Electromagnetic heterogeneous integration for high-frequency power conversion

Due to the superior features of wide bandgap(WBG) transistors, the performance boundaries of WBG-based converters are improved compared to their Si-based counterparts. However, due to their high-frequency operation, the potential of WBG transistors cannot be fully exploited if they are considered as a simple drop-in replacement for Si-based transistors. This thesis discusses several issues caused by employing discrete electromagnetic components in high-frequency applications, including switching performance optimization, magnetic loss modeling and common-mode (CM) noise suppression. However, existing discrete electromagnetic implementations cannot regulate parasitic parameters well, which is important for efficient switching and CM noise attenuation. Moreover, increasing high-frequency magnetic loss for magnetic components is hard to optimize with existing magnetic loss modeling tools. To overcome these challenges, this thesis proposes a novel heterogeneous electromagnetic integration technology. Discrete ceramic capacitors and ferrite cores are employed for electromagnetic components with large value requirements due to their high passive value density and low loss in high frequency applications. Organic dielectric layers are utilized for capacitive components, which have low-value requirements but high demands for minimizing parasitic effects. Based on this concept, a heterogeneous integrated GaN module is constructed, integrating decoupling and filter capacitors with reduced parasitic inductance. In the studied case, experimental results show a reduction in a 6% turn-off overshoot, and a 25 dBμV decrease in peak CM noise compared to conventional PCB technology. To realize a better trade-off between accuracy and speed for magnetic loss modeling, the proposed method integrates analytical models into the ANNs. In this case, the proposed method achieves an accuracy of less than 3% with an implementation time of only a few milliseconds. The proposed heterogeneous concept is also applied to reduce the CM noises in planar transformers. Based on the analytical model of CM noise current, CM noises in the planar transformers are reduced by the regulation of layer-to-layer capacitances. In the studied case, measured CM noises are reduced by approximately 32% by employing the proposed method without the use of any auxiliary components.