EPE Association: EPE 1987 - 10 - Lecture Session 1.10: INDUCTION HEATING CONVERTERS

EPE 1987 - 10 - Lecture Session 1.10: INDUCTION HEATING CONVERTERS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1987 - Conference > EPE 1987 - 10 - Lecture Session 1.10: INDUCTION HEATING CONVERTERS

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   TRANSISTORS ARE REPLACING VALVES IN INDUCTION HEATING GENERATORS
By Jacques Nuns [View]
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Abstract: Presentation of a 25 kW, 20 to 100 kHz generator equipped with four "dual thyristor" control transistorized switches (patented by professor H. FOCH). This generator, commercialized by CELES, results from cooperation between ENSIEEH Toulouse, CELES and EDF. In this commuiqué, in addition to the advantages of the utilization of transistors controlled as "dual thyristors" to feed a "series" type oscillating circuit, we shall emphasize the "test-control" part of this voltage converter, required for its starting and its frequency adaptation, whatever the load.

   A SERIES-RESONANT INVERTER FOR INDUCTION HEATING
By J. P. Ferrieux; J. P. Keradec; Y. Baudon [View]
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Abstract: This paper presents a series-resonant inverter for induction heating. A theoretical study of the heated object and a computer simulation by the finit element method have been carried out to calculate the equivalent circuit parameters. The converter operates with COMFET transistors arranged in a half-bridge. Experimental results obtained with a 1.2 kW inverter are given.

   MEDIUM-FREQUENCY GTO INVERTER FOR INDUCTION HEATING APPLICATIONS
By Luigi Malesani; Paolo Tenti [View]
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Abstract: The use of GTOs as switches in resonant inverters for induction heating is investigated. Proper gate control and other provisions are described, which allow zero turn-off time operation of the GTOs, considerably reducing the commutation losses. Thus high operating frequencies can be obtained. Inverter implementation and control criteria are discussed, with particular reference to the parallel scheme. A 10 kW GTO inverter prototype was built, capable of frequencies over 40kHz. Good efflciencies, up to 87% at rated conditions, were obtained. Inverter behaviour is illustrated and experimental results are reported.

   HIGH FREQUENCY CURRENT INVERTER WITH PARALLEL RESONANT LOAD FOR INDUCTION HEATING
By P. Casella; Pham Huu Phut; A. Berthon [View]
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Abstract: For industrial induction heating applications, requiring frequencies greater than 100 kHz, triode valve oscillators power supplies have been used. For some years, studies have been made to replace these oscillators with transistorized power supplies. In the range of power of some kW and frequency greater than 200 kHz, power MOSFET transistors are well suitable. These transistors require low drive power and paralleling for higher power is easy. In this paper, a current source inverter (2 kW, 200 kHz) with power MOSFETS has been built. The load is a parallel resonant one. A phase locked loop circuit has been designed to maintain switching frequency nearer the load resonant frequency, and the load current in advance of phase with the voltage. So, transistor switching losses are reduced to the minimum and no snubber circuits are required.

EPE 1987 - 10 - Lecture Session 1.10: INDUCTION HEATING CONVERTERS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1987 - Conference > EPE 1987 - 10 - Lecture Session 1.10: INDUCTION HEATING CONVERTERS
	[return to parent folder]

	TRANSISTORS ARE REPLACING VALVES IN INDUCTION HEATING GENERATORS By Jacques Nuns	[View] [Download]
Abstract: Presentation of a 25 kW, 20 to 100 kHz generator equipped with four "dual thyristor" control transistorized switches (patented by professor H. FOCH). This generator, commercialized by CELES, results from cooperation between ENSIEEH Toulouse, CELES and EDF. In this commuiqué, in addition to the advantages of the utilization of transistors controlled as "dual thyristors" to feed a "series" type oscillating circuit, we shall emphasize the "test-control" part of this voltage converter, required for its starting and its frequency adaptation, whatever the load.

	A SERIES-RESONANT INVERTER FOR INDUCTION HEATING By J. P. Ferrieux; J. P. Keradec; Y. Baudon	[View] [Download]
Abstract: This paper presents a series-resonant inverter for induction heating. A theoretical study of the heated object and a computer simulation by the finit element method have been carried out to calculate the equivalent circuit parameters. The converter operates with COMFET transistors arranged in a half-bridge. Experimental results obtained with a 1.2 kW inverter are given.

	MEDIUM-FREQUENCY GTO INVERTER FOR INDUCTION HEATING APPLICATIONS By Luigi Malesani; Paolo Tenti	[View] [Download]
Abstract: The use of GTOs as switches in resonant inverters for induction heating is investigated. Proper gate control and other provisions are described, which allow zero turn-off time operation of the GTOs, considerably reducing the commutation losses. Thus high operating frequencies can be obtained. Inverter implementation and control criteria are discussed, with particular reference to the parallel scheme. A 10 kW GTO inverter prototype was built, capable of frequencies over 40kHz. Good efflciencies, up to 87% at rated conditions, were obtained. Inverter behaviour is illustrated and experimental results are reported.

	HIGH FREQUENCY CURRENT INVERTER WITH PARALLEL RESONANT LOAD FOR INDUCTION HEATING By P. Casella; Pham Huu Phut; A. Berthon	[View] [Download]
Abstract: For industrial induction heating applications, requiring frequencies greater than 100 kHz, triode valve oscillators power supplies have been used. For some years, studies have been made to replace these oscillators with transistorized power supplies. In the range of power of some kW and frequency greater than 200 kHz, power MOSFET transistors are well suitable. These transistors require low drive power and paralleling for higher power is easy. In this paper, a current source inverter (2 kW, 200 kHz) with power MOSFETS has been built. The load is a parallel resonant one. A phase locked loop circuit has been designed to maintain switching frequency nearer the load resonant frequency, and the load current in advance of phase with the voltage. So, transistor switching losses are reduced to the minimum and no snubber circuits are required.