碳化硅功率器件非线性建模及应用研究

发布时间：2018-09-02 06:06

【摘要】：碳化硅(SiC)材料因其宽禁带、高临界电场和高热导率等特性受到了行业的广泛关注,近年来相继推出了商品化的SiC功率器件,但可靠性问题是制约其发展的瓶颈之一。众所周知,功率器件的可靠性主要受高温和高电场等瞬态非线性行为的影响,引起器件内部参数和外部电特性的退化,从而降低器件的可靠性和使用寿命。为揭示SiC功率器件的瞬态非线性行为与其物理参数的内在联系,需借助于精确地器件模型来加以描述,然而现有的SiC功率器件模型多为线性模型,且没有考虑结温变化对其物理参数的实时影响,导致仿真精度具有一定的局限性。因此,开展SiC功率器件的非线性建模对提高其可靠性和使用寿命具有重要意义。本文从SiC功率器件的工作机理出发,针对SiC BJT和SiC MOSFET两种功率器件进行了非线性建模,首先采用Haar小波构建了Si C BJT物理模型的数值分析方法,同时提出了一种基于时变温度反馈的SiC MOSFET电热耦合模型建模方法,在此基础上开展了SiC功率器件的瞬态非线性行为研究,仿真和实验结果的对比分析验证了以上方法的有效性。本文主要进行了以下研究工作:(1)针对SiC BJT建模中双极性扩散方程(Ambipolar Diffusion Equation,ADE)求解精度的问题,提出了基于Haar小波法的SiC BJT物理建模法。模型从SiC BJT工作机理出发,利用半导体物理理论分析其内部动力学行为和各区间激励与响应的关系,将Haar小波法运用于ADE求解中,仿真结果与傅里叶级数法进行了对比,研究表明Haar小波法可有效提高器件物理模型的求解精度。(2)提出了一种基于时变温度反馈的SiC MOSFET电热耦合模型建模方法。模型从Si C MOSFET工作机理出发,综合分析了SiC MOSFET模块、热网络模块和功率损耗模块的作用关系,将功率损耗和热网络模块引入建模,实时反馈器件结温和更新温度相关参数。该方法能更好地反映SiC MOSFET在导通和开关过程中的性能特点,仿真结果验证了模型的可行性。(3)SiC MOSFET电热耦合模型的应用与实验验证。将SiC MOSFET功率器件应用于E类逆变器中,设计了SiC MOSFET器件的驱动电路,并搭建了E类逆变器实验样机。SiC MOSFET采用CREE公司的C2M0160120D,实验结果证实了模型的有效性。
[Abstract]:Silicon carbide (SiC) materials have attracted wide attention due to their wide band gap, high critical electric field and high thermal conductivity. In recent years, commercial SiC power devices have been introduced, but reliability is one of the bottlenecks to its development. It is well known that the reliability of power devices is mainly affected by transient nonlinear behavior such as high temperature and high electric field, which results in the degradation of internal parameters and external electrical characteristics of the devices, thus reducing the reliability and service life of the devices. In order to reveal the relationship between the transient nonlinear behavior of SiC power devices and their physical parameters, it is necessary to describe them by means of precise device models. However, most of the existing SiC power device models are linear models. The real time effect of junction temperature on its physical parameters is not considered, which leads to the limitation of simulation precision. Therefore, it is important to develop nonlinear modeling of SiC power device to improve its reliability and service life. Based on the working mechanism of SiC power devices, the nonlinear modeling of SiC BJT and SiC MOSFET power devices is presented in this paper. Firstly, a numerical analysis method of Si C BJT physical model based on Haar wavelet is constructed. At the same time, a modeling method of SiC MOSFET electrothermal coupling model based on time-varying temperature feedback is proposed. On this basis, the transient nonlinear behavior of SiC power devices is studied. The effectiveness of the above method is verified by the comparison of simulation and experimental results. The main work of this paper is as follows: (1) aiming at the accuracy of solving bipolar diffusion equation (Ambipolar Diffusion Equation,ADE) in SiC BJT modeling, a SiC BJT physical modeling method based on Haar wavelet method is proposed. Based on the working mechanism of SiC BJT, the dynamic behavior of the model and the relation between the excitation and response of each interval are analyzed by using the semiconductor physics theory. The Haar wavelet method is applied to the solution of ADE. The simulation results are compared with the Fourier series method. The results show that Haar wavelet method can effectively improve the accuracy of the device physical model. (2) A SiC MOSFET electrothermal coupling model modeling method based on time-varying temperature feedback is proposed. Based on the working mechanism of Si C MOSFET, the relationship among SiC MOSFET module, thermal network module and power loss module is analyzed synthetically. The power loss and thermal network module are introduced into the model, and the real-time feedback device junction and temperature parameters are updated. This method can better reflect the performance characteristics of SiC MOSFET in the process of conduction and switching. The simulation results verify the feasibility of the model. (3) the application and experimental verification of the electrothermal coupling model of) SiC MOSFET. The SiC MOSFET power device is applied to the class E inverter, and the driving circuit of the SiC MOSFET device is designed. The experimental prototype of the class E inverter. Sic MOSFET uses C2M0160120D of CREE Company. The experimental results prove the validity of the model.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN386

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