Design and analysis of a resonant induction motor

Abstract

Induction motors (IMs) with round and solid rotors are widely utilized in mining, water pumping, and agricultural applications due to their robustness, low cost, and minimal maintenance. However, their rated performance is often unsatisfactory, characterized by low torque and efficiency. This article proposes a resonant induction motor (RIM) to explore the series resonant principle for enhancing IM performance at minimal cost. In contrast to prior designs requiring resonant capacitors occupying 70% of the EM active volume (stator/rotor windings and core), the proposed RIM reduces this to only 5% of the EM active volume. This is particularly relevant for round and solid rotor IMs with poor rated performance. First, the motor's static parameters and the required resonant capacitors are analyzed and calculated using the equivalent circuit and the two-dimensional eddy current field finite element method (2D-EC-FEM). Subsequently, a RIM prototype is constructed to validate the theoretical analysis. Experimental results from the RIM prototype, which incorporates appropriate electromagnetic parameters and integrates resonant capacitors into the stator windings, demonstrate significant performance enhancements. Under the same voltage supply and rated conditions, the RIM achieves a higher power factor, greater maximum torque, and an improved torque-efficiency correlation compared to a conventional IM.