结合平衡和滤波技术抑制GaN电源转换器的电磁干扰

A Method for Suppressing Electromagnetic Interference of GaN Converter Utilizing Balance and Filter Technologies

针对GaN Boost型电源转换器的电磁干扰降低电源可靠性的问题,提出了一种结合阻抗平衡和滤波技术抑制GaN Boost电源转换器电磁干扰的方法。由于阻抗平衡技术利于抑制低频共模电磁干扰,而滤波技术利于抑制高频共模电磁干扰,所以将两者结合以抑制GaN Boost型电源转换器的共模电磁干扰。首先用GaN高电子迁移率晶体管搭建功率级电路;然后用耦合电感替代功率级电感,并在耦合电感的输出端加上电容以平衡寄生参数的影响;最后加入共模电感以抑制高频共模电磁干扰,综合考虑抑制效果和电路面积,合理选择滤波器共模电感值。该组合方法与阻抗平衡单项技术相比,能有效地抑制高频共模电磁干扰;与滤波器单项技术相比,减小了电路面积。仿真结果表明,抑制后与抑制前的电磁干扰相比,在200kHz^10MHz低频范围内,电源转换器的共模电磁干扰的抑制量达到40~60dB;在10~30 MHz高频范围内,电源转换器的共模电磁干扰的抑制量约为80dB。

A hybrid method to suppress electromagnetic interference（EMI）is proposed to improve the problem that the reliability of GaN boost converters is reduced by EMI and the method combines the impedance balance and filter techniques.Since the impedance balance technique has the advantage of effectively suppressing low-frequency common-mode EMI,and the filter technique can easily suppress high-frequency common-mode EMI,both the techniques are combined to reduce the common-mode EMI of the GaN boost converter.The GaN high electron mobility transistor is used to build power circuit,then a coupled inductance is used to replace the inductance of power circuit,and a capacitance is added in the output of the coupled inductance to balance the parasitic parameters.Finally,a common-mode inductor is used to suppress the highfrequency common-mode EMI,and the filter inductance is reasonably chosen by trading off between the EMI reduction and circuit area.The hybrid method not only suppresses the highfrequency common-mode EMI more effectively than the impedance balance technique does,butalso occupies less circuit area than the filter technique does.Simulation results show that the hybrid method leads to a 40-60 dB reduction of the common-mode EMI in the range of 200kHz-10 MHz and a 80 dB reduction in the range of 10-30 MHz.