A comprehensive design for high power density common mode EMI inductor

Abstract

this paper initiated a discussion on the design methodology and scaling of high power density common mode inductors and proposed a comprehensive step-by-step design procedure for common mode (CM) chokes. In additional to conventional design method, this paper proposed to include CM volt-second impacts on the saturation and CM core-loss in design considerations. Moreover, this paper explored the scaling of CM chokes with different design constraints, which are determined by different material and geometry. This study formulates a comprehensive design procedure of common mode choke for high-density power converters.I.

A Hybrid Common Mode Choke Optimization Method for Input Line EMI Filter Design

“…4b varying ID, OD, H, and θ. All the cases of HCMCs in this table verify the constraints of saturation (8) and effective use of window area (9). Table I contains also accepted and rejected cases with respect to the constraints of the minimum required CM inductance (10) and the stability of the converter (14).…”

“…Hence to avoid saturation and guarantee the effective usage of the core window area there are two design constraints to ensure when sizing the CM inductor. The constraint on the saturation is verified with respect to ID taking into consideration (7) and it's defined as in (8):…”

“…Furthermore, since this inductance is an air-cored inductor, it never saturates at any level of current keeping sustainable filtering performance which favors the usage of a toroidal CMC for CM and DM noise suppression. This inherent parasitical parameter has been addressed in several research papers, either as a constraint in the design of CMCs which is the case in [8]- [10] or to act as a formal DM inductor in EMI filters design as in [11]- [18]. References [19], [20] reported the designable parameter for a CMC.…”

Predicting Common-Mode Inductor Current Using a Time-Domain Hysteresis Model

“…Several works regarding CMIs are available. For instance, a design procedure for a dc-side toroid-shaped CMI is presented in [1]. The effect of both differential-mode (DM) current and CM volts-seconds across the inductor are considered in the inductor sizing.…”

“…A common denominator in [1]- [3] is that the CMIs are assumed to be magnetically linear. Typically, the CM current through the inductor is much smaller than the DM current.…”