access icon free Modelling and experimental demonstration of a litz coil-based high-temperature induction heating system for melting application

This study presents analytical and numerical modelling and experimental demonstration of a litz wire-based induction heating system suitable for high-temperature application such as melting. The use of litz wire in induction heating coil minimises the skin effect and proximity effect and in turn improves the system efficiency. This makes it superior compared with a solid wire and copper tube induction coil. However, the limitation of litz wire is temperature withstanding capacity of the strand insulation material as a result of which it is rarely used in high-temperature applications (>700°C). Numerical modelling of induction heating process was done by using magnetic vector potential formulation and Fourier equations. Temperature-dependent material properties were taken account to precisely model the induction heating process. Analytically estimated and measured equivalent impedances of litz coil were compared at different frequency (1–20 kHz) for initial validation of simulation. The number of turns and frequency were selected as per required litz coil efficiency and induced power in crucible. Finally during the experimental demonstration, crucible and litz coil temperatures were measured by ‘K’ type thermocouples and were compared with simulation results. The maximum temperature of ∼750°C could be attained in the design while limiting the litz coil temperature within 85°C.

Inspec keywords: insulating materials; pipes; numerical analysis; melting; thermocouples; induction heating; temperature measurement; vectors; Fourier analysis; electric impedance measurement; wires (electric); skin effect; coils

Other keywords: Fourier equation; proximity effect; solid wire; frequency 1 kHz to 20 kHz; numerical modelling; temperature 85 degC; litz wire-based induction heating system; strand insulation material; skin effect; temperature-dependent material property; high-temperature induction heating system; copper tube induction coil; melting application; magnetic vector potential formulation; temperature measurement; litz induction heating coil; K type thermocouple

Subjects: Sensing devices and transducers; Thermal variables measurement; Process heating; Impedance and admittance measurement; Insulation and insulating coatings; Inductors and transformers; Dielectric materials and properties; Linear algebra (numerical analysis)

