EPE Association: EPE 1999 - Topic 10a: EMC

EPE 1999 - Topic 10a: EMC
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1999 - Conference > EPE 1999 - Topic 10: SYSTEMS ENGINEERING > EPE 1999 - Topic 10a: EMC

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   An Innovative Gate Drive to Control Electromagnetic Perturbations...
By F. Costa; E. Labouré; F. Wilmot; F. Forest [View]
[Download]

Abstract: The high frequency electromagnetic perturbations emitted by a static converter can be reduced by different methods : adding filters and shieldings is the most common one, decreasing dV/dt and dI/dt with soft switching techniques [1] is another solution. Gate drive control is also a valuable solution [2], [3]. The focus of this paper concerns this late point. It has been noticed that high frequency perturbations (range 1-30MHz) are entirely determined by the switching transients [4]. So an improved gate drive has been developed to control accurately the current shape during switching, in order to get a hardly decreasing perturbation spectrum.

   Conducted EMI Optimization by Variable Frequency PWM Techniques
By M. Cacciato; A. Consoli; G. Scarcella; A. Testa [View]
[Download]

Abstract: A common problem to face in designing any electric motor drive today consists in forcing the generated electromagnetic emissions to stay inside the boundaries stated by recently introduced electromagnetic compatibility standards. Conventional design approaches cope with such a problem by adding suitable filters on standard power stages. Alternatively, specific power stage design techniques can be applied allowing to obtain better results in terms of power converter costs, reliability and sizes. Along this way, a viable alternative to the EMC filters approach consists in exploiting optimized PWM strategies, allowing to reduce the generated electromagnetic pollution. The present paper points out the advantages in using Variable Frequency Pulsewidth Modulation Techniques instead of conventional, fixed frequency approaches, in terms of generated high frequency stray current components, that are the main responsible of conducted electromagnetic emissions. Particularly, an experimental comparative evaluation is presented between conventional modulation techniques and different variable frequency approaches.

   Design for EMC in Switched-Mode Power Supplies
By P. Vallittu; T. Laurinen; I. Nisonen; S. Ritamäki [View]
[Download]

Abstract: Our paper gives some design guidelines for efficient EMC design in a typical switched-mode power supply configuration. In practice, trial-and-error is inevitable during EMC design process. In this paper, instead of only presenting some basic EMC design rules we also present some good design tips which have been learned as a result of trial-and-error. An AC/DC rectifier having a typical medium power level topology, is used as a practical case example.

   Determination of DI/DT Allowing to a Solid Switch to Commute on t...
By F. Guitton; D. Magnon [View]
[Download]

Abstract: all applications using solid switches to commute the mains require the addition of input filters to limit the EMI within the standard level. We will present a theoretical study of the di/dt on linear, exponential and sine waveforms, so that conducted EMI do not exceed the standard, without any mains filter. The results are then applied successfully, for the NF EN 55014 standard, to an ASDÆË cell built around a ¡§normally-on¡¨ GTO.

   Effectiveness of Supply Decoupling Capacitors for Digital Circuits
By J. Balcells; J. Gago; D. González [View]
[Download]

Abstract: A model to assess EMI decoupling effectiveness of capacitors used in the supply of digital circuits is obtained and validated. Experimental results show that the optimal value for the decoupling capacitor depends on the series inductance of the decoupling circuit and also of the internal capacitance of the digital device.

   Electromagnetic and Acoustic Emissions From a Digitally Controlle...
By L. Xu; Z.Q. Zhu; D. Howe [View]
[Download]

Abstract: The electromagnetic interference and the radiated acoustic noise from a microprocessor-controlled induction machine are investigated, with particular reference to comparing the influence of PWM strategies, viz. space vector and random PWM, with direct torque control. In contrast to space vector PWM which results in concentrated harmonic spectrum and tonal acoustic noise emission, random PWM and direct torque control strategy result in similar wideband harmonic spectra and indeed less irritating atonal acoustic noise. However, they produce almost identical conducted and radiated EMI spectra, on which it was found that there exist dominant discrete peaks due to the energy concentrated into discrete bands by the action of periodic signals on the external and internal buses of the microprocessor system. A technique, referred to as software waiting loop length control (SWLLC), is proposed to reduce the radiated EMI from digital PWM drive system. By randomly changing the length of the software waiting loops, discrete EMI components can be spread across a larger frequency range. Using this technique, significant reduction of radiated interference levels has been achieved in a typical PWM drive system.

   EMC Filter to Suppress Travelling Waves on Inverter-Motor Power Lines Between Inverter and Motor
By P. Feuerstack; B. Orlik [View]
[Download]

Abstract: Power converters for motor drives with fast switching semiconductors and a high pulse frequency allow motors of almost ideal sinusoidal shape, but the voltage applied to the motor contains a lot of harmonics. Besides the resulting EMC problems it comes to an additional stress on the coil isolation due to the high du/dt of the motor voltage. There is an intensification of this effect, if the motor is connected to the inverter with an electrical long (e.g. 100 m.) power line, because the voltage blocks generated by the converter are reflected on both ends of the line. The result is an HF oscillation on the line after each switching activity of one of the power semiconductors, fading away in a slow balancing process. A second effect of the reflections are overvoltage peaks at the motor terminals of up to the double of the dc-link voltage. This paper deals with EMC filters to avoid the reflections at at least one end of the inverter motor power line. The filters work as a transmission line termination according to the HF-TEM theory, the aim is to transfer the voltage blocks to the motor with only a minimum of deformation, and to reduce the overvoltage at the motor terminals.

   EMI Suppression Techniques Comparison in a AC/DC PWM Switching Converter with PFC to be used in Linear Power Systems
By F. P. Ridao; J. M. Carrasco; L. G. Franquelo [View]
[Download]

Abstract: A special low EMI switching power supply has been designed and mounted in this paper to be used in a Linear Power Amplifier. Conducted EMI interference has been measured and compared with a typical not regulated power supply. New interference suppression techniques have been included in this prototype based on a special power circuit design, filtering and shielding, that show excellent performance in the suppression of EMI interference.

   Implementation of Low Cost Current Probes for Conducted EMI Interface Measure in Power Systems
By F. P. Ridao; J. M. Carrasco; E. Galván; L. G. Franquelo [View]
[Download]

Abstract: In this work, three complementary low cost current probes have been designed and implemented for conducted interference measurement in the range between 3kHz and 300MHz. Current probes are specially useful in common mode and differential mode current measurement in switching power converters. In this paper, these three current probes are characterised and compared with very expensive commercial probes.

   Parasitic Currents in PWM Voltage Inverter-Fed Asynchronous Motor Drives
By I. Dolezel; J. Škramlík; V. Valouch [View]
[Download]

Abstract: The paper deals with analysis of the common and differential mode currents in a system consisting of the transistor PWM inverter, a long cable and an induction motor. Several representations of the motor and the cable suitable for determining both steady state and transient responses in a wide range of frequencies (tens kHz-tens MHz) have been proposed in common with finding the transfer functions of individual parts of these models in the particular modes. The results are compared with data obtained from a lot of experiments and simulations.

   PFC Full Bridge Rectifier EMI Forecast Analysis
By J. C. Crebier; M. Brunello; J. P. Ferrieux [View]
[Download]

Abstract: Switched mode power supplies must comply with EMC standards. A new forecast method is proposed to study EMI of PFC boost derived rectifiers. Based