Consideration on new theoretical solutions of special electric machines using specialized soft of electromagnetic field numerical analysis

Transcription

1 Recent Researches in Software Engineering, Parallel an Distribute Systems Consieration on new theoretical solutions of special electric machines using specialize soft of electromagnetic fiel numerical analysis Nicolae JULA Military Technical Acaemy Bucharest, Romania Tuor URSU Sistem Euroteh SRL Buzau, Romania Nicolae POPOVICIU Hyperion University of Bucharest Bucharest, Romania Costin CEPISCA Politehnica University of Bucharest Bucharest, Romania Rau OBREJA Sistem Euroteh SRL Buzau, Romania Abstract. Special electric machines have a large fiel of application an actual requirements for electromechanical systems clam new an very performing solutions. There are a lot of papers on this subject, but anytime is manatory to o something else to help users to evelop high level systems. Main intention of the authors for this paper is to present a moality to analyze an to esign a new solution of electric machine only trough finite element metho. Actually, the users are asking for very performing electric machines, having high ensity torque that means to evelop as higher as possible torque in a relative small volume, relative to the usual electric machines. To esign such electric machines there is only one way to use numerical methos base on finite element metho. The most part of specialists that present these aspects are working in the fiel of special electrical machines since more than 0 years, eveloping many solutions an esigns for high performances special electric machines. Key wors: finite element metho; special electric machine; high performances; pancake; irect rive. General consierations Our purpose for this paper is to present some aspects on special electric machines high ensity torque an power. More exactly, the attention will be focuse brushless motors use in very accurate rive systems, high performances. The necessity to o compact rive systems an actual worl economical situation etermine the manufacturers to concept special integrate rive systems, where it is foun less three funamental requirements: minimal specific weight (kg/w), high reliability an low manufacturing costs. ISBN:

2 Recent Researches in Software Engineering, Parallel an Distribute Systems For this purpose has to be evelope a brushless servomotor having a factionary number of slots per magnetic pole. As the team that presents this paper ha researche, ha esigne an ha prouce such kin of systems, will escribe in this article the methos use in evelopment. Hall Sensors output. Brushless servomotors with factionary number of slots per magnetic pole versus classic concept In most part of applications, are using, in special electric rive systems, servomotors base on permanent magnets, high energy. It is known the general theory of electric machines, three phase, in accorance with that we nee minimum one slot per pole an phase. So, for a machine with two poles we nee minimum 6 lots, only to o right wining, not to obtain high performances, but minimum minimorum number of slots is for two poles. To have meium performances, we nee three slots per pole an phase, that is to say 8 slots for a machine with two poles. But in practice, the machines are esigne with many poles, usually 6 poles or 8 poles. There are an special machines, having more than 40 poles. On this way, we nee from 48 slots to 7 slots, or even to 60 slots. If we are base only on classic theories an methos, sometimes it is impossible, or very ifficult to esign a special servomotor. Setting out from the above, to be on market an to be a competitive partner, a proucer must search for an fin no conventional solutions. The general iea for this action is to use any actual acknowlegements, but to create new theories an methos, that are viability in certain restrictive conitions for the main electric, energetic an mechanical parameters that the application imposes to the electric rive system, respectively to each component of system. Our team has now many no conventional solutions for special brushless servomotors, from that some aspects will be presente more etaile below. First of all, please fin below a schema to explain operating principle of a servomotor controlle by Hall sensors. Angle Con trol Cir cuit Fig. Schema to explain operating principle of a servomotor controlle by Hall sensors. The example is for a two pole pair servomotor an is starting from the most simplifie solution for a classical motor: slots for poles. Even it is not consiere as normal an classic wining, this solution is not enough goo when a very high ensity of torque (torque versus total weight or total volume) is require. In this situation, our team have evelope a stronger solution, able to o a very high torque ensity: slots for 4 poles. This solution is basic solution, because for certain application can be use a multiplication factory, from two to one hunre, epening of: ensity of torque; imensions; accuracy etc. The example from below is referring to a mathematic moel for numerical analysis of electromagnetic fiel base on 6 slots an 8 poles. [,,] The servomotor can be consiere as a certain number of complex electric an magnetic circuits (having resistive an inuctive elements sitting in a magnetic fiel. [4,5,6] Using an aequate numerical analysis of electromagnetic fiel metho can be compute any intereste magnitues (torque, back e.m.f., ensity flux, spee, magnetic potential etc.). By using of other mathematic methos, can be preetermine some of these magnitues, to be possible to o a proper moel for numerical analysis of electromagnetic fiel metho. The following example is to pre-etermine back e.m.f. It is consiere as referential one of winings, for that phase shift is consiere zero egrees. The back e.m.f. iagram is as follows: 5 e( α ) = α E, () π for π 0 ; + kπ 5 ISBN:

