performance and analysis of 3 phase induction motor using ... · induction motor. the dual stator...

Performance and analysis of 3 phaseinduction motor using Ansys Maxwell

Anagha Soman1, Nupur Lokhande2

and Dr. D G Bhardwaj31Asst. Professor,

Bharati Vidyapeeth Deemed University,COE Pune

[email protected] Student,

Bharati Vidyapeeth Deemed University,COE Pune

[email protected]

January 9, 2018

Abstract

It is evident that an induction motor is very reliable, ro-bust and efficient machine used for various industrial appli-cations under various loading conditions. Induction motorsare cheaper in cost, rugged in construction and require verylittle maintenance. This paper focuses on performance as-pects and censorious fields in the design of such a machine.A laboratory precursor of three phase double stator induc-tion motor (DSIM) is drafted and contrived to delve intoassorted facets. Induction machines with a two dissimilarpole stator windings have been put to effective use since itfunctions well in the power fields. Since they have dimin-ished pulsation when the torque is lesser. Three phase sup-ply with variable frequency is fed to the two stator windingsof DSIM which proves out to be very expedient. Throughthis, not only the torque pulsations are reduced consider-ably, but increased commutation frequency is also achieved

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International Journal of Pure and Applied MathematicsVolume 118 No. 16 2018, 269-281ISSN: 1311-8080 (printed version); ISSN: 1314-3395 (on-line version)url: http://www.ijpam.euSpecial Issue ijpam.eu

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as compared to simple machines. The analysis of this ma-chine is executed employing FINITE ELEMENT METHODat steady state level. Analysis has been carried out for 4-pole and 12-pole motor; their behaviour has been studiedand compared. The tools used for this analysis are AN-SYS Maxwell 2D and RMxprt. RMxprt is instrumental innot only giving classical motor performance parameters, butalso spawns an outright transfer of the 3D or 2D geometryin conjunction with all electrical as well as electromagneticproperties. The conclusions retrieved are conferred and pre-sumptions are drawn.

Key Words and Phrases: Induction motor, perfor-mance, analysis, finite element method, RMxprt, Maxwell2D, Ansys

1 Introduction

The performance analysis of a dual stator winding induction drivehas been described and studied in this paper. The contemplatedinduction machine consists of a standard squirrel cage motor withtwo separate windings wound for a dissimilar number of poles. Thecontemplated drive bids advantages like speed sensor less opera-tion, improved reliability, and more flexibility to manipulate theresultant torque-speed curve of the motor.

There are two major types of dual stator machines which aresplit-wound and self-cascaded. The split-wound machine was pop-ularized in earlier times as a begetter to increase the total powercapability of large synchronous generators [1]. Ever since then,they have been used in various other applications ranging from syn-chronous machines to large pumps and compressors. Split-woundmotors are responsible for making it conceivable to prolong thepower spectrum of solid state based drives beyond the power com-petence of a lone inverter and more freshly, new multilevel topolo-gies have also been developed [2]. Also, at the hand of the implicitrepetition, it is asserted that the system exhibits a superior authen-ticity [3][4][5]. In a split-wound machine, the stator comprises oftwo complementary but independent three-phase windings woundfor the like number of poles. Both stators are provided with thesame frequency and the rotor is a standard squirrel cage.

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Among the various multiphase drive solutions, one of the mostalluring and widely practised is the dual stator winding squirrel cageinduction motor. The dual stator induction motor has two separatethree-phase stator windings, partaking the same machine core andcommon squirrel cage rotor winding. In this paper, the analysis of4-pole and 12-pole induction motor has also been studied.

2 Dual Stator IM Drive

The prospective induction machine comprises of a classic die castsquirrel cage rotor and a stator with two independent windingswound for a diverse number of poles (4/12). Any sequence of dis-similar pole numbers can be used, but to optimize the magneticmaterial, avoid local saturation and more stator losses, it has beenobserved that the most beneficial arrangement should have a poleratio 1:3.

