Investigation of Gallium Nitride Devices in High-Frequency LLC Resonant Converters
Investigation of Gallium Nitride Devices in High-Frequency LLC Resonant Converters
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DOI：
10.1109/tpel.2016.2528291
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发表时间：
2017
影响因子：
6.7
通讯作者：
Weimin Zhang;Fred Wang;D. Costinett;L. Tolbert;B. Blalock
中科院分区：
文献类型：
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作者：
Weimin Zhang;Fred Wang;D. Costinett;L. Tolbert;B. Blalock
新出现的氮化镓(GaN)器件具有超快的开关速度和低的导通电阻，这可能会为功率转换器提供重大改进。本文研究了GaN器件在LLC谐振转换器中的优点，并定量地评估了GaN器件提高转换器效率的能力。首先，基于谐振工作的LLC谐振变流器的分析模型，建立了器件和变流器设计参数与器件损耗的关系。由于GaN器件的有效输出电容较低，GaN基设计与硅基设计相比，器件损耗降低了约50%。其次，对一次侧和二次侧电流不对称引起的变压器绕组额外损耗提出了新的观点。基于有限元分析(FEA)仿真中的绕组损耗模型，将装置和设计参数与绕组损耗联系起来。与硅基设计相比，GaN基设计的绕组损耗降低了18%。最后，为了从实验上验证GaN器件的优势，搭建了400~12V、300W、1 MHz GaN基和硅基LLC谐振转换器样机并进行了测试。GaN基变流器的效率提高了1%，损耗降低了24.8%。
Newly emerged gallium nitride (GaN) devices feature ultrafast switching speed and low on-state resistance that potentially provide significant improvements for power converters. This paper investigates the benefits of GaN devices in an LLC resonant converter and quantitatively evaluates GaN devices' capabilities to improve converter efficiency. First, the relationship of device and converter design parameters to the device loss is established based on an analytical model of LLC resonant converter operating at the resonance. Due to the low effective output capacitance of GaN devices, the GaN-based design demonstrates about 50% device loss reduction compared with the Si-based design. Second, a new perspective on the extra transformer winding loss due to the asymmetrical primary-side and secondary-side current is proposed. The device and design parameters are tied to the winding loss based on the winding loss model in the finite element analysis (FEA) simulation. Compared with the Si-based design, the winding loss is reduced by 18% in the GaN-based design. Finally, in order to verify the GaN device benefits experimentally, 400- to 12-V, 300-W, 1-MHz GaN-based and Si-based LLC resonant converter prototypes are built and tested. One percent efficiency improvement, which is 24.8% loss reduction, is achieved in the GaN-based converter.