EPE Association: EPE 2005 - Topic 12-3b - DS: PFC systems, EMI and overvoltage protection

EPE 2005 - Topic 12-3b - DS: PFC systems, EMI and overvoltage protection
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 12: POWER SUPPLIES > EPE 2005 - Topic 12-3b - DS: PFC systems, EMI and overvoltage protection

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   A 20 kHZ HIGH SPEED HEXFET FQS DIRECT AC-AC CHOPPER: OPERATING AND IMPROVEMENT OF EMC CONDUCTED MODES
By RASOANARIVO Ignace [View]
[Download]

Abstract: This paper presents firstly the performances of a 20 kHz direct ac-ac chopper with high speed four quadrants switches (FQS), and deals after with a simple and original technique the improvement of the EMC conducted mode of this converter. This technique is associated on a bus bar connection by thin copper planar and lamellar

   A double resonance generator simulation using a hybrid approach
By GODOY Emmanuel; BUISSON Jean; CORMERAIS Herve; GUEGUEN Herve; ZAINEA Marius [View]
[Download]

Abstract: An important and significant class of hybrid systems, also called switching systems, is represented by physical systems with switches. In the electrical domain, switching systems are encountered mainly in power electronics, where the commutating elements are the diodes, the thyristors, IGBTs, etc. Thus, in power electronics applications, systems are operating in commutation, mixing the continuous and the discrete behaviors. The use of hybrid techniques can then constitute an effective method allowing a structured and systematic approach for the modeling, analysis and control. The objective of this paper is to simulate, using a hybrid approach, the behavior of a double resonance generator. This kind of generator is used for medical imagery applications, requiring high tensions, typically 40 kV to 200 kV, associated with high powers (about 100 kW). The proposed method in this paper is a general method, based on the bond graph representation, to obtain a simulation model with Simulink in the event tracking method framework. The simulation is designed as an enumeration of dynamics associated with each configuration of switches, while a Stateflow block ensures the commutation between configurations. The whole system has to respect the necessary conditions for consistency.

   A Simple PID Autotuning Method for Digitally Controlled dc-dc Boost Converters
By STEFANUTTI Walter; GHIONI Massimo; SAGGINI Stefano; MATTAVELLI Paolo [View]
[Download]

Abstract: This paper proposes a simple PID autotuning technique for digitally controlled dc-dc boost converters using the relay feedback technique. Controller parameter tuning is obtained introducing small perturbations on the output voltage by including a relay in the control feedback and ensuring closed-loop operation during the autotuning procedure. Moreover, including the PID regulator in the relay feedback loop, the controller parameters are directly tuned according to the specified dynamic requirement. The proposed algorithm is simple, it requires small tuning times and it is fully compliant with the cost/complexity constraints of integrated digital ICs. Simulation results and experimental results confirm the validity and effectiveness of the proposed solution.

   A Unity Power Factor PWM Rectifier Reducing the Number of Sensors
By ITAKO Kazutaka [View]
[Download]

Abstract: In this paper, a new control method of a reversible PWM rectifier is discussed, where the input voltage sensor and the DC current sensor are eliminated; the performance corresponds to that of the original system can be obtained by estimating the input voltage and DC load current from measured input current and DC output voltage. By using this method, the simplified circuit configuration with half number of required sensors and reduction of the cost will be realized. Because when the system has an inverter load, the DC load current includes the high switching frequency components, it will be impossible to use directly the DC load current for the feed-forward control. Therefore, the treatment of the DC load current for the feed-forward control is also investigated.

   AC-Side Current Waveform Improvement of Single-Phase Rectifiers Using a Triple-Frequency PWM Scheme
By MIYASHITA Osamu; NAGASHIMA Norihiro; YOSHIDA Toshiya; OHGOE Yasuharu [View]
[Download]

Abstract: This paper proposes and discusses single-phase rectifiers with a triple-frequency pulsewidth modulation (PWM) scheme. The rectifiers consist of high-, medium-, and low-power sub-converters operated at low, medium, and high frequencies, respectively. The proposed rectifier can equivalently operate as one rectifier that delivers the highest power at the highest frequency defined in the triple-frequency PWM rectifier. A parallel type of the rectifier is mainly discussed in this paper. A cascade type is also considered. In both configurations, current harmonics on the ac-side are greatly reduced, and an approximate unity power-factor is obtained. Experimental and simulation results verify the usefulness of the method.

