電壓源換流器論文輕型高壓直流輸電系統(tǒng)的非線性控制策略研究

1、電壓源換流器論文：輕型高壓直流輸電系統(tǒng)的非線性控制策略研究【中文摘要】隨著可關(guān)斷電力電子器件(Insulated-gate Bipolar Transistor, IGBT; Gate-Turn Off Thyrisitor, GTO等)和PWM技術(shù)的發(fā)展,基于電壓源換流器的輕型高壓直流輸電(Voltage Sourced Converter-High Voltage Direct Current, VSC-HVDC)系統(tǒng)越來(lái)越受到人們的關(guān)注。與傳統(tǒng)的HVDC輸電系統(tǒng)相比,該輸電技術(shù)具有可向無(wú)源網(wǎng)絡(luò)供電、無(wú)換相失敗危險(xiǎn)、有功功率和無(wú)功功率獨(dú)立控制和易于構(gòu)成多端直流輸電系統(tǒng)等優(yōu)點(diǎn)。本文著重研究V

2、SC-HVDC輸電系統(tǒng)的非線性控制策略。第一種方法,建立起雙端無(wú)窮大VSC-HVDC輸電系統(tǒng)在同步旋轉(zhuǎn)dq坐標(biāo)系下的暫態(tài)非線性數(shù)學(xué)模型,采用狀態(tài)反饋精確線性化的方法,把非線性的數(shù)學(xué)模型轉(zhuǎn)化成線性的形式。然后,運(yùn)用變結(jié)構(gòu)的控制方法,設(shè)計(jì)整流側(cè)和逆變側(cè)的控制器,從而實(shí)現(xiàn)直流側(cè)電壓恒定和有功、無(wú)功功率的獨(dú)立解耦控制；第二種采用無(wú)源性理論的方法,建立VSC在同步旋轉(zhuǎn)dq坐標(biāo)系下的暫態(tài)非線性數(shù)學(xué)模型,驗(yàn)證了系統(tǒng)的無(wú)源性。外環(huán)采用定直流側(cè)電壓和定有功功率、無(wú)功功率來(lái)生成內(nèi)環(huán)dq軸參考電流id*,iq*；內(nèi)環(huán)采用無(wú)源性理論的控制方法,設(shè)計(jì)無(wú)源性控制器,用來(lái)追蹤參考電流,以達(dá)到控制直流側(cè)電壓和獨(dú)立調(diào)節(jié)有功和無(wú)

3、功功率的。最后,基于MATLAB的仿真結(jié)果表明了該控制器能實(shí)現(xiàn)有功功率和無(wú)功獨(dú)立控制,在負(fù)載擾動(dòng)的情況下,具有良好的暫態(tài)控制性能和很強(qiáng)的魯棒性。本文還建立了對(duì)無(wú)源網(wǎng)絡(luò)供電的VSC-HVDC輸電系統(tǒng)的數(shù)學(xué)模型,整流側(cè)采用狀態(tài)反饋精確線性化的方法對(duì)非線性數(shù)學(xué)模型進(jìn)行解耦,然后用變結(jié)構(gòu)的控制方法設(shè)計(jì)控制器；逆變側(cè)利用穩(wěn)態(tài)數(shù)學(xué)模型,利用前饋解耦的控制方法設(shè)計(jì)控制器。最后,基于MATLAB的仿真結(jié)果表明該控制器具有良好的啟動(dòng)和故障恢復(fù)性能,也能實(shí)現(xiàn)有功功率和無(wú)功獨(dú)立控制?！居⑽恼縒ith the development of self-commutated power electronic devi

4、ces (Insulated-Gate Bipolar Transistor, IGBT; Gate-Turn Off Thyrisitor, GTO and so on) and PWM technique, HVDC based on the Voltage Source Converter (VSC-HVDC) has got more and more attention. The VSC-HVDC transmission system has many advantages compared with the traditional HVDC system. For example

5、, it can realize the power supply to passive network, and avoid the risk of commutation failure, and obtain the individual control of active power and reactive power, and is also easy to construct multi-terminal DC system.Two nonlinear control strategies for the VSC-HVDC transmission system are main

6、ly studied in this paper. In the first strategy, a nonlinear transient mathematical model of VSC-HVDC transmission system in synchronously rotating dq frame is built. To design the controller for this nonlinear system directly, the approach of state feedback exact linearization is adopted to change

7、the nonlinear mathematical model into the linear one; then utilizing the variable structure control method, the controllers for rectifying side and inversion side are designed, thus the constant voltage at DC side and independent decoupling control for active power and reactive power can be implemen

8、ted.In the second strategy, a nonlinear transient mathematical model of VSC-HVDC in synchronously rotating dq frame is developed and the passivity of the system is also verified. In order to realize the decoupling control between the active power and reactive power, a dual closed loop control strate

9、gy is established. The control strategy includes an outer loop, which contains the DC voltage together with active and reactive power regulators used to generate the inner dq-axis reference currents id*,iq*; and an inner loop, which consists of a passivity-based current controller that applied to tr

10、ack the reference currents. Finally, a MATLAB-based simulation model is constructed for simulation analysis of the controllers proposed. Simulation results show that the designed controllers possess satisfied transient control performance and strong robustness.A nonlinear transient mathematical mode

11、l of VSC-HVDC system in synchronously rotating dq frame is developed. In rectifier side, the approach of state feedback exact linearization is adopted to change the nonlinear mathematical model into the linear one, and the variable structure control method is used to design controllers; in the inverter side, the feedforward decoupling control strategy is adopted to design controllers. At last, the MATLAB simulation results show that the controller has excellent startup and fault recovery performances, and can realize independent decoupling control for active and reactive power.【關(guān)鍵詞】電壓源換流器 高壓直