Eddy current losses in electrical steels subjected to matrix and classical PWM excitation waveforms

Iron losses due to flux harmonics in stator cores of pulsewidth-modulation [PWM] inverter-fed induction motors have a major effect on system efficiency. Novel direct ac-ac matrix converters involve no dc-link function and enable adjustment of power factor. This paper presents experimental results of magnetic losses in two nonoriented electrical steels magnetized under different excitation, characteristic of PWM, and matrix converters. Results show the beneficial effect of a specific voltage supply (phase-to-neutral) from matrix converters on the performance of electrical steels. Iron losses in laminations excited by matrix converter waveforms were up to 30% lower than that under PWM excitation due to reduced eddy-current losses.