A Novel Approach to MTPA Tracking Control of AC Drives in Vehicle Propulsion Systems

Abstract

In today's hybrid or fully electric vehicles, two types of propulsion machines can mainly be found: induction machines (IM) and interior permanent magnet synchronous machines. They are highly utilized and operated in magnetic saturation regions where inductance parameters change nonlinearly. The energy efficiency of both drives depends strongly on the choice of reference currents within field-oriented control. The paper shows two approaches for the determination of well-adjusted current components for both machines. First, model-based optimization is performed. It uses machine models considering saturation and loss models including the inverter. Second, a newly developed online-optimization scheme based on a discrete search method is presented. Simulation results show its advantages over recently published solutions for both machine types. Finally, experimental results at a drive test bench are presented. They prove the fast convergence and correct function of the proposed method.