基于电压控制的三相逆变器并网谐波控制策略研究

发布时间：2018-09-14 14:56

【摘要】：非线性负载和分布式电源的大规模使用带来了一系列的电能质量问题。在实际应用中，即使并网逆变器不向电网注入谐波，电网中的大量非线性负载仍然会导致电网电压畸变。为了解决该问题，本文尝试将谐波补偿功能附加在并网逆变器中，研究表明，在对并网逆变器合理控制和规划的情况下，分布式电源就可以提高分布式电源的效率和电能质量。本文首先重点介绍了基于双二阶广义积分的软件锁相环技术，该锁相技术对谐波畸变不敏感，能够在畸变的电压背景下有效得提取出所需要的电网相角信息。其次对三相电压源型逆变器的并网两种控制策略，即电压控制和电流控制进行对比分析。主要对现如今常用的并网控制策略PQ控制、V/f控制分别进行介绍。对逆变器并网运行的仿真结果表明，两种方法都能顺利实现该策略的控制目标，效果良好。通常来说，有源电力滤波广泛应用电流控制来抑制谐波干扰。然而，对于并网应用，尤其是考虑到孤岛运行时，经常用到例如V-f控制等电压控制的方法，因为这种方法可以直接提供电压和频率补偿。如此看来，传统的有源滤波中所用的电流控制谐波补偿策略难以直接用于并网逆变器控制。为了克服这个缺陷，本课题研究了一种新颖的电压控制方法，该方法可以跟电压控制(如V-f控制、下垂控制等)分布式发电系统连接，这对微网中的电压和频率支持非常重要。本文对传统的基于电流控制的谐波抑制策略进行简单的回顾。在此基础上研究基于电压控制的谐波抑制策略。与基于电流控制的谐波抑制策略相比，这种方法在保证相同补偿效果的前提下，更加灵活可靠，并且实现了与并网逆变器基于电压控制的控制策略的融合。为了进一步验证本文使用的方案，搭建了以TMS320F2812DSP为核心控制单元的硬件平台，编写了系统软件程序，最后在实验平台上对方案进行了实验研究。结果表明，，本文可以通过控制并网逆变器来控制谐波，并且可以使并网逆变器灵活切换于谐波补偿、不补偿与谐波抑制三种模式，提高了并网逆变器的实用性
[Abstract]:Nonlinear load and large-scale use of distributed power have brought about a series of power quality problems. In practical applications, even if the grid-connected inverter does not inject harmonics into the grid, a large number of nonlinear loads in the power network will still lead to the voltage distortion of the grid. In order to solve this problem, this paper attempts to add harmonic compensation function to grid-connected inverter. The research shows that the efficiency and power quality of distributed power supply can be improved under the condition of reasonable control and planning of grid-connected inverter. In this paper, the software phase-locked loop technique based on two-order generalized integral is introduced. The phase-locked loop is insensitive to harmonic distortion and can extract the phase angle information of power network effectively under the background of distorted voltage. Secondly, the voltage control strategy and current control strategy of three phase voltage source inverter are compared and analyzed. This paper mainly introduces the current grid-connected control strategy, PQ control and V / F control, respectively. The simulation results of grid-connected inverter show that the two methods can achieve the control goal of the strategy successfully and the effect is good. In general, active power filter widely uses current control to suppress harmonic interference. However, voltage control methods such as V-f control are often used for grid-connected applications, especially considering the operation of isolated islands, because this method can directly provide voltage and frequency compensation. Therefore, the current control harmonic compensation strategy used in traditional active filter is difficult to be directly used in grid-connected inverter control. In order to overcome this shortcoming, a novel voltage control method is proposed, which can be connected with the voltage control (such as V-f control, droop control, etc.) distributed generation system, which is very important for the voltage and frequency support in the microgrid. In this paper, the traditional harmonic suppression strategy based on current control is reviewed briefly. On this basis, the harmonic suppression strategy based on voltage control is studied. Compared with the harmonic suppression strategy based on current control, this method is more flexible and reliable on the premise of the same compensation effect, and realizes the fusion with the voltage control strategy of grid-connected inverter. In order to further verify the scheme used in this paper, the hardware platform with TMS320F2812DSP as the core control unit is built, and the system software program is written. Finally, the experimental research on the scheme is carried out on the experimental platform. The results show that this paper can control harmonics by controlling grid-connected inverter, and can make grid-connected inverter switch to three modes of harmonic compensation, non-compensation and harmonic suppression, which improves the practicability of grid-connected inverter.
【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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