不同耦合系数下的交错并联电流连续模式Boost功率因数校正变换器的传导电磁干扰

Conducted Electromagnetic Interference of Interleaved Continuous Current Mode Boost Power Factor Correction Converter with Different Coupling Coefficients

分析采用耦合电感的交错并联Boost功率因数校正变换器工作于电感电流连续模式时,耦合系数的变化对传导电磁干扰(EMI)的影响。将变换器中两开关管的漏源极电压作为传导干扰噪声源,分析变换器的共模噪声和差模噪声的传输路径,并且推导出噪声传输路径的等效电路。讨论传导噪声源在工频周期里不同谐波频率点的幅值变化,给出噪声源随频率变化的趋势,继而得到变换器在不同耦合系数下共模干扰和差模干扰的频谱图。在确定的耦合电感磁心的情况下,设计滤波器时,为了使功率密度最大化,推导出变换器的临界耦合系数。最后通过实际测试验证了理论分析的正确性。

For the interleaved Boost power factor correction (PFC) converter with coupled inductor operating in continuous current mode (CCM), the effects of the coupling coefficient on conducted electromagnetic interference (EMI) were analyzed in this paper. The drain and source voltages of the two switches in the converter were taken as the sources of conducted interference noise. Then the transmission path circuit of the common mode (CM) noise and differential mode (DM) noise of the converter were analyzed, and the equivalent circuit of the noise transmission path was deduced. The amplitude variation of the conducted interference source at different harmonic frequency points in a line cycle was discussed, and the attenuation trend of the noise source amplitude with frequency was given. Thus, the spectrum diagrams of CM noise and DM noise of the converter under different coupling coefficients were obtained. In the case of a certain coupled inductor core, the critical coupling coefficient of the converter was derived in order to maximize the power density when designing the EMI filter. Finally, the analysis was verified by actual tests.