Measuring and Separating Conducted Three-Wire Emissions from a Fault-Tolerant, NPC Propulsion Inverter with a Split-Battery Using Hardware Separators Based on HF Transformers
Journal article, 2021

Conducted emissions on the traction battery's power cables in EVs must be limited to avoid unwanted electromagnetic interference (EMI). When designing an EMI filter, it is advantageous to have information of the common mode (CM) and differential mode (DM) noise levels. This article deals with the measurement and separation of the dc side's three-wire DM/CM noise of a fault-tolerant three-level neutral-point-clamped (NPC) inverter with a split-battery system. Two hardware separators, based on small-circuit highfrequency transformers, were developed to identify the dc side's CM, line-DM, and phase-DM noise levels. Their characterized CM and DM rejection ratios for the frequency range from 150 kHz to 110 MHz are at least -33 and -21 dB, respectively. The separated noise of the NPC inverter was measured, using an inductive load, when operating the inverter with three-level and two-level modulation, resembling normal operation and a possible operation under fault, respectively. A simple three-wire CM model of the used testbed and the DM power module oscillation were derived to validate the separated noise's resonance peaks/valleys. It has been seen that the CM noise is dominant, especially below 10 MHz, except for the power module oscillations. Furthermore, when using the two-level modulation, in the case of a clamping diode fault, the noise levels are increased by about 3 dB.

Common mode (CM)

electromagnetic emissions (EME)

noise measurement

electromagnetic interference (EMI)

electromagnetic compatibility

differential mode (DM)

neutral-point-clamped (NPC) inverter


Anton Kersten

Chalmers, Electrical Engineering, Electric Power Engineering, Electrical Machines and Power Electronics

Karl Oberdieck

RWTH Aachen University

Jerome Gossmann

RWTH Aachen University

Andreas Bubert

RWTH Aachen University

Rolf Loewenherz

RWTH Aachen University

Markus Neubert

RWTH Aachen University

Torbjörn Thiringer

Chalmers, Electrical Engineering, Electric Power Engineering, Electrical Machines and Power Electronics

Rik W.De Doncker

RWTH Aachen University

IEEE Transactions on Power Electronics

0885-8993 (ISSN)

Vol. 36 1 378-390 9110723

Subject Categories

Other Physics Topics

Signal Processing

Other Electrical Engineering, Electronic Engineering, Information Engineering



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