Development of Super Premium Efficiency Synchronous Reluctance Motor

Abstract

Electric motors are the largest consumer of electricity in India. The International newlineElectro-technical Commission has framed the efficiency standard from standard newlineefficiency to ultra-super premium efficiency. To increase the efficiency standard and newlineto reduce the energy consumption of the electric motors are the paramount focus by newlineany motor manufacturers. In this research work, line start synchronous reluctance newlinemotor is developed for super-premium efficiency within the frame size of standard newlineefficiency. The research work starts with a feasibility study on a single-phase line start synchronous reluctance motor to understand the efficiency improvement by replacing the induction rotor with a reluctance rotor. The main objective of this research is to build an optimal three-phase line start synchronous reluctance motor (LSSynRM) with super-premium efficiency without changing the stator geometry and frame size of standard efficiency machine (IM). Various rotor configurations of LSSynRM have been designed, optimized, fabricated and tested. An acoustic test has been conducted to measure the noise level of the developed LSSynRM. The observed noise level of the initial LSSynRM was not found to be within the IEC standard for cast iron motors. An additional cage in rotor direct axis has been introduced in the initial rotor to minimize the acoustic level. The additional cage rotor with reduced torque ripple has been fabricated and tested. The test results of the two fabricated rotor structures confirm that the acoustic level is well below the standard but power factor is not satisfied with the IE4 level. To improve the power factor an axially laminated LSSynRM has been studied through FEA. The fabrication steps such as folding, stacking and screwing, wire cut, die-casting and milling process of axial LSSynRM has been explained in detail. From the test results, it is observed that the proposed axial rotor provides an optimal power factor. Thermal analysis has been carried out to study the temperature rise for the developed LSSy