Dynamic tuning of dynamic matrix control of steam temperature

A technique of controlling a steam generating boiler system includes dynamically tuning a rate of change of a disturbance variable (DV) to control operation of a portion of the boiler system, and in particular, to control a temperature of output steam to a turbine. The rate of change of the DV is dynamically tuned based on a magnitude of an error or difference between an actual and a desired level of an output parameter, e.g., output steam temperature. In an embodiment, as the magnitude of the error increases, the rate of change of the DV is increased according to a function f(x). A dynamic matrix control block uses the dynamically-tuned rate of change of the DV, a current output parameter level, and an output parameter setpoint as inputs to generate a control signal to control a field device that, at least in part, affects the output parameter level.