EPE Association: NORpie 2002 - Topic 05: CONVERTERS II

NORpie 2002 - Topic 05: CONVERTERS II
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2002 > NORpie 2002 - Topic 05: CONVERTERS II

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   Effect of the Magnetization Inductance on Forward Converter with Active Clamp
By V. Tuomainen; J. Kyyrä [View]
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Abstract: Magnetization inductance of the transformer plays a key role in Forward topology that is equipped with an active clamp circuit. The energy content of the inductance can be used to discharge the parasitic capacitance of the primary switch prior to turning-on of the device and in theory a zero-voltage-switching is achievable. This paper includes a study of the impact of the magnetization inductance on the operation of the Forward with active clamp and which, moreover, uses self-driven synchronous rectifiers. Paper includes analysis of the converter and measured results from a 3.4 V and 30 A prototype converter.

   Evaluation of the Different Soft-Switching Topologies for High-Power Applications
By G. Demetriades; H.-P. Nee [View]
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Abstract: High-frequency DC-DC converters are nowadays widely used in a diversity of power electronic applications. High-operating frequencies, entail a reduction in size of the passive components, such as inductors, capacitors and power transformers. By moving to higher operating frequencies with conventional hard-switching (square-current waveforms) topologies, the transistor switching losses increase at both turn-on and turn-off. High-dissipation spikes occur more often and as a result the average transistor losses are increased. Circuit parasitics such as semiconductor junction capacitance, transformer leakage inductance and winding capacitance, are major factors hindering high-frequency operation of the conventional hard-switched PWM converters. Lower switching losses can be achieved by associating a resonating L-C tank. Current and/or voltage waveforms become more or less sinusoidal and with a proper control strategy, the switching losses can be dramatically reduced. This paper is reffered to high-power aplications. High-voltage input of some tens of KV is considered on the primary side meanwhile high-current of some hundreds of ampere is considered on the secondary side. The operating frequency is in the rate of some KHz and the power rating is in the scale of some MW. The major objective of this paper is to propose alternatives with lower production cost and with better operating characteristics compared with the conventional configurations. The scope of this paper is to identify the optimum topologies and evaluate them taking into consideration their operational behaviour and the component stress parameters as obtained by simulations and in some cases by laboratory measurements.

   The Line Current THD and Power Loss Consideration of VIENNA I Rectifier under Distorted Mains Voltages
By T. Viitanen; H. Tuusa [View]
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Abstract: This paper describes the steady-state simulation results of the three-level VIENNA I three-phase rectifier under distorted mains (230V / 400V @ 50 Hz) voltages. The rectifier is designed to operate at 50 kW rated output power. The total harmonic mains voltage distortion is 8.6%. The operation of teh rectifier is examined in case of L- and LCL-type AC-filters. The DC-link voltage is set at 650V. The applied constant switching frequency is 3.5kHz. Simulations are carried out with Simplorer (R). Component models are non-ideal. On the basis of teh simulation results, the line current THD and the losses of the active and passive components are determined.

   On Conversion Losses in SLR- and LCC-Topologies
By P. Ranstad; G. Demetriades [View]
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Abstract: A comparison on losses in an slr- vs an lcc-converter is presented. It is shown that, due to a higher conversion ratio, the lss-converter can be designed to have lower losses. The work is performed by use of MATLAB calculations and PSPICE simulations. The results are experimentally verified. The measurements are performed on a 60kW converter in an industrial application.

   Steady State Analysis of Modified Dither Converter
By V. Tuomainen; J. Kyyrä [View]
[Download]

Abstract: Modified Dither converter is a Buck-Boost type Single-Stage converter. the converter has an advantage over some other type of Single-Stage converters, like the BIFRED and BIBRED, since it does not suffer from a particularly high steady state bulk capacitor voltage, until at very low loads. This feature allows the output part of the converter to be designed to operate in the continuous conduction mode over a wide range of loads. However, the advantage is gained at a price of a little bit complicated circuit structure, which includes a tapped transformer. This paper presents a detailed analysis of the steady state operation of the circuit. Equations to determine the steady state voltages and currents in the circuit are provided. The analysis is verified with simulated results from a 150 W modeified Dither converter.

