基于SiC器件的三相电流型PWM整流器的研究与实现

发布时间：2018-05-27 11:01

本文选题：电流型PWM整流器 + 叠流时间　；参考：《南京航空航天大学》2016年硕士论文

【摘要】：随着电力电子设备的大量使用,谐波和无功损耗对于电网的影响也越来越严重,PWM整流器作为功率因数校正方法,具有功率因数可控,谐波含量低等优点。PWM整流器按照输出源特性可以分为电压型PWM整流器和电流型PWM整流器,电流型PWM整流器相比于电压型PWM整流器起步比较晚,但随着器件、调制技术的发展,电流型PWM整流器的应用范围也越来越广泛,如在电机驱动、超导储能、数据中心等场合,因此电流型PWM整流器的研究应用成为国内外研究热点。本文首先对电流型PWM整流器进行了原理分析并建立了该拓扑结构的数学模型,对电流型PWM整流器的信号发生技术进行了探索分析,给出了驱动信号的具体生成方法。此外讨论了本论文样机所使用的控制方法,为后面的分析研究提供了良好的基础。接着本文重点研究了电流型PWM整流器驱动信号里的叠流时间。首先分析了叠流时间对于开关管之间电流换流的影响,得出叠流时间会造成开关管部分零电压导通和零电流关断;接着分析了叠流时间对于开关损耗的影响,提出了叠流时间的选取下限;根据叠流时间对开关管间电流换流的影响,分析一个调制周期内每种换流情况,得到加入叠流时间前后的交流侧电流波形,通过对比得到一个调制周期的交流侧叠流情况,对其进行傅里叶分析,得到叠流谐波与叠流时间的关系式,经过仿真和实验验证了理论分析的正确性,说明了叠流时间的存在会引起网侧电流谐波含量增加。此外,本文还提出一种叠流谐波的抑制方法,该方法根据三相桥臂中点电压大小关系分区使用正负斜率锯齿载波进行调制,能有效抑制叠流时间带来的谐波,通过仿真和实验验证了该方法的有效性。本文设计了3kW基于SiC MOSFET的三相电流型PWM整流器,给出了该样机的具体设计方法,对样机进行了实验测试,实验波形验证了样机设计的正确性。最后对电流型PWM整流器的开关管进行了损耗分析,给出了SiC MOSFET与Si IGBT的理论损耗对比,并分别对基于两种器件的电流型PWM整流器样机进行了效率测试和网侧电流谐波含量测试,给出了效率对比曲线与网侧电流谐波含量对比曲线,说明了SiCMOSFET相比于Si IGBT在电流型PWM整流器的应用优势。
[Abstract]:With the extensive use of power electronic equipment, the influence of harmonic and reactive power loss on power network is becoming more and more serious. As a power factor correction method, PWM rectifier has controllable power factor. The advantages of low harmonic content .PWM rectifier can be divided into voltage-source PWM rectifier and current-source PWM rectifier according to the characteristics of output source. The current-source PWM rectifier starts later than the voltage-source PWM rectifier, but with the development of device and modulation technology, The application of current-source PWM rectifier is more and more extensive, such as motor drive, superconducting energy storage, data center and so on. Therefore, the research and application of current-source PWM rectifier has become a research hotspot at home and abroad. In this paper, the principle of the current-source PWM rectifier is analyzed and the mathematical model of the topology is established. The signal generation technology of the current-source PWM rectifier is analyzed, and the method of generating the driving signal is given. In addition, the control method used in the prototype is discussed, which provides a good basis for the later analysis. Then this paper focuses on the stack time in the drive signal of current-source PWM rectifier. Firstly, the effect of stack time on current commutation between switches is analyzed, and it is concluded that stack time will result in partial zero voltage conduction and zero current turn-off of switch tube, and then the effect of stack time on switching loss is analyzed. According to the influence of stack time on current commutation between switches, the current waveform of AC side before and after adding stack time is obtained by analyzing each commutation condition in a modulation period. By comparing and analyzing the overlapping current of an AC side with a modulation period, the formula of the relationship between the stack harmonic and the stack time is obtained. The correctness of the theoretical analysis is verified by simulation and experiment. It is shown that the existence of stacking time will increase the harmonic content of the current in the grid side. In addition, this paper also proposes a method for suppressing the stack current harmonics, which is modulated by positive and negative slope sawtooth carriers according to the voltage relationship between the midpoint of the three-phase bridge arm, which can effectively suppress the harmonics brought by the stack current time. The effectiveness of the method is verified by simulation and experiments. In this paper, a three-phase current-source PWM rectifier based on SiC MOSFET for 3kW is designed, and the concrete design method of the prototype is given. The experimental results show that the design of the prototype is correct. Finally, the loss analysis of the switch of current-source PWM rectifier is carried out, the theoretical loss comparison between SiC MOSFET and Si IGBT is given, and the efficiency and current harmonic content of current-source PWM rectifier based on two kinds of devices are tested respectively. The efficiency contrast curve and the current harmonic content contrast curve on the grid side are given. The advantages of SiCMOSFET in the application of current-source PWM rectifier compared with Si IGBT are explained.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM461

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