自适应对消EMI滤波器研发思路探究

Research on a Development Idea for Adaptive EMI Cancellation Filter

自适应滤波器是一种高通滤波器,工作时电源电流不通过滤波器的电感,可将强信号的抑制问题转变为弱信号的对消问题。针对电磁干扰(EMI)滤波问题,提出一种自适应对消EMI滤波器的研发思路。自制符合频域要求的卡钳,一是用于检测输出电磁干扰,当作系统的参考信号;二是用以执行信号的对消。当对消结果不满足系统衰减要求时,反馈反向自动增益放大器和相位补偿器进行调整,直到满足系统的衰减要求。通过配置的功率运算放大器和相位补偿器,可进一步提高高频相位的补偿效果。对卡钳的插入损耗进行测试,表明自适应对消EMI滤波器可在10 kHz~100 MHz内的多数频率下实现良好的信号对消效果。该滤波器可有效解决大功率需求与器件精密化、轻量化之间的矛盾,以及以往电源滤波器存在的静音技术难题。

Adaptive filter is a kind of high-pass filter.When it works,the current of the power supply does not pass through the inductance of the filter,which can turn the suppression of strong signals into the cancellation of weak signals.Aiming at the problem of electromagnetic interference(EMI)filtering,a development idea of adaptive EMI cancellation filter is proposed.Calipers that meet the requirements of frequency domain are self-made,in which,one is used to output electromagnetic interference as the reference signal of the system,the other is used for signal cancellation.When the signal cancellation result does not meet the attenuation requirements of the system,the feedback inverse automatic gain amplifier and phase compensator are adjusted until the attenuation requirements of the system are met.By configuring the power operational amplifier and phase compensator,the phase compensation effect at high frequency is further improved.The insertion loss of the caliper is tested,which shows that the adaptive EMI cancellation filter can achieve good signal cancellation effect at most frequencies within 10 kHz~100 MHz.The filter can effectively solve the contradiction between high power demand and precision and light weight of devices,as well as the mute technological problem existed in previous power filters.