电压源换流器论文轻型高压直流输电系统的非线性控制策略研究

1、电压源换流器论文：轻型高压直流输电系统的非线性控制策略研究【中文摘要】随着可关断电力电子器件(Insulated-gate Bipolar Transistor, IGBT; Gate-Turn Off Thyrisitor, GTO等)和PWM技术的发展,基于电压源换流器的轻型高压直流输电(Voltage Sourced Converter-High Voltage Direct Current, VSC-HVDC)系统越来越受到人们的关注。与传统的HVDC输电系统相比,该输电技术具有可向无源网络供电、无换相失败危险、有功功率和无功功率独立控制和易于构成多端直流输电系统等优点。本文着重研究V

2、SC-HVDC输电系统的非线性控制策略。第一种方法,建立起双端无穷大VSC-HVDC输电系统在同步旋转dq坐标系下的暂态非线性数学模型,采用状态反馈精确线性化的方法,把非线性的数学模型转化成线性的形式。然后,运用变结构的控制方法,设计整流侧和逆变侧的控制器,从而实现直流侧电压恒定和有功、无功功率的独立解耦控制；第二种采用无源性理论的方法,建立VSC在同步旋转dq坐标系下的暂态非线性数学模型,验证了系统的无源性。外环采用定直流侧电压和定有功功率、无功功率来生成内环dq轴参考电流id*,iq*；内环采用无源性理论的控制方法,设计无源性控制器,用来追踪参考电流,以达到控制直流侧电压和独立调节有功和无

3、功功率的。最后,基于MATLAB的仿真结果表明了该控制器能实现有功功率和无功独立控制,在负载扰动的情况下,具有良好的暂态控制性能和很强的鲁棒性。本文还建立了对无源网络供电的VSC-HVDC输电系统的数学模型,整流侧采用状态反馈精确线性化的方法对非线性数学模型进行解耦,然后用变结构的控制方法设计控制器；逆变侧利用稳态数学模型,利用前馈解耦的控制方法设计控制器。最后,基于MATLAB的仿真结果表明该控制器具有良好的启动和故障恢复性能,也能实现有功功率和无功独立控制。【英文摘要】With 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.【关键词】电压源换流器 高压直