基于下垂控制的三电平逆变器并脱网平滑切换研究

发布时间：2018-03-24 16:29

本文选题：分布式发电　切入点：双模式运行　出处：《燕山大学》2014年硕士论文

【摘要】：随着环境和能源问题的日益严重，，人们越来越重视可再生能源的开发与利用。分布式发电技术的优势在于可以充分利用各种分散存在的可再生能源，现已成为新能源应用的主要手段。大电网与分布式发电系统相结合是降低投资，减少能耗，提升系统供电可靠性、灵活性的主要方法，是未来的主要研究方向。分布式发电系统在孤岛运行模式与并网运行模式之间的无缝切换是实现大电网与分布式发电系统相结合的研究重点，也正是本文的研究内容。本文首先分析了二极管箝位三电平逆变器的工作原理和调制方法，针对传统空间矢量调制扇区判断复杂、三角函数运算多等问题提出了一种改进的空间矢量调制算法。该算法可以实现一步判断出目标矢量所在扇区，且无三角函数运算，更适用于FPGA控制，节省大量资源与时间。本文接着研究了适用于下垂控制的主动同步算法，在分析前人研究成果的基础上，简化了主动同步控制器的结构，使得控制更简单有效。然后针对使用传统下垂控制的逆变器在并网切换时会产生有功冲击，在并网稳定运行时存在无功交换的问题，提出了一种改进下垂控制方法。该方法消除了有功冲击和无功交换，实现了两种模式间的无缝切换。最后对本文提出的改进进行了仿真验证，并搭建了二极管箝位三电平逆变并网平台，采用DSP和FPGA组成主控电路，编写了完整的控制程序，通过实验证明了本文提出的控制方法的正确性。
[Abstract]:With the increasingly serious environmental and energy problems, people pay more and more attention to the development and utilization of renewable energy. The advantage of distributed power generation technology is that it can make full use of a variety of distributed renewable energy sources. The combination of large power grid and distributed generation system is the main way to reduce investment, reduce energy consumption, improve the reliability and flexibility of power supply. The seamless switching of distributed generation system between island operation mode and grid-connected operation mode is the focus of research on the combination of large power grid and distributed generation system, which is also the research content of this paper. In this paper, the working principle and modulation method of diode clamped three-level inverter are analyzed. In this paper, an improved space vector modulation algorithm is proposed for many trigonometric function operations. This algorithm can be used to determine the sector of the target vector in one step, and has no trigonometric function operation, so it is more suitable for FPGA control. This paper then studies the active synchronization algorithm suitable for droop control, and simplifies the structure of active synchronization controller based on the analysis of previous research results. It makes the control simpler and more effective. Then, the inverter with traditional droop control will produce active power impact when switching grid-connected, and there is the problem of reactive power exchange in the stable operation of grid-connected. An improved droop control method is proposed, which eliminates active power shock and reactive power exchange, and realizes seamless switching between the two modes. Finally, the improvement is simulated and verified, and a diode clamped three-level inverter grid-connected platform is built. The main control circuit is composed of DSP and FPGA, and a complete control program is written. The experimental results show that the proposed control method is correct.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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