EPE Association: EPE 1989 - 19 - Lecture Session 3.2: ELECTRONIC POWER SUPPLY SYSTEMS

EPE 1989 - 19 - Lecture Session 3.2: ELECTRONIC POWER SUPPLY SYSTEMS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 19 - Lecture Session 3.2: ELECTRONIC POWER SUPPLY SYSTEMS

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   OPERATION AND CONTROL REQUIREMENTS FOR A GTO USED IN A PARALLEL RESONANT INVERTER FOR INDUCTION HEATING
By A. Mertens; H.-Ch. Sudelny [View]
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Abstract: While the GTO has been used in PWM inverter drives for several years, its application in medium frequency induction heating inverters has gained interest only recently. The use of turn-off devices in parallel resonant inverters offers some appreciable benefits over conventional thyristors. This paper presents an investigation of the switching behaviour of GTOs in this circuit. Experimental results are obtained in a test circuit, where both turn-on and turn-off of the devices can be observed. The influence of different methods of current commutation on turn-on and turn-off losses is discussed, and an optimum mode of operation is proposed. The requirements to the control of the inverter are derived, and an adequate control system is outlined. First experimental results obtained in a GTO inverter are presented.

   CONTRIBUTION OF BLOCKABLE POWER ELEMENTS (GTOS) TO RESONANT CONVERTERS FOR INDUCTION HEATING
By Didier Ferrer; Jacques Roux; Jacques Nuns; Jean Louis Peureux [View]
[Download]

Abstract: This article shows how the GTO, used for natural switching in resonant converters will reach operating frequencies of around 20kHZ which are particularly interesting for induction heating. The reliability of the converter is improved and the problems posed by cooling are minimized. After the analysis of the different converter structures during continuous conduction, the authors highlight two set ups which appear well suited to operator frequencies extending from 10 to 20 kHZ; the current inverter and the voltage inverter for which self-pilot capability means that the load current is delayed with respect to the voltage. The principle of the controls, the implementation of these converters and the results of experiments are given in this article.

   THE DESIGN AND OPERATION OF THREE-PHASE STATIC PARALLEL UNINTERRUPTIBLE POWER SUPPLIES
By D. C. Wong; K. Bouwknegt [View]
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Abstract: Single-phase, low power Static Uninterruptible Power Supplies (SUPS) based on the Parallel design concept have been known for some years. However, at ratings above 10 kVA, three-phase systems based on a Series design are almost universally used. Despite its common usage, the Series SUPS has a number of disadvantages which may be effectively overcome by the application of the Parallel design concept. This mode of operation allows the inverter to run lightly loaded even when the SUPS itself is supplying its full rated output. In addition, the input rectifier required by the Series type is eliminated, leading to increased efficiency and virtually no input voltage distortion. A method of applying the Parallel concept to the design of higher power (220 kVA) three-phase SUP's, offering the advantages mentioned above, is presented.

   NEW SINUSOIDAL LINE-CURRENT PWM CONTROL-BASED HF LINK CONVERTER FOR UPS EQUIPMENT
By A. Chibani; M. Nakaoka [View]
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Abstract: This paper relates to a high-frequency (HF) link AC to DC converter with sinusoidal input current and high-quality power factor. A bridge configuration is used for both boosting and inverting stages. Input line current is sensed and firing of the power transistors S1 to S4 is inhibited using pulse-width modulation (PWM) modulator. The proposed AC to DC converter comprising control circuitry for instantaneous current control implementation is capable of providing a wide range regulated output direct voltage. The proposed converter is intended for a HF link Uninterruptible-Power-Supply (UPS) equipment. Performance evaluation is carried-out through theoretical and experimental means .

   MICROPROCESSOR CONTROLLED INVERTER FOR UPS APPLICATIONS
By K. Jezernik; M. Milanovic; D. Zadravec [View]
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Abstract: The article describes and analyses three control methods for UPS systems. The first method is the hysteresis control with a single measured value. The second method is the microprocessor based, constant frequency PWM with a dead-beat controller. The third one is method with the use of variable structure controler-sliding mode. There are made comparisons about all three control methods with respect of harmonic spectrum of sinusoidal output voltage. Presented are the simulation and experimental results of a single phase UPS and a three phase UPS with DY transformer.

   HIGH VOLTAGE SOLID-STATE PULSER FOR HIGH REPETITION-RATE GAS LASERS
By A. L. Keet; M. Groenenboom [View]
[Download]

Abstract: An all solid-state pulser for the excitation of a high repetition-rate TEA CO2 laser is described. In contrast to convertional thyratron switched pulsers, the pulser is based upon a series connection of 5 fast switching thyristors. The high voltage is generated by a pulse transformer. The required pulse duration is achieved by application of a combination of parallel and series magnetic compression circuits. The power supply gives an average power of 8 kW, a pulse energy of 20 J and a repetition rate of 400 Hz. The peak voltage is 40 kV and the pulse duration is 500 ns. The power supply has been successfully operated on a dummy-load with an overall efficiency of about 70% at maximum power. The pulser has been operating with the CO2-laser at the maximum repetition-rate allowed by the laser of about 150 Hz.

