| 摘要 |
<p>A control system for controlling a process having at least one significant parameter has a primary control loop responsive to the rate of change of the magnitude of the parameter and a secondary cascaded control loop responsive to the magnitude of the parameter representing a time integral of the rate of change of the magnitude of the parameter. In prior art systems which are responsive to rate of change and to magnitude of a parameter, it is usual to have a primary control loop responsive to the magnitude of the parameter and a secondary control loop which imposes some secondary limitations on the rate at which the magnitude can change. Such prior art systems suffer two disadvantages. Firstly, due to interaction between the primary and secondary loops, the procedure for adjusting the controller gains to achieve optimum or near optimum control of the individual loops as well as of the two loops acting in concert typically involves a successive approximations approach, and so can be relatively cumbersome and difficult. Secondly, automatic gain control may not be easily applied. However in the control system according to the invention, the primary control is of the rate of change of the magnitude of the parameter and this may control the magnitude of the parameter for example as a time integral of the rate of change. This facilitates obtaining optimum or near optimum stability and regulation in the control of the rate of change of the magnitude of the parameter as well as in the control of the parameter itself; it also permits automatic gain control to be easily applied.</p> |