   An Active Filter for Eliminating Harmonics and Interharmonics in the Input Current to an AC Voltage Controller for Refrigeration and Air-conditioning Applicatio
By SHAMMAS Noel; TENNAKOON Sarath; JODEYRI Hassan; LEHAL Tarinderjit [View]
[Download]

Abstract: Energy saving motor controllers for refrigeration and air-conditioning applications operate at the minimum input power point by finding the optimum firing angle of the thyristors in the motor controller. Consequently, the distorted input current contains harmonics, sub-harmonics, and interharmonics whose frequencies change with the motor speed. Therefore passive filters are not suitable and the best solution is to use an active filter. A single phase active filter with simple constant frequency switching is able to reduce waveform distortion by eliminating a sufficient range of frequencies and offers a low cost solution. Theoretical analysis of the full-bridge and half-bridge topologies led to the development of design equations and curves. Simulation of a half-bridge active filter confirmed the design equations

   Buck-Boost Integrated Forward Converter
By NIE Zhong; EMADI Ali [View]
[Download]

Abstract: An integrated converter is a synthesized converter based on the overall system integration, which is simplified by the system objective and can implement the system functions similar to the discrete converters. An integrated converter consists of converter sets; each converter set has a special function defined by the designer. A family of DC/DC buck boost based integrated rectifier with two active switches can be derived by the integration concept. In this paper, buck boost Forward integrated converter is proposed and fully explained. Five different operating modes, formulation, waveforms, output/input voltage ratio characteristics, small-signal models, transfer function, simulation results, and experimental verification are presented in detail.

   Circuit Oriented Average Modeling of Switching Power Converters
By CUADROS Carlos [View]
[Download]

Abstract: Effective features from various modeling methods are complemented with analog simulation, series expansion practices and heuristic guidelines to get a systematic and versatile method to derive accurate and efficient Circuit Oriented Large Signal Average Models (COLSAMs) that approximate the slow dynamics manifold of the relevant state variables for PWM dc to dc and three-phase to dc power converters. These COLSAMs can cover both CCM and DCM operation and they are much cheaper, computation wise, than switching models. From the converter’s operating waveforms and topological stages this method leads primarily to simple and effective input-output oriented models that represent transfer as well as loading characteristics of the converter. Since these models are time invariant and continuous they can be linearized at an operating point to obtain small-signal models that approximate the dynamics of the original PWM system around an orbit. The models are primarily intended for software circuit simulators to take advantage of intrinsic features such as transient response, linearization, etc. without changing simulation environment, but many mathematics simulator can be used with the set of equations obtained by applying Kirchoff’s laws to the COLSAMs. The latter also provide physical insight to help with power stage and control design. A new average model to cover both CCM and DCM operation for the ZVS Full-Bridge PWM converter was developed and its high accuracy is verified with simulations from a switching behavioral model for several component values.

   Combined Electrical and Thermal Modeling in Power Supplies
By MALYNA D.V.; FERREIRA J.A.; BAUER P.; DUARTE J.L.; HENDRIX M.A.M.; VANDENPUT A.J.A.; DE JONG E.C.W. [View]
[Download]

Abstract: The integrated simulation of electrical and thermal behavior of an AC-DC power supply is investigated. The approach is based on a conventional electric circuit model combined with a thermal resistive model, processed by a unique simulation program that provides fast steady state calculations. Results are critically compared to actual thermal measurements.

   DESIGN OF PFC AC/DC FLYBACK CONVERTER FOR LOW VOLTAGE APPLICATIONS
By KYRITSIS Anastasios; PAPANIKOLAOU Nikolaos; TATAKIS Emmanuel [View]
[Download]

Abstract: This paper presents an appropriate design scheme for a high–efficiency high–power–factor AC/DC flyback converter with low output voltage. For this purpose the voltage and current stresses as well as the power losses on the switches are going to be analytically calculated. The whole theoretical analysis concludes to a design criterion concerning the selection of the transformer turns ratio, so as to minimize the semiconductor losses. Finally, simulation and experimental results are presented, validating the theoretical analysis and the proposed design scheme.

   Digital Control Methods for Current Sharing of Interleaved Synchronous Buck Converter
By UNDELAND Tore M.; ANDREASSEN PaL [View]
[Download]

Abstract: The quasi square wave operation of the synchronous buck with interleaved parallel outputs has been successfully used in low voltage high current DC-supply for microprocessors. This topology results in fast transient response and high power density.In this paper, two digital control strategies for current sharing control are tested by simulation in Simulink, and tested in the laboratory. The digital current control methods are tested using a 150 MHz Texas Instrument TMS320F2812 DSP and studied with regard to the current reference step response.The results from the simulations and the experiments show that it is possible to increase control performance by using a predictive controller but that this would require extra cost and design effort to implement a low noise and high bandwidth measurement hardware on the output voltage.

   Fast Waveform and EMI Calculation of a PFC Converter
By LUeRKENS Peter [View]
[Download]

Abstract: Waveforms of switched mode converters are usually determined by simulation in the time domain. In particular, off-line converters, which change duty cycle and/or switching frequency cyclically, do not allow the calculation of the behavior by assuming an average operating point, representative for all time instances during a mains cycle. This leads to the necessity to simulate a time span, which covers at least one mains cycle. On the other hand, time domain simulations by circuit simulators need small integration steps to achieve numerical stability, especially when the switching frequency of the converter is high. The result is a long simulation time.This paper describes an efficient method, producing complex converter waveforms by using template functions. In addition to current and voltage waveforms a fast estimation of the EMI level is produced. Measurements show the validity.

   Mains harmonic reduction circuits using non linear inductances
By SCHETTERS Kees; DUeRBAUM Thomas; KUeBRICH Daniel [View]
[Download]

Abstract: Regulations like IEC 1000-3-2 impose limits on the line input current harmonics. Passive solutions to obtain mains harmonic reduction still dominate the consumer and PC market segment. Some inductors used in practical designs operate in the saturation region even at power levels to be tested for compliance. On the other hand, nearly all publications dealing with design of the passive MHR circuits assume a linear inductor. This paper investigates the usefulness of non linear inductors in passive MHR circuits by extracting the nonlinearity, measuring the compliance, modeling the inductor by an appropriate fit function and extrapolating the design to other power levels.

   MATHEMATICAL MODELLING AND DIGITAL CONTROL FOR POWER SUPPLIES OF CURRENT PULSED FOR WELDING MACHINE
By CORRÊA JoãO; BOLHOSA Denis; PEREIRA Aldo; JUNIOR Petronio [View]
[Download]

Abstract: This work presents the development of a welding machine MIG/MAG (Metal Gás Inerte/Metal Active Gás) whose exit current is pulsed, the control was developed starting from a simplified mathematical model, what allowed the elaboration of a program of simpler digital control. The mathematical model was based on equivalent circuits of the components of the process. These equivalent circuits allowed to characterize a variable of the process denominated stick out, this was modeled as being a variable resistance, allowing the control of the welding as being function just of that resistance. The circuits were simulated in MATLAB/SIMULINK and their data were compared with experimental results, allowing to validate the proposed model. The digital control was developed with base in the acquisition of current data and voltage through sensor, and digital processed using the microcontroller PIC16F877. The project of the potency circuit was elaborated with characteristics similar to the welding machines conventional and commercially available. An implementation was developed in the form of a prototype in real scale with use of power structures and IGBT, with capacity of up to 300 amperes. The experimental results are compared with the theoretical data, the one that allows do one analyzes comparative and of acting of the system.

   MINIMIZATION OF THE SOURCE CURRENT DISTORTION IN SYSTEMS WITH SINGLE-PHASE ACTIVE POWER FILTERS AND ADDITIOANL FASSIVE FILTER DESIGNED BY GENETIC ALGORITHMS
By KOSIOROWSKI Stanislaw; SWIATEK Boguslaw; KLEMPKA Ryszard [View]
[Download]

Abstract: The paper presents the results of the tests of a laboratory single-phase active filter which employs intelligent power module. The filter control system based on artificial neural networks is described. In order to mitigate the high friquency component of the current a passive filter was designed. The results of simulation tests based on genetic algorithms were used for the selection of the parameters of the filter elements. The results of the simulation and experimental tests obtained from laboratory arrangement are presented.

   Modeling the LIFT DC-DC Converter in the State Space Discrete Time
By RIVA Marco; MARANESI Piero; BELLONI Federico [View]
[Download]

Abstract: The lift technique has been widely described in the literature by Luo et al. They focus on the steady state operation of the power cells mainly. On the other side, a complete dynamic characterisation is missing up to now.This paper provides the dynamic models of the lift power cells and converters.Capacitive switching characterizes their operation and modeling can be obtained with high accuracy adopting the same procedures that are well suited for describing the dynamic behaviours of other switched capacitor circuits, f.i. the Cockcroft-Walton multipliers. The approach is the state space discrete timeprotocol with some additional tricks for the precise evaluation of the sampled data values and of the matrices A, B, C and D.The paper describes how to derive the coefficients of the state space matrices of the Luo lift converter and makes reference to a software tool for the automatic analysis.The transfer function matrix of the power cell provides six transfer functions that are plotted versus frequency.After assigning a suitable feedback network, the converter is characterized by four closed loop transfer functions. Forecasts of the frequency responses are compared with experimental results.

   Steady-state Time-domain Simulation of Power Converters Using a Differentiation Matrix
By COSTA Fabiano; FERNANDES Darlan; NAIDU S. R.; ALMEIDA L. A. L. [View]
[Download]

Abstract: A technique for simulating the steady-state response of power converters has been proposed in this paper. The technique is based on the definition of a differentiation matrix. It converts differential into algebraic equations and provides the signals in the time domain. This allows obtain directly the steady-state responses of power converters without to generate all the previous transients points. The Differentiation matrix is still simple to apply and is rapidly convergent. The accuracy of the technique has been established and the responses of three circuits with soft-switching and feedback control has been presented.

   SWITCHING CELL OPTIMISATION MINIMISING THE COMMON MODE CURRENT FOR THE POWER FACTOR CORRECTOR
By MAGNON Didier; LE BUNETEL Jea; BALCELLS Josep; PUZO Antoine; GONZALEZ David; BREHAUT Stephane; GAGO Javier [View]
[Download]

Abstract: This paper presents the problem of common mode electromagnetic interference. We study the common mode current phenomena on a single converter like the Boost converter. This converter operates in power factor corrector mode. The advantage of this structure is the presence of one switching commutation cell only. This limits the number of voltage pollution source creating common electromagnetic interference. The elements that intervene in the mechanic of pollution, are switching frequency, the rise and fall time of switches, the parasitic capacitance between electric circuit ant the ground plan, the floating voltage of the converter. In this paper, we are interested in the two last points.

   The Realisation of the Control of an AC/DC Converter Using a Motor Control DSP
By MORRISON Richard; POWER Daithi; EGAN Michael [View]
[Download]

Abstract: A Digital Signal Processor (DSP) controlled, isolated, power factor corrected, two-stage ac/dc converter is presented. All the control functionality is implemented using the 28 pin, Analog Devices DSP, ADMCF328, which is referenced to the secondary. The primary control voltages are magnetically sensed. The dc/dc stage control voltages are sensed using the AD7811 ADC. The internal serial port of this device is used to serially transmit its output data to the DSP.

   Zero-Crossing Distortion in Grid-Coupled AC-DC Converters
By RYCKAERT Wouter; MELKEBEEK Jan; DE GUSSEME Koen; DE VLEESCHAUWER Vera; VAN DE SYPE David [View]
[Download]

Abstract: Zero-crossing distortion in modern rectifiers and inverters may have different causes: the commutation dead time, the use of diode bridge rectifiers, discontinuities in the PWM-generation. . . In this paper another cause of zero-crossing distortion is analysed: when a security dead time is inserted between the gate signals of two switches in the same leg, some line current distortion may appear close to the zero-crossing of the line current due to errors in the sampling of that line current. An overview of the sampling requirements for a digitally controlled full-bridge ac-dc converter is given and a detailed analysis of the line current distortion is performed. The analysis is verified with experimental waveforms and a solution is proposed to decrease the linecurrent distortion.

