Real-Time Parameter Estimation in Back-EMF Self-Sensing Mode with the Synergy of Induction Machine Deadbeat-Direct Torque and Flux Control Drives

Back-EMF self-sensing is commonly used in induction machine (IM) drive systems for cost and reliability considerations. Deadbeat-direct torque and flux control (DB-DTFC) has shown to be a highly effective method for IM control with a fixed switching frequency. Accurate machine parameters are critical for low speed back-EMF self-sensing and low speed DB-DTFC. Using unique properties of IM DB-DTFC drives, this paper proposes a general solution for real-time parameter estimation in the back-EMF self-sensing mode. The paper documents the low speed parameter sensitivity of back-EMF self-sensing based IM DB-DTFC drives. The paper then recognizes the potential synergy of IM back-EMF self-sensing and DB-DTFC and investigates two real-time parameter estimation methods based on flux injection and based on model reference adaptive systems (MRAS). Finally, by considering properties of the two methods, an operating region-based real-time parameter estimation system in IM DB-DTFC self-sensing drives is proposed and experimentally evaluated.