EPE Association: EPE 1997 – 47: Dialogue Session DS9d: POWER CONDITIONING, POWER FACTOR CORRECTION

EPE 1997 – 47: Dialogue Session DS9d: POWER CONDITIONING, POWER FACTOR CORRECTION
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 47: Dialogue Session DS9d: POWER CONDITIONING, POWER FACTOR CORRECTION

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   ALTERNATIVE APPROACHES TO IMPROVE POWER FACTOR
By Luc Wuidart [View]
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Abstract: Since January 96, the European equipment manufacturers have to comply with the fECI 000-3-2 standard The mandatory compliance pushed many off-line Switched Mode Power Supply (SMPS) designers to use a Boost Power Factor Corrector (PFC) as preregulator stage. Below 300W of power capability, two alternative approaches can comply with the standard by limiting the cost impact on the overall converter. A first approach consists in transforming conventional SMPS topologies into "Inherent High Power Factor" (IHPF) structures which still need a serial coil. These IHPF topologies easily comply with all classes of the standard while achieving Power Factor values above 0.95. The second approach takes advantage from the standard Class D definition through a 1 00/120Hz "line current shaping". It mainly allows to escape from the constraining Class D to the much more favourable Class A. Such a current shaping based front-end circuits can achieve PF-values up to 0.8 without any coil.

   POWER FACTOR CORRECTOR WITH A MULTIPLIER CONTROL STAGE BASED ON THE DELTA-SIGMA TECHNIQUE
By E. Dallago; G. Sassone; M. Storti [View]
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Abstract: Delta-Sigma modulation is currently used as an intermediate stage in ND and DJ A conversion, and recently it has also been adopted in signal processing to perform arythmetic operations. Some types of Power Factor Correction circuits, introduced· in the electric power area to sinusoidally shape the AC line current and to place it in phase with the line voltage, contain in the control stage a multiplier block which could be advantageously realized with the Delta-Sigma technique. This work describes the implementation of such a multiplier block and reports the preliminary experimental results carried out on a laboratory prototype of the complete PFC system.

   SINGLE-STAGE ISOLATED UNITY POWER FACTOR CORRECTION SCHEME WITH SINGLE OUTPUT VOLTAGE CONTROL LOOP, AUTOMATIC CURRENT SHAPING AND FAST OUTPUT VOLTAGE REGULATION
By H. Jorquera; D. Sadarnac [View]
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Abstract: This paper introduces a new scheme for a single-stage unity power factor corrector. This structure is composed of a buck-boost converter cell followed by a series/parallel converter combined into a single stage. A very interesting property of the buck-boost allows the attainment of a unity power factor when it works in discontinuous current mode with a constant duty ratio. A single output voltage control loop and a pulse width modulation control strategy at constant frequency ensure a minimum of circuit complexity.

   ANALYSIS AND INFLUENCE OF MODULATION SCHEME ON THE SIZING OF THE INPUT FILTER IN A PWM RECTIFIER SYSTEM
By F. R. Walsh; J. F. Moynihan; P. J. Roche; M. G. Egan; J. M. D. Murphy [View]
[Download]

Abstract: This paper examines the influence of the modulation scheme on the sizing of the input filter in a Pulse Width Modulated (PWM) rectifier system. The examination is based on an analysis of Space Vector Modulation (SVM) schemes using a novel wall model based approach. The impact of using a standard Double Edged SVM scheme is compared with a 60° bus clamped scheme. The filtering requirements and associated filter size to meet the VDE0871 Class A limit for each modulation scheme are considered. The modulation schemes and the associated filter size are compared on the basis of equal switching frequency and equal switching losses.

   A THREE PHASE PWM BOOST RECTIFIER WITH HIGH POWER FACTOR OPERATION AND AN ACCEPTABLE CURRENT THD USING ONLY THREE SWITCHES
By C. H. Treviso; V. J. Farias; J. B. Vieira Jr.; L. C. de Freitas [View]
[Download]

Abstract: A three phase PWM Boost rectifier using three and six switches and operating with input power factor correcting properties is presented in this paper. The almost unity power factor operation is obtained by using a bang-bang hysteresis current waveshaping technique but with fixed switching frequency. The operational characteristics of the converter are verified by simulation.

