EPE Association: EPE 1993 - 53 - Dialogue Session DS4.2: POWER SUPPLIES: APPLICATIONS

EPE 1993 - 53 - Dialogue Session DS4.2: POWER SUPPLIES: APPLICATIONS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1993 - Conference > EPE 1993 - 53 - Dialogue Session DS4.2: POWER SUPPLIES: APPLICATIONS

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   BIDIRECTIONAL CONTINUOUS-MODE FLYBACK INVERTOR
By A. J. Skinner [View]
[Download]

Abstract: This paper describes a high frequency single-stage inverter utilising a bidirectional continuous-mode flyback topology intended for use in an off-line ups. The inverter consists of an input switching-stage connected to the primary of a coupled inductor (flyback transformer) and uses a synchronous rectifier on the secondary to allow bidirectional power flow. The inverter requires one wound component and may be realised using only four power switches resulting in a low component count. Average current-mode control is employed using the weighted sum of inductor primary and secondary currents as a continuous control parameter representing the magnetising current of the inductor core. This allows the use of the continuous conduction mode without the risk of core saturation, so that the core may be fully utilised. Operation of the inverter bas been examined and verified experimentally on a prototype inverter with a design rating of 400 VA.

   FRONT-END CONVERTER SYSTEM FOR DISTRIBUTED POWER SUPPLY
By S. T. Hadjivassilev; J. Pforr; L. Hobson [View]
[Download]

Abstract: A converter system has been developed for application as a front-end converter for distributed power supplies. The system consists of a cascade connection of a novel three-phase rectifier stage with a push-pull buck converter as a first stage and a resonant half-bridge converter as a second stage. Analysis of the converter has been derived and a decision procedure has been formulated. The final converter design has been simulated using the circuit simulation program PSPICE. Finally, a full-size prototype converter has been built and tested to prove theoretical results. The developed converter system provides transformer-isolated output voltage of 48V when operated off-line from a 415V three-phase mains supply. The maximum output power delivered to the load is 2.5kW. The converter provides nearly sinusoidal input current waveforms with approximately unity power factor drawn from all three phases of the three-phase supply.

   A SIMPLE CONVERTER FOR DC-SUPPLY OF FLUORESCENT LAMPS
By M. M. Silva; A. S . Simões; A. V. Anunciada [View]
[Download]

Abstract: A new circuit for low-voltage DC-supply of fluorescent lamps is described. It has inherent lamp current limitation (ballast action), and provides the high voltage pulses and electrode heating which are required for the lamp ignition. The proposed circuit is applicable in automotive, emergency and portable light sources. The circuit is simple, and is believed to be advantageous with respect to existing circuits for these applications.

   LOW POWER CONVERTER FOR HIGH TEMPERATURE APPLICATIONS
By P. J. Viverge; J. J. Rousseau; J. P. Chante; B. Allard [View]
[Download]

Abstract: This paper covers the analysis from 20°C to 185°C of the realisation bases and behaviour of a low power 220V AC / 15V DC converter. The study shows the evolution of the converter components and elements versus temperature. The devices are tested alone and inside their environment. After the choice of the power supply structure, we propose rules, remarks and cautions for such type of converter for low and high temperature electronic as well. This field and its applications enable realisations of high-temperature systems while allowing the reduction of cooling devices for ambient atmosphere. Actually we use a 20W power supply during 400 hours at 185°C then 100 hours at 200°C.

   A COST-EFFECTIVE DC/DC-CONVERTER WITH INTEGRATED UPS-FUNCTION
By Berthold Fuld [View]
[Download]

Abstract: A new DC/DC-converter with integrated UPS-function is described. The solution has important advantages compared to other UPS-approaches:
- Minimized number of conversion stages
- Very high efficiency during battery operation
- No interruption at line failure
- Small volume
- Low cost
A conventional DC/DC-converter is supplemented by a second input winding of the transformer, a second switch-circuit and a charge circuit. Only one control circuit for both inputs is necessary: the change from line to battery operation is natural. At battery operation only one conversion stage between battery and load is necessary, this gives a very high efficiency. The charge circuit can be realized as a simple buck-stage, for converters with 50% max. duty cycle it must work in the discontinuous mode.The same winding of the transformer as for battery operation is used. Simulation results show the function of the system.

   A SIMPLIFIED MODEL OF CURRENT-CONTROLLED SWITCHING CONVERTERS IN DISCONTINUOUS CURRENT-MODE
By G. Lirer; A. G. M. Strollo; A. Luciano [View]
[Download]

Abstract: A simplified circuit oriented model is developed for the analysis of current-mode switching converters operated in discontinuous current-mode. The model is based on an equivalent circuit representation of the power switch following the same approach already applied in literature to modeling duty-ratio programmed PWM converters. In this way an easy derivation of both DC and small-signal characteristics of the converter is achieved. Applications of the proposed model to buck and buck-boost topologies are presented.