EPE 2005 - Topic 12-3b - DS: PFC systems, EMI and overvoltage protection
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 12: POWER SUPPLIES > EPE 2005 - Topic 12-3b - DS: PFC systems, EMI and overvoltage protection
	[return to parent folder]

	A 20 kHZ HIGH SPEED HEXFET FQS DIRECT AC-AC CHOPPER: OPERATING AND IMPROVEMENT OF EMC CONDUCTED MODES By RASOANARIVO Ignace	[View] [Download]
Abstract: This paper presents firstly the performances of a 20 kHz direct ac-ac chopper with high speed four quadrants switches (FQS), and deals after with a simple and original technique the improvement of the EMC conducted mode of this converter. This technique is associated on a bus bar connection by thin copper planar and lamellar

	A double resonance generator simulation using a hybrid approach By GODOY Emmanuel; BUISSON Jean; CORMERAIS Herve; GUEGUEN Herve; ZAINEA Marius	[View] [Download]
Abstract: An important and significant class of hybrid systems, also called switching systems, is represented by physical systems with switches. In the electrical domain, switching systems are encountered mainly in power electronics, where the commutating elements are the diodes, the thyristors, IGBTs, etc. Thus, in power electronics applications, systems are operating in commutation, mixing the continuous and the discrete behaviors. The use of hybrid techniques can then constitute an effective method allowing a structured and systematic approach for the modeling, analysis and control. The objective of this paper is to simulate, using a hybrid approach, the behavior of a double resonance generator. This kind of generator is used for medical imagery applications, requiring high tensions, typically 40 kV to 200 kV, associated with high powers (about 100 kW). The proposed method in this paper is a general method, based on the bond graph representation, to obtain a simulation model with Simulink in the event tracking method framework. The simulation is designed as an enumeration of dynamics associated with each configuration of switches, while a Stateflow block ensures the commutation between configurations. The whole system has to respect the necessary conditions for consistency.

	A Simple PID Autotuning Method for Digitally Controlled dc-dc Boost Converters By STEFANUTTI Walter; GHIONI Massimo; SAGGINI Stefano; MATTAVELLI Paolo	[View] [Download]
Abstract: This paper proposes a simple PID autotuning technique for digitally controlled dc-dc boost converters using the relay feedback technique. Controller parameter tuning is obtained introducing small perturbations on the output voltage by including a relay in the control feedback and ensuring closed-loop operation during the autotuning procedure. Moreover, including the PID regulator in the relay feedback loop, the controller parameters are directly tuned according to the specified dynamic requirement. The proposed algorithm is simple, it requires small tuning times and it is fully compliant with the cost/complexity constraints of integrated digital ICs. Simulation results and experimental results confirm the validity and effectiveness of the proposed solution.

	A Unity Power Factor PWM Rectifier Reducing the Number of Sensors By ITAKO Kazutaka	[View] [Download]
Abstract: In this paper, a new control method of a reversible PWM rectifier is discussed, where the input voltage sensor and the DC current sensor are eliminated; the performance corresponds to that of the original system can be obtained by estimating the input voltage and DC load current from measured input current and DC output voltage. By using this method, the simplified circuit configuration with half number of required sensors and reduction of the cost will be realized. Because when the system has an inverter load, the DC load current includes the high switching frequency components, it will be impossible to use directly the DC load current for the feed-forward control. Therefore, the treatment of the DC load current for the feed-forward control is also investigated.

	AC-Side Current Waveform Improvement of Single-Phase Rectifiers Using a Triple-Frequency PWM Scheme By MIYASHITA Osamu; NAGASHIMA Norihiro; YOSHIDA Toshiya; OHGOE Yasuharu	[View] [Download]
Abstract: This paper proposes and discusses single-phase rectifiers with a triple-frequency pulsewidth modulation (PWM) scheme. The rectifiers consist of high-, medium-, and low-power sub-converters operated at low, medium, and high frequencies, respectively. The proposed rectifier can equivalently operate as one rectifier that delivers the highest power at the highest frequency defined in the triple-frequency PWM rectifier. A parallel type of the rectifier is mainly discussed in this paper. A cascade type is also considered. In both configurations, current harmonics on the ac-side are greatly reduced, and an approximate unity power-factor is obtained. Experimental and simulation results verify the usefulness of the method.

