| 摘要 |
A five level inverter comprises six switch tubes (QH1, QH2, QL1, QL2, QL3, QL4), two inductors (L1, L2), four capacitor units (C1, C2, C3, C4) and two reverse current preventing devices (D1, D2). The common terminal of the third capacitor unit (C3) and the fourth capacitor unit (C4) is connected with the common terminal of the first capacitor unit (C1) and the second capacitor unit (C2). The third capacitor unit (C3) and the fourth capacitor unit (C4) are used as the output filter circuit of the inverter, and the common terminal of the third capacitor unit (C3) and the fourth capacitor unit (C4) is used as the midpoint of the DC bus. In the inverter, the electric potential of the midpoint of the DC bus or the positive or the negative pole of the DC power supply (DC) relative to the midpoint of the output filter circuit is relatively stable, and surge voltage with power frequency or high frequency relative to ground will not occur at the positive or the negative pole of the DC bus, thus the leakage current problem will not appear. Additionally, the output efficiency of the five level inverter is relatively high, so that the five level inverter is adapted to the application field of photovoltaic power generation and so on. |
