大功率高频变压器的直流偏磁与杂散电容问题研究

DC bias and stray capacitance are two key issues currently limiting the applications of high-power high-frequency transformers. This project will focus on these two issues, and the main research contents include: (1) developing a high-precision magnetic field and circuit coupled model of the high-frequency transformers considering the DC bias characteristics of the nanocrystalline magnetic cores, exploring active DC bias control strategies for nanocrystalline high-frequency transformers, including steady-state DC bias correction and transient DC bias control algorithms; (2) developing a systematic equivalent circuit model for analyzing high-frequency electromagnetic oscillation in the stray capacitance of transformers that is excited by the switching transient, extracting the stray capacitance parameters in the equivalent circuit by both electromagnetic simulations and experimental measurements, exploring the oscillation suppression methods through the snubber circuit and gate control of switching devices. Through the research, the DC bias mechanism of the high-power high-frequency transformers will be deeply understood, the reliability and utilization ratio of the magnetic flux density of the high-power high-frequency nanocrystalline transformers will be substantially improved. Also the mechanism of the electromagnetic oscillation in the stray capacitance of transformers that is excited by the switching transient will be understood, and the oscillation be effectively suppressed.

直流偏磁问题与杂散电容问题是目前限制大功率高频变压器应用的两个关键问题。本项目围绕这两个问题展开研究，主要研究内容包括：（1）建立考虑纳米晶磁芯直流偏磁特性的高频变压器高精度磁场-电路耦合模型，探索针对纳米晶高频变压器的主动偏磁控制策略，包括稳态偏磁校正与暂态偏磁控制算法；（2）建立分析开关暂态导致的高频变压器杂散电容电磁震荡问题的系统级等效电路模型，通过电磁仿真计算与实验测量提取等效电路中杂散电容参数，探索通过开关器件缓冲吸收和门极电路进行震荡抑制的方法。通过本项目研究，探明大功率高频变压器直流偏磁问题的物理机理，有效提高大功率纳米晶高频变压器的安全可靠性与磁密利用率；探明高频变压器杂散电容电磁震荡问题的物理机理，从震荡的激励侧得到有效抑制震荡的方法。

直流偏磁问题与杂散电容问题是目前限制大功率高频变压器应用的两个关键问题。本项目围绕这两个问题展开研究，主要研究内容包括：（1）建立纳米晶高频变压器的直流偏磁模型，探索针对纳米晶高频变压器的主动偏磁控制策略，包括稳态偏磁校正与暂态偏磁控制算法；（2）建立分析开关暂态导致的高频变压器杂散电容电磁震荡问题的系统级等效电路模型，通过电磁仿真计算与实验测量提取等效电路中杂散电容参数，探索通过开关器件缓冲吸收和门极电路进行震荡抑制的方法。通过本项目研究，探明大功率高频变压器直流偏磁问题的物理机理，有效提高大功率纳米晶高频变压器的安全可靠性与磁密利用率；探明高频变压器杂散电容电磁震荡问题的物理机理，从震荡的激励侧得到有效抑制震荡的方法。