an impedance wL= 1.6 W.在选定的电路中，电网变压器额定功率是4KV（中等），1MVA带有10%的泄露，阻抗为 wL= 1.6 W。 Similarly a line-line voltage of 4 kV gives a line to neutral voltage of4/3 kV kV, and as we are using peak quantities in the dq conversion, vd = (4/3) 2 kV = 3.26 kV同样的，4KV的线对线电压有效值为4/3 kV kV，在dq变换中当峰值电压为vd = (4/3) 2 kV = 3.26 kV.The detection of the ac grid voltage reference angle and the generation of d and q components of current (as required in Fig 6) are done in a straightforward manner using a d-q transformation block as in Fig. 7.如图7所示，交流电网电压参考角检测和dq部分电流的产生（如图6所要求）是用dq转换模块直接实现的。The selection of idref for the grid side converter is through the control circuit shown in Fig 8, which attempts to keep the capacitor voltage at its rated value by adjusting the amount of real power. 电网侧变换器idref的选择是通过图8所示的控制电路实现的,图8所示的控制电路试图通过调节有功功率从而实现保持电容电压处于额定值。The reactive power order is dialed in, but could have been generated by a similar controller whose objective would be to keep the ac voltage at some set point.无功功率被输入，其 本可以用一个相似的控制器来产生，该控制器的作用是保持交流电压处于设定值。If these reference voltages vdref1 and vqref1 (Fig. 6) are applied at the secondary of the transformer, the desired currents idref and iqref will flow in the circuit. 如果图6中的参考电压vdref1 和vqref1在变压器的次级被引用，目标电流idref 和iqref将会流入电路。 The remaining parts of the controls are standard PWM controls. 剩下来的控制部分是标准的脉宽调制控制。The control blocks shown in Fig 9 convert the above references to phase and magnitude, taking care to limit the magnitude to the maximum rating of the grid side VSC converter.图9所示的控制模块转换上面参考值得相位和大小，注意限制 网侧VSC整流器的最大额定值的大小。The reference for each of the three phase voltages is then generated by an inverse dq transformation.通过dq逆变换产生每个三相电压值的参考值。EaphivsEdVsmagVaVbVci1ai1ci1bi1aGsT1 + sTi1betai1alfai1q0.01326YXmagXphiYp_to_rphii1di1di1qG1 + sTStatorto RotoralfaDQbetaG1 + sTGsT1 + sTXYYr to pXmagphiABC3 to 2 TransformalfabetaXYYr to pXmagphiValfasABC3 to 2 TransformalfabetaVbetasphiD+F-Detection of d-q components of currents. The washoutfilters remove dc components. Phase change of 0.01326 radcorrects washout filter phase errorDetection of system voltageFig 7: Generation of quantities required for the controller in Fig. 6系统电压的检测d-p组件电流的检测。过滤掉直流组件。0.01326弧度的相位变化纠正过滤的相位误差。产生图6所需的数据Fig 8: Voltage controller电压控制器Fig.10 shows a standard sinusoidal PWM controller, in which each of the phase voltages is compared with a high frequency triangle wave to determine the firing pulse patterns.图10显示了一个标准的正弦PWM控制器，其中每相电压与高频三角波对比来决定激励脉冲图形。产生PWM参考电压Vdref1Vqref1XYYr to pXmagphimag_of_vvqrefYXmagXphiYp_to_rvdrefGeneration of PWM Reference VoltagesVarefVcrefVbrefABC2 to 3Transformalfabetato StatorDQRotoralfabetaMagnitude LimiterphiFig 9: Phase reference voltage generator相参考电压发生器1.26 kHz SPWM Firing Pulse generator 1.26 kHz的SPWM激励脉冲发生器ABCompar-atorABCompar-atorABCompar-atorVaref*0.2*0.2VbrefVcref1.26 kHz SPWM Firing Pulse generatorIGBTFIRINGPULSEST1sT5sDelayTT4sDelayTT3sDelayTT6sDelayTT2sDelayTDelayT*0.2PWM andIGBT FiringControlVcmagVamagVbmagphitritriphiphiFig 10: SPWM pulse generatorSPWM脉冲发生器Tests:The following tests can be conducted to check the operation. Set the generator on “speed Control”, i.e., the machine will run at the speed designated by the slider. This is realistic because any externally connected wind turbine model would interface to the machine module through the “speed signal”. Set the speed to 0.8 pu.接下来的测试可以用来检查操作。设置发电机处在“速度控制”上，也就是说该机器将在滑块所指定的速度下运行。这是现实的，因为任何外部连接的风力涡轮机模型都将通过“速度信号”与机器模块联系起来。设置速度为0.8pu。Set idref=0.5 pu and iqref =0 pu for the rotor side converter and vref = 10 kV and iqref (Q order) for the grid side converter. Start the system. Observe that the powers are indeed as expected. Increase idref (rotor converter) to 1 pu. The change should be effected without any change in the reactive power. Similarly change iqref to 0.3 pu. And observe that P does not change. 设置转子侧变换器的idref=0.5 pu、iqref=0 pu，设置网侧转换器的vref = 10 kV、iqref (Q order 可能是Q阶)。开始系统。观察到的能量确实如预期的那样。增加idref（转子变换器）到1 pu。在无功功率不变的情况下，变化应该会被影响。同样改变iqref 为0.3pu。观察到P没有改变。Change machine speed to 1.1 pu., with (rotor side) idref=0.5 pu and iqref =0. Notice that the torque stays the same, but the power goes up with no change in reactive power. This is because keeping idref constant maintains constant torque, and so P is proportional to speed.改变机械速度为1.1pu、（转子侧）idref=0.5pu和iqref =0。注意扭矩保持不变，但功率上升，无功功率不变。这是因为恒定的idref维持了恒定的转矩，而且因此P是正比于速度的。Monitor grid side converter currents. Observe that the dc capacitor voltage remains fixed at its rated value and grid side currents are in phase with the ac voltage.监视网侧转换器电流。观察直流电容电压保持固定在其额定值下，而且网侧电流与交流电压同相。References:1) R. Pena, J.C. Clare and G.M. Asher, “Doubly fed induction generator using back to back PWM converters and its application to variable speed wind energy generation”, IEE Proc. Electrical Power Applications, Vol. 143., No.3., May 1996.Appendix 附录A. Current Ref. PWM (CRPWM) PWM(CRPWM)参考电流Current Reference PWM allows for the generation of any arbitrary current waveform in an R-L load. 参考电流PWM允许在R-L负载线路上形成任意电流波形。As shown in Fig. A1, an upper and lower tolerance band is placed around the desired reference waveform for the current as in the above figure.如图A1所示，一个上下公差范围被置于所期望的参考电流波形周围。 If the actual current is below the lower threshold, the upper switch (T1/D1) is turned on which applies a positiv