EPE Association: EPE 2005 - Topic 03-4b - DS: Power converter circuits and control

EPE 2005 - Topic 03-4b - DS: Power converter circuits and control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 03: SOFT SWITCHING CONVERTERS AND CONTROL > EPE 2005 - Topic 03-4b - DS: Power converter circuits and control

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   A Non-Resonantly Coupled Parallel Resonant Converter for Stand-Alone Applications
By DAI Chaobo; MOLLOV Stefan; FORSYTH Andrew [View]
[Download]

Abstract: A non-resonantly coupled Parallel Resonant Converter (PRC) is used for domestic UPS applications, achieving both high efficiency and high power density. In contrast with the conventional PRC, the non-resonantly coupled method results in modest ratings of the resonant components and smaller stresses on power electronic devices, which is important for high throughput power applications. With the hybrid control strategy, i.e. frequency control combined with phase shift control, the converter maintains Zero-Voltage-Switching (ZVS) throughout the low-frequency cycle, which results in reduced switching losses and EMI. However, this control strategy exhibits disappointing performance for the light load operation. By contrast, the phase shift control strategy shows higher performance and better adaptability over a wide load range. A correction look-up table for the light load operation generated from the steady-state characteristics of the converter improves the shape of the output voltage. Results from both time-domain simulations and a 3kW prototype are presented to demonstrate the converter as a strong candidate for stand-alone and utility-interfaced applications.

   Active Gate Driver Used for dV/dt Control and active voltage clamping in an IGBT Stack
By RASMUSSEN Tonny [View]
[Download]

Abstract: For high voltages converters stacks of IGBTs can be used if the static and dynamic voltage sharing among the IGBTs can be applied. dVCE/dt should also be controlled in order not to damage insulation material. This paper describes theory and measurements of an active gate driver for stacking IGBTs. For the measurements two series connected standard IGBTs made for hard switching applications are used. Problems are shown and proposals for improvements are given.

   Application of Packet Control Method for a High Power High Voltage Flyback Converter to Reduce the Noise Influence
By EMADI Ali; SADRIYEH Mohammad Reza; MOHAMMADI Abbas; KABOLI Shahriyar; ZOLGHADRI Mohammad Reza [View]
[Download]

Abstract: In the regulated switching power supplies, the output voltage is usually sampled across a resistive voltage divider. In high voltage applications, the resistance of the voltage divider is very high in order to reduce its power loss. Therefore, these resistors are very good receivers of environment noise. This paper introduces a new control method for a high power, high voltage Flyback converter insensitive to the noise caused by ringing due to the leakage reactance of a high voltage Flyback converter. In this method, output voltage is sampled in an intentionally extended cycle to be sure that all the oscillations are damped. Therefore there is no need to additional damping circuits and snubbers network and the efficiency of converter is not reduced. This method is applicable to any Flyback converter in discontinues conduction mode. Mathematical concept is introduced and simulation and experimental results are presented.

   Gate Driver With Efficient Energy Recovery For a 3MHz Resonant Converter.
By LABOURE ERic; JARROUSSE Jea; COSTA Francois; THOMAS Philippe [View]
[Download]

Abstract: This paper shows a new insulated gate driver with efficient energy recovery for the top and bottom switches of an half bridge. This gate driver is design to drive the main switches of a 3MHz resonant converter (48V/3.3V 20Watts). The originality of this driver comes from its low number of devices and its high frequency operation even if it drives switches having a high gate capacitor, as TrenchMos. The gate driver theoretically only provides the power dissipated by the internal power mosfet gate resistance. This gate driver is dedicated to high frequency resonant converter with a 0.5 duty cycle.