   HOW TO FIND THE BEST SOLUTlON FOR POWER CONVERTERS AND FOR THE NEW PRINCIPLE OF OPERATION
By Dejan Srajber [View]
[Download]

Abstract: Applying the postulates of power electronics, all power converters can be classified in four basic groups, each with two analogous circuits, one for voltage and one for current sources and loads. Furthermore, this new systematical presentation leads to all known converter designs and the new solution (the patent applied) for inverter designs. Advantages of the presented new principle of operation in inverter design are:
- The transformer for galvanic isolation and voltage level adjustment can operate at the frequency of the switching elements;
- The number of transistors is reduced by 50% comparing to conventional design using a high frequency transformer;
- Simple control, using two independent first order regulators;
- lnherent overload and output short circuit protection;
- Simple parallel operation of devices, with different rated powers, without special distribution controllers;
- Safe operation of the switches, without danger of short circuit currents and overvoltages due to errors in the transistor base drives.

   Converter Systems for Industry and Chemistry Applications
By Reinhard Joho; Albert Kloss [View]
[Download]

Abstract: For arc furnaces and electrolytic process applications, multipuls converters with output currents up to 100 kA per unit are used. Currents of this magnitude require converter branches with up to 20 thyristors connected in parallel. The current distribution between the parallel-connected thyristors is one of the most difficult problems in the design of the converters.

   PROGRAMMABLE AC POWER SOURCE
By H. van der Broeck; P. Lürkens [View]
[Download]

Abstract: The development of a 1kVA AC power source is presented which provides programmable sinusoidal output voltages. Both, output amplitude and output frequency can be set over a large range. The desired values can be programmed via a keyboard and a display or from a personal computer. The power source operates at the 220V / 50Hz / 60Hz mains and draws a sinusoidal current from the line. The output voltage is isolated from the input circuit. lt is also possible to operate the power source without the mains because internal batteries are installed. The system consists of switched mode power electronics and thus operates at a high efficiency. Another feature of the system is that 3 single phase units can be synchronized to form a three phase voltage power source. The AC power source is very well suited for testing appliances, consumer products, motors or other equipment which has to be supplied by the single phase mains. It may also be used within a production line in order to check automatically whether the device under test operates reliably in the specified voltage frequency range.

EPE 1993 - 53 - Dialogue Session DS4.2: POWER SUPPLIES: APPLICATIONS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1993 - Conference > EPE 1993 - 53 - Dialogue Session DS4.2: POWER SUPPLIES: APPLICATIONS
	[return to parent folder]

	BIDIRECTIONAL CONTINUOUS-MODE FLYBACK INVERTOR By A. J. Skinner	[View] [Download]
Abstract: This paper describes a high frequency single-stage inverter utilising a bidirectional continuous-mode flyback topology intended for use in an off-line ups. The inverter consists of an input switching-stage connected to the primary of a coupled inductor (flyback transformer) and uses a synchronous rectifier on the secondary to allow bidirectional power flow. The inverter requires one wound component and may be realised using only four power switches resulting in a low component count. Average current-mode control is employed using the weighted sum of inductor primary and secondary currents as a continuous control parameter representing the magnetising current of the inductor core. This allows the use of the continuous conduction mode without the risk of core saturation, so that the core may be fully utilised. Operation of the inverter bas been examined and verified experimentally on a prototype inverter with a design rating of 400 VA.

	FRONT-END CONVERTER SYSTEM FOR DISTRIBUTED POWER SUPPLY By S. T. Hadjivassilev; J. Pforr; L. Hobson	[View] [Download]
Abstract: A converter system has been developed for application as a front-end converter for distributed power supplies. The system consists of a cascade connection of a novel three-phase rectifier stage with a push-pull buck converter as a first stage and a resonant half-bridge converter as a second stage. Analysis of the converter has been derived and a decision procedure has been formulated. The final converter design has been simulated using the circuit simulation program PSPICE. Finally, a full-size prototype converter has been built and tested to prove theoretical results. The developed converter system provides transformer-isolated output voltage of 48V when operated off-line from a 415V three-phase mains supply. The maximum output power delivered to the load is 2.5kW. The converter provides nearly sinusoidal input current waveforms with approximately unity power factor drawn from all three phases of the three-phase supply.

	A SIMPLE CONVERTER FOR DC-SUPPLY OF FLUORESCENT LAMPS By M. M. Silva; A. S . Simões; A. V. Anunciada	[View] [Download]
Abstract: A new circuit for low-voltage DC-supply of fluorescent lamps is described. It has inherent lamp current limitation (ballast action), and provides the high voltage pulses and electrode heating which are required for the lamp ignition. The proposed circuit is applicable in automotive, emergency and portable light sources. The circuit is simple, and is believed to be advantageous with respect to existing circuits for these applications.

