A Practical Iron Loss Calculation for AC Filter Inductors Used in PWM Inverters

A novel iron loss calculation method is proposed based on an iron loss map for an ac filter inductor used in a pulsewidth-modulation (PWM) inverter. The iron loss map, previously reported by the authors, is created by measuring the dynamic minor loop on the B-H plane, and this is used for the calculation of inductor iron loss in the dc chopper circuit. However, in the case of an ac filter inductor used in a PWM inverter, the iron loss map cannot be directory applied to the iron loss calculation. In this paper, an iron loss calculation for an ac filter inductor is presented by expanding the loss map method. We describe the principle of expansion and the practical procedure for the calculation, which utilizes the loss map and a conventional circuit simulator. Iron loss for the ac filter inductor under some typical modulation methods of the PWM inverter are calculated and discussed with regard to the relation between the modulation methods and iron loss. The calculated results are verified using experimental results from a 500-W inverter setup. The inductor loss and conversion efficiency of the PWM inverter are measured for each modulation method.