Figure 1: Dual Stator Induction Motor

In order to dodge deep saturation, the maximum magnetic load-ing created by the mixed aftermath of the two stator mmfs shouldbe analogous to that of an equivalent single stator winding con-struction. To retain the saturation level in the stator teeth, thepeak air gap flux must be preserved. Also, to retain the loadingof the stator yoke the peak flux density per pole should be inter-changeable in both the dual stator and single stator construcions.

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Omitting space harmonics, this will be consummated by culling [6]

Bg4 = 0.819B0

Bg12 = 0.543B0 (1)

where B0, Bg4 and Bg12 represent the maximum air gap fluxdensities created by a proportionate single stator, the 4-pole and12-pole stator windings correspondingly. The rotor of the DSIMis classic squirrel cage, which makes sure that both stator currentdistributions will concurrently couple with the rotor flux to createthe aimed torque. Due to the decoupling reaction composed bywindings with dissimilar number of poles the DSIM acts as twoautonomous induction machines mechanically coupled using shaft.For our machine, general assumptions have been taken into consid-eration which is as under:

• Trivial saturation

• Homogeneous air gap

• Stator windings sinusoidally dispersed

• No electrical linkage among stators

• Trivial inter-bar current

3 Maxwell 2D and Ansys

ANSYS Maxwell is the economic electromagnetic field simulationsoftware for designers who are engaged for fabricating and analysing3-D and 2-D electromagnetic and electromechanical equipment, whichincludes motors, actuators, transformers, sensors and coils. Maxwell2D is a great-performance bilateral program kit that puts to use thefinite element analysis (FEA) to determine electric, magneto static,eddy current, and transient problems. Maxwell 2D determines theelectromagnetic field problems for a given model with pertinent ma-terials, boundaries and source conditions applying Maxwell’s equa-tions over a finite region of space [7-9].

Differential forms of Maxwells equations are as follows:

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3.1 FEM and Adaptive Meshing

With an aim to glean the set of algebraic equations which we needto solve, the geometry of the problem is discretized on its own intoinfinitesimal elements (e.g. Triangles in 2D). All the model solidswill be meshed on its own by the mesher. The aggregation of alltriangles is said to be the finite element mesh of the model or merelythe mesh.

3.2 RMxprt

Engineers who design electrical machines and generators now havethe advantage to augment ANSYS Maxwell with ANSYS RMxprt,a template-based design tool. Together Maxwell and RMxprt havebeen successful to make a truly tailor-made machine design flow inorder to cater to the market demand for surpassing efficiency andlower cost machines. Putting to use the classical analytical motortheory and equivalent magnetic circuit methods, RMxprt can calcu-late machine performance, make initial sizing decisions and performhundreds of ”what if” analyses in a matter of seconds. A key as-set of RMxprt is that it is capable of automatically setting up anentire Maxwell project (2-D/3-D) which can also include geometry,materials as well as boundary conditions. The set up includes thepertinent symmetries and excitations with coupling circuit topol-ogy for meticulous electromagnetic transient analysis. RMxprt au-tomatically generates a reduced order model, considering the non-linearities and eddy effects, and transmits it to Simplorer, wherefurther electric drive analysis can be achieved. Likewise, RMxprtcan successfully set up the tilor-made driving circuit topology as astand-alone component in Simplorer which can be coupled with thecorresponding electric machine reduced order model.

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4 Squirrel Cage motor design using RMx-

prt

Most commonly AC motors use squirrel cage rotor. The motoremblematically cast aluminium or copper poured between the ironlaminates of the rotor. The considerable fragment of the rotorcurrents flow through the bars and varnished laminates. UsingRMxprt, a 1.3 kW three phase squirrel cage induction motor isdesigned and analysed. The material assigned for laminated steelsof rotor and stator is 50C350. The windings allotted are copper.The user interface for a 4-pole RMxprt is shown in Fig. 2.

Figure 2: RMxprt User Interface (4-pole)

Since the RMxprt is a template based tool, the time requisitefor analysis is in order of seconds. The results are shown in Table1.

Table 1. RMxprt Results (4-pole)

Similarly, the design of 12-pole motor is also carried out using

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RMxprt as follows. The material assigned for laminated steels ofrotor and stator is 50C350. The windings allotted are copper. Theuser interface for a 12-pole RMxprt is shown in Fig. 3.

