| 摘要 |
PURPOSE:To obtain 3-phase AC output having highly approximate sinusoidal wave by providing a DC power source capable of independently setting a voltage from switching modes of the respective phases of an inverter and simplifying a base driving circuit. CONSTITUTION:3-Phase bridge type switching circuit 3 is connected in series with one voltage-dividing terminals P1 and N1 of voltage dividing circuits R1-R3, C1- C3 for dividing the voltage of a variable DC power source into 1/4 and 3/4 voltage outputs, and 3-phase bridge type switching circuit 4 is connected in series with the other voltage-dividing terminals P2 and C2 thereof. The output terminals of the switching circuits 3, 4 are commonly connected so that the synthesized voltage of these three terminals becomes approximately zero. Thus, it is not necessary to change the switching mode according to the output frequency as in the conventional device, and the output voltage can be readily varied with stable operating characteristics ranging from low to high frequencies with a simple base driving circuit. |
