Patent ID: 11880187
Assignee: TOSHIBA MITSUBISHI—ELECTRIC INDUSTRIAL SYSTEMS CORPORATION
Field: Control (Instruments)
Classification: CPC G  B | IPC G

Claim 0:
1. A steel plant control device, comprising:
a subtractor that outputs a deviation between a target value and a control variable, the control variable being fed back from a control object;
a PI controller that receives an input of the deviation and outputs a first manipulated variable for reducing the deviation by using a proportional action and an integral action;
a first-order lag controller that outputs a second manipulated variable, the second manipulated variable being obtained by multiplying the deviation by a proportional gain and further multiplying by a first-order lag element; and
an adder that outputs to the control object a final manipulated variable, the final manipulated variable being obtained by adding the second manipulated variable to the first manipulated variable;
wherein, in a band that is lower than a first frequency, a gain of the PI controller is higher than a gain of the first-order lag controller; in a band from the first frequency to a second frequency that is higher than the first frequency, the gain of the first-order lag controller is higher than the gain of the PI controller; and in a band that is higher than the second frequency, the gain of the PI controller is higher than the gain of the first-order lag controller, and
wherein the band from the first frequency to the second frequency is a band that causes load change and characteristic change of the control object after the deviation converges to zero.