| 摘要 |
PURPOSE:To ensure the balance of the output voltage despite the unbalanced input voltage by detecting the output voltage for each phase to control the 3-phase voltage. CONSTITUTION:The 3-phase AC voltage is received by 3-phase input terminals 1-3 and then decomposed into three single-phase voltages to be supplied to single-phase voltage control units 7-9. The outputs of these units 7-9 are synthesized after voltage control done by these units. Then 3-phase AC voltages are delivered from 3-phase output terminals 4-6. In this case, the voltage elements having phases corresponding to output voltage detecting lines 11-13 are applied to the units 7-9 respectively, and then compared with the reference voltage for each unit. Then the output voltage is controlled so as to eliminate the deviation between said voltage element and the reference voltage. While an output voltage control mode changeover switch 17 is switched to perform the control with priority given to the 3-phase balance to obtain the 3-phase voltage having a high degree of balance with no fixture of the reference voltage. |
