Coupled Inductor Design for Interleaved Three-level Active Neutral Point Clamped Inverters Considering EMI Noise Reduction

Abstract

This paper presents the coupled inductor design for interleaved three-level active neutral point clamped (ANPC) inverter considering electromagnetic interference (EMI) noise reduction. Compared to two-level case, the scenarios involved in the three-level space vector modulation (SVM) are more complicated when analyzing the volt-seconds of the coupled inductor for paralleled three-level inverter. At system level, the purpose of converter interleaving is to reduce EMI noise and ripple current in most applications, and coupled inductor design should consider the needs of EMI noise reduction and EMI filter design. These issues are discussed in this paper. The relationship between circulating current and EMI noise is illustrated. EMI filter corner frequency as a function of interleaving angle is analytically derived, and optimal interleaving angle for maximum common-mode (CM) filter and differential-mode (DM) filter corner frequencies is discussed. Coupled inductor design methodology for interleaved three-level inverters with SVM is then presented. Experiments on two interleaved ANPC inverters are conducted. The results verify the coupled inductor design. With the derived optimal interleaving angle, the CM and DM EMI noise are significantly reduced.