	An Active Filter for Eliminating Harmonics and Interharmonics in the Input Current to an AC Voltage Controller for Refrigeration and Air-conditioning Applicatio By SHAMMAS Noel; TENNAKOON Sarath; JODEYRI Hassan; LEHAL Tarinderjit	[View] [Download]
Abstract: Energy saving motor controllers for refrigeration and air-conditioning applications operate at the minimum input power point by finding the optimum firing angle of the thyristors in the motor controller. Consequently, the distorted input current contains harmonics, sub-harmonics, and interharmonics whose frequencies change with the motor speed. Therefore passive filters are not suitable and the best solution is to use an active filter. A single phase active filter with simple constant frequency switching is able to reduce waveform distortion by eliminating a sufficient range of frequencies and offers a low cost solution. Theoretical analysis of the full-bridge and half-bridge topologies led to the development of design equations and curves. Simulation of a half-bridge active filter confirmed the design equations

	Buck-Boost Integrated Forward Converter By NIE Zhong; EMADI Ali	[View] [Download]
Abstract: An integrated converter is a synthesized converter based on the overall system integration, which is simplified by the system objective and can implement the system functions similar to the discrete converters. An integrated converter consists of converter sets; each converter set has a special function defined by the designer. A family of DC/DC buck boost based integrated rectifier with two active switches can be derived by the integration concept. In this paper, buck boost Forward integrated converter is proposed and fully explained. Five different operating modes, formulation, waveforms, output/input voltage ratio characteristics, small-signal models, transfer function, simulation results, and experimental verification are presented in detail.

	Circuit Oriented Average Modeling of Switching Power Converters By CUADROS Carlos	[View] [Download]
Abstract: Effective features from various modeling methods are complemented with analog simulation, series expansion practices and heuristic guidelines to get a systematic and versatile method to derive accurate and efficient Circuit Oriented Large Signal Average Models (COLSAMs) that approximate the slow dynamics manifold of the relevant state variables for PWM dc to dc and three-phase to dc power converters. These COLSAMs can cover both CCM and DCM operation and they are much cheaper, computation wise, than switching models. From the converter’s operating waveforms and topological stages this method leads primarily to simple and effective input-output oriented models that represent transfer as well as loading characteristics of the converter. Since these models are time invariant and continuous they can be linearized at an operating point to obtain small-signal models that approximate the dynamics of the original PWM system around an orbit. The models are primarily intended for software circuit simulators to take advantage of intrinsic features such as transient response, linearization, etc. without changing simulation environment, but many mathematics simulator can be used with the set of equations obtained by applying Kirchoff’s laws to the COLSAMs. The latter also provide physical insight to help with power stage and control design. A new average model to cover both CCM and DCM operation for the ZVS Full-Bridge PWM converter was developed and its high accuracy is verified with simulations from a switching behavioral model for several component values.

	Combined Electrical and Thermal Modeling in Power Supplies By MALYNA D.V.; FERREIRA J.A.; BAUER P.; DUARTE J.L.; HENDRIX M.A.M.; VANDENPUT A.J.A.; DE JONG E.C.W.	[View] [Download]
Abstract: The integrated simulation of electrical and thermal behavior of an AC-DC power supply is investigated. The approach is based on a conventional electric circuit model combined with a thermal resistive model, processed by a unique simulation program that provides fast steady state calculations. Results are critically compared to actual thermal measurements.

	DESIGN OF PFC AC/DC FLYBACK CONVERTER FOR LOW VOLTAGE APPLICATIONS By KYRITSIS Anastasios; PAPANIKOLAOU Nikolaos; TATAKIS Emmanuel	[View] [Download]
Abstract: This paper presents an appropriate design scheme for a high–efficiency high–power–factor AC/DC flyback converter with low output voltage. For this purpose the voltage and current stresses as well as the power losses on the switches are going to be analytically calculated. The whole theoretical analysis concludes to a design criterion concerning the selection of the transformer turns ratio, so as to minimize the semiconductor losses. Finally, simulation and experimental results are presented, validating the theoretical analysis and the proposed design scheme.

