High-Frequency Harmonic Effects on Low-Frequency Iron Losses

The study of iron losses in electrical machines represents a major interest in academic and industrial environment, especially in case of systems with high-frequency (HF) harmonic content in the supply voltage. In this context, this paper presents an analysis concerning the impact of HF injection on low-frequency (LF) iron losses. A new phenomenon is observed in a toroidal magnetic circuit with nonoriented electrical steel laminations, supplied by the superposition of two sinusoidal voltages at low and high frequencies. The experimental results show that the injection of HF harmonics (0-10 kHz) in the toroid affects the distribution of low frequencies in the steel in a way that the LF iron losses decrease of about 25%. An explanation for this phenomenon might be attributable to motion mechanism of Bloch walls.