3 Recent Researches in Software Engineering, Parallel an Distribute Systems e ( α ) = E, () for π 4π ; + kπ π e( α ) = α E, () 5 π for 4π 6π ; + kπ 5 5 e( α ) = E, (4) for 6π 9π ; + kπ π e( α ) = α E, (5) π 5 for 9π ; π + kπ 5 u u u = R i = R = R i i ( l i ) ( l i ) N ϕe N ϕe e ( l i) N ϕ (9) To characterize a ynamic operating regime, it has to be ae an an equation of ynamic balance of torques: or: Ω J = m m f m s (0), ( m ) Ω= m f m s () J The notations aopte for electric parameters from relations () () are the classical one from general theory of electric machines, those in transitional regime.. Moeling an results using finite element metho Fig. Back e.m.f. for one phase Taking into consieration that phase shift between any two phases is π/ electrical egrees, can be expresse the formula for the other two phase back e.m.f. e α) = e ( ) (6) ( α π e ( α) = e α (7) 4π e ( α) = e α (8) The above relations are use to express operating electric circuit relations (simplifie forms, use to pre-eterminate parameters): Fig. Excitation fiel as is the result of numerical analysis of fiel- finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) [7,8,9] ISBN:

4 Recent Researches in Software Engineering, Parallel an Distribute Systems Fig.6 Normal excitation magnetic flux ensity iagram, as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Fig.4 Wining fiel as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Fig.7 Normal wining magnetic flux ensity iagram as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Fig.5 Superposition between excitation fiel an wining fiel as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Fig.8 Normal component of superposition between excitation fiel an wining fiel as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) ISBN:

5 Recent Researches in Software Engineering, Parallel an Distribute Systems Magnetic flux on A phase Magnetic Fluxul flux aferent on B phase fazei A Fluxul aferent fazei B Magnetic flux on C phase Fluxul aferent fazei C Fig.9 Diagram of magnetic flux on A, B an C phases (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Fig. Moule of wining magnetic flux ensity iagram as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Supply current. on A phase Tem Supply pe faza current. A on B phase Tem pe faza B Tem pe faza C Curentul pe faza A Supply current. on C phase Back e.m.f. on A phase Back e.m.f. Curentul on B pe phase faza B Curentul pe faza C Back e.m.f. on C phase Fig.0 Diagram of back e.m.f. an supply current on A, B an C phases (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Fig. Moule of superposition between excitation fiel an wining fiel as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Fig. Moule of excitation magnetic flux ensity iagram, as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) Fig.4 Vector potential of excitation magnetic fiel iagram, as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) ISBN:

6 Recent Researches in Software Engineering, Parallel an Distribute Systems possibility to use this configuration. Only numerical analysis of electromagnetic fiel, using finite element metho, offers any elements, clearly, emonstrating the power of this metho. Base on numerical analysis metho results, it was esigne an manufacture such kin of electric machine an test results on this machine have shown that it is one of the most powerful solutions. References: Fig.5 Vector potential of wining magnetic fiel iagram, as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) [] Haberman R., Elementary applie partial ifferential Equations, Prentice-Hall, 987. [] Ierusalimschy R., Figueireo L. H., Celes W., Reference Manual of the e Programming, Language Lua an [] Allaire P. E., Basics of the finite element metho, W.C. Brown Publishing CO, 985 [4] Silvester P. P., Finite elements for electrical engineers, Cambrige University Press, 990 [5] Pop, N., Vlaareanu, L., Pop, P. Fimite Element Analysis of Quasistatic Frictional Contact Problems with an Incremental-Iteractiv Algorithm. Proceeings of the 8 th WSEAS Intrenational Conference On Applications of Electrical Engineering, Houston, USA, April 0-May, 009. Fig.6 Vector potential of superposition between excitation an wining magnetic fiel as the result of numerical analysis of fiel - finite element metho (Raial moel for special electric machine in the configuration of 6 slots an 8 poles) 4. Conclusion The parameters represente in iagrams from fig. 6 to 6, obtaine using finite element metho, were experimental prove trough irect tests on the physical prototype manufacture esigning the motor accoring with the results of the moel. Metho rightness was highlighte by experimental measurements that valiate the theoretical results obtaine using this metho. Configuration slots an 4 poles seems apparently can not be use to evelop an to esign an electric machine. There is not a classic metho to emonstrate certainly the [6] Carstea, I. Avance Algorithms for Comple Problems in Electrical Engineering. Proceeings of the 9 th WSEAS International Conference on Mathematical Methos an Computational Techniques in Electrical Engineering, Arcachon, France, October -5, 007. [7] Iliescu, M., Nutu, E., Georgescu, L. Finite Element Metho Simulation an Rapi Prototyping. Proceeing of the 8 th WSEAS International Conference on Electric Power Systems, High Voltages, Electric Machines, Venice, Italy, November -, 008. [8] Jaykumar K. Solanki, Nimit K. Sheath, Rajal H. Patel., Three Dimensional Finit Element Analysis of Doubly Salient Permanent Magnet Motor with Skewe Rotor Teeth. Proceeings of the st WSEAS International Conference on Finit Differences-Finit Elements-Finit Volumes-Bounary Elements, (F-an-B 08), Malta, September -, 008. [9] Meerker, D. C., Maslen, H. E., Analysisan Control of a Three Pole Raial Magnetic Bearing. Tenth International Symposium on Magnetic Bearings, Martigny, Switzerlan, Aug ISBN: