Real-time direct field-oriented and second order sliding mode controllers of induction motor for electric vehicles applications

This paper presents a comparison between two control techniques: Direct Field-Oriented Control (DFOC) and Second Order Sliding Mode Control (SOSMC), both on real-time implementations. DFOC is one of the most popular control strategies in the industry for induction motor drives and has the advantage to produce a continuous control signal, helping to extend life of electric vehicle batteries. On the other hand SOSMC is based on the super-twisting algorithm, which reduces chattering, rejects disturbances and produces a continuous control signal. To modulate the inverter pulses, Space Vector Modulation (SVM) is used and to estimate the rotor flux, a sliding mode observer is applied. Real-time implementation of these controllers have been successfully done, using a 1/4 hp induction motor prototype. Results are presented to illustrate the respective advantages and drawbacks. The proposed schemes allow easy integration of these kind of vehicles into a system of systems configuration.