A Higher-Order Loss-Separation Model for Fast Estimation of Core Loss in High-Frequency Transformers

Abstract

The core loss calculation is essential for the design and performance evaluation of high-frequency transformers. It is related to the dimensions, temperature rises performance, and operating efficiency of transformer designs. Some scholars have examined the correlation between the characteristics of the core and losses, such as the core air gap length and the core structure; some investigations have also analyzed the effects of harmonics, distortion flux, and other factors on core losses. However, in reality, the core operating environment of high-frequency transformers is very complex, and achieving the required accuracy of loss model calculations is difficult. This paper discussed the insufficiency of the classical Bertotti loss separation model in estimating core loss under non-sinusoidal excitation of high-frequency transformers. Based on the derivation and modification of the classical loss model, the magnetic performance test platform of the nanocrystalline core material was established. In order to obtain a higher-order correction calculation method for the core loss of high-frequency transformers under trapezoidal wave excitation, the experimentally measured loss curves of nanocrystalline materials were further corrected. Finally, the accuracy of the correction model was verified by changing the loss results by varying the trapezoidal wave rise time constant.

Keywords

• High-frequency transformer
• non-sinusoidal excitation
• core loss
• Bertotti loss separation model
• hysteresis
• eddy current