Active control of combustion instability via IMC

Two IMC approaches are applied to the active control of combustion instability. The process is lightly damped, unstable, non-minimum phase, and thus difficult to control. It is observed that the direct IMC approach needs to find exact cancellation of the unstable poles for design and implementation thus is not proper for the control of combustion instability, instead, the two-step IMC approach can retain the IMC structure if a simple feedback controller can be found to stabilize the process. Simulations show that the two-step IMC controller can achieve better disturbance rejection performance, and the actuator dynamics do not have to be considered in the controller design.