基于虚拟同步发电机的定子双绕组异步风电系统并网运行与控制

发布时间：2018-05-14 10:22

本文选题：定子双绕组异步发电机 + 虚拟同步发电机　；参考：《江苏大学》2017年硕士论文

【摘要】：随着能源短缺与环境保护问题的日益突出,极大地推动了风力发电的发展。用于风力发电的定子双绕组异步发电机具有结构简单、无刷、可靠性高等特点而被受到广泛关注。采用虚拟同步发电机控制技术的并网逆变器与电网相连,可提高定子双绕组异步发电机系统的并网友好性。随着风电系统的渗透力越来越高,风电并网系统必须具备低电压穿越的能力。论文以基于虚拟同步发电机的定子双绕组异步发电机并网和低电压穿越为研究对象,主要包括以下内容:首先,建立定子双绕组异步发电机并网系统前级的数学模型。在对控制绕组电流解耦的基础上,采用电压外环、电流内环的双闭环控制策略,保证了发电机输出电压的稳定性。然后,建立定子双绕组异步发电机并网系统后级的数学模型,建立起有功功率、无功功率与频率、相角、电压幅值之间的关系,通过预同步控制策略实现虚拟同步发电机的平滑并网。在采用虚拟同步发电机控制技术并网的基础上,建立电网故障下逆变器的数学模型,通过对电网故障过程进行分析,提出基于PR电流控制器的算法,与虚拟同步发电机的控制算法的切换,从而实现电网故障下虚拟同步发电机的低电压穿越,通过仿真验证了电网故障下PR电流控制器的可行性和正确性。在电网故障发生时刻,采用切换控制算法来限制并网电流,并向电网提供无功功率,通过相角的同步实现正常状态变成故障状态的平滑切换。另一方面,电网由故障状态变成正常状态,待电网故障结束后50ms至200ms之内可直接进行两个模式的切换,使系统运行于正常并网的控制算法。通过仿真验证了虚拟同步发电机的低电压穿越控制策略的可行性和稳定性。设计了定子双绕组异步发电机系统的硬件和软件。硬件上完成了功率器件的选型、控制侧滤波电感的设计、直流侧电容的和励磁电容的设计,并对发电机侧控制电路的关键参数进行分析。软件上完成了程序的初始化、电压和电流的采样、数据的定标与一阶惯性滤波、定向角度求取、坐标变换、电流滞环比较等。最后,通过一台原动机代替风力机拖动发电机运行,采用电压外环、电流内环的双闭环系统,实现了定子双绕组异步发电机系统的发电。
[Abstract]:With the energy shortage and environmental protection problems becoming increasingly prominent, the development of wind power generation has been greatly promoted. The stator double winding asynchronous generator used in wind power generation is widely concerned because of its simple structure, brushless structure and high reliability. The grid-connected inverter with virtual synchronous generator control technology is connected to the power grid, which can improve the grid-friendliness of the stator double-winding asynchronous generator system. With the increasing permeability of wind power system, wind power grid connection system must have the ability of low voltage traversing. In this paper, the stator double winding asynchronous generator based on virtual synchronous generator and low voltage traversing are taken as the research object. The main contents are as follows: firstly, the mathematical model of the stator double winding asynchronous generator grid-connected system is established. On the basis of decoupling the control winding current, the output voltage stability of the generator is ensured by using the double closed loop control strategy of the voltage outer loop and the current inner loop. Then, the mathematical model of the back stage of the stator double-winding asynchronous generator grid-connected system is established, and the relationship between active power, reactive power and frequency, phase angle and voltage amplitude is established. The smooth grid connection of virtual synchronous generator is realized by pre-synchronous control strategy. On the basis of using virtual synchronous generator control technology to connect to grid, the mathematical model of inverter under power network fault is established, and the algorithm based on PR current controller is put forward by analyzing the fault process of power network. The low voltage traversing of the virtual synchronous generator is realized by switching with the control algorithm of the virtual synchronous generator, and the feasibility and correctness of the PR current controller under the power network fault are verified by simulation. The switching control algorithm is used to limit the grid-connected current and to provide reactive power to the power network at the time of the fault. The smooth switching of the normal state into the fault state can be realized by synchronizing the phase angle. On the other hand, the power network changes from the fault state to the normal state. After the fault is over, two modes can be switched directly from 50ms to 200ms, which makes the system run in the normal grid-connected control algorithm. The feasibility and stability of the low voltage traversing control strategy of virtual synchronous generator are verified by simulation. The hardware and software of the stator double winding asynchronous generator system are designed. The selection of power devices, the design of control side filter inductors, the design of DC side capacitors and excitation capacitors are completed in hardware, and the key parameters of generator side control circuit are analyzed. The program initialization, voltage and current sampling, data calibration and first-order inertial filtering, orientation angle calculation, coordinate transformation, current hysteresis comparison and so on have been completed in the software. Finally, the generator is driven by a prime mover instead of the wind turbine, and the stator windings asynchronous generator system is realized by using a double closed loop system of voltage outer loop and current inner loop.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM614;TM315

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