SiC单相光伏逆变器效率分析

发布时间：2018-06-29 14:51

本文选题：SiC + MOSFET　；参考：《浙江大学》2014年硕士论文

【摘要】：SiC功率器件优异的性能引起了广泛关注,在光伏发电中应用研究也是当前的热点。对单相光伏逆变的主要结构以及常用的单相逆变器结构进行了综述,逆变器是光伏逆变器系统的核心环节,本文将SiC MOSFET应用于光伏逆变器中,研究SiC MOSFET对于逆变器效率提升的影响。 SiC MOSFET的特性与传统的Si MOSFET有很大的差别,而且常用于高速开关的场合,易出现误触发现象。根据SiC MOSFET的特性以及应用特点,在电路结构、电阻设计、驱动电压、可靠性设计等方面进行综合考虑,设计了SiC MOSFET驱动电路。 SiC MOSFET体二极管反向恢复特性优异,能够直接应用于全桥硬开关逆变器中,为了提升逆变器的功率密度,将SiC MOSFET全桥逆变器的开关频率提高至100kHz,对逆变器的主要参数进行了设计。器件工作于硬开关状态,根据电路的工作状态,进行了逆变器布局优化,以减小关键回路上的杂散电感；并分析了逆变器的效率,与基于Si MOSFET的20kHz H6逆变器进行了效率对比；同时将SiC MOSFET全桥逆变器的工作频率降低至20kHz,并进行了效率分析。最后搭建了实验平台,测试了相应的效率曲线,并进行了对比。对100kHz的SiC MOSFET全桥逆变器的损耗进行了研究分析,找出影响其效率的主要因素。为了进一步提高逆变器的效率,根据逆变器的工作状态,在逆变器中采用了ZVS软开关技术。首先对软开关电路的工作过程进行了阐述,并进行了相关参数的设计；其次,根据电路的工作状态,对软开关逆变器的效率进行了分析,并与硬开关全桥逆变器的效率进行了对比。搭建了SiC MOSFET软开关逆变器实验平台,观察逆变器的工作波形,与理论分析进行对比,验证该软开关技术的合理性；测试逆变器的效率,在不同的功率下调整软开关的相关参数,使逆变器的效率最大化,并将软开关逆变器的实验效率曲线与硬开关的效率曲线进行对比。
[Abstract]:The excellent performance of sic power devices has attracted wide attention, and the application of sic power devices in photovoltaic power generation is also a hot spot. The main structure of single-phase photovoltaic inverter and the common single-phase inverter structure are summarized. The inverter is the core link of photovoltaic inverter system. In this paper, sic MOSFET is applied to photovoltaic inverter. The effect of sic MOSFET on the efficiency of inverter is studied. The characteristics of sic MOSFET are very different from those of traditional Si MOSFET. According to the characteristics and application characteristics of sic MOSFET, the drive circuit of sic MOSFET is designed in terms of circuit structure, resistance design, drive voltage and reliability design. In order to increase the power density of the inverter, the switching frequency of sic MOSFET full-bridge inverter is raised to 100 kHz. The main parameters of the inverter are designed. According to the working state of the circuit, the inverter layout is optimized to reduce the stray inductance in the key circuit, and the efficiency of the inverter is analyzed, which is compared with the 20kHz H6 inverter based on Si MOSFET. At the same time, the operating frequency of sic MOSFET full-bridge inverter is reduced to 20 kHz, and the efficiency is analyzed. Finally, the experiment platform is built, and the corresponding efficiency curve is tested and compared. The loss of 100 kHz sic MOSFET full-bridge inverter is analyzed and the main factors affecting its efficiency are found out. In order to further improve the efficiency of the inverter, ZVS soft switching technology is adopted in the inverter according to the working state of the inverter. First of all, the working process of soft-switching circuit is described, and the design of related parameters is carried out. Secondly, according to the working state of the circuit, the efficiency of soft-switching inverter is analyzed. The efficiency of the inverter is compared with that of the hard switching full-bridge inverter. The experimental platform of sic MOSFET soft switching inverter is built, the working waveform of the inverter is observed and compared with the theoretical analysis, the rationality of the soft switching technology is verified, the efficiency of the inverter is tested, and the relevant parameters of the soft switch are adjusted at different power levels. The efficiency of the inverter is maximized and the experimental efficiency curve of the soft-switching inverter is compared with that of the hard-switching inverter.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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