Power conversion efficiency prioritized AC filter inductor design for three-phase PWM inverter

This study was conducted to develop a design method of power density and efficiency maximization for three-phase pulse-width modulated (PWM) inverters that include AC filter. A tradeoff relationship exists between power density and efficiency. In general, increasing the switching frequency is known to increase the switching device loss and decrease the volume of the passive components. A three-phase PWM inverters design should consider the balance between conversion efficiency and inverter volume. However, best of our knowledge, no practical study has focused on the optimal design of a three-phase PWM inverter that includes an AC filter. This is because the iron loss of the AC filter inductor changes in complicated ways depending on the DC-bias excitation, amplitude of switching ripple current, etc. Therefore, the present authors clarified this iron loss mechanism and realized a highly accurate iron loss calculation method in previous studies. In this paper, the relationship between efficiency and volume for the switching frequency was analyzed when the AC filter inductor was designed for minimal loss by adjusting the core diameter, height, and number of winding turns. The efficiency and volume optimization achieved by designing a proper inductor was verified via comparison with a base design.