Figure 3: RMxprt User Interface (12-pole)

Since the RMxprt is a template based tool, the time requisitefor analysis is in order of seconds. The results are shown in Table2.

Table 2. RMxprt Results (12-pole)

5 Squirrel cage motor design using Maxwell

The motor specified above is relocated from RMxprt to Maxwellwith a direct channel. Maxwell uses the accurate finite elementmethod to determine static, frequency-domain, and time varyingelectromagnetic and electric fields. The parameters of the motorare same, as shown in Table 1 and 2 for 4 and 12-pole respectively.

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The automatic flexible meshing technique of Maxwell-2D is usedfor meshing.

As a result of analysis, the magnetic flux density during themaximum current, the current vs time, torque vs time and graphicsfor the defined motor with 4-pole are obtained and presented at Fig.5 (a), (b), and (c) respectively.

Figure 5(a): Magnetic flux density

Figure 5(b): Phase current vs Time

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Figure 5(c): Torque vs Time

Similarly the magnetic flux density during the maximum cur-rent, the current vs time, torque vs time and graphics for the definedmotor with 12-pole are obtained and presented at Fig. 6 (a), (b),and (c) respectively.

Figure 6(a): Magnetic flux density

Figure 6(b): Phase current vs Time

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Figure 6(c): Torque vs Time

Speaking about the dual stator three phase induction motor,the torque vs. time for dual stator winding can be found in Fig.7(a).

Figure 7(a): Torque vs. Time (Dual Stator)

Similarly, the power vs. time results for dual stator windingthree phase induction motor can be observed in Fig. 7(b).

Figure 7(b): Powers vs. Time (Dual Stator)

It is observed here that the moving torque by dual stator wind-ing induction motor is more as compared to 4-pole single statorwinding induction motor.

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We also observe that the powers in dual stator winding stabilisesfaster as compared to the 4-pole single stator winding inductionmotor.

6 Conclusion

In this paper, ANSYS Maxwell 2D and RMxprt software tools areused to create a squirrel cage motor design and to analyse it. Themotor parameters and characteristics can be precisely calculatedand predicted in terms of field computation and analysis results.Also it is seen that by developing the computer technology and in-creasing computing times, the FEM tools are becoming more ben-eficial to analyse the motor. The proposed DSIM has a standardsquirrel cage rotor and two stator windings wound for a dissimilarnumber of poles. The main benefit of the drive is its better capabil-ity to operate. This trait is particularly useful for implementationof speed sensor less schemes and it adds a new degree of flexibilityto standard control methods currently used in AC drives. We havealso seen in this paper how the torque and power curves of singlestator and dual stator winding induction motor varies.

References

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[3] R. W. Menzies, P. Steimer, and J. K. Steinke, Five-level GTOinverters for large induction motor drives, IEEE Transactionson Industry Applications, Vol.30, No.4, July/August 1994, pp.938944.

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[5] J. C. Salmon and B. W. Williams, A split-wound inductionmotor design to improve the reliability of PWM inverter drives,IEEE Transactions on Industry Applications, Vol. IA-26, No.1, January/February 1990, pp. 143-150

[6] A. R. Mu noz-Garca, Analysis and control of a dual statorwinding squirrel cage induction machine, Ph.D. Dissertation,University of Wisconsin-Madison, 1999.

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[8] Qiu Changli; Cheng Jihang; Li Jingquan, Simulation analysisof the performance of linear introduction motor in Maxwell 2D,Electrical & Electronics Engineering (EEESYM), 2012 IEEESymposium on , vol., no., pp.360,363, 24-27 June 2012

[9] Mei-shan Jin; A-lin Hou; Chang-li Qiu; Da-chuan Chen, AMaxwell 2D emulated analysis in the performance of linear in-troduction motor, Computer, Mechatronics, Control and Elec-tronic Engineering (CMCE), 2010 International Conference on, vol.4, no., pp.348,351, 24-26 Aug. 2010

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