Work

Multi-Level PWM core loss tester employing switch-mode power amplifiers

Year: 2026

Type: article

Abstract: A soft magnetic core loss tester originally designed for sinusoidal flux excitation has been modified to enable multi-level PWM excitation. The setup is used to characterize an automotive-grade stator core under magnetic flux densities up to 1.4 T, fundamental frequencies up to 400 Hz, switching frequencies between 4 and 16 kHz, with PWM voltage levels reaching up to seven. The experimental platform is programmed to emulate modular multi-level converters, providing insights into the formation and development of minor hysteresis loops across a wide range of PWM conditions. For each modulation level, the amplitude ratio and switching frequency are varied to offer a comprehensive view of the magnetic loss behavior under realistic converter-driven excitations. The results reveal that increasing the number of PWM voltage levels significantly alters the hysteresis behavior, replacing minor loops with a ripple-like phenomenon and reducing core losses and harmonic distortion. • A novel methodology to measure core losses due to voltage-source inverters is presented. • Switch-mode power amplifier is employed to emulate multi-level PWM excitation. • The impact of PWM modulation strategies has been investigated on an automotive stator core. • Increasing modulation levels transforms minor loops into low-loss ripples. • THD and loss reduction saturate beyond five voltage levels.

Source: Journal of Magnetism and Magnetic Materials

DOI: 10.1016/j.jmmm.2026.174020

Authors: Leonardo Colombo, Peter Stahre, Avo Reinap, Pontus Fyhr, Mats Alaküla

Institution: Lund University

Language: English

Topic: Magnetic Properties and Applications

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,210

Funder: Energimyndigheten