基于全桥LLC多谐变换器微型三相逆变器的研究

发布时间：2018-03-25 15:05

本文选题：全桥LLC　切入点：无差拍　出处：《江苏大学》2017年硕士论文

【摘要】：能源是人类社会生产生活的基础,但现今大量使用化石燃料正带来了一系列环境问题。以风能、太阳能为主的新能源发电,以其可再生、广泛存在、无污染等优点,正逐渐成为化石能源的替代品,也为世界解决环境污染与能源短缺这一问题提供了新途径。随着微型逆变器在商业应用中不断增加,三相微型逆变器以其发电效率高、三相功率平衡等独特优点得到了越来越多的发展。本课题研究的对象是分布式新能源发电中的两级式三相微型逆变器,主要讨论逆变器的控制优化。首先,运用数学方法推导了逆变器的模型,通过数学运算建立逆变器在不同坐标系下的数学模型。然后针对传统PI控制无法解决逆变器输出电流静态误差且参数整定困难、系统超调过大等问题,阐述了一种基于直接功率控制的无差拍控制策略,以解决MCU在控制上和采样上的延时效应问题。在本课题中的DC/DC升压环节采用的是全桥LLC多谐变换器,此变换器最大的优点是可以在全负载范围内实现软开关,在获得高增益的同时大大降低升压过程中的开关损耗,从而提高整机能量转换效率和功率密度。在本课题中的DC/AC逆变环节中,应用了软件锁相环技术而非传统的硬件锁相,指出了过零点锁相在复杂电网条件下的弊端。说明了DSOGI锁相环的基本结构和分析了其工作原理,并针对其在电网含有较多谐波时暴露出的缺点做出优化,使用了一种具有谐波消除功能的MSOGI锁相环并获得较好效果。在对本文中所提的理论详细分析后,利用Matlab/Simulink、PSIM等软件,对电路各个模块创建了仿真模型,在满足系统要求基础上对前文的理论进行验证,证明了无差拍控制方法对逆变系统调整控制的可行性。搭建实验样机,详细说明了逆变系统各个部分的硬件电路设计。使用TI公司的高性能DSP处理芯片TMS320F28035作为实验样机的控制芯片,实现了电流无差拍控制与SVPWM调制方式,最终证明了本系统的可行性。
[Abstract]:Energy is the basis of human society's production and life, but nowadays the extensive use of fossil fuels is bringing a series of environmental problems. The new energy, mainly wind energy and solar energy, has the advantages of renewable, widespread, pollution-free, and so on. It is becoming a substitute for fossil energy and provides a new way to solve the problem of environmental pollution and energy shortage in the world. With the increasing commercial application of micro-inverters, three-phase micro-inverters have high power generation efficiency. The unique advantages of three-phase power balance have been more and more developed. The object of this research is the two-stage three-phase miniature inverter in distributed new energy generation, which mainly discusses the control optimization of the inverter. The mathematical model of inverter is derived by mathematical method, and the mathematical model of inverter in different coordinate system is established by mathematical operation. Then, the static error of output current and the difficulty of parameter setting can not be solved by traditional Pi control. In order to solve the problem of delay effect of MCU in control and sampling, a non-beat control strategy based on direct power control is presented. In this paper, the full-bridge LLC multi-harmonic converter is used in the DC/DC boost. The biggest advantage of this converter is that it can realize soft switching in the full load range and reduce the switching loss in the boost process while obtaining high gain. In order to improve the energy conversion efficiency and power density of the whole machine, the software phase-locked loop technology is used in the DC/AC inverter of this subject instead of the traditional hardware phase-locked loop. This paper points out the disadvantages of zero-crossing phase-locked loop in complex power system, explains the basic structure of DSOGI PLL and analyzes its working principle, and optimizes its shortcomings when there are more harmonics in the power network. A kind of MSOGI phase-locked loop with harmonic elimination function is used and good results are obtained. After detailed analysis of the theory proposed in this paper, a simulation model is created for each module of the circuit by using Matlab / Simulink PIM software. On the basis of satisfying the requirements of the system, the above theory is verified, and the feasibility of adjusting the control of the inverter system by the non-beat control method is proved. The experimental prototype is built. The hardware circuit design of each part of the inverter system is described in detail. Using TI's high performance DSP processing chip TMS320F28035 as the control chip of the experimental prototype, the current non-beat control and the SVPWM modulation mode are realized. Finally, the feasibility of the system is proved.
【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】：TM46;TM464

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