   IMPROVEMENT METHODS OF CONVERSION QUALITY IN THREEPHASE AC LINE POWER CONTROLLERS - CIRCUIT TOPOLOGY AND BASIC PROPERTIES
By R. Strzelecki; Z. Fedyczak; G. Kobylecki; R. Kasperek [View]
[Download]

Abstract: In the paper, basic topologies of three-phase AC line conditioners have been specified and described, which give the possibility of the conversion quality improvement in comparison to AC line conditioners with thyristor power controllers applied universally as yet in industrial practice. Namely, the following circuits are presented: with thyristor power controller and resonance passive filter or parallel active power filter, with PWM AC line power·controller, with additional power displ~cement source and "intelligent" transformer power controller. Moreover basic properties of these circuits have been specified and on the base of own research works their general estimation has been presented, considering the conversion quality in relation to the AC line conditioner with an ideal transformer treated as a reference converter.

   USING TWO-INPUT BUCK POST-REGULATOR TO OBTAIN HIGH QUALITY FLYBACK POWER FACTOR CORRECTOR
By M. M. Hernando; P. Villegas; J. Sebastian; F. Nuno [View]
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Abstract: A new method to improve dynamic response of Power Factor Correctors (PFCs) is developed in this paper and applied to a Flyback PFC. The method is based on the use of a very high efficient post-regulator with two inputs instead of only one. This two-input postregulator (called Two-Input Buck, TIBuck) exhibits very high efficiency due to the fact that only a part of the total power undergoes a power conversion process. This post -regulator needs a two-output PFC at its inputs, which can easily obtained in PFCs with transformers such as Flyback or Sepic PFCs. A prototype of a Flyback PFC with a TIBuck post-regulator has been designed and optimized to be used in a 200W distributed power supply system for telecom. As a result, a reduction of 16 times in the bulk capacitor has been achieved with a efficiency penalty of only 0.97. With the use of the Average Current Mode Control, lower bulk capacitors can be used to obtain a very low voltage ripple at the output.

EPE 1997 – 47: Dialogue Session DS9d: POWER CONDITIONING, POWER FACTOR CORRECTION
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 47: Dialogue Session DS9d: POWER CONDITIONING, POWER FACTOR CORRECTION
	[return to parent folder]

	ALTERNATIVE APPROACHES TO IMPROVE POWER FACTOR By Luc Wuidart	[View] [Download]
Abstract: Since January 96, the European equipment manufacturers have to comply with the fECI 000-3-2 standard The mandatory compliance pushed many off-line Switched Mode Power Supply (SMPS) designers to use a Boost Power Factor Corrector (PFC) as preregulator stage. Below 300W of power capability, two alternative approaches can comply with the standard by limiting the cost impact on the overall converter. A first approach consists in transforming conventional SMPS topologies into "Inherent High Power Factor" (IHPF) structures which still need a serial coil. These IHPF topologies easily comply with all classes of the standard while achieving Power Factor values above 0.95. The second approach takes advantage from the standard Class D definition through a 1 00/120Hz "line current shaping". It mainly allows to escape from the constraining Class D to the much more favourable Class A. Such a current shaping based front-end circuits can achieve PF-values up to 0.8 without any coil.

	POWER FACTOR CORRECTOR WITH A MULTIPLIER CONTROL STAGE BASED ON THE DELTA-SIGMA TECHNIQUE By E. Dallago; G. Sassone; M. Storti	[View] [Download]
Abstract: Delta-Sigma modulation is currently used as an intermediate stage in ND and DJ A conversion, and recently it has also been adopted in signal processing to perform arythmetic operations. Some types of Power Factor Correction circuits, introduced· in the electric power area to sinusoidally shape the AC line current and to place it in phase with the line voltage, contain in the control stage a multiplier block which could be advantageously realized with the Delta-Sigma technique. This work describes the implementation of such a multiplier block and reports the preliminary experimental results carried out on a laboratory prototype of the complete PFC system.