EPE 1989 - 19 - Lecture Session 3.2: ELECTRONIC POWER SUPPLY SYSTEMS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 19 - Lecture Session 3.2: ELECTRONIC POWER SUPPLY SYSTEMS
	[return to parent folder]

	OPERATION AND CONTROL REQUIREMENTS FOR A GTO USED IN A PARALLEL RESONANT INVERTER FOR INDUCTION HEATING By A. Mertens; H.-Ch. Sudelny	[View] [Download]
Abstract: While the GTO has been used in PWM inverter drives for several years, its application in medium frequency induction heating inverters has gained interest only recently. The use of turn-off devices in parallel resonant inverters offers some appreciable benefits over conventional thyristors. This paper presents an investigation of the switching behaviour of GTOs in this circuit. Experimental results are obtained in a test circuit, where both turn-on and turn-off of the devices can be observed. The influence of different methods of current commutation on turn-on and turn-off losses is discussed, and an optimum mode of operation is proposed. The requirements to the control of the inverter are derived, and an adequate control system is outlined. First experimental results obtained in a GTO inverter are presented.

	CONTRIBUTION OF BLOCKABLE POWER ELEMENTS (GTOS) TO RESONANT CONVERTERS FOR INDUCTION HEATING By Didier Ferrer; Jacques Roux; Jacques Nuns; Jean Louis Peureux	[View] [Download]
Abstract: This article shows how the GTO, used for natural switching in resonant converters will reach operating frequencies of around 20kHZ which are particularly interesting for induction heating. The reliability of the converter is improved and the problems posed by cooling are minimized. After the analysis of the different converter structures during continuous conduction, the authors highlight two set ups which appear well suited to operator frequencies extending from 10 to 20 kHZ; the current inverter and the voltage inverter for which self-pilot capability means that the load current is delayed with respect to the voltage. The principle of the controls, the implementation of these converters and the results of experiments are given in this article.

	THE DESIGN AND OPERATION OF THREE-PHASE STATIC PARALLEL UNINTERRUPTIBLE POWER SUPPLIES By D. C. Wong; K. Bouwknegt	[View] [Download]
Abstract: Single-phase, low power Static Uninterruptible Power Supplies (SUPS) based on the Parallel design concept have been known for some years. However, at ratings above 10 kVA, three-phase systems based on a Series design are almost universally used. Despite its common usage, the Series SUPS has a number of disadvantages which may be effectively overcome by the application of the Parallel design concept. This mode of operation allows the inverter to run lightly loaded even when the SUPS itself is supplying its full rated output. In addition, the input rectifier required by the Series type is eliminated, leading to increased efficiency and virtually no input voltage distortion. A method of applying the Parallel concept to the design of higher power (220 kVA) three-phase SUP's, offering the advantages mentioned above, is presented.

	NEW SINUSOIDAL LINE-CURRENT PWM CONTROL-BASED HF LINK CONVERTER FOR UPS EQUIPMENT By A. Chibani; M. Nakaoka	[View] [Download]
Abstract: This paper relates to a high-frequency (HF) link AC to DC converter with sinusoidal input current and high-quality power factor. A bridge configuration is used for both boosting and inverting stages. Input line current is sensed and firing of the power transistors S1 to S4 is inhibited using pulse-width modulation (PWM) modulator. The proposed AC to DC converter comprising control circuitry for instantaneous current control implementation is capable of providing a wide range regulated output direct voltage. The proposed converter is intended for a HF link Uninterruptible-Power-Supply (UPS) equipment. Performance evaluation is carried-out through theoretical and experimental means .

	MICROPROCESSOR CONTROLLED INVERTER FOR UPS APPLICATIONS By K. Jezernik; M. Milanovic; D. Zadravec	[View] [Download]
Abstract: The article describes and analyses three control methods for UPS systems. The first method is the hysteresis control with a single measured value. The second method is the microprocessor based, constant frequency PWM with a dead-beat controller. The third one is method with the use of variable structure controler-sliding mode. There are made comparisons about all three control methods with respect of harmonic spectrum of sinusoidal output voltage. Presented are the simulation and experimental results of a single phase UPS and a three phase UPS with DY transformer.

	HIGH VOLTAGE SOLID-STATE PULSER FOR HIGH REPETITION-RATE GAS LASERS By A. L. Keet; M. Groenenboom	[View] [Download]
Abstract: An all solid-state pulser for the excitation of a high repetition-rate TEA CO2 laser is described. In contrast to convertional thyratron switched pulsers, the pulser is based upon a series connection of 5 fast switching thyristors. The high voltage is generated by a pulse transformer. The required pulse duration is achieved by application of a combination of parallel and series magnetic compression circuits. The power supply gives an average power of 8 kW, a pulse energy of 20 J and a repetition rate of 400 Hz. The peak voltage is 40 kV and the pulse duration is 500 ns. The power supply has been successfully operated on a dummy-load with an overall efficiency of about 70% at maximum power. The pulser has been operating with the CO2-laser at the maximum repetition-rate allowed by the laser of about 150 Hz.