References

    1. 1)
      • 17. Davies, E.J.: ‘Conduction and induction heating’ (Peter Peregrinus Ltd, London, UK, 1990).
    2. 2)
      • 4. Acero, J., Alonso, R., Burdio, J.M., et al: ‘Frequency dependent resistance on Litz wire planner winding for domestic induction heating appliances’, IEEE Trans. Power Electron., 2006, 21, (4), pp. 856866.
    3. 3)
      • 26. http://www.professionalplastics.com/professionalplastics/ThermalPropertiesofPlasticMaterials.pdf, accessed January 2017.
    4. 4)
      • 15. Adrian, B., Nistor, D.T., Teodor, L.: ‘Considerations on the design of a low power induction heating system’. Int. Symp. on Fundamental of Electrical Engineering, University Polytechnica of Bucharest, Romania, 28–29 November 2014.
    5. 5)
      • 12. Wojda, R.P., Kazimierczuk, M.K.: ‘Winding resistance of Litz wire and multi strand inductors’, IET Power Electron., 1996, 5, (2), pp. 257268.
    6. 6)
      • 22. Davies, E.J., Simpson, P.G.: ‘Induction heating handbook’ (McGraw Hill, New York, 1979).
    7. 7)
      • 11. Bartoli, M., Noferi, N., Reatti, A., et al: ‘Modeling of Litz-wire winding losses in high frequency power inductors’. IEEE Power Electronics Specialists Conf., 1996, vol. 2, pp. 16901696.
    8. 8)
      • 23. http://www.ceramaterials.com/images/Ceramaterials_Ceramic_Paper_Properties.pdf, accessed January 2017.
    9. 9)
      • 25. www.engineeringtoolbox.com/convective-heat-transfer-d_430.html, accessed January 2017.
    10. 10)
      • 8. Bennet, E., Larson, S.C.: ‘Effective resistance of alternating current of multilayer winding’, Trans. Am. Inst. Elect. Eng., 1940, 59, pp. 10101017.
    11. 11)
      • 2. Lope, I., Acero, J., Carretero, C.: ‘Analysis and optimization of the efficiency of induction heating applications with Litz – wire planner and solenoidal coil’, IEEE Trans. Power Electron., 2006, 31, (7), pp. 50895101.
    12. 12)
      • 6. Dowell, P.L.: ‘Effects of eddy currents in transformer windings’, Proc. IEE, 1966, 113, (8), pp. 13871394.
    13. 13)
      • 3. Sullivan, C.R.: ‘Optimal choice for number of strands in a Litz wire transformer winding’, IEEE Trans. Power Electron., 1999, 14, (2), pp. 283291.
    14. 14)
      • 19. Jang, J.Y., Chiu, Y.W.: ‘Numerical and experimental thermal analysis for a metallic hollow cylinder subjected to step wise electromagnetic induction heating’, Appl. Therm. Eng., 2007, 27, pp. 18831894.
    15. 15)
      • 7. Perry, M.P.: ‘Multiple layer series connected winding design for minimum losses’, IEEE Trans. Power Appar. Syst., 1979, PAS-98, pp. 116123.
    16. 16)
      • 9. Ferreira, J.A.: ‘Analytical computation of AC resistance of round and rectangular Litz wire windings’, IEE Proc. B, 1992, 139, (1), pp. 2125.
    17. 17)
      • 18. Wadhwa, C.L.: ‘Electrical power systems’ (New Age International Publishers, New Delhi, 2014).
    18. 18)
      • 16. Todd, A.J., Norma, H. P., Lindsey, M.G., et al: ‘Approximate analytical solution for induction heating of solid cylinders’, Appl. Math. Model., 2016, 40, (4), pp. 27702782.
    19. 19)
      • 20. Patidar, B., Hussain, M.M., Jha, S.K., et al: ‘Analytical, numerical and experimental analysis of induction heating of graphite crucible for melting of nonmagnetic materials’, IET Electr. Power Appl., 2017, 11, (3), pp. 342351.
    20. 20)
      • 14. Kennedy, M.W., Akhtar, S., Bakken, J.A., et al: ‘Empirical verification of a short coil correction factor’, Trans. Ind. Electron., 2014, 61, (5), pp. 25732583.
    21. 21)
      • 13. Martinez, J.L., Babic, S., Akyel, C.: ‘On evaluation of inductance, DC resistance, and capacitance of coaxial inductors at low frequencies’, IEEE Trans. Magn., 2014, 50, (7), pp. 112.
    22. 22)
      • 5. Kennedy, M.W., Akhtar, S., Bakken, J.A., et al: ‘Review of classical design methods as applied to aluminum billet heating with induction coils’. EPD Congress, San Diego, California, 27 February–3 March 2011, pp. 707722.
    23. 23)
      • 21. Yi, X.: ‘Electromagnetic-thermal modeling for high-frequency air-core permanent magnet motor of aircraft application’. Master thesis, University of Illinois, Urbana-Champaign, 2016.
    24. 24)
      • 24. http://www.ceramicfiber.net/ceramicfiberpaper.htm, accessed January 2017.
    25. 25)
      • 27. Necati Ozisik, M.: ‘Heat conduction’ (John Wiley & Sons Inc., New York, 1993).
    26. 26)
      • 1. Rudnev, V., Loveless, D., Cook, R., et al: ‘Handbook of induction heating’ (INDUCTOHEAT Inc., Madison Heights, MI, USA, 2003).
    27. 27)
      • 10. Sullivan, C.R., Zhang, R.Y.: ‘Analytical model for effect of twisting on Litz wire losses’. IEEE Workshop on Control and Modeling for Power Electronics (COMPEL), Paper 2–3, 2014, pp. 110.
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-epa.2017.0256
Loading

Related content

content/journals/10.1049/iet-epa.2017.0256
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Loading