   Minimising in-rush current at resonant converter start-up
By ENO Otu; THOMPSON David [View]
[Download]

Abstract: This paper proposes a solution to the large start-up input current-inrush problem in a dc-dc converter without the use of a current-limiting resistor.The converter topology is H-bridge and designed to step up the input dc voltage. Resonance is achieved by resonating the transformer’s leakage inductance with a suitable capacitor. The output from the transformer is rectified and filtered to provide a stiff dc voltage at the input to an inverter linking a utility grid. It is the inrush current to the filter capacitor that is under consideration. Evidence for the magnitude of the inrush confirms the problem.From an analysis of the problem it is deduced that traditional single-chip soft-start circuits are of limited use for this application. An extension of this analysis provides the basis of an algorithm to reduce the inrush current magnitude. From this it is shown that a DSP has the means of assisting this problem.Experimental results of a DSP-controlled resonant converter are presented in support of the technique. These confirm the basis of the analysis and proposed solution.

   Modelling of Asymmetrical Pulse Width Modulation with Frequency Tracking Control using Phasor Transformation for Half-bridge Series Resonant Induction Cookers
By REIMANN Tobias; BERGER Gotthard; SCHERF Marko; PETZOLDT Juergen; TIAN Jian [View]
[Download]

Abstract: A FPGA-based asymmetrical pulse width modulation (APWM) with frequency tracking control method is introduced for half-bridge series resonant induction cookers. Two control loops within FPGA are implemented. Phase-locked loop (PLL) is used as frequency tracking control to keep ZVS over wide range, APWM as power regulation. Large and small signal PSPICE compatible circuit model are obtained by phasor transformation. Dynamic models for half-bridge series resonantinduction cooker are extracted from these circuits, and their characteristics are analysed. Finally models are verified and conclusions are given.

   NEW SOLUTIONS TO THE OLD PROBLEMS OF BUCK AND BOOST CONVERTERS
By KRASNIKOV Yurii [View]
[Download]

Abstract: A new snubber circuit for a diode recovery in boost and buck converters has been proposed. A distinct from the well-known snubber circuits, the new one restricts the reverse current amplitude, rather than the derivative di/dt. The value of the recovery current can be chosen in a relatively wide range by means of one circuit parameter.A new boost converter with a continuous output current has also been proposed. It does not require an output capacitor with high current capability.Basic relationships are derived, advantages of the new solutions are described and application areas are specified.

   Phase control of resonant power supply inverters
By MEINS JueRgen; CZAINSKI Robert; TURKI Faical [View]
[Download]

Abstract: Resonant power supply involves the use of Zero-Current-Switching (ZCS) high-frequency inverters. The load can be considered as a bandpass, so that a variation of its resonant frequency (by decreasing of distance of the power consumer) means that the inverter switches at higher current which can damage the IGBTs. This paper proposes a closed-loop-control of the inverter frequency to preserve the ZCS condition.

   Resonant Boost Converter Operating above its Resonant Frequency
By NAGY IstvaN; BARTAL PeTer; BUTI BalaZs [View]
[Download]

Abstract: The paper contains an investigation of the high frequency operation of a dual channel resonant Boost converter. The energy is transmitted through the two channels of the converter from its input to the output using a switched capacitor. Because of the two channels the load of the converter elements is distributed therefore its application is recommended in the medium or higher power ranges. An advantage of the converter is that in discontinuous current conduction mode (DCM) it can work in soft-switched mode too. A drawback of DCM operation is the higher output voltage ripple and the unfavorable utilization of the power handling capabilities of its components compared to the continuous current conduction (CCM) operation. The paper presents the conditions of operating the converter above the resonant frequency of its inherent L-C ringing circuit, and represents its beneficial effects. The considerations are verified by simulation results.

   The Serial Resonant Converter with Controlled Rectifier Stage
By FOSSAS Enric; CONESA Alfonso; PIQUE Robert [View]
[Download]

Abstract: This paper introduces and analyzes a new serial resonant converter derived from the classical SRC, with controlled switches at the rectifier stage. The output current is controlled and regulated by the above mentioned stage, allowing to keep the resonant magnitudes bounded. We perform the first harmonic approximation analysis to the structure and obtain the state space model solution. Experimental results from a prototype are also presented to support the developed analysis.

