Energy efficient sensorless scalar control for full speed operating range IM drives

This paper proposes a low-cost implementation of energy saving strategies in scalar control IM Drives including high speeds in a wide working range. This loss reduction control algorithm approximates and adapts to scalar control some optimized analytical relationships, proposed in vector control, for low cost implementation. Basically an “optimal” slip from the energetic point of view is calculated in every speed range condition and the IM drive is forced to operate at this suitable slip angular frequency, that assures loss reduction especially at light loads. Numerical simulations and experimental validation confirm the effectiveness of the proposed control strategy, highlighting pros and cons of such implementation.