Efficiency improvement of a 12-pole 17.5 kW induction motor using converter-fed wound rotor

This paper investigates an induction machine using a novel concept of a converter-fed rotor. The stator is directly connected to the grid while the rotor is fed by a converter with a floating capacitor over the dc-link. In earlier work this topology has shown to be capable of improving the power factor and efficiency of a 4-pole induction machine. This paper explores the possibility to improve the power factor and efficiency of a squirrel-cage 12-pole 17.5 kW induction machine by redesigning the cage rotor to a wound rotor to enable connection of the rotor windings to the converter. A standard 12-pole squirrel-cage induction machine (SCIM) with an inherent low power factor is studied. A wound rotor induction machine (WRIM) is then analytically designed. The performance of the designed WRIM using the analytical model is shown to agree with the results from the finite element (FEM) simulations, thus verifying the correctness of the model. The analytical model is then further used to design different WRIMs with different dimensions and rotor slot numbers. Performances of these designed WRIMs show good potential for power factor and efficiency improvement. Particularly, an optimum efficiency improvement of 6.8%, compared with the original SCIM, has been achieved.

[1]  Yanmei Yao,et al.  Optimum operating point of an induction machine using a rotor integrated converter with a floating capacitor , 2016, 2016 IEEE 8th International Power Electronics and Motion Control Conference (IPEMC-ECCE Asia).

[2]  Fei Xiao,et al.  A novel stand-alone dual stator-winding induction generator with static excitation regulation , 2005, IEEE Transactions on Energy Conversion.

[3]  Thomas A. Lipo,et al.  Power factor enhancement of induction machines by means of solid-state excitation , 1989 .

[4]  Yanmei Yao,et al.  Power Factor Improvement and Dynamic Performance of an Induction Machine With a Novel Concept of a Converter-Fed Rotor , 2016, IEEE Transactions on Energy Conversion.

[5]  John Salmon,et al.  A cage rotor induction generator capable of supplying reactive power , 2013, 2013 IEEE International Symposium on Industrial Electronics.

[6]  N. Perera,et al.  A grid-connected induction machine capable of operation at unity and leading power factor , 2013, 2013 IEEE Energy Conversion Congress and Exposition.

[7]  Chandur Sadarangani,et al.  Electrical Machines- Design and Analysis of Introduction and permanent Magnet Motors , 2006 .

[8]  P. Purkait,et al.  Anomalies in harmonic distortion and Concordia pattern analyses in induction motors due to capacitor bank malfunctions , 2009, 2009 International Conference on Power Systems.

[9]  Yanmei Yao,et al.  Analysis of an induction machine using a rotor integrated converter with a floating capacitor , 2015, 2015 18th International Conference on Electrical Machines and Systems (ICEMS).

[10]  Muneaki Ishida,et al.  High efficiency, unity power factor VVVF drive system of an induction motor , 1991 .

[11]  K. Al-Haddad,et al.  Optimal control of a grid connected variable speed wind energy conversion system based on squirrel cage induction generator , 2012, IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society.

[12]  R. Spee,et al.  Comparative evaluation of power-factor improvement techniques for squirrel-cage induction motors , 1990, Conference Record of the 1990 IEEE Industry Applications Society Annual Meeting.

[13]  F.J.T.E. Ferreira,et al.  Novel Multiflux Level, Three-Phase, Squirrel-Cage Induction Motor for Efficiency and Power Factor Maximization , 2008, IEEE Transactions on Energy Conversion.

[14]  Chandan Chakraborty,et al.  Dual stator induction generator with controllable reactive power capability , 2014, 2014 IEEE 23rd International Symposium on Industrial Electronics (ISIE).

[15]  E. R. Laithwaite,et al.  Cage-rotor induction motor with unity power factor , 1982 .

[16]  O. P. Malik,et al.  Power factor correction of induction motors using PWM inverter fed auxiliary stator winding , 1999 .

[17]  Thomas A. Lipo,et al.  Series compensated PWM inverter with battery supply applied to an isolated induction generator , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.

[18]  J. Espinoza,et al.  Control of an induction machine fed by an indirect matrix converter with unity displacement power factor operating with an unbalanced AC-supply , 2012, 2012 15th International Power Electronics and Motion Control Conference (EPE/PEMC).

[19]  Hamid A. Toliyat,et al.  Comparison and assessment of current-source-inverter-fed induction motor drive systems with unity power factor , 2003, IECON'03. 29th Annual Conference of the IEEE Industrial Electronics Society (IEEE Cat. No.03CH37468).