分布式独立光伏发电系统逆变电源及其并联的研究

【作者】 王昉；

【导师】 颜世钢；

【作者基本信息】 山东大学 ， 电力电子与电力传动， 2007， 硕士

【摘要】 当前世界能源短缺以及环境污染问题严重，能源问题已经引起世界范围内的广泛关注。随着新能源的开发越来越受到重视，太阳能利用技术得以迅速发展，光伏发电成为一个重要的研究领域。近年来，光伏技术不断发展，太阳能光伏发电系统将逐渐由现在的补充能源向替代能源过渡。独立发电(Stand-alone)系统和并网发电(Grid-connected)系统将成为光伏应用的主流。本文就光伏系统中的一些关键问题——如高频链逆变器拓扑结构、逆变电源输出波形数字化控制策略以及逆变器模块并联方案等方面做出详细的理论分析，建立仿真模型，提出了相应的控制方案，并进行了试验验证。首先，在电压源型高频链逆变电源模型的基础上建立了逆变器连续时间域和离散时间域的数学模型，为控制系统的设计提供了理论基础。利用PSIM仿真软件建立逆变器仿真模型，用以验证控制方案的可行性和有效性。随后，详细的研究了基于电压反馈的离散重复控制技术。通过对系统稳定性和稳态误差的分析，明晰了重复控制在消除输出电压周期性波形畸变的原理。由于重复控制存在一个基波周期的延迟，严重影响了系统的动态响应特性，本文研究了基于重复控制的复合控制策略。复合控制不仅保留了重复控制消除周期性波形畸变的能力，同时大大提高了系统的动态响应速度。通过试验表明，该复合控制方式可以大大的减小谐波畸变率，这为模块间的并联带来很大的方便。接着，采用一种实现瞬时值均流的分布式并联控制方法实现光伏逆变电源系统的模块并联。基于平均电流法原理，通过连接各并联模块的3条低频信号总线实现均流，无需专门的控制模块。各并联模块完全等同。只用一个调节器，既调节输出电压、同时又实现环流抑制。通过试验证实，并联系统在各种条件下都具有很好的动态响应性能和均流效果。最后，应用数字化控制成功的进行了系统试验，对关键的试验波形做出了分析，总结了试验数据，讨论了试验中出现的一些问题并对下一步的工作提出几点看法。更多还原

【Abstract】 Shortage of energy sources and pollution of environment in the world are becoming more and more serious. Worldwide attention has been paid on this issue. Given pervasive renewable energy, the solar energy exploitation, especially photovoltaic (PV) generation is developed rapidly and gradually becomes an important research field. Recently, with the development of PV technology ,the role of PV generation systems is gradually changed from supplemental energy to substitute energy. And stand-alone and grid-connected PV generation systems will be the trend among PV applications. This paper deals with such key problems as the topology of high-frequency line inverter, digital control technologies for the output voltage waveform of the inverter power supply, the multi-module redundant inverter system and so on by establishing related simulation models, applying novel control strategies and experiments validation.First, on the basis of circuit model of voltage mode high-frequency line inverter power supply, the continuous and discrete space-state mathematic models are established, which provide theoretical basis for the design of control system. the inverter simulation model is established by the simulation software of PSIM, which is used to validate the feasibility of every control strategy.Next, the repetitive control technology is studied for the PV inverter based on voltage feedback control scheme. According to the research on trace error and stability, mechanism that the repetitive control eliminates the periodical distortion of the output voltage is clean. The defect of repetitive control is its one based-period delay on control, which affects the dynamic response characteristic of the system, multiple control strategy based on repetitive control is applied to improve inverter transient response characteristic. The experiment result shows that the harmonic distortion of output voltage wave is reduced by the multiple control strategy , which can provide advantages to the parallel inverter system. Then, a distributed control scheme with instantaneous current sharing is developed for redundant parallel inverter power supply system. Current sharing based upon the average current method is realized by using a shared bus to connect all the parallel modules without extra control modules. The shared bus consists of only there noise insensitive lines regardless of how many modules are in parallel. The voltage regulator also serves as the current deviation controller. As a result, the system has fast dynamic response and equal current load sharing under every condition.Finally, the experiment results are achieved and the important waveforms are discussed. Some questions are provided and some advice for future work are given out.更多还原