| 摘要 |
PURPOSE:To prevent generation of an abnormal output by designing the circuit that an input and an output of an integration term are almost zero so as to avoid an electric charge from being stored in a capacitor when the control operation is selected by a changeover switch. CONSTITUTION:A feedback circuit 11 feedback a signal of a control variable 12 to a set value Vi, a feedback circuit 13 uses the control variable 12 as the set value V1 to apply feedback control to an output V0 of a PiD circuit, and both the feedback circuits 11, 13 are changed by a changeover switch 14. Further, a feedback circuit 15 is a circuit applying feedback by using an integration arm 16 and summed at a summing point 18 via a large gain G (G=G1+G>=+GD) being the sum of the gain G1, the gain Gi of the integration term and the gain GD of a differentiation term 17. In using the term 19 as a proportion term of the gain Gp and an input Va and an output Vb of the integration term 16 are expressed by a transfer function, then the result is expressed in equation I. Then Va=V1G1/(1+GiG1G) and Vb=V1GiG1/(1+GiG1G) are obtained and when the gain G is sufficiently large, the control variables Va, Vb are nearly zero and the capacitor of the integration term stores no electric charge. |
