计及寄生参数的高频功率变换器能效分析与研究

发布时间：2019-02-23 10:00

【摘要】：随着电力电子装置不断向着高频、大功率的方向发展，高频变换器中存在的寄生参数对其工作特性的影响也日趋显著。开关管的开关过程中，电流变化率(di/dt)可达几百A/μs，在寄生电感的作用下，引起过高的电压尖峰而损坏开关器件、增加开关损耗和电磁干扰噪声；同时，此过程中的电压变化率(du/dt)也很高，过高的du/dt作用于寄生电容导致电路功耗增加并破坏电路的可靠性；此外，寄生电阻的存在则会直接造成高频变换器的功率损耗，并对高频响应、测量误差以及开关脉冲波形和稳定运行等造成不利影响。本文致力于计及寄生参数的高频功率变换器能效分析与研究，内容涵盖了电力电子器件寄生参数的模型建立及其测量提取和行为特性分析，功率器件的损耗建模和功率变换器的效率分析等内容。论文的主要工作如下：分析了影响高频变换器功率和效率的各个因素，并在计及寄生参数的基础之上，提出了新型能效分析的评价指标，综合考虑制约能效特性的各类参数对其产生的影响，以保证高频变换器系统可以更好的实现高功率、高效率的能量输出。针对现有IGBT功率损耗模型或计算量太大，或计算精度不足的弊端，在计及IGBT寄生参数的前提下，详细分析了IGBT开通和关断过程中的等效电路图，并逐一推导了相应的损耗公式，提出了一种新型功率损耗建模方法，考虑到IGBT振荡过程中的功率损耗，可以更加准确的估算电路功耗。以Buck变换器为例，建立了计及寄生参数的变换器效率模型并分析变换器的效率特性。采用Saber软件进行效率仿真验证，并利用Matlab工具箱的拟合工具对效率模型进行系数拟合，可以通过输入、输出功率采样，在电路具体运行参数未知的情况下，根据效率函数模型估算变换器的效率。进一步地，逐一分析IGBT寄生参数对Buck变换器效率的影响，通过仿真测量得到输入、输出功率，并计算相应的效率值。搭建高频大功率ZVZCS移相全桥变换器实验平台，测量并记录不同输出功率下的效率，，通过比较发现，本文提出的计及寄生参数的功率损耗模型和效率模型较之于传统的模型更加精确，且与实验结果具有很好的一致性。
[Abstract]:With the development of power electronic devices in the direction of high frequency and high power, the influence of parasitic parameters in high frequency converters on their working characteristics is becoming more and more significant. In the switching process of the switch, the current change rate (di/dt) can reach several hundred A / 渭 s. Under the action of parasitic inductance, the voltage spike is too high and the switch device is damaged, and the switching loss and electromagnetic interference noise are increased. At the same time, the rate of voltage change (du/dt) in the process is also very high, too high du/dt effect on parasitic capacitance leads to increase the power consumption and destroy the reliability of the circuit. In addition, the existence of parasitic resistance will directly cause the power loss of the high frequency converter, and will have a negative impact on the high frequency response, measurement error, switching pulse waveform and stable operation. This paper is devoted to the energy efficiency analysis and research of high frequency power converters taking into account parasitic parameters. It covers the modeling of parasitic parameters of power electronic devices, the measurement and extraction of parasitic parameters, and the analysis of behavior characteristics. Loss modeling of power devices and efficiency analysis of power converters. The main work of this paper is as follows: the factors that affect the power and efficiency of the high frequency converter are analyzed, and based on the parasitic parameters, the evaluation index of the new energy efficiency analysis is put forward. In order to ensure the high power and high efficiency energy output of the high frequency converter system, the influence of all kinds of parameters which restrict the energy efficiency characteristics is considered synthetically in order to ensure that the high frequency converter system can achieve the high power and high efficiency energy output. In view of the disadvantages of the existing IGBT power loss model or too much calculation or insufficient calculation precision, the equivalent circuit diagram in the process of IGBT turn-on and turn-off is analyzed in detail, and the corresponding loss formulas are deduced one by one, taking into account the parasitic parameters of IGBT. A new power loss modeling method is proposed. Considering the power loss during IGBT oscillation, the power consumption can be estimated more accurately. Taking the Buck converter as an example, the efficiency model of the converter with parasitic parameters is established and the efficiency characteristics of the converter are analyzed. The efficiency is verified by Saber software, and the coefficient of the efficiency model is fitted by the fitting tool of Matlab toolbox. The efficiency model can be sampled by input and output power, and the operation parameters of the circuit are unknown. The efficiency of the converter is estimated according to the efficiency function model. Furthermore, the effect of parasitic parameters of IGBT on the efficiency of Buck converter is analyzed one by one. The input and output power is obtained by simulation measurement, and the corresponding efficiency values are calculated. The experiment platform of high-frequency and high-power ZVZCS phase-shifted full-bridge converter is built to measure and record the efficiency under different output power. The proposed power loss model and efficiency model with parasitic parameters are more accurate than the traditional model and are in good agreement with the experimental results.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

【参考文献】