| 摘要 |
PURPOSE:To set an effective load voltage to a reference set constant voltage accurately, by controlling the phase of an AC power supply with a microcomputer. CONSTITUTION:A fluctuated voltage of an AC power supply E is detected with a fluctuation voltage detecting circuit 1 and the voltage is converted into a digital quantity at an A/D converter 2. A microcomputer 3 operates the amount of phase control based on an input from the A/D converter. On the other hand, zero-cross pulses from a zero cross pulse generating circuit 7 start a counter 8 to count a phase angle. When this counting value is coincident with the result of the above operation, the microcomputer gives a phase controlling signal to a switching circuit 4 to conduct it. A voltage applied to a load 5 is detected with a detecting circuit 6 and inputted to the microcomputer 3 via the A/D converter 2 and the difference with an effective load voltage is operated and the phase control amount taking into consideration the amount of compensation is operated to control the switching circuit 4. Thus, the effective load voltage can be maintained to a reference set voltage. |
