| 摘要 |
PURPOSE:To simplify constitution by forming the AC circuit side only by elements controlling power, such as a semiconductor control rectifying device, a phase synchronous signal generating section, etc. CONSTITUTION:An arithmetic section 12 conducts PID arithmetical operation using signals E4 as measuring value and signals EO as set value, and outputs control signals E5. The control signals E5 are digitally converted into signals E6 by means of a V/F converter 14, and transmitted to a counter 17. A zero-cross detecting circuit 16 detects the zero-cross point of the voltage wave-form ESO of a power supply 2, and outputs signals E7. Photo thyristors PS1, PS2 are ON- OFF controlled by the output of the counter 17. The firing angle of a voltage wave-form ES1 applied to the motor 1 is controlled through the operation of the photo thyristors PS1, PS2. |
