宽禁带器件构成的变流器3D结构寄生参数建模及系统优化

The wide band gap (WBG) power device makes the converter with higher dv/dt and di/dt as well as higher switching frequency, as compared to Si devices. Thus, the parasitics become a bottleneck to the complete usage of the fast switching characteristics of the WBG. The present researches of the parasitics mainly focus on the component and the simple structure inside the converter. The analytical and numerical methods can not be directly taken to the parasitic research of the 3D structure of the whole converter. However, the increase of the switching frequency and speed increases the impedance of the structural parasitics, which were often ignored, and further change the circuit operation. The project researches the modeling of the parasitics of the 3D structure of the converter that composes of the WBG. Based on this research the project further deals with optimization of the 3D structure and the circuit design. The main research involves: The project proposes the circuit-field decouple method, and model the overall parasitics of the whole 3D structure of the converter by the combination of the analytical and numerical method. The project proposes a quasistatic-like method to compute the electromagnetic field in time domain and derives the reduced order transmission line model of the structure in a fast transient field. The project researches the steady state operation the converter, the switching transient and the common-mode current of the converter by considering the structural parasitics. The projects optimize the key structure and the circuit. The project builds two platforms of photovoltaic inverters to justify the methods, and researches the method of accurate measurement.

相比Si器件，宽禁带器件给变流器带来了更高的开关频率、更大的dv/dt和di/dt，因此寄生参数成为充分发挥其快速特性的主要瓶颈之一。现有寄生参数建模研究主要集中在元器件和变流器局部简单结构，其解析和数值方法不能直接运用到变流器3D整体结构。而开关速度和开关频率的提高会增大常被忽略的结构寄生参数的阻抗，进而改变电路运行。本课题研究宽禁带器件构成的变流器3D结构寄生参数的建模方法，在此基础上对结构和电路进行优化。主要研究有：提出路场解耦计算的方法，通过解析与数值融合的方法对变流器3D结构全局寄生参数系统化建模；提出电磁场时域类准静场计算方法，在快速暂态电磁场中，建立结构降阶传输线模型；考虑结构寄生参数，研究变流器稳态运行、开关过程和共模电流；对宽禁带器件构成的变流器关键结构和电路设计提出优化方法；搭建两套光伏逆变器平台验证理论并探索精确测量的方法。

电力电子装置3D结构寄生参数在宽禁带器件的高速高频特性充分使用中起重要作用。相较以往研究主要关注元器件本身寄生参数建模，本项目以运用SiC器件的中大功率变流器为例，系统研究3D结构寄生参数建模方法及优化：1）对于典型全局叠层母排结构，考虑电容和开关管位置及端子结构、电路运行状态，提出了一套完整的、由粗入细的、数值与解析融合的寄生网络建模方法。对于典型光伏板系统结构，研究了寄生电容模型及雨水对其寄生电容的影响，提出了优化措施；2）对于快速暂态场，提出了以级数展开求解MAXWELL方程理论为基础的计算方法，能快速求解结构寄生参数高阶电路模型；3）分析了关键结构寄生参数对开关过程、系统共模电流和器件均流的影响，并提出了相应的结构优化方案和系统性能提升方案。基于上述理论方法，研制了复杂“运行结构”叠层母排系统电感网络提取软件和考虑结构寄生参数下器件并联均流计算软件，运用到企业逆变器产品设计中。同时提出的抑制寄生参数波动共模滤波网络设计方法和共模噪声与系统损耗协同抑制方法，为企业进一步提升SiC器件频率提供了设计参考。本项目以特定运用为例研究的3D结构寄生参数的建模及系统优化方法，属于共性研究，可以延拓到其他高频高速装置设计。