   Transformerless voltage clamp circuit applied to a soft switched DC/AC current source inverter
By DI STEFANO Roberto; MARIGNETTI Fabrizio; CANCELLIERE Piergiacomo; DELLI COLLI Vincenzo [View]
[Download]

Abstract: The selection of a regenerative, battery powered, DC/AC converter for uninterruptible power supply or traction applications is a compromise among the following major issues: efficiency, output waveforms quality, ruggedness, and cost. A zero current switching current source inverter represents a suitable solution in terms of losses and output wave shape; furthermore, the opportunity to use thyristors maintaining the capability to withstand short circuit contains cost and confers ruggedness. Ishikawa proposed an effective topology, but this topology requires a transformer with very low leakage inductance to contain the voltage stress of switching devices. This paper proposes and analyzes a modified zero current switching DC/AC current source inverter. The proposed topology includes a transformerless voltage clamp circuit overcoming the aforementioned problem. Furthermore, the circuit obtains a zero current turn off for each switch. The paper overviews the zero current switching DC/AC current source inverter, proving its functionality by means of numerical simulations.

   Using an CLC Low-Pass Filter to Reduce the Consequences of Aging in Steady-State Regime of DC-DC Converters
By CARDOSO Antonio; AMARAL Acacio [View]
[Download]

Abstract: This paper presents a filter that can be used in the design of DC-DC converters, in order to mitigate the pernicious effects of the electrolytic capacitor’s equivalent series resistance (ESR), in steady state regime. The aging of electrolytic capacitors, used for smoothing the output voltage manifests itself by the increase of their ESR, and as a consequence of that, the output voltage ripple becomes very large. In this manner, the study of solutions to this problem is a very important subject for converters designers in low and medium power range. This paper shows that the use of a CLC filter reduces significantly the output voltage ripple without increasing too much the converter size. A study about the additional filtering expenses, like the impact on converter size and cost will be presented. Several theoretical, simulated and experimental results are presented for a buck type DC-DC converter, with different output filters, operating in the continuous conduction mode (CCM).

EPE 2005 - Topic 03-4b - DS: Power converter circuits and control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 03: SOFT SWITCHING CONVERTERS AND CONTROL > EPE 2005 - Topic 03-4b - DS: Power converter circuits and control
	[return to parent folder]

	A Non-Resonantly Coupled Parallel Resonant Converter for Stand-Alone Applications By DAI Chaobo; MOLLOV Stefan; FORSYTH Andrew	[View] [Download]
Abstract: A non-resonantly coupled Parallel Resonant Converter (PRC) is used for domestic UPS applications, achieving both high efficiency and high power density. In contrast with the conventional PRC, the non-resonantly coupled method results in modest ratings of the resonant components and smaller stresses on power electronic devices, which is important for high throughput power applications. With the hybrid control strategy, i.e. frequency control combined with phase shift control, the converter maintains Zero-Voltage-Switching (ZVS) throughout the low-frequency cycle, which results in reduced switching losses and EMI. However, this control strategy exhibits disappointing performance for the light load operation. By contrast, the phase shift control strategy shows higher performance and better adaptability over a wide load range. A correction look-up table for the light load operation generated from the steady-state characteristics of the converter improves the shape of the output voltage. Results from both time-domain simulations and a 3kW prototype are presented to demonstrate the converter as a strong candidate for stand-alone and utility-interfaced applications.

	Active Gate Driver Used for dV/dt Control and active voltage clamping in an IGBT Stack By RASMUSSEN Tonny	[View] [Download]
Abstract: For high voltages converters stacks of IGBTs can be used if the static and dynamic voltage sharing among the IGBTs can be applied. dVCE/dt should also be controlled in order not to damage insulation material. This paper describes theory and measurements of an active gate driver for stacking IGBTs. For the measurements two series connected standard IGBTs made for hard switching applications are used. Problems are shown and proposals for improvements are given.