	Digital Control Methods for Current Sharing of Interleaved Synchronous Buck Converter By UNDELAND Tore M.; ANDREASSEN PaL	[View] [Download]
Abstract: The quasi square wave operation of the synchronous buck with interleaved parallel outputs has been successfully used in low voltage high current DC-supply for microprocessors. This topology results in fast transient response and high power density.In this paper, two digital control strategies for current sharing control are tested by simulation in Simulink, and tested in the laboratory. The digital current control methods are tested using a 150 MHz Texas Instrument TMS320F2812 DSP and studied with regard to the current reference step response.The results from the simulations and the experiments show that it is possible to increase control performance by using a predictive controller but that this would require extra cost and design effort to implement a low noise and high bandwidth measurement hardware on the output voltage.

	Fast Waveform and EMI Calculation of a PFC Converter By LUeRKENS Peter	[View] [Download]
Abstract: Waveforms of switched mode converters are usually determined by simulation in the time domain. In particular, off-line converters, which change duty cycle and/or switching frequency cyclically, do not allow the calculation of the behavior by assuming an average operating point, representative for all time instances during a mains cycle. This leads to the necessity to simulate a time span, which covers at least one mains cycle. On the other hand, time domain simulations by circuit simulators need small integration steps to achieve numerical stability, especially when the switching frequency of the converter is high. The result is a long simulation time.This paper describes an efficient method, producing complex converter waveforms by using template functions. In addition to current and voltage waveforms a fast estimation of the EMI level is produced. Measurements show the validity.

	Mains harmonic reduction circuits using non linear inductances By SCHETTERS Kees; DUeRBAUM Thomas; KUeBRICH Daniel	[View] [Download]
Abstract: Regulations like IEC 1000-3-2 impose limits on the line input current harmonics. Passive solutions to obtain mains harmonic reduction still dominate the consumer and PC market segment. Some inductors used in practical designs operate in the saturation region even at power levels to be tested for compliance. On the other hand, nearly all publications dealing with design of the passive MHR circuits assume a linear inductor. This paper investigates the usefulness of non linear inductors in passive MHR circuits by extracting the nonlinearity, measuring the compliance, modeling the inductor by an appropriate fit function and extrapolating the design to other power levels.

	MATHEMATICAL MODELLING AND DIGITAL CONTROL FOR POWER SUPPLIES OF CURRENT PULSED FOR WELDING MACHINE By CORRÊA JoãO; BOLHOSA Denis; PEREIRA Aldo; JUNIOR Petronio	[View] [Download]
Abstract: This work presents the development of a welding machine MIG/MAG (Metal Gás Inerte/Metal Active Gás) whose exit current is pulsed, the control was developed starting from a simplified mathematical model, what allowed the elaboration of a program of simpler digital control. The mathematical model was based on equivalent circuits of the components of the process. These equivalent circuits allowed to characterize a variable of the process denominated stick out, this was modeled as being a variable resistance, allowing the control of the welding as being function just of that resistance. The circuits were simulated in MATLAB/SIMULINK and their data were compared with experimental results, allowing to validate the proposed model. The digital control was developed with base in the acquisition of current data and voltage through sensor, and digital processed using the microcontroller PIC16F877. The project of the potency circuit was elaborated with characteristics similar to the welding machines conventional and commercially available. An implementation was developed in the form of a prototype in real scale with use of power structures and IGBT, with capacity of up to 300 amperes. The experimental results are compared with the theoretical data, the one that allows do one analyzes comparative and of acting of the system.

	MINIMIZATION OF THE SOURCE CURRENT DISTORTION IN SYSTEMS WITH SINGLE-PHASE ACTIVE POWER FILTERS AND ADDITIOANL FASSIVE FILTER DESIGNED BY GENETIC ALGORITHMS By KOSIOROWSKI Stanislaw; SWIATEK Boguslaw; KLEMPKA Ryszard	[View] [Download]
Abstract: The paper presents the results of the tests of a laboratory single-phase active filter which employs intelligent power module. The filter control system based on artificial neural networks is described. In order to mitigate the high friquency component of the current a passive filter was designed. The results of simulation tests based on genetic algorithms were used for the selection of the parameters of the filter elements. The results of the simulation and experimental tests obtained from laboratory arrangement are presented.

