【作者】 杨钦超；

【导师】 郭世明；

【作者基本信息】 西南交通大学 ， 电力电子与电力传动， 2012， 硕士

【摘要】 本文以微逆变器为研究对象,对当前的微逆变器的拓扑结构进行了深入的分析研究。每种结构都有自己的优缺点和使用场合,本文选择了电流型微逆变器进行深入研究。由于反激型是电流型微逆变器的基础,所以本文对反激型微逆变器进行详细的分析研究,主要研究了微逆变器的拓扑结构和反激型微逆变器的损耗分布,还对并网的控制技术和最大功率跟踪技术进行了研究和仿真分析,设计了主电路的器件和系统硬件电路,该研究工作对于光伏并网微逆变器具有一定的参考价值。首先,文章论述了光伏并网结构的分类,随后介绍了微逆变器的概念和微逆变器所具有的优点和不足以及关键性技术。研究了并网微逆变器的拓扑结构的特点,分析了电压型和电流型微逆变器的典型结构优缺点和特点以及应用场合。其次,文章主要阐述了电流型微逆变器的并网工作原理,然后计算了电路中开关管的电压和电流应力,为后面的开关损耗计算以及变压器、主电路的元器件的选择提供了依据。分析计算了原边开关管和副边开关管、二极管以及变压器的损耗,并绘出电路的损耗的分布图,最终得出与损耗相关的主要因素以及降低损耗需要改变的因素,这对于设计电流型的微逆变器具有重要的指导意义。再次,文章对光伏并网系统的最大功率跟踪控制问题进行了研究,通过比较分析最大功率跟踪的几种方法,选择适合本设计的最大功率方法,然后研究了最大功率跟踪的控制策略问题,研究分析了多级和单级控制策略以及多级控制中的前级和后级控制,从理论上分析了单级控制中的三环控制和双环控制的区别,同时对最大功率跟踪的算法和效果进行了仿真分析。对固定开关频率的控制方法进行了详细的研究,建立了反激型微逆变器的小信号模型,得到了逆变器传递函数,然后分析网压前馈对进网电流的影响,设计了电流环PI控制器,对进网电流控制的算法和效果进行了仿真分析。最后,文章对反激电流型微逆变器的主电路器件和硬件电路进行了设计,根据前面的理论分析研究,设计出相对损耗比较低高频变压器、开关管和二极管,并且设计了检测电路和电源管理电路,还对软件的总体设计给予了说明,最后进行了独立负载的实验。更多还原

【Abstract】 In this paper, micro-inverter has been studied and the current micro-inverter topologies have conducted deeply. Each structure has its own advantages and disadvantages and the occasions which can be applied.The paper has researched the current micro-inverter. The flyback current micro-inverter is the base, so micro-inverter flyback has been detailed analyzed, and mainly studied the micro-inverter flyback topology and the distribution of loss, researched and simulation analyzed the network control and maximum power point tracking technology, designed the main circuit of the device and system hardware circuit. The research for the photovoltaic grid-connected micro-inverter has a significant reference value.Firstly, the article has discussed the classification of photovoltaic grid structure, then the concept of micro-inverter and its advantages and disadvantages and its key technologies of micro-inverter has been introduced.Characteristics of the grid-connected micro-inverter topology has been discussed, and the advantages, disadvantages, characteristics and applied surrounding of the typical structure of voltage and current micro-inverter have been studied.Secondly, the photovoltaic grid structure’s working principle of the current micro-inverter has been mainly discussed in this paper, then the voltage and current stress of the switch circuit has been calculated in order to provide a basis for the choice of components and the switching loss calculation and transformer in the main circuit. The primary side switch and the switch of the secondary tubes, diodes and transformer losses have analyzed and calculated, and the map of the circuit loss has been drawed. To some conclusions, the main factors related to the loss and the changed factor that can decline the loss have been obtained, which has an important guiding significance for the design of the current type of micro-inverter.Thirdly, the tracking the maximum power of the photovoltaic grid-connected systems’s control problems have been studied through comparative analyzing several methods of the maximum power point tracking to find the maximum power for this design. Then the maximum power tracking control strategy has been studied, and analyzed the control strategy of multi-stage and single stage and multi-level control before class and after class control loop. The difference in the single-level control and dual-loop control is analyzed theoretically, while the maximum power point tracking algorithms and the effects have been simulation analyzed. Fixed switching frequency control method has been reseached in detail to establish a small-signal model of the flyback-type micro-inverters, inverter transfer function, and then the network voltage feed-forward network access current has been analyzed, the current loop PI controller hes been designed and the net current control algorithm and the effect has been simulation analyzed.Finally, the flyback current micro-inverter main circuit devices and hardware circuit have been designed. According to the previous theoretical analysis, a relatively low loss high frequency transformer, switch and diode have been designed, and the detection circuit and power management circuits have been designed, the overall design of the software to instructions have alse been designed, and finally a load independent experiments has been made.更多还原