A topology named L-LC resonant inverter (RI) for induction heating (IH) applications takes most of the merits of the conventional series and parallel resonant schemes, while eliminating their limitations. In this paper, fundamental frequency AC analysis of L-LC RI is revisited, and a new operating point is suggested featuring enhanced current gain and near in-phase operation as compared to the conventional operating point. An approximate analysis of the circuit with square-wave voltage source is also described highlighting the effect of auxiliary inductor on the source current waveform. The analysis also leads to an optimum choice of the auxiliary inductance. The requirements of the metal organic vapour phase epitaxy (MOVPE) system in which a graphite susceptor is required to be heated to 1200°C demanding a 25？kW, 25？kHz IH power supply, the configuration of developed IH system, and experimental results are presented. 1. Introduction The induction heating (IH) [1] is commonly used for heat treatment of metals (hardening, tempering, and annealing), heating prior to deformation (forging, swaging, upsetting, bending, and piercing), brazing and soldering, shrink fitting, coating, melting, crystal growing, cap sealing, sintering, carbon vapor deposition, epitaxial deposition, and plasma generation. IH is a noncontact method. The heat is generated only in the part, not in the surrounding area except by radiation. The location of the heating can be defined to a specified area on the metal component, thereby achieving accurate and consistent results. As heating occurs in the object itself, IH is considered more efficient than alternative methods. An IH system comprises a basic induction power source which provides the required power output at the required power frequency, complete with matching components, an induction coil assembly, a method of material handling, and some method of cooling. Generally, full-bridge or half-bridge resonant inverters (RIs) are most commonly used as the power supplies for IH. The equivalent model of an IH coil with work piece can be represented in simplified form by an equivalent inductance ( ) and resistance ( ) as shown in Figure 1. If the IH coil is directly fed from a supply, the ratio of apparent to real power will be large. Therefore, the IH coil is properly compensated by capacitors and additional inductors in suitable configuration so that minimum reactive power is drawn from the source. Additionally to match the load voltage-current requirements to the available source, a matching network is required. The matching is
References
[1]
C. A. Tudbury, Basics of Induction Heating. vol. 1, Library of Congress Catalog Number 60-8958, 1960.
[2]
I. Millán, J. M. Burdío, J. Acero, O. Lucía, and S. Llorente, “Series resonant inverter with selective harmonic operation applied to all-metal domestic induction heating,” IET Power Electronics, vol. 4, no. 5, pp. 587–592, 2011.
[3]
ó. Lucía, J. M. Burdio, I. Millan, J. Acero, and D. Puyal, “Load-adaptive control algorithm of half-bridge series resonant inverter for domestic induction heating,” IEEE Transactions on Industrial Electronics, vol. 56, no. 8, pp. 3106–3116, 2009.
[4]
P. K. Jain, J. R. Espinoza, and S. B. Dewan, “Self-started voltage-source series-resonant converter for high-power induction heating and melting applications,” IEEE Transactions on Industry Applications, vol. 34, no. 3, pp. 518–525, 1998.
[5]
H. P. Ngoc, H. Fujita, K. Ozaki, and N. Uchida, “Phase angle control of high-frequency resonant currents in a multiple inverter system for zone-control induction heating,” IEEE Transactions on Power Electronics, vol. 26, no. 11, pp. 3357–3366, 2011.
[6]
F. Forest, E. Labouré, F. Costa, and J. Y. Gaspard, “Principle of a multi-load/single converter system for low power induction heating,” IEEE Transactions on Power Electronics, vol. 15, no. 2, pp. 223–230, 2000.
[7]
R. Bonert and J. D. Lavers, “Simple starting scheme for a parallel resonance inverter for induction heating,” IEEE Transactions on Power Electronics, vol. 9, no. 3, pp. 281–287, 1994.
[8]
E. J. Dede, V. Esteve, J. Garcia, A. E. Navarro, E. Maset, and E. Sanchis, “Analysis of losses and thermal design of high-power, high-frequency resonant current fed inverters for induction heating,” in Proceedings of the 19th International Conference on Industrial Electronics, Control and Instrumentation, pp. 1046–1051, November 1993.
[9]
E. J. Dede, J. Jordan, J. V. Gonzalez, J. Linares, V. Esteve, and E. Maset, “Conception and design of a parallel resonant converter for induction heating,” in Proceedings of the 6th Annual Applied Power Electronics Conference and Exposition (APEC '91), pp. 38–44, March 1991.
[10]
E. J. Dede, J. Jordan, J. A. Linares et al., “On the design of medium and high power current fed inverters for induction heating,” in Proceedings of the IEEE Industry Applications Society Annual Meeting, pp. 1047–1053, October 1991.
[11]
V. Chudnovsky, B. Axelrod, and A. L. Shenkman, “An approximate analysis of a starting process of a current source parallel inverter with a high-Q induction heating load,” IEEE Transactions on Power Electronics, vol. 12, no. 2, pp. 294–301, 1997.
[12]
L. Hobson and D. W. Tebb, “Transistorized power supplies for induction heating,” International Journal of Electronics, vol. 59, no. 5, pp. 543–552, 1985.
[13]
F. P. Dawson and P. Jain, “A comparison of load commutated inverter systems for induction heating and melting applications,” IEEE Transactions on Power Electronics, vol. 6, no. 3, pp. 430–441, 1991.
