Modeling and Model Predictive Control of a Premixed Turbocharged Natural Gas Engine

In this paper, a pre-mixed fuel model is proposed and a model predictive control(MPC) strategy is applied to a pre-mixed turbocharged natural gas engine. It is used in genset and the control objective is to track the target speed and air-fuel ratio(AFR), while resisting load disturbance. The pre-mixed fuel system makes the engine a strongly coupled two-input two-output system. Two methods for processing a crucial parameter in the model are presented, and two linearized models are obtained. Based on these two methods, same MPC control strategy is applied to these models respectively. The method 2 which uses polynomial fitting to treat this parameter as a function of system variables, more specifically reveals the coupling characteristics than method 1. The simulation results show that the MPC with method 2 has better control performance.