	SINGLE-STAGE ISOLATED UNITY POWER FACTOR CORRECTION SCHEME WITH SINGLE OUTPUT VOLTAGE CONTROL LOOP, AUTOMATIC CURRENT SHAPING AND FAST OUTPUT VOLTAGE REGULATION By H. Jorquera; D. Sadarnac	[View] [Download]
Abstract: This paper introduces a new scheme for a single-stage unity power factor corrector. This structure is composed of a buck-boost converter cell followed by a series/parallel converter combined into a single stage. A very interesting property of the buck-boost allows the attainment of a unity power factor when it works in discontinuous current mode with a constant duty ratio. A single output voltage control loop and a pulse width modulation control strategy at constant frequency ensure a minimum of circuit complexity.

	ANALYSIS AND INFLUENCE OF MODULATION SCHEME ON THE SIZING OF THE INPUT FILTER IN A PWM RECTIFIER SYSTEM By F. R. Walsh; J. F. Moynihan; P. J. Roche; M. G. Egan; J. M. D. Murphy	[View] [Download]
Abstract: This paper examines the influence of the modulation scheme on the sizing of the input filter in a Pulse Width Modulated (PWM) rectifier system. The examination is based on an analysis of Space Vector Modulation (SVM) schemes using a novel wall model based approach. The impact of using a standard Double Edged SVM scheme is compared with a 60° bus clamped scheme. The filtering requirements and associated filter size to meet the VDE0871 Class A limit for each modulation scheme are considered. The modulation schemes and the associated filter size are compared on the basis of equal switching frequency and equal switching losses.

	A THREE PHASE PWM BOOST RECTIFIER WITH HIGH POWER FACTOR OPERATION AND AN ACCEPTABLE CURRENT THD USING ONLY THREE SWITCHES By C. H. Treviso; V. J. Farias; J. B. Vieira Jr.; L. C. de Freitas	[View] [Download]
Abstract: A three phase PWM Boost rectifier using three and six switches and operating with input power factor correcting properties is presented in this paper. The almost unity power factor operation is obtained by using a bang-bang hysteresis current waveshaping technique but with fixed switching frequency. The operational characteristics of the converter are verified by simulation.

	IMPROVEMENT METHODS OF CONVERSION QUALITY IN THREEPHASE AC LINE POWER CONTROLLERS - CIRCUIT TOPOLOGY AND BASIC PROPERTIES By R. Strzelecki; Z. Fedyczak; G. Kobylecki; R. Kasperek	[View] [Download]
Abstract: In the paper, basic topologies of three-phase AC line conditioners have been specified and described, which give the possibility of the conversion quality improvement in comparison to AC line conditioners with thyristor power controllers applied universally as yet in industrial practice. Namely, the following circuits are presented: with thyristor power controller and resonance passive filter or parallel active power filter, with PWM AC line power·controller, with additional power displ~cement source and "intelligent" transformer power controller. Moreover basic properties of these circuits have been specified and on the base of own research works their general estimation has been presented, considering the conversion quality in relation to the AC line conditioner with an ideal transformer treated as a reference converter.

	USING TWO-INPUT BUCK POST-REGULATOR TO OBTAIN HIGH QUALITY FLYBACK POWER FACTOR CORRECTOR By M. M. Hernando; P. Villegas; J. Sebastian; F. Nuno	[View] [Download]
Abstract: A new method to improve dynamic response of Power Factor Correctors (PFCs) is developed in this paper and applied to a Flyback PFC. The method is based on the use of a very high efficient post-regulator with two inputs instead of only one. This two-input postregulator (called Two-Input Buck, TIBuck) exhibits very high efficiency due to the fact that only a part of the total power undergoes a power conversion process. This post -regulator needs a two-output PFC at its inputs, which can easily obtained in PFCs with transformers such as Flyback or Sepic PFCs. A prototype of a Flyback PFC with a TIBuck post-regulator has been designed and optimized to be used in a 200W distributed power supply system for telecom. As a result, a reduction of 16 times in the bulk capacitor has been achieved with a efficiency penalty of only 0.97. With the use of the Average Current Mode Control, lower bulk capacitors can be used to obtain a very low voltage ripple at the output.