	Modeling the LIFT DC-DC Converter in the State Space Discrete Time By RIVA Marco; MARANESI Piero; BELLONI Federico	[View] [Download]
Abstract: The lift technique has been widely described in the literature by Luo et al. They focus on the steady state operation of the power cells mainly. On the other side, a complete dynamic characterisation is missing up to now.This paper provides the dynamic models of the lift power cells and converters.Capacitive switching characterizes their operation and modeling can be obtained with high accuracy adopting the same procedures that are well suited for describing the dynamic behaviours of other switched capacitor circuits, f.i. the Cockcroft-Walton multipliers. The approach is the state space discrete timeprotocol with some additional tricks for the precise evaluation of the sampled data values and of the matrices A, B, C and D.The paper describes how to derive the coefficients of the state space matrices of the Luo lift converter and makes reference to a software tool for the automatic analysis.The transfer function matrix of the power cell provides six transfer functions that are plotted versus frequency.After assigning a suitable feedback network, the converter is characterized by four closed loop transfer functions. Forecasts of the frequency responses are compared with experimental results.

	Steady-state Time-domain Simulation of Power Converters Using a Differentiation Matrix By COSTA Fabiano; FERNANDES Darlan; NAIDU S. R.; ALMEIDA L. A. L.	[View] [Download]
Abstract: A technique for simulating the steady-state response of power converters has been proposed in this paper. The technique is based on the definition of a differentiation matrix. It converts differential into algebraic equations and provides the signals in the time domain. This allows obtain directly the steady-state responses of power converters without to generate all the previous transients points. The Differentiation matrix is still simple to apply and is rapidly convergent. The accuracy of the technique has been established and the responses of three circuits with soft-switching and feedback control has been presented.

	SWITCHING CELL OPTIMISATION MINIMISING THE COMMON MODE CURRENT FOR THE POWER FACTOR CORRECTOR By MAGNON Didier; LE BUNETEL Jea; BALCELLS Josep; PUZO Antoine; GONZALEZ David; BREHAUT Stephane; GAGO Javier	[View] [Download]
Abstract: This paper presents the problem of common mode electromagnetic interference. We study the common mode current phenomena on a single converter like the Boost converter. This converter operates in power factor corrector mode. The advantage of this structure is the presence of one switching commutation cell only. This limits the number of voltage pollution source creating common electromagnetic interference. The elements that intervene in the mechanic of pollution, are switching frequency, the rise and fall time of switches, the parasitic capacitance between electric circuit ant the ground plan, the floating voltage of the converter. In this paper, we are interested in the two last points.

	The Realisation of the Control of an AC/DC Converter Using a Motor Control DSP By MORRISON Richard; POWER Daithi; EGAN Michael	[View] [Download]
Abstract: A Digital Signal Processor (DSP) controlled, isolated, power factor corrected, two-stage ac/dc converter is presented. All the control functionality is implemented using the 28 pin, Analog Devices DSP, ADMCF328, which is referenced to the secondary. The primary control voltages are magnetically sensed. The dc/dc stage control voltages are sensed using the AD7811 ADC. The internal serial port of this device is used to serially transmit its output data to the DSP.

	Zero-Crossing Distortion in Grid-Coupled AC-DC Converters By RYCKAERT Wouter; MELKEBEEK Jan; DE GUSSEME Koen; DE VLEESCHAUWER Vera; VAN DE SYPE David	[View] [Download]
Abstract: Zero-crossing distortion in modern rectifiers and inverters may have different causes: the commutation dead time, the use of diode bridge rectifiers, discontinuities in the PWM-generation. . . In this paper another cause of zero-crossing distortion is analysed: when a security dead time is inserted between the gate signals of two switches in the same leg, some line current distortion may appear close to the zero-crossing of the line current due to errors in the sampling of that line current. An overview of the sampling requirements for a digitally controlled full-bridge ac-dc converter is given and a detailed analysis of the line current distortion is performed. The analysis is verified with experimental waveforms and a solution is proposed to decrease the linecurrent distortion.