基于DSP的智能化光伏并网逆变器设计

发布时间：2018-02-23 23:37

本文关键词： 光伏逆变器 DSP 智能化双闭环 MPPT　出处：《广东工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：目前,随着我国能源结构的逐步调整和国家政策的不断改革,分布式小型光伏并网发电正在逐步向单位和个人开放,分布式并网发电即将成为光伏发电的主流。并网逆变器是光伏并网发电系统的关键环节,因此设计智能、高效、可靠的小型光伏并网逆变器,促进分布式光伏并网发电系统的普及与应用,将具有十分重要的现实意义。本文以DSP控制的2KW两级式无变压器光伏并网逆变器为设计目标,详尽叙述了逆变器的设计过程。首先,在分析了国内外逆变器发展现状和关键技术的基础上确立了逆变器的目标参数,并根据目标参数确立了整体设计方案。硬件部分：主电路采用两级式无变压器拓扑结构、控制电路选用了DSP2812作为主控芯片。控制算法部分：确立了最大功率点跟踪(Maximum Power Point Tracking,MPPT)控制算法、并网逆变控制策略、锁相环(Phase Locked Loop,PLL)同步锁相算法、正弦脉宽调制(Sinusoidal Pulse Width Modulation, SPWM)生成与控制方式、PID控制算法。接着分模块对逆变器进行了硬件电路设计,包括硬件总体结构、DC/DC Boost升压电路参数、DC/AC全桥逆变电路参数、DSP核心板、DSP控制底板、IGBT驱动板、反激式开关电源板的设计,给出了具体的参数设计推导过程和电路原理图。然后具体阐述了逆变器的MPPT控制算法、双闭环并网逆变控制策略和SPLL控制算法。通过对扰动观察法的改进并结合DC/DC Boost升压电路的特点,实现了变步长占空比扰动法的MPPT控制算法；以对称规则采样SPWM波生成方法和增量式PI算法为基础,在DC/AC全桥逆变电路中实现了基于SPWM的双闭环并网逆变控制策略;利用DSP的CAP捕获单元,分频率跟踪和相位同步两部分,实现了网压的SPLL控制算法。最后对逆变器的软件程序进行了设计,包括DSP程序设计步骤和优化方法、DSP资源分配、软件总体规划、主程序设计、子程序设计及ARM人机界面设计,给出了具体的软件实现过程和程序流程图。同时搭建了实验平台,对逆变器进行了软硬件集成实验,得出了实验结果,并对结果进行了分析。实验结果表明所设计的逆变器基本达到了预期的设计要求。
[Abstract]:At present, with the gradual adjustment of China's energy structure and the continuous reform of national policies, distributed small-scale photovoltaic grid-connected power generation is gradually opening to units and individuals. Grid-connected inverter is the key link of grid-connected photovoltaic power generation system, so it is necessary to design intelligent, efficient and reliable small-scale photovoltaic grid-connected inverter. It will be of great practical significance to promote the popularization and application of distributed photovoltaic grid-connected generation system. In this paper, the design process of 2KW two-stage transformerless photovoltaic grid-connected inverter controlled by DSP is described in detail. Firstly, the target parameters of inverter are established on the basis of analyzing the current situation and key technologies of inverter at home and abroad. According to the target parameters, the overall design scheme is established. The hardware part: the main circuit adopts a two-stage transformer free topology, In the control circuit, DSP2812 is selected as the main control chip. Part of the control algorithm, the maximum Power Point tracking control algorithm, the grid-connected inverter control strategy, the phase-locked loop phase Locked Loop PLL synchronous phase-locking algorithm are established. Sinusoidal Pulse Width Modulation (SPWM) generation and control methods are used in pid control algorithm. Then, the hardware circuit of the inverter is designed, including the design of the DC / DC DC / DC Boost boost circuit parameters and the DC / AC full-bridge inverter circuit parameters such as the DSPs core board, the DSP control board, the IGBT drive board, the flyback switch power supply board, the design of the DC / AC full-bridge inverter circuit parameters and the design of the DC / AC full-bridge inverter circuit parameters. The design and derivation process of parameters and the circuit schematic diagram are given. Then, the MPPT control algorithm of inverter, double closed loop grid-connected inverter control strategy and SPLL control algorithm are introduced in detail. The disturbance observation method is improved and the characteristics of DC/DC Boost boost circuit are combined. The MPPT control algorithm of variable step duty cycle perturbation method is implemented, and based on the symmetric regular sampling SPWM wave generation method and incremental Pi algorithm, the double closed loop grid-connected inverter control strategy based on SPWM is implemented in the DC/AC full-bridge inverter circuit. The SPLL control algorithm of network voltage is realized by using the CAP acquisition unit of DSP, which is divided into two parts: frequency tracking and phase synchronization. Finally, the software program of the inverter is designed, including the steps and optimization methods of DSP programming, software master planning, main program design, subprogram design and ARM man-machine interface design. At the same time, the experiment platform is built, and the hardware and software integration experiment of the inverter is carried out, the experimental results are obtained and the results are analyzed. Experimental results show that the designed inverter basically meets the expected design requirements.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464;TM615

【引证文献】