单相单级式光伏并网逆变器设计

论文摘要

随着全球能源资源的减少,新能源的开发成为全球共同的焦点。近几年,光伏发电的兴起给日益紧缺的能源带来了新的希望。光伏发电以其巨大的储存能量,适用范围广、绿色环保在所有新能源中占有重要的地位。因此,对光伏系统的研究,对未来能源问题的解决具有重要的意义和研究价值。本文主要研究光伏发电系统的可调度系统蓄电池充电系统和不可调度系统3KW单级式光伏并网逆变系统。主要研究两个系统MPPT算法的MATLAB仿真和实验实现及整个系统的软硬实现,系统的开发平台分别为PIC18F23K20,开发环境为MAPLAB和TMS320 C2812,其开发环境为CCStduio 3.3。首先,论文阐述了蓄电池充电系统的主电路DC/DC拓扑结构,分析基于Buck电路和Sepic电路的工作原理和基于半桥PWM的控制模式。设计主电路电感、储能电容参数,选择合理的功率开关管的设,通过实验对设计结果进行验证,在一定输入光伏电源下能完成对蓄电池的稳定充电。针对3KW单级式光伏并网逆变系统,分析主电路在双极性PWM控制下工作模式,设计输入平波电容参数,输出滤波电感参数,通过MATLAB仿真及实验验证,3KW逆变系统能在固定负载给定下稳定工作,且THD<5%。其次,本文主要完成光伏系统MPPT算法的研究。针对光伏蓄电池充电系统,根据对蓄电池充电特性的研究结合主电路工作特性,研究调节变器占空比的MPPT算法,在实现系统中得到验证其能源利用率可达90%以上。针对3KW单级式光伏并网逆变系统,研究光伏电池数学模型和工作暂态特性的基础上,研究分析传统MPPT算法的功率电压法和改进型功率电压法以及基于电荷流积的MPPT新型算法,通过MATLAB仿真和实验结果,其新型算法具有较好的实时性和稳定性,能源利用率可达95%以上。对光伏并网逆变系统进行孤岛效应研究。研究分析主动检测法和被动检测法,把输出电压过压、欠压被动检测发应用的实验系统中,系统能及时检测孤岛效应的产生,作出保护。最后,完成实验系统软硬件设计。本实验系统设计合理可靠,实验数据较为科学。光伏蓄电池充电系统能完成MPPT状态下稳定给蓄电池充电,充电效率达85%。单相3KW单级式光伏并网逆变系统成功并网,且并网电流THD<5%。

论文目录

• 摘要
• ABSTRACT
• CHAPTER ONE Introduction
• 1.1. Introduction
• 1.1.1. Solar power energy
• 1.1.2. The disadvantages of solar power energy
• 1.1.3. The advantages of solar power
• 1.2. introduction to how to turn solar power energy into electricity
• 1.2.1. how solar power works
• 1.2.2. introduction to status of photovoltaic power generation development
• 1.2.3. status of photovoltaic power generation development
• 1.2.4. the development of solar photovoltaic system in some countries network profiles
• 1.2.5. status of china's photovoltaic industry
• 1.3. the forefront of research problems
• 1.4. chapter in summary
• CHAPTER TWO Off-grid system controller
• 2.1. Off-grid system controller main circuit design and work principle
• 2.1.1. Photovoltaic system DC/DC converter
• 2.2. Buck convert main circuit design and work principle
• 2.2.1. Buck converter when the inductor current in continuous working principle
• 2.2.2. The basic relationship between the inductor current when circuit is the continuous mode
• 2.2.3. Sepic converter main circuit design and work theory
• 2.2.4. The main circuit topology and control method
• 2.2.5. When the inductor current is in continuous Sepic convert method
• 2.2.6. Basic relation between the circuit and the inductor current when is in continuous mode
• 2.3. Maximum power point tracking （MPPT）
• 2.3.1. Buck transform MPPT controllers based on tracking theory
• 2.3.2. Solar street light control system to achieve MPPT algorithm
• 2.3.3. The structure of grid-connected inverter and its control methods
• 2.3.4. The Hysteresis current control method
• 2.3.5. Current detection software control
• 2.4. Chapter in summary
• CHAPTER THREE On-grid system controller
• 3.1.Photovoltaic cells and analysis of mathematical model
• 3.1.1. The realization of PV battery system and the MPPT algorithm
• 3.1.2. Single-stage photovoltaic inverter system implementation and the MPPT algorithm
• 3.2. Single-phase inverter with the basic principles and techniques
• 3.2.1. Single-stage and dual-stage
• 3.2.2. The topology of the inverter system
• 3.3. Proportional -resonant current control
• 3.3.1. Design of current controller with PR-regulator
• 3.4. PR and Analysis of the composition of the controller
• 3.4.1. PR controller open-loop transfer function
• 3.4.2. PR controller parameter tuning
• 3.5. Chapter in summary
• CHAPTER FOUR On-grid system controller hardware and software design
• 4.1. The control system structure
• 4.2. Inverter and grid structure and control principle
• 4.3. Single stage photovoltaic grid connected inverter hardware system
• 4.3.1. Main circuit
• 4.3.2. Circuit drive
• 4.3.3. Sampling circuit
• 4.3.4. Protection circuit
• 4.3.5. Auxiliary power
• 4.4. Single stage photovoltaic grid connected inverter software system
• 4.4.1. CPU clock frequency
• 4.4.2. SPI settings
• 4.4.3. A/D
• 4.4.4. PWM
• 4.4.5. The system to achieve software flow chart
• 4.5. Chapter in summary
• References
• Conclusion
• Paper published during the study
• Acknowledgements