【作者】 吴波；

【导师】 薛家祥； 郑照红；

【作者基本信息】 华南理工大学 ， 工程硕士（专业学位）， 2019， 硕士

【摘要】 光伏发电在国内外发展迅猛,已然成为电网的重要组成部分。光伏发电和储能系统相结合是光伏发电的发展趋势,其有效缓解了光伏功率波动的问题,减少对电网的冲击,降低光伏能量弃光率。论文通过分析光伏技术的发展方向,提出课题的研究意义和背景。本文对光伏储能发电系统软硬件进行设计,在建立的硬件平台基础上,对光伏MPPT控制、并网控制、充放电控制以及能量分级管理进行研究。论文主要完成如下工作:(1)基于直流母线结构设计3KW光伏储能发电系统硬件结构。设计“Boost+全桥”光伏并网系统和“推挽+移相全桥”充放电系统。对各功率电路磁性元件及功率器件进行设计与选型,仿真验证结果表明所设计的硬件电路满足系统运行要求。(2)研究光伏储能发电系统各功能模块控制算法。在前级Boost最大功率跟踪装置中,采用基于模糊控制的扰动观察法,实现变步长MPPT跟踪,仿真结果表明该控制算法有较好的追踪精度,动态响应速度快,光伏功率波动时系统可在0.3s内重新稳定;在后级全桥电路并网过程中,采用“电压PI外环+电流PR内环”控制方法,提升了系统并网性能,仿真结果显示并网谐波可降低至3.37%;在蓄电池充放电过程中,对电压电流进行双闭环控制,实现改进型四阶段充电算法。(3)研究光伏储能系统的能量管理策略。基于母线电压分级法分析系统的多种运行工作模式及能量流动方向,对离网与并网切换过程中控制方法进行分析。为实现光伏储能发电系统的监控管理,基于WiFi232模块实现对整个光伏储能发电系统的本地监控以及阿里云端监控。实验结果表明监控平台能够稳定可靠地实现预定功能。(4)在自行研制样机的基础上建立了试验平台,对辅助电源、信号调理电路、最大功率跟踪、充放电系统进行验证试验,并进行系统模式切换测试。试验结果表明所设计的系统有良好的工作性能:前级Boost电路最大功率点跟踪效率可以达到99.89%,并能够实现多峰追踪功能;后级全桥电路进行离并网和整流试验,离网输出稳定,动态响应速度快,额定功率下并网谐波低至3.86%,功率因数高达98.84%;系统工作模式切换过程中,无明显电压电流尖峰冲击,实现工作模式的快速平稳过渡。更多还原

【Abstract】 With the rapid development of photovoltaic power generation at home and abroad,it has become an important part of the power grid.The combination of photovoltaic power generation and energy storage system is the development trend of photovoltaic power generation,which effectively alleviates the problem of photovoltaic power fluctuation,reduces the impact on the grid,and reduces the photovoltaic energy abandonment rate.Through the analysis of the development direction of photovoltaic technology,the research significance and background of the subject are put forward.In this paper,the software and hardware of photovoltaic energy storage power generation system are designed.Based on the hardware platform,photovoltaic MPPT control,grid-connected control,charge and discharge control and energy hierarchical management are studied.The main work of this paper is as follows:(1)The hardware structure of 3KW photovoltaic energy storage power generation system is designed based on DC bus structure.The "Boost + Full Bridge" photovoltaic grid-connected system and the "Push-Pull + Phase-Shift Full Bridge" charging and discharging system are designed.The magnetic components and power devices of each power circuit are designed and selected.The simulation results show that the designed hardware circuit meets the system operation requirements.(2)The control algorithm of each functional module of photovoltaic energy storage power generation system is studied.In the former Boost maximum power tracking device,the disturbance observation method of fuzzy control is used to realize MPPT tracking with variable step size.The simulation results show that the control algorithm has good tracking accuracy,fast dynamic response,and the system can be stabilized within 0.3 seconds when the photovoltaic power fluctuates.In the latter full-bridge circuit grid-connected process,the control method of "voltage PI outer loop + current PR inner loop" is adopted.The simulation results show that the grid-connected harmonics can be reduced to 3.37%.When the battery is working,the voltage and current in the charging and discharging process are controlled,and the improved four-stage charging algorithm is realized by double closed-loop control.(3)The energy management strategy of photovoltaic energy storage system is studied.Based on the bus voltage grading method,the operation modes and energy flow directions of the system are analyzed,and the control methods in the process of off-grid and grid-connected switching are analyzed.In order to realize the monitoring and management of photovoltaic energy storage and power generation system,local monitoring of the whole photovoltaic energy storage and power generation system and Ali cloud monitoring are realized based on WiFi232 module.The experimental results show that the monitoring platform can achieve the predetermined functions stably and reliably.(4)On the basis of self-developed prototype,a test platform was established to verify the auxiliary power supply,signal conditioning circuit,maximum power tracking,charging and discharging system,and to test the mode switching of the system.The experimental results show that the designed system has good performance: the maximum power point tracking efficiency of the former Boost circuit can reach 99.89%,and it can achieve multi-peak tracking function;the latter full-bridge circuit carries out off-grid and rectifier tests,the output of off-grid is stable,the dynamic response speed is fast,the grid-connected harmonics under rated power is as low as 3.86%,and the power factor is as high as 98.84%;In the process of switching,there is no obvious voltage and current spike impact,and the fast and smooth transition of working mode is realized.更多还原