OPTIMAL PROPORTIONAL PLUS INTEGRAL CONTROL FOR REGULATOR AND TRACKING PROBLEMS.

Two new design methods are proposed for optimal PI control which give fast recovery from load disturbances without producing large overshoots associated with set-point changes. Unlike existing methods, such as set-point filtering or any other scheme that essentially detunes the controller for set-point changes, the proposed methods do not increase the rise time significantly in order to reduce overshoot. The first method resets the integral term in the control law when the new set point is reached. The second method is a modified model-following approach that does not increase the overall dimension of the system. Two numerical examples demonstrate that the proposed methods are superior to alternatives such as set-point filtering and conventional model following.