Optimal design of integrated EMI filter

The electromagnetic interference (EMI) filter usually occupies a large portion of size of the power supply, and has a direct impact on the power density. For the power supply which employs a current-fed converter after the rectifier, a large input inductor is required. The proper selection of the input inductor and EMI filter will result in significant size reduction. This paper addresses the issue of size reduction. By defining the EMI filter and the input inductor together as the integrated EMI filter, the relationship between the total volume of the integrated EMI filter and the current ripple is investigated. The results show that the total volume of the integrated EMI filter is minimized when the peak to peak current ripple equals 10% of the average input current