基于DSP28335的单相光伏发电并网逆变系统

发布时间：2019-01-30 07:32

【摘要】：由于环境污染的严重和全球能源的急剧紧缺,人们对可再生能源的需求越来越迫切。光伏发电因其清洁无污染并且可持续而得到了重视。单相光伏并网逆变系统越来越受到人们的重视。如何有效增加光伏系统的效率,保证系统的稳定运行非常重要。针对这一问题,本文展开相关研究分析,主要包括以下几点:(1)在研究光伏电池的工作原理、数学建模基础上,分析了传统的MPPT算法,并提出了新型算法——基于恒定电压法和修正的变步长电导增量法相结合的最大功率点跟踪方法。利用MATLAB软件对其建模,结果显示新算法能够提高系统跟踪的快速性和稳定性;经过比较PWM调制方式的优缺点,确定后级逆变采用单极性倍频SPWM(正弦脉宽调制)技术,采用电压、电流双闭环比例-积分反馈控制策略。(2)提出了单相光伏并网逆变系统的总体设计方案,前级升压采用Boost升压电路和推挽升压电路相结合,后级DC/AC逆变采用全桥逆变电路。在Boost电路中实现最大功率点跟踪并给储能蓄电池充电,推挽升压电路将蓄电池电压升高到350V左右输送到全桥逆变电路进行逆变。(3)对系统的硬件电路进行设计,包括Boost升压电路、推挽升压电路、DC/AC全桥逆变电路、驱动电路、LCL滤波电路、电压电流采样调理电路、过零点比较电路以及相关保护电路等。选用DSP28335作为控制芯片,利用CCS3.3开发软件对系统进行编写程序并进行调试。(4)研制了一台实验样机,并进行升压、逆变、并网等相关实验,利用示波器等实验仪器观察采集系统实验波形,并对其进行量化分析,验证了本文所设计的单相光伏并网逆变系统的合理性。
[Abstract]:Due to the serious environmental pollution and the sharp shortage of global energy, the demand for renewable energy is becoming more and more urgent. Photovoltaic power generation has been paid attention to because of its clean and non-pollution and sustainable. Single-phase photovoltaic grid-connected inverter system has been paid more and more attention. It is very important to increase the efficiency of photovoltaic system and ensure the stable operation of the system. Aiming at this problem, this paper carries out related research and analysis, mainly including the following: (1) on the basis of studying the working principle of photovoltaic cells and mathematical modeling, the traditional MPPT algorithm is analyzed. A new algorithm, the maximum power point tracking method based on constant voltage method and modified variable-step conductance increment method, is proposed. Using MATLAB software to model the system, the results show that the new algorithm can improve the system tracking speed and stability; After comparing the advantages and disadvantages of PWM modulation mode, it is determined that unipolarity frequency doubling SPWM (sinusoidal pulse width modulation) technique and voltage are used in the back stage inverter. Current double closed loop proportional integral feedback control strategy. (2) the overall design scheme of single-phase photovoltaic grid-connected inverter system is proposed. The front stage boost adopts Boost boost circuit and push-pull boost circuit. The whole bridge inverter circuit is used in the DC/AC inverter. The maximum power point tracking is realized in the Boost circuit and the energy storage battery is charged. The push-pull boost circuit raises the battery voltage to 350 V or so and conveys the battery voltage to the full-bridge inverter circuit for inverter. (3) the hardware circuit of the system is designed. It includes Boost boost circuit, push-pull boost circuit, DC/AC full-bridge inverter circuit, driving circuit, LCL filter circuit, voltage and current sampling conditioning circuit, zero-crossing comparison circuit and related protection circuit. DSP28335 is selected as the control chip, and the system is programmed and debugged by using the CCS3.3 development software. (4) A prototype is developed, and related experiments, such as booster, inverter and grid connection, are carried out. By using oscilloscope and other experimental instruments to observe the experimental waveform of the acquisition system and analyze it quantificationally, the rationality of the single-phase photovoltaic grid-connected inverter system designed in this paper is verified.
【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】：TM615;TM464

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