	LOW POWER CONVERTER FOR HIGH TEMPERATURE APPLICATIONS By P. J. Viverge; J. J. Rousseau; J. P. Chante; B. Allard	[View] [Download]
Abstract: This paper covers the analysis from 20°C to 185°C of the realisation bases and behaviour of a low power 220V AC / 15V DC converter. The study shows the evolution of the converter components and elements versus temperature. The devices are tested alone and inside their environment. After the choice of the power supply structure, we propose rules, remarks and cautions for such type of converter for low and high temperature electronic as well. This field and its applications enable realisations of high-temperature systems while allowing the reduction of cooling devices for ambient atmosphere. Actually we use a 20W power supply during 400 hours at 185°C then 100 hours at 200°C.

	A COST-EFFECTIVE DC/DC-CONVERTER WITH INTEGRATED UPS-FUNCTION By Berthold Fuld	[View] [Download]
Abstract: A new DC/DC-converter with integrated UPS-function is described. The solution has important advantages compared to other UPS-approaches: - Minimized number of conversion stages - Very high efficiency during battery operation - No interruption at line failure - Small volume - Low cost A conventional DC/DC-converter is supplemented by a second input winding of the transformer, a second switch-circuit and a charge circuit. Only one control circuit for both inputs is necessary: the change from line to battery operation is natural. At battery operation only one conversion stage between battery and load is necessary, this gives a very high efficiency. The charge circuit can be realized as a simple buck-stage, for converters with 50% max. duty cycle it must work in the discontinuous mode.The same winding of the transformer as for battery operation is used. Simulation results show the function of the system.

	A SIMPLIFIED MODEL OF CURRENT-CONTROLLED SWITCHING CONVERTERS IN DISCONTINUOUS CURRENT-MODE By G. Lirer; A. G. M. Strollo; A. Luciano	[View] [Download]
Abstract: A simplified circuit oriented model is developed for the analysis of current-mode switching converters operated in discontinuous current-mode. The model is based on an equivalent circuit representation of the power switch following the same approach already applied in literature to modeling duty-ratio programmed PWM converters. In this way an easy derivation of both DC and small-signal characteristics of the converter is achieved. Applications of the proposed model to buck and buck-boost topologies are presented.

	HOW TO FIND THE BEST SOLUTlON FOR POWER CONVERTERS AND FOR THE NEW PRINCIPLE OF OPERATION By Dejan Srajber	[View] [Download]
Abstract: Applying the postulates of power electronics, all power converters can be classified in four basic groups, each with two analogous circuits, one for voltage and one for current sources and loads. Furthermore, this new systematical presentation leads to all known converter designs and the new solution (the patent applied) for inverter designs. Advantages of the presented new principle of operation in inverter design are: - The transformer for galvanic isolation and voltage level adjustment can operate at the frequency of the switching elements; - The number of transistors is reduced by 50% comparing to conventional design using a high frequency transformer; - Simple control, using two independent first order regulators; - lnherent overload and output short circuit protection; - Simple parallel operation of devices, with different rated powers, without special distribution controllers; - Safe operation of the switches, without danger of short circuit currents and overvoltages due to errors in the transistor base drives.

	Converter Systems for Industry and Chemistry Applications By Reinhard Joho; Albert Kloss	[View] [Download]
Abstract: For arc furnaces and electrolytic process applications, multipuls converters with output currents up to 100 kA per unit are used. Currents of this magnitude require converter branches with up to 20 thyristors connected in parallel. The current distribution between the parallel-connected thyristors is one of the most difficult problems in the design of the converters.

	PROGRAMMABLE AC POWER SOURCE By H. van der Broeck; P. Lürkens	[View] [Download]
Abstract: The development of a 1kVA AC power source is presented which provides programmable sinusoidal output voltages. Both, output amplitude and output frequency can be set over a large range. The desired values can be programmed via a keyboard and a display or from a personal computer. The power source operates at the 220V / 50Hz / 60Hz mains and draws a sinusoidal current from the line. The output voltage is isolated from the input circuit. lt is also possible to operate the power source without the mains because internal batteries are installed. The system consists of switched mode power electronics and thus operates at a high efficiency. Another feature of the system is that 3 single phase units can be synchronized to form a three phase voltage power source. The AC power source is very well suited for testing appliances, consumer products, motors or other equipment which has to be supplied by the single phase mains. It may also be used within a production line in order to check automatically whether the device under test operates reliably in the specified voltage frequency range.