Isolated multi-level inverter using 3-phase transformers

In this paper, we proposed the isolated multi-level inverter using 3-phase transformers. It makes possible to use a single DC power source due to employing low frequency transformers. In this inverter, the number of transformer could be reduced compare with an existing 3-phase multi-level inverter using single phase transformer. Using phase angle control method with switching frequency equal to output fundamental frequency, harmonics component of output voltage and switching loss can be reduced. Lastly, we tested the proposed prototype inverter to clarify the proposed electric circuit and reasonableness of control signal for the proposed inverter.