Real-time loss minimization control in induction machines based on DSP TMS320LF2812

Abstract

This paper presents a DSP based implementation of simple and very useful control algorithm for the real-time efficiency optimization of the indirect vectorcontrolled induction motor drives. Conventional field-oriented induction motor drives operate at rated flux even at low load. To improve the efficiency of the existing induction motors, it is important to regulate the magnetization flux of the motor in the desired operating range. This paper presents techniques for minimizing power loss (the copper and core losses) of induction motor based on determination of an optimum flux level for the efficiency optimization of the vector-controlled induction motor drive. An induction motor (IM) model in d-q coordinates is referenced to the rotor magnetizing current. Thus the decomposition into d-q components in the steady-state motor model can be utilized in deriving the motor loss model. The algorithm offers a fast convergence. The complete closed loop vector control of the proposed LMC-based IM drive is successfully implemented in real-time using digital signal processor DSP TMS320LF2812 for 1HP motor induction motor. The close agreement between the simulation by Matlab/Simulink and the experimental results confirms the validity and usefulness of the proposed techniques. The proposed LMC in a comparison with conventional FOC can reduce total losses from 5% to 67.2% for all load ranges.