Comparison between predictive and scalar control strategies for minimizing losses in induction motors

Induction motors (IM) are widely used in various industrial applications and significantly contribute to energy consumption worldwide. In many of these applications, the machines are subjected to loads that are less than nominal, which directly impacts the energy efficiency of these motors. This work investigates the operation of a induction motor to minimize energy consumption using different control strategies, such as scalar control (SC), model predictive torque control (MPTC), and model predictive current control (MPCC). The basis of this study is to simulate, using the mathematical model of the induction motor, several operating points for load torque and speed, analysing the machine performance behaviour for different magnetic flux references. The results were a comparison of the efficiency gains obtained for each control strategy over a wide operating range and an analysis of the dynamic response of the controllers at low speed. The scalar control achieved a maximum efficiency gain of 30.44%, MPTC obtained efficiency gains of up to 16. 44%, and the MPCC control reached 16.6% for a 1 HP motor with a lower reference speed and mechanical load. The potential for optimizing efficiency was demonstrated for the three strategies presented, noting limitations at low speed in the dynamic response of the scalar control and the more robust dynamic of the MPTC, which maximized efficiency without loss of performance.