柔性直流输电系统主回路参数与系统运行行为的关系研究

发布时间：2018-07-17 22:03

【摘要】：柔性直流输电技术在风电并网工程、可再生能源并网工程、孤岛供电工程以及分布式发电并网工程等诸多领域得到了广泛应用,而主回路的参数以及控制系统的性能对整个系统的运行行为有着极为重要的影响。因此,研究柔性直流输电系统主回路参数与系统运行行为的关系,并基于此对主回路参数进行设计具有重要的现实意义。本文对柔性直流输电系统建模、控制器设计、主回路中的参数与系统运行行为的关系进行了研究,主要包括以下几个方面的内容:分析了柔性直流输电系统的运行机理,建立其在abc静止坐标系下的数学模型,考虑到在abc坐标下控制器设计的困难,建立了在dq旋转坐标下的数学模型。设计了基于直接电流控制的双闭环控制器,从系统传递函数的角度出发,采用极点配置的方法对内环电流控制器、外环电压控制器、外环功率控制器的PI参数进行设计。为了提高系统抗扰动性能,引入负载电流前馈控制对外环电压控制器进行了改进。研究了主回路参数与系统运行行为的关系。针对电感与系统运行行为的关系,分析了电感对电压源换流器四象限运行、快速电流跟踪、谐波电流抑制、功率因数的影响,基于此给出了满足这些性能指标的电感取值范围;针对电容与系统运行行为的关系,分析了电容对电压环跟随特性以及直流电压波动抑制的影响,并基于此给出了满足这些性能指标的电容取值范围。最后,在PSCAD/EMTDC平台搭建了一个柔性直流输电系统仿真模型,采用双闭环控制器,内环采用电流控制器,外环一端采用定有功功率、定无功功率控制,另一端采用定直流电压、定无功功率控制。根据文中给出的主回路电感和电容的设计方法,在搭建的仿真模型中对比分析了主回路参数变化时系统运行行为指标的变化。主回路参数选择之后的仿真结果验证了参数选择方法的正确性,所选择的主回路参数能够满足电压源换流器和控制器的正常运行,为实际工程应用打下了一定的基础。
[Abstract]:Flexible direct current transmission technology has been widely used in wind power grid connection project, renewable energy grid connection project, island power supply project and distributed generation grid connection project, etc. The parameters of the main loop and the performance of the control system have an extremely important impact on the operation behavior of the whole system. Therefore, it is of great practical significance to study the relationship between the main loop parameters and the operation behavior of the flexible direct current transmission system, and to design the main circuit parameters based on this. In this paper, the modeling of flexible direct current transmission system, the design of controller, the relationship between the parameters in the main loop and the operation behavior of the system are studied. The main contents are as follows: the operation mechanism of the flexible direct current transmission system is analyzed. The mathematical model in abc stationary coordinate system is established. Considering the difficulty of controller design in abc coordinate, the mathematical model under dq rotation coordinate is established. A double closed loop controller based on direct current control is designed. From the point of view of system transfer function, the Pi parameters of inner loop current controller, outer loop voltage controller and outer loop power controller are designed by pole assignment method. In order to improve the anti-disturbance performance of the system, the load current feedforward control is introduced to improve the outer loop voltage controller. The relationship between the main loop parameters and the operation behavior of the system is studied. In view of the relationship between inductance and system operation behavior, the influence of inductor on the four-quadrant operation of voltage source converter, fast current tracking, harmonic current suppression and power factor is analyzed. Based on this, the range of inductance to meet these performance indexes is given. In view of the relationship between capacitance and system operation behavior, the influence of capacitance on the following characteristics of voltage loop and the suppression of DC voltage fluctuation is analyzed. Based on this, the range of capacitance values satisfying these performance indexes is given. Finally, a simulation model of the flexible DC transmission system is built on the PSCAD / EMTDC platform, which adopts a double closed loop controller, a current controller in the inner loop, a constant active power, a constant reactive power control at one end of the outer loop, and a constant DC voltage at the other end. Constant reactive power control. According to the design method of the inductance and capacitance of the main loop in this paper, the variation of the operating behavior index of the system when the parameters of the main loop are changed is compared and analyzed in the simulation model. The simulation results after selecting the main circuit parameters verify the correctness of the parameter selection method. The selected main circuit parameters can meet the normal operation of the voltage source converter and controller, which lays a certain foundation for the practical engineering application.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM721.1

【参考文献】