The Design Of Low-Frequency Active Filter Based On EMI

The conduct emission can bring the interference source noise to the EUT equipment by power lines. Base on the GJB151A-CE101 criterion, the conduct emission limit frequency from 100Hz to the higher in alternating current. Nevertheless the frequency bound of traditional power filter is normally from several KHz to 1GHz, that is difficult to achieve the request of GJB. This paper mainly discuss the power active filter by TMS320VC5402 DSP high speed chips.This paper discuss the theory of traditional power filter, and presents the design idea of power active filter for power lines. Then we design and simulate third-order butterworth low-pass filter and power amplifier circuit. And compared the two methods of adaptive filter— LMS and RLS by simulation. Then choose LMS to achieve the hard and soft ware design of adaptive notch filter. Finally, we use EMSCAN to test the electromagnetic interference of PCB. Results show that the power active filter has better effect and reach anticipative target.