This chapter presents an analysis with mutual consideration of the characteristics of semiconductor components used as switching devices in a DC-AC inverter and the characteristics of the magnetic material constituting the iron core of electrical equipment. The on-voltage characteristics of semiconductor components affect the magnetic hysteresis characteristics of the magnetic material considerably. Besides, we introduce a numerical calculation method based on the play model that can take into account the interaction between these characteristics efficiently. The play model is utilized to consider and express the magnetic hysteresis phenomenon; this model can calculate a magnetic flux density waveform (magnetic field strength waveform) from an arbitrary magnetic field strength waveform (magnetic flux density waveform) by preparing several magnetic hysteresis loops for the identification process. Because the conventional play model only can express the magnetic hysteresis in the DC field, the classical eddy current theory and the Cauer equivalent circuit theory are additionally applied in this study for considering the eddy currents in the AC field. In particular, the Cauer theory is used to analyze the reaction magnetic field caused by the carrier frequency in the pulse-width modulation (PWM) inverter excitation, where the skin effect cannot be ignored. To validate the effectiveness of the designed calculation method, an example of magnetic characteristics under the PWM inverter excitation using two different types of semiconductor components with high and low on-voltages is conducted. Finally, magnetic hysteresis loops obtained by the calculation method and those obtained by experimental measurements are compared and evaluated.