	Application of Packet Control Method for a High Power High Voltage Flyback Converter to Reduce the Noise Influence By EMADI Ali; SADRIYEH Mohammad Reza; MOHAMMADI Abbas; KABOLI Shahriyar; ZOLGHADRI Mohammad Reza	[View] [Download]
Abstract: In the regulated switching power supplies, the output voltage is usually sampled across a resistive voltage divider. In high voltage applications, the resistance of the voltage divider is very high in order to reduce its power loss. Therefore, these resistors are very good receivers of environment noise. This paper introduces a new control method for a high power, high voltage Flyback converter insensitive to the noise caused by ringing due to the leakage reactance of a high voltage Flyback converter. In this method, output voltage is sampled in an intentionally extended cycle to be sure that all the oscillations are damped. Therefore there is no need to additional damping circuits and snubbers network and the efficiency of converter is not reduced. This method is applicable to any Flyback converter in discontinues conduction mode. Mathematical concept is introduced and simulation and experimental results are presented.

	Gate Driver With Efficient Energy Recovery For a 3MHz Resonant Converter. By LABOURE ERic; JARROUSSE Jea; COSTA Francois; THOMAS Philippe	[View] [Download]
Abstract: This paper shows a new insulated gate driver with efficient energy recovery for the top and bottom switches of an half bridge. This gate driver is design to drive the main switches of a 3MHz resonant converter (48V/3.3V 20Watts). The originality of this driver comes from its low number of devices and its high frequency operation even if it drives switches having a high gate capacitor, as TrenchMos. The gate driver theoretically only provides the power dissipated by the internal power mosfet gate resistance. This gate driver is dedicated to high frequency resonant converter with a 0.5 duty cycle.

	Minimising in-rush current at resonant converter start-up By ENO Otu; THOMPSON David	[View] [Download]
Abstract: This paper proposes a solution to the large start-up input current-inrush problem in a dc-dc converter without the use of a current-limiting resistor.The converter topology is H-bridge and designed to step up the input dc voltage. Resonance is achieved by resonating the transformer’s leakage inductance with a suitable capacitor. The output from the transformer is rectified and filtered to provide a stiff dc voltage at the input to an inverter linking a utility grid. It is the inrush current to the filter capacitor that is under consideration. Evidence for the magnitude of the inrush confirms the problem.From an analysis of the problem it is deduced that traditional single-chip soft-start circuits are of limited use for this application. An extension of this analysis provides the basis of an algorithm to reduce the inrush current magnitude. From this it is shown that a DSP has the means of assisting this problem.Experimental results of a DSP-controlled resonant converter are presented in support of the technique. These confirm the basis of the analysis and proposed solution.

	Modelling of Asymmetrical Pulse Width Modulation with Frequency Tracking Control using Phasor Transformation for Half-bridge Series Resonant Induction Cookers By REIMANN Tobias; BERGER Gotthard; SCHERF Marko; PETZOLDT Juergen; TIAN Jian	[View] [Download]
Abstract: A FPGA-based asymmetrical pulse width modulation (APWM) with frequency tracking control method is introduced for half-bridge series resonant induction cookers. Two control loops within FPGA are implemented. Phase-locked loop (PLL) is used as frequency tracking control to keep ZVS over wide range, APWM as power regulation. Large and small signal PSPICE compatible circuit model are obtained by phasor transformation. Dynamic models for half-bridge series resonantinduction cooker are extracted from these circuits, and their characteristics are analysed. Finally models are verified and conclusions are given.

	NEW SOLUTIONS TO THE OLD PROBLEMS OF BUCK AND BOOST CONVERTERS By KRASNIKOV Yurii	[View] [Download]
Abstract: A new snubber circuit for a diode recovery in boost and buck converters has been proposed. A distinct from the well-known snubber circuits, the new one restricts the reverse current amplitude, rather than the derivative di/dt. The value of the recovery current can be chosen in a relatively wide range by means of one circuit parameter.A new boost converter with a continuous output current has also been proposed. It does not require an output capacitor with high current capability.Basic relationships are derived, advantages of the new solutions are described and application areas are specified.

