IMC based wastegate control using a first order model for turbocharged gasoline engine

The basis of constructing an Internal Model Controller (IMC) are the plant model and its inversion. The construction of an appropriate invertible plant model is one of the challenges in implementation of an IMC on a nonlinear system. In this work we study the control of a turbocharged gasoline engine using a wastegate actuator. The turbocharged engine is typically represented using a fourth or higher order model. A first order representation of this system (or single state) is obtained via singular perturbation. The resulting model is invertible, and is cast into the standard structure of IMC. We also include the throttle actuator into consideration during the reduced order model development. The IMC is implemented on a full order nonlinear model for evaluation and the performance is compared to a PI controller with similar feed-forward action.