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

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.