【作者】 史磊；

【导师】 王蔚； 邵方媛；

【作者基本信息】 长春工业大学 ， 电气工程（专业学位）， 2018， 硕士

【摘要】 国家能源的短缺以及环境恶化影响着着人民生活、阻碍着社会发展,风能作为清洁能源之一在世界新型可再生能源序列中发展十分迅速。各高效和各研发机构对风电机组和并网逆变器的控制技术研究促进了风能在我国的发展利用,在此发展背景下,本文主要针对变速恒频双馈风力发电系统的最大风能追踪、变速恒频及能量的双向流动技术和逆变器并网控制技术做主要研究,具体内容如下:简要分析风力发电技术的发展方向和基本概念以及双馈风力发电系统的理论基础。根据现在科学研究的成果,建立了两相同步旋转坐标系下双馈电机的数学模型,以此模型分析了电网电压恒定条件下的两种传统矢量控制技术。根据转子侧和电网侧变换器的控制目标,建立了变换器的数学模型。根据变速恒频风力发电系统在四个不同区域的运行状态,给出了有功功率参考值的精确计算,使与系统框图相结合。最后通过仿真验证了转子侧变换器的控制系统。双馈发电机可以很好地响应风速的变化,及时调整发电机的转速,并使其以最佳速度工作。当双馈发电机在不同状态切换时,从转子侧输出的电流波形中可以看到转子侧变换器很好地实现了能量的双向流动以及保证了频率稳定性。针对网侧变换器的工作原理和数学模型提出基于dq变换的前馈解耦PQ控制控制并网年逆变器。风电并网运行时,通过软件锁相技术(PLL)从电网处获取相位和频率信息,传递给PQ控制器,再通过PQ控制器得到逆变器输出的功率P和Q,经过功率计算得出电流内环的参考值,有功与无功的参考值分别根据双馈电机输出功率来设定。这时将逆变器的输出电流在上述旋转dq坐标系下分解后获得两个电流分量,进而得到有功、无功瞬时表达式,使并网逆变器输出电能满足电网需求。最后在MATLAB/Simulink环境下对双馈风力发电机和并网逆变器建立了仿真模型,仿真结果证明了对风力发电机的采用的的控制技术能够满足双馈电机的运行要求,在电网电压恒定的条件下系统的静态和动态性能良好。对并网逆变器采用的控制技术能够恒功率输出,逆变器输出的电压电流波形满足并网要求。验证了所采用控制技术的正确性、科学性,对我国在风电的发展进程中有一定推动作用。更多还原

【Abstract】 National energy shortages and environmental degradation affect people’s lives and hinder social development.Wind energy,as one of clean energy,has developed rapidly in the world’s new renewable energy sequence.Various high-efficiency and R&D institutions’ research on control technologies for wind turbines and grid-connected inverters has promoted the development and utilization of wind energy in China.Under this background,this paper focuses on the maximum wind energy tracking of variable-speed constant-frequency doubly-fed wind power generation systems.The main research of VSCF and energy two-way flow technology and inverter grid-connected control technology is as follows:Briefly analyze the development direction and basic concepts of wind power generation technology and the theoretical basis of doubly-fed wind power generation system.Based on the results of current scientific research,a mathematical model of a doubly-fed machine in a two-phase synchronous rotating coordinate system was established.Based on this model,two conventional vector control techniques under constant voltage conditions of the grid were analyzed.Based on the control objectives of the rotor-side and grid-side converters,a mathematical model of the converter was established.According to the operating status of the VSCF wind power system in four different regions,the accurate calculation of the reference value of the active power is given,which is combined with the system block diagram.Finally,the rotor-side converter control system was verified by simulation.Doubly-fed generators can respond well to changes in wind speed,adjust the speed of the generator in time,and make it work at optimal speed.When the doubly-fed generator is switched in different states,it can be seen from the current waveform output from the rotor side that the rotor-side converter well realizes bidirectional flow of energy and ensures frequency stability.According to the working principle and mathematical model of the grid-side converter,a feed-forward decoupled PQ control and grid-connected year inverter based on dq transformation is proposed.When the wind power is connected to the grid,the phase and frequency information is obtained from the power grid through the software phase lock technology(PLL)and passed to the PQ controller.The power P and Q of the inverter output are obtained through the PQ controller and calculated through the power calculation.Reference values of the current inner loop,active and reactive reference values are set according to the output power of the doubly fed motor.At this moment,the output current of the inverter is decomposed in the above-mentioned rotating coordinate system to obtain two current components,and then the instantaneous expressions of active and reactive power are obtained,so that the output power of the grid-connected inverter meets the power grid demand.Finally,a simulation model for doubly-fed wind generators and grid-connected inverters was established in MATLAB/Simulink environment.The simulation results proved that the control technology adopted for wind turbines can meet the operational requirements of doubly-fed machines,and the grid voltage The static and dynamic performance of the system is good under constant conditions.The control technology used for the grid-connected inverter can be constant power output,and the voltage and current waveforms output by the inverter meet the grid connection requirements.It verifies the correctness and scientificity of the control technology used,and it has a certain role in promoting the development of wind power in China.更多还原