Nonlinear modeling of Electro-pneumatic actuator for Variable Nozzle Turbocharger control

In this paper, we have developed a detailed mathematical model for a Variable Nozzle Turbocharger (VNT) pneumatic actuator controlled by an Electro-pneumatic Pressure Converter (EPC). This model may require complex calculations for control purpose, therefore it has been simplified in two manners. In the first, the equation of flow dynamics has been replaced by a static equation based on pressure and EPC-position mapping. In the second, the dynamics of the EPC have been neglected and replaced by a static gain. These models have been simulated and compared with experimental data. The complete model as well as the simplified models have shown good accuracy.