| 摘要 |
1485247 Retroactive control systems SULZER BROS Ltd 15 April 1976 [17 April 1973] 15660/76 Heading G3R A PI or PID controller incorporates means for delaying response to changes in the set point, whereby to prevent the controlled system being overloaded by a sudden large change in the set point. In Fig. 2, the essential features are: proportional (or proportional-differential) units 53, 62 receiving the actual and desired value inputs N, N s ; an integrator 54; and a delay device 63. The output, control, signal f responds as shown to the difference between the output of unit 62 and the combined outputs of units 53 and 54. The transmission factors of units 53 and 62 are different. The delay introduced by unit 63 may be adjustable. The controller of Fig. 2, is designed for a thermal power plant, Fig. 1 (not shown), in which both temperature and pressure are controlled in a steam-turbine installation driving an electrical generator. Figs. 3a to 3d (not shown) compare the response of the Fig. 2, controller with that of conventional controllers for thermal power plant.
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