本文關鍵詞：電網(wǎng)擾動下雙饋式風力發(fā)電機組的分析與控制　出處：《華北電力大學》2014年博士論文　論文類型：學位論文

  更多相關文章： 風能轉化系統(tǒng)(WECS) 雙饋發(fā)電機(DFIG) dq原理 磁場定向控制(FOC)

【摘要】：本文基于矢量控制或磁場定向控制的方法對雙饋風電機組(DFIG)的風能轉化系統(tǒng)(WECS)在電網(wǎng)擾動情況下的運行特性進行了深入研究,并將磁鏈作為描述DFIG模型的基本變量。詳細推導了三相靜止到兩相旋轉的dq變換,第一步是三相靜止到兩相靜止坐標變換,第二步是由兩相靜止到兩相旋轉坐標變換。建立了三相靜止坐標系下的雙饋感應電機的模型,通過dq變換,建立了兩相旋轉坐標系下的雙饋感應電機模型。在雙饋式風電機組中,網(wǎng)側變流器以及轉子側變流器的控制起到至關重要的作用。對于網(wǎng)側變流器,采用基于網(wǎng)側電壓定向的矢量控制來保持直流側電壓的恒定并控制轉子和電網(wǎng)之間的無功流動,電網(wǎng)電壓定向在d軸,q軸分量為0。并假定電網(wǎng)電壓恒定,利用d軸電流分量和q軸電流分量分別控制有功功率和無功功率。鎖相環(huán)檢測電網(wǎng)電壓的位置角,為dq坐標變換提供相角。利用電壓外環(huán)維持直流母線電壓恒定,網(wǎng)側電流參考值是直流母線電壓參考值與實際值的偏差經(jīng)過PI控制獲得,對網(wǎng)側電流的參考值和實際值之間的偏差進行控制獲得網(wǎng)側變流器的控制信號。對于轉子側變流器,采用基于定子電壓定向的矢量控制轉子電流的dq分量,從而實現(xiàn)對無功功率和有功功率的控制,其中,定子電壓定向在d軸。為了簡化控制和計算轉子dq軸電流參考值,假設定子勵磁電流恒定,并且忽略漏磁。為了實現(xiàn)最大風能追蹤,轉速實際值與參考值之間的偏差經(jīng)過PI控制得到轉子側d軸電流分量,無功功率參考值與實際值的偏差經(jīng)過獲得PI控制得到轉子側q軸電流分量,對轉子側電流的參考值和實際值之間的偏差進行控制獲得轉子側變流器的控制信號,形成了基于定子電壓定向的DFIG有功、無功功率解耦控制策略。基于上述建立的轉子側變流器和網(wǎng)側變流器模型,對雙饋式風電機組進行控制,并利用MATLAB/SIMULINK進行了仿真并驗證了模型的正確性。 本文對雙饋式風電機組的五種運行工況進行了仿真,分別是：正常運行、電網(wǎng)電壓擾動、風速擾動、系統(tǒng)頻率擾動和無功功率參考值擾動。仿真結果表明：在正常運行狀態(tài)下,轉子側變流器的控制策略可以實現(xiàn)有功功率和無功功率的解耦控制,轉子磁鏈和定子磁鏈保持常數(shù)。當電網(wǎng)側電壓突然增加時,定子電流和轉子電流減小,此時無功功率也減�。划旊娋W(wǎng)側電壓突然減小時,定子電流和轉子電流增加,由于變流器吸收一部分能量,直流側電壓首先會升高,經(jīng)過一段時間的調整后維持在初值。風速的改變直接影響到轉子的轉速,槳距角會達到最佳值來保證從風能中,吸收的功率最大。當風速超過額定風速時,槳距角將會動作,使風力機吸收的風功率不再增加,風力機此時輸出額定功率。系統(tǒng)中頻率的微小改變不會對系統(tǒng)的可靠性產(chǎn)生影響,但當頻率變化比較大的時,系統(tǒng)會受到較大影響。當無功功率指令增加時,定子電流和轉子電流增加,而轉子轉速減小。
[Abstract]:Based on the vector control method or field oriented control of double fed wind generator (DFIG) wind energy conversion system (WECS) in the power grid operation characteristics under perturbations is studied, and the flux as the basic variables describing the DFIG model deduced in detail. The three-phase static to the two-phase rotating dq transformation, the first step is to three-phase static two-phase static coordinate transform, the second step is to the two-phase rotating coordinate transformation by two-phase stationary. The doubly fed induction motor three-phase static coordinate system of the model, through the dq transform, established the DFIG model of two-phase rotating coordinate system. In the doubly fed wind turbine. The network side converter and the rotor side converter control plays a crucial role. For the grid side converter, based on the vector control of grid side voltage oriented to maintain constant DC voltage control and rotor and power grid The reactive power flow between the grid voltage oriented in the d axis, q axis component 0. and assuming constant voltage control, active power and reactive power of the d axis and the q axis current component currents. The phase-locked loop detection voltage position angle, provide phase angle of dq coordinate transformation. The use of voltage loop to maintain the DC link voltage constant, the net side current reference value of DC bus voltage is the reference value of the deviation between the actual values obtained by the PI control of the grid current reference value and the actual value of the deviation between the control signal to gain control of the grid side converter. For the rotor side converter, the DQ component of the stator voltage oriented vector based on the control of the rotor current, so as to realize the control of active power and reactive power of the stator voltage oriented in the d axis. In order to simplify the control and calculation of rotor DQ axis current value, assuming that the stator excitation current constant Set, and ignore the magnetic leakage. In order to achieve the maximum wind power tracking speed, the actual value and the reference value of the deviation between the PI control by rotor side d axis current component, reactive power reference value and the actual value of the deviation obtained by PI control of rotor side Q axial current component of rotor current reference value and the actual the value of the deviation between the control gain control signal of the rotor side converter is formed based on the stator voltage oriented DFIG active and reactive power decoupling control strategy. The model of rotor side converter and grid side converter is established based on the above, the control of the doubly fed wind turbine, and simulates and verifies the correctness of the model the use of MATLAB/SIMULINK.
In this paper, five kinds of operating conditions of the doubly fed wind turbine are simulated, respectively: normal operation, voltage disturbance, wind disturbance, system frequency disturbance and reference value of reactive power disturbance. The simulation results show that under normal operating conditions, the rotor side converter control strategy can realize active power and no reactive power decoupling control, rotor flux and stator flux is constant. When the sudden increase of grid side voltage, stator current and rotor current decreases, the reactive power is reduced; when the grid voltage suddenly decreases, stator current and rotor current is increased, because the absorption part of the energy converter, DC side voltage first increased, after a period of adjustment and maintenance in the initial value. The wind speed change directly affects the rotor speed, pitch angle will achieve the best value to ensure the power absorbed from the wind, when the maximum. The wind speed exceeds the rated wind speed, the pitch will move, wind power of the wind absorption is not increased, then the output of wind turbine rated power system frequency. Minor changes will not affect the reliability of the system, but when the frequency is relatively large changes, the system will be subject to greater impact. When the reactive power command increased when the stator current and rotor current and rotor speed increases, decreases.

【學位授予單位】：華北電力大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TM315
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本文編號：1411665