| 摘要 |
PURPOSE:To ensure the smooth and quick rising energization, by storing the time series phase angle data for soft starting accorded with the rise characteristics of a load and then reading out said angle data synchronously with the cycle of a power supply to decide the ON or OFF phase. CONSTITUTION:The power supply voltage is digitized after the full wave rectification and fed to a microcomputer MPU12. At the same time, the pulse of a zero-cross pulse generating circuit 13 is also fed to the MPU12. The MPU12 refers to the output voltage phase angle of the preceding data from a table of relation between the power supply voltage of a memory and the phase angle of output voltage and then delivers the gate time corresponding to the above- mentioned phase angle through a timer to trigger the switching element. In such a system, a sudden rise is given to the increment pattersn of conducting parts S1-Sn of the outut voltage with a relation t=t1. Hereafter the increment patterns are raised gradually up to t=tp, and then the inclination is more increased after tp to set the output voltage at the rated value with t=tn. These gate times t1-tn are written into the MPU12 as a timer table and then executed by the MPU12. |