NORpie 2002 - Topic 05: CONVERTERS II
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2002 > NORpie 2002 - Topic 05: CONVERTERS II
	[return to parent folder]

	Effect of the Magnetization Inductance on Forward Converter with Active Clamp By V. Tuomainen; J. Kyyrä	[View] [Download]
Abstract: Magnetization inductance of the transformer plays a key role in Forward topology that is equipped with an active clamp circuit. The energy content of the inductance can be used to discharge the parasitic capacitance of the primary switch prior to turning-on of the device and in theory a zero-voltage-switching is achievable. This paper includes a study of the impact of the magnetization inductance on the operation of the Forward with active clamp and which, moreover, uses self-driven synchronous rectifiers. Paper includes analysis of the converter and measured results from a 3.4 V and 30 A prototype converter.

	Evaluation of the Different Soft-Switching Topologies for High-Power Applications By G. Demetriades; H.-P. Nee	[View] [Download]
Abstract: High-frequency DC-DC converters are nowadays widely used in a diversity of power electronic applications. High-operating frequencies, entail a reduction in size of the passive components, such as inductors, capacitors and power transformers. By moving to higher operating frequencies with conventional hard-switching (square-current waveforms) topologies, the transistor switching losses increase at both turn-on and turn-off. High-dissipation spikes occur more often and as a result the average transistor losses are increased. Circuit parasitics such as semiconductor junction capacitance, transformer leakage inductance and winding capacitance, are major factors hindering high-frequency operation of the conventional hard-switched PWM converters. Lower switching losses can be achieved by associating a resonating L-C tank. Current and/or voltage waveforms become more or less sinusoidal and with a proper control strategy, the switching losses can be dramatically reduced. This paper is reffered to high-power aplications. High-voltage input of some tens of KV is considered on the primary side meanwhile high-current of some hundreds of ampere is considered on the secondary side. The operating frequency is in the rate of some KHz and the power rating is in the scale of some MW. The major objective of this paper is to propose alternatives with lower production cost and with better operating characteristics compared with the conventional configurations. The scope of this paper is to identify the optimum topologies and evaluate them taking into consideration their operational behaviour and the component stress parameters as obtained by simulations and in some cases by laboratory measurements.

	The Line Current THD and Power Loss Consideration of VIENNA I Rectifier under Distorted Mains Voltages By T. Viitanen; H. Tuusa	[View] [Download]
Abstract: This paper describes the steady-state simulation results of the three-level VIENNA I three-phase rectifier under distorted mains (230V / 400V @ 50 Hz) voltages. The rectifier is designed to operate at 50 kW rated output power. The total harmonic mains voltage distortion is 8.6%. The operation of teh rectifier is examined in case of L- and LCL-type AC-filters. The DC-link voltage is set at 650V. The applied constant switching frequency is 3.5kHz. Simulations are carried out with Simplorer (R). Component models are non-ideal. On the basis of teh simulation results, the line current THD and the losses of the active and passive components are determined.

	On Conversion Losses in SLR- and LCC-Topologies By P. Ranstad; G. Demetriades	[View] [Download]
Abstract: A comparison on losses in an slr- vs an lcc-converter is presented. It is shown that, due to a higher conversion ratio, the lss-converter can be designed to have lower losses. The work is performed by use of MATLAB calculations and PSPICE simulations. The results are experimentally verified. The measurements are performed on a 60kW converter in an industrial application.

	Steady State Analysis of Modified Dither Converter By V. Tuomainen; J. Kyyrä	[View] [Download]
Abstract: Modified Dither converter is a Buck-Boost type Single-Stage converter. the converter has an advantage over some other type of Single-Stage converters, like the BIFRED and BIBRED, since it does not suffer from a particularly high steady state bulk capacitor voltage, until at very low loads. This feature allows the output part of the converter to be designed to operate in the continuous conduction mode over a wide range of loads. However, the advantage is gained at a price of a little bit complicated circuit structure, which includes a tapped transformer. This paper presents a detailed analysis of the steady state operation of the circuit. Equations to determine the steady state voltages and currents in the circuit are provided. The analysis is verified with simulated results from a 150 W modeified Dither converter.