	Phase control of resonant power supply inverters By MEINS JueRgen; CZAINSKI Robert; TURKI Faical	[View] [Download]
Abstract: Resonant power supply involves the use of Zero-Current-Switching (ZCS) high-frequency inverters. The load can be considered as a bandpass, so that a variation of its resonant frequency (by decreasing of distance of the power consumer) means that the inverter switches at higher current which can damage the IGBTs. This paper proposes a closed-loop-control of the inverter frequency to preserve the ZCS condition.

	Resonant Boost Converter Operating above its Resonant Frequency By NAGY IstvaN; BARTAL PeTer; BUTI BalaZs	[View] [Download]
Abstract: The paper contains an investigation of the high frequency operation of a dual channel resonant Boost converter. The energy is transmitted through the two channels of the converter from its input to the output using a switched capacitor. Because of the two channels the load of the converter elements is distributed therefore its application is recommended in the medium or higher power ranges. An advantage of the converter is that in discontinuous current conduction mode (DCM) it can work in soft-switched mode too. A drawback of DCM operation is the higher output voltage ripple and the unfavorable utilization of the power handling capabilities of its components compared to the continuous current conduction (CCM) operation. The paper presents the conditions of operating the converter above the resonant frequency of its inherent L-C ringing circuit, and represents its beneficial effects. The considerations are verified by simulation results.

	The Serial Resonant Converter with Controlled Rectifier Stage By FOSSAS Enric; CONESA Alfonso; PIQUE Robert	[View] [Download]
Abstract: This paper introduces and analyzes a new serial resonant converter derived from the classical SRC, with controlled switches at the rectifier stage. The output current is controlled and regulated by the above mentioned stage, allowing to keep the resonant magnitudes bounded. We perform the first harmonic approximation analysis to the structure and obtain the state space model solution. Experimental results from a prototype are also presented to support the developed analysis.

	Transformerless voltage clamp circuit applied to a soft switched DC/AC current source inverter By DI STEFANO Roberto; MARIGNETTI Fabrizio; CANCELLIERE Piergiacomo; DELLI COLLI Vincenzo	[View] [Download]
Abstract: The selection of a regenerative, battery powered, DC/AC converter for uninterruptible power supply or traction applications is a compromise among the following major issues: efficiency, output waveforms quality, ruggedness, and cost. A zero current switching current source inverter represents a suitable solution in terms of losses and output wave shape; furthermore, the opportunity to use thyristors maintaining the capability to withstand short circuit contains cost and confers ruggedness. Ishikawa proposed an effective topology, but this topology requires a transformer with very low leakage inductance to contain the voltage stress of switching devices. This paper proposes and analyzes a modified zero current switching DC/AC current source inverter. The proposed topology includes a transformerless voltage clamp circuit overcoming the aforementioned problem. Furthermore, the circuit obtains a zero current turn off for each switch. The paper overviews the zero current switching DC/AC current source inverter, proving its functionality by means of numerical simulations.

	Using an CLC Low-Pass Filter to Reduce the Consequences of Aging in Steady-State Regime of DC-DC Converters By CARDOSO Antonio; AMARAL Acacio	[View] [Download]
Abstract: This paper presents a filter that can be used in the design of DC-DC converters, in order to mitigate the pernicious effects of the electrolytic capacitor’s equivalent series resistance (ESR), in steady state regime. The aging of electrolytic capacitors, used for smoothing the output voltage manifests itself by the increase of their ESR, and as a consequence of that, the output voltage ripple becomes very large. In this manner, the study of solutions to this problem is a very important subject for converters designers in low and medium power range. This paper shows that the use of a CLC filter reduces significantly the output voltage ripple without increasing too much the converter size. A study about the additional filtering expenses, like the impact on converter size and cost will be presented. Several theoretical, simulated and experimental results are presented for a buck type DC-DC converter, with different output filters, operating in the continuous conduction mode (CCM).