| 摘要 |
PURPOSE: To make it possible to deal with a single-phase three-wire type power supply and a single-phase two-wire type power supply by one kind of an inverter by changing over one output phase of first and second half bridge inverters at 180 deg. at the time of the single-phase three-wire type AC power supply. CONSTITUTION: A single-phase inverter device is connected so that the line-to- line voltage of single-phase three-wire type AC power supplies 13, 14 is detected by two pairs of transformers 18a, 18b, detected voltage V1 , V2 , is input to a discrimination circuit 35, and the single-phase three-wire type AC power supplies or single-phase two-wire type AC power supplies are confirmed automatically. A transfer contact 33 is changed over to the (a) side at the time of a three wire type and to the (b) side at the time of a two wire type through a changeover circuit 32 by the discrimination circuit 35. A current reference I1 is connected at a point (b) and I2 at a point (a), a current reference, in which phase differs at 180 deg., is input to an amplifier 21 by the transfer contact 33, and a carrier signal, in which phase differs at 180 deg. from V23 , is input to a comparator 25 through a polarity inversion circuit 34 in the carrier signal V23 of PWM. Accordingly, one kind of the inverter can correspond to the single-phase three- wire type power supply and the single-phase two-wire type power supply. |
