T字型三电平IGBT模块瞬态行为研究

发布时间：2018-08-23 09:48

【摘要】：大功率变流器是智能电网的核心装置,T字型三电平逆变电路是其中一种新型的应用。IGBT作为系统中的核心部件,其行为特征与系统相互作用,是保障系统高可靠性、安全性以及效率的决定因素之一。本文以T字型三电平拓扑为切入点,研究IGBT的瞬态行为,从而为提升系统可靠性及优化系统设计做出理论及实证支持。本文研究了T字型三电平逆变电路的14种换流模式。理论分析结果显示：在每种输出模式下,IGBT模块会表现出特殊的瞬态行为特征,并会触发IGBT的Vce退饱和检测电路,使其产生误触发故障,停止输出,关断系统,进而影响系统稳定性。本文通过建立15kW逆变电路实验平台首次验证了T字型三电平IGBT模块对Vce退饱和检测电路造成的误触发现象,也验证了输出电流和二极管的电容效应会加剧该误触发几率。同时根据实验结果,得到了可改善该现象的控制策略。另外,本文针对T字型三电平电路大功率使用环境下对IGBT模块并联的需求,首次对该型IGBT模块的并联瞬态行为做了理论及实验分析。具体地分析了结温差异对并联瞬态行为的影响,对比了T字型三电平与两电平的并联区别。实验结果证明IGBT的并联开通行为的一致性在一定温差下能够得到提升。而对关断行为来说,当温差增加时,其能量损耗不匹配度将上升,同时其过压风险和di/dt风险也会加剧。并且,由于T字型的特殊拓扑,并联时会形成多余的电流通道,增加损耗。最后,T字型三电平模块的并联效果优于二电平并联。本文的理论及实验结果,不仅为电路的DSP实现或硬件驱动保护电路实现提供了参考意义,保护其不受非预期型故障的影响。同时也为T字型三电平逆变电路大功率实现过程中的散热和结构设计提供了改善指导意义。
[Abstract]:High-power converter is the core device of smart grid, the three-level inverter circuit is a new type of application. IGBT is the core component of the system. Its behavior characteristics interact with the system and ensure the high reliability of the system. One of the determinants of safety and efficiency. In this paper, the transient behavior of IGBT is studied by using T-shaped three-level topology as the starting point, which provides theoretical and empirical support for improving the reliability of the system and optimizing the design of the system. In this paper, 14 commutation modes of T-shaped three-level inverter circuits are studied. The results of theoretical analysis show that: in each output mode, the IGBT module will exhibit special transient behavior characteristics, and will trigger the Vce desaturation detection circuit of IGBT, which will cause the malfunction, stop the output and turn off the system. Then the stability of the system is affected. In this paper, an experimental platform of 15kW inverter circuit is established to verify for the first time the misfiring of T-shaped three-level IGBT module to Vce desaturation detection circuit. It is also verified that the output current and the capacitive effect of diode will aggravate the false trigger probability. At the same time, according to the experimental results, the control strategy to improve the phenomenon is obtained. In addition, aiming at the requirement of parallel connection of IGBT module in the high power environment of T-shaped three-level circuit, the transient behavior of this type of IGBT module is analyzed theoretically and experimentally for the first time. The effect of the end temperature difference on the transient behavior of parallel is analyzed and the parallel difference between T type three level and two level is compared. The experimental results show that the consistency of parallel opening behavior of IGBT can be improved under certain temperature difference. For turn-off behavior, when the temperature difference increases, the energy loss mismatch will increase, and the risk of overvoltage and di/dt will also increase. Moreover, due to the special topology of the T type, extra current channels will be formed in parallel, which will increase the loss. Finally, the parallel effect of T-shaped three-level module is better than that of two-level parallel. The theoretical and experimental results in this paper not only provide a reference for the DSP implementation of the circuit or the realization of the hardware drive protection circuit, but also protect it from unexpected faults. At the same time, it also provides guidance for the heat dissipation and structure design in the realization of high power T type three-level inverter circuit.
【学位授予单位】：复旦大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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