[14]
G. L. Fischer and H.-C. Doht, “Inverter system for inductive tube welding utilizing resonance transformation,” in Proceedings of the 29th Institute for Advanced Study (IAS) Annual Meeting, pp. 833–840, October 1994.
[15]
J. Espi, E. Dede, A. Ferreres, and R. Garcia, “Steady-state frequency analysis of the L-LC resonant inverter for induction heating,” in Proceedings of the IEEE International Power Electronics Congress Technical Proceedings (CIEP '96), pp. 22–28, 1999.
[16]
J. M. Espi, E. J. Dede, E. Navarro, E. Sanchis, and A. Ferreres, “Features and design of the voltage-fed L-LC resonant inverter for induction heating,” in Proceedings of the 30th Annual IEEE Power Electronics Specialists Conference (PESC '99), pp. 1126–1131, July 1999.
[17]
J. M. Espí and E. J. Dede, “Design considerations for three element L-LC resonant inverters for induction heating,” International Journal of Electronics, vol. 86, no. 10, pp. 1205–1216, 1999.
[18]
S. Chudjuarjeen, A. Sangswang, and C. Koompai, “An improved LLC resonant inverter for induction-heating applications with asymmetrical control,” IEEE Transactions on Industrial Electronics, vol. 58, no. 7, pp. 2915–2925, 2011.
[19]
E. J. Dede, J. Gonzalez, J. A. Linares, J. Jordan, D. Ramirez, and P. Rueda, “25-kW/50-kHz generator for induction heating,” IEEE Transactions on Industrial Electronics, vol. 38, no. 3, pp. 203–209, 1991.
[20]
S. Dieckerhoff, M. J. Ryan, and R. W. De Doncker, “Design of an IGBT-based LCL-resonant inverter for high-frequency induction heating,” in Proceedings of the IEEE Industry Applications Conference and 34th IAS Annual Meeting, pp. 2039–2045, October 1999.
[21]
J. M. E. Huerta, E. J. D. G. Santamaría, R. G. Gil, and J. Castelló-Moreno, “Design of the L-LC resonant inverter for induction heating based on its equivalent SRI,” IEEE Transactions on Industrial Electronics, vol. 54, no. 6, pp. 3178–3187, 2007.
[22]
K. Nishida, S. Haneda, K. Hara, H. Munekata, and H. Kukimoto, “MOVPE of GaN using a specially designed two-flow horizontal reactor,” Journal of Crystal Growth, vol. 170, no. 1-4, pp. 312–315, 1997.
[23]
Y.-S. Kwon, S.-B. Yoo, and D.-S. Hyun, “Half-bridge series resonant inverter for induction heating applications with load-adaptive PFM control strategy,” in Proceedings of the 14th annual Applied Power Electronics Conference and Exposition (APEC '99), pp. 575–581, March 1999.
[24]
H. W. Koertzen, J. D. Van Wyk, and J. A. Ferreira, “Comparison of swept frequency and phase shift control for forced commutated series resonant induction heating converters,” in Proceedings of the Conference Record of the IEEE Industry Applications and 30th IAS Annual Meeting, pp. 1964–1969, October 1995.
[25]
J. M. Burdío, L. A. Barragán, F. Monterde, D. Navarro, and J. Acero, “Asymmetrical voltage-cancellation control for full-bridge series resonant inverters,” IEEE Transactions on Power Electronics, vol. 19, no. 2, pp. 461–469, 2004.
[26]
L. Grajales and F. C. Lee, “Control system design and small-signal analysis of a phase-shift-controlled series-resonant inverter for induction heating,” in Proceedings of the IEEE Power Electronics Specialist Conference, pp. 450–456, 1995.
[27]
L. Grajales, J. A. Sabate, K. R. Wang, W. A. Tabisz, and F. C. Lee, “Design of a 10？kW, 500？kHz phase-shift controlled series-resonant inverter for induction heating,” in Proceedings of the 28th Annual Meeting of the IEEE Industry Applications Conference, pp. 843–849, October 1993.
[28]
N. A. Ahmed, “High-frequency soft-switching AC conversion circuit with dual-mode PWM/PDM control strategy for high-power IH applications,” IEEE Transactions on Industrial Electronics, vol. 58, no. 4, pp. 1440–1448, 2011.
[29]
V. Esteve, E. Sanchis-Kilders, J. Jordán et al., “Improving the efficiency of IGBT series-resonant inverters using pulse density modulation,” IEEE Transactions on Industrial Electronics, vol. 58, no. 3, pp. 979–987, 2011.
[30]
C.-J. Tseng and C.-L. Chen, “Passive lossless snubbers for dc/dc converters,” in Proceedings of the 13th Annual Applied Power Electronics Conference and Exposition (APEC '98), pp. 1049–1054, February 1998.
[31]
M. Borage and S. Tiwari, “On the development of 30 kVA, 430 Hz sine wave inverter for DC accelerator application,” in Proceedings of the Indian Particle Accelerator Conference (InPAC '11), IUAC, New Delhi, India, February 2011.
[32]
A. Kats, G. Ivensky, and S. Ben-Yaakov, “Application of integrated magnetics in resonant converters,” in Proceedings of the IEEE 12th Applied Power Electronics Conference, pp. 925–930, February 1997.
