Constrained state-feedback control of permanent magnet synchronous machines for automotive applications

Torque control of permanent magnet synchronous machines (PMSMs) employed in automotive applications is a challenging problem. These applications are characterized by fast dynamics that are subject to physical and control constraints. The goal of this paper is to provide a controller synthesis method that can deal with these challenges. To this end, a one step ahead model predictive state-feedback control scheme based on flexible Lyapunov functions concept was designed. The quadratic constraints related to the system states and control inputs are approximated with polytopic constraints, which are linear constraints. Moreover, the rotor temperature behavior, which is crucial in automotive applications, is taken into account in the controller synthesis methodology. Then, the resulting MPC problem is reduced to a linear program to be solved at each sample instant. The effectiveness of the developed synthesis method is illustrated using a realistic simulation scenario. The simulated results show significant improvement compared with the classical PI approach.