并网变流器的无电压传感器控制方法研究
发布时间：2019-04-07 15:37
【摘要】：新能源分布式发电凭借其环境友好,可再生等优点,并网电能比重不断增加,但在高渗透率并网接入的背景下,对传统电网的规划设计与稳定运行带来挑战。功率变换器件具有实时性、准确性和高效性等一些突出优点,可以促进可再生能源发电系统与大电网系统之间能量的高效、灵活转化,这对于推动未来智能电网的发展起到重要作用。无电压传感器方法在并网变流器中的应用能够节省一定的硬件资源,提高系统运行的可靠性,对扩展可再生能源开发和优化配电网的运行与建设具有重要意义。首先针对三相三线制电压型PWM变流器介绍了其在不同坐标系中数学模型及基本控制策略,分析了瞬时功率理论在功率变换器件中的应用并阐述变流器在自然坐标系中基于电压定向的控制策略。然后系统阐述了无电压传感器控制策略方法的研究,包括基于虚拟电机磁链的无电压传感器方法,提出基于二阶广义积分滤波原理的无电压传感器观测方法以及基于三阶广义积分滤波原理的无电压传感器观测方法,并统一在自然坐标系中利用估算所得电压信息进行定向控制。按照平均值模型方法结合占空比信号来代替传统开关信号重新描述变流器模型,论证了所提基于广义积分方法所构建出的电压观测环节的方法。进一步的对比分析了三种无电压传感器方法所得网侧电压估算值,利用快速傅里叶变换绘出估算电压谐波含量图,比较了各方法所得电压的总谐波畸变率大小。在同等实验条件下,针对三种无电压传感器方法分别加入一定量的直流偏移分量,得出基于三阶广义积分滤波的无电压传感器方法具有更好的抑制直流分量的功能,并测试该策略在接入光伏并网逆变工作状态中的性能。最后,基于dSPACE搭建了并网变流器实验平台并验证文中所述三种无电压传感器控制策略。对比分析试验结果表明,在自然坐标系中基于三种无电压传感器方法所得电压估算信息进行定向控制均可良好运行,其中基于广义积分方法所得网侧电压信息较传统基于虚拟电机磁链方法其总谐波畸变率更小,具有更好的准确性,且基于三阶广义积分滤波的电压估算方法具有更好直流分量抑制能力。
[Abstract]:New energy distributed power generation has the advantages of environment-friendly and renewable, and the proportion of grid-connected electric energy is increasing. However, under the background of high permeability connected to the grid, it brings challenges to the planning and design and stable operation of the traditional power grid. The power converter has some outstanding advantages, such as real-time, accuracy and high efficiency, which can promote the efficient and flexible conversion of energy between the renewable energy generation system and the large power grid system. This plays an important role in promoting the future development of smart grid. The application of voltage sensor-free method in grid-connected converter can save a certain amount of hardware resources and improve the reliability of system operation. It is of great significance to expand the development of renewable energy and optimize the operation and construction of distribution network. Firstly, the mathematical model and basic control strategy of three-phase three-wire voltage source PWM converter in different coordinate systems are introduced. The application of instantaneous power theory in power converter is analyzed and the control strategy based on voltage orientation in natural coordinate system is expounded. Then, the control strategy of voltage-free sensor is studied systematically, including the method of voltage-free sensor based on virtual motor flux linkage. Based on the second-order generalized integral filtering principle and the third-order generalized integral filtering principle, a voltage-free sensor-free observation method is proposed. And unified in the natural coordinate system using the estimated voltage information for directional control. According to the mean value model method and duty cycle signal to replace the traditional switching signal to redescribe the converter model, the proposed method of voltage observation based on the generalized integral method is demonstrated. The network side voltage estimation values obtained by three non-voltage sensor methods are compared and analyzed. The estimated voltage harmonic content diagram is plotted by fast Fourier transform, and the total harmonic distortion rate of the voltage obtained by each method is compared. Under the same experimental conditions, the voltage-free sensor method based on the third-order generalized integral filter can restrain the DC component better than the other three non-voltage sensor methods, by adding a certain amount of DC offset components to each of the three non-voltage sensor methods, which is based on the third-order generalized integral filtering. The performance of this strategy in grid-connected inverter is tested. Finally, a grid-connected converter experimental platform is built based on dSPACE, and the three control strategies without voltage sensor are verified. The experimental results show that the directional control based on the voltage estimation information obtained by three non-voltage sensor methods can operate well in the natural coordinate system. Compared with the traditional virtual motor flux linkage method, the total harmonic distortion rate is smaller and the accuracy is better than the traditional virtual motor flux method, which is based on the generalized integral method to obtain the voltage information on the grid side. The voltage estimation method based on the third-order generalized integral filter has better DC component suppression ability.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46
本文编号：2454169
[Abstract]:New energy distributed power generation has the advantages of environment-friendly and renewable, and the proportion of grid-connected electric energy is increasing. However, under the background of high permeability connected to the grid, it brings challenges to the planning and design and stable operation of the traditional power grid. The power converter has some outstanding advantages, such as real-time, accuracy and high efficiency, which can promote the efficient and flexible conversion of energy between the renewable energy generation system and the large power grid system. This plays an important role in promoting the future development of smart grid. The application of voltage sensor-free method in grid-connected converter can save a certain amount of hardware resources and improve the reliability of system operation. It is of great significance to expand the development of renewable energy and optimize the operation and construction of distribution network. Firstly, the mathematical model and basic control strategy of three-phase three-wire voltage source PWM converter in different coordinate systems are introduced. The application of instantaneous power theory in power converter is analyzed and the control strategy based on voltage orientation in natural coordinate system is expounded. Then, the control strategy of voltage-free sensor is studied systematically, including the method of voltage-free sensor based on virtual motor flux linkage. Based on the second-order generalized integral filtering principle and the third-order generalized integral filtering principle, a voltage-free sensor-free observation method is proposed. And unified in the natural coordinate system using the estimated voltage information for directional control. According to the mean value model method and duty cycle signal to replace the traditional switching signal to redescribe the converter model, the proposed method of voltage observation based on the generalized integral method is demonstrated. The network side voltage estimation values obtained by three non-voltage sensor methods are compared and analyzed. The estimated voltage harmonic content diagram is plotted by fast Fourier transform, and the total harmonic distortion rate of the voltage obtained by each method is compared. Under the same experimental conditions, the voltage-free sensor method based on the third-order generalized integral filter can restrain the DC component better than the other three non-voltage sensor methods, by adding a certain amount of DC offset components to each of the three non-voltage sensor methods, which is based on the third-order generalized integral filtering. The performance of this strategy in grid-connected inverter is tested. Finally, a grid-connected converter experimental platform is built based on dSPACE, and the three control strategies without voltage sensor are verified. The experimental results show that the directional control based on the voltage estimation information obtained by three non-voltage sensor methods can operate well in the natural coordinate system. Compared with the traditional virtual motor flux linkage method, the total harmonic distortion rate is smaller and the accuracy is better than the traditional virtual motor flux method, which is based on the generalized integral method to obtain the voltage information on the grid side. The voltage estimation method based on the third-order generalized integral filter has better DC component suppression ability.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46
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