Flatness Based Optimal Control for Induction Machine Drives

摘要

Aim of this study is to derive an efficient method and problem formulation for optimal control of induction machines in variable speed drives, as used for example in electric vehicles. Induction machine dynamics are thus represented as a differential flat system and voltage source inverter losses are considered as an average value model. Based on the canonical form of the equivalent flat system, a nonlinear discrete finite horizon optimal control problem with a predefined torque and speed profile is introduced. If it is required to find a global solution, this problem can be efficiently solved by discrete dynamic programming or, when time is of essence, by means of sequential quadratic programming. The former is applied to a practical electric vehicle load cycle with limiting voltage constraints. The solution demonstrates how optimal control methods may be beneficial to drive design.