中间电容式光伏升压变换器的设计与控制

发布时间：2018-05-04 05:29

本文选题：中间电容型变换器 + 零电压转换　；参考：《山东大学》2017年硕士论文

【摘要】：组串型光伏逆变器由于其配置灵活、MPPT效率高、可靠性高等特点,正在得到越来越广泛的应用。然而,传统的组串型光伏逆变器受制于直流升压拓扑,造成功率半导体器件电压/电流应力大,损耗大等,已无法适应新型高效率低成本组串型逆变器的发展。该论文提出一种适用于组串式光伏逆变器直流变换级的中间电容变换器,该中间电容型变换器大幅度减轻了功率半导体器件的电压/电流应力,开关/导通耗损等;相较传统拓扑,所提出的中间电容型直流变换器具有明显优势。为进一步降低功率半导体器件的损耗,提升转换效率,本文进一步提出了适用于该中间电容型变换器的零电压转换电路并探索了其运行原理与设计方法,并利用工程样机考证了所提出零电压转换电路的适用性。为了提升该中间电容型变换器在光伏功率不均衡与电网电压不对称的工况下的性能,本文分别提出了中间电容电压适应性控制策略与电网电压不对称下的运行策略。所提出的控制与运行方法提升了光伏阵列的发电量,降低了中间电容型变换器的过电压风险,并且改进了并网电流的波形质量。研究的主要内容如下:(1)分析了光伏并网逆变器应用近况,并综述了组串型光伏并网逆变器的研究近况。(2)研究了中间电容型直流变换器拓扑及其零电压转换辅助电路,分析了拓扑及其辅助电路的基本工作原理,并详细阐述了电路设计方法。(3)研究了中间电容电压适应性控制策略,分析了功率流图与实施方式,并通过仿真与实验验证了所提出的适应性控制策略。(4)研究了中间电容型变换器在电网电压不对称下的控制策略,分析了直流侧二次震荡现象并提出了对应的电路设计方法。
[Abstract]:Because of its flexible configuration, high efficiency and high reliability, series-type photovoltaic inverters are becoming more and more widely used. However, the traditional series photovoltaic inverter is constrained by the DC boost topology, resulting in high voltage / current stress and high loss of power semiconductor devices, so it can not adapt to the development of a new type of high efficiency and low cost series inverter. In this paper, a kind of intermediate capacitor converter is proposed, which is suitable for the series photovoltaic inverter. The intermediate capacitor converter can greatly reduce the voltage / current stress and switching / on-loss of power semiconductor devices. Compared with the traditional topology, the proposed intermediate capacitor DC / DC converter has obvious advantages. In order to further reduce the loss of power semiconductor devices and improve the conversion efficiency, this paper further proposes a zero-voltage conversion circuit suitable for the intermediate capacitor converter, and explores its operation principle and design method. The applicability of the proposed zero-voltage conversion circuit is verified by engineering prototype. In order to improve the performance of the intermediate capacitor converter under the condition of unbalanced photovoltaic power and asymmetric voltage, the adaptive control strategy of the intermediate capacitor voltage and the operation strategy of the voltage asymmetry are proposed in this paper. The proposed control and operation methods improve the power generation of photovoltaic arrays, reduce the risk of overvoltage of intermediate capacitive converters, and improve the waveform quality of grid-connected current. The main contents of this paper are as follows: (1) the recent application of PV grid-connected inverter is analyzed, and the research status of serial-type PV grid-connected inverter is summarized. (2) the topology of intermediate capacitive DC converter and its zero-voltage conversion auxiliary circuit are studied. The basic working principle of topology and its auxiliary circuit is analyzed, and the circuit design method is described in detail. The adaptive control strategy of intermediate capacitor voltage is studied, and the power flow diagram and implementation mode are analyzed. The adaptive control strategy proposed in this paper is verified by simulation and experiment. The control strategy of the intermediate capacitor converter under the voltage asymmetry is studied. The secondary oscillation on the DC side is analyzed and the corresponding circuit design method is proposed.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46;TM615

【相似文献】