| Title |
PLL for Unbalanced Three-Phase Utility Voltage using Positive Sequence Voltage Observer |
| Authors |
Hyeong-Su Kim ; Jong-Woo Choi |
| Keywords |
PLL(Phase Locked Loop); State observer; Unbalanced source; APF(All Pass Filter); Custom Power Devices |
| Abstract |
The number of transformer and the size of transformer in inverter using 3-phase transformer could be reduced compare with a multi-level inverter using single phase transformer. but still the 3-phase transformer inverter needs many switches. In this study, we proposed the isolated multi-level inverter using 3-phase transformers and common arm, in this paper. Also, using phase angle control method with switching frequency equal to output fundamental frequency, harmonics component of output voltage and switching loss can be reduced. Finally, We tested multi-level inverter to clarify electric circuit and reasonableness through Matlab simulation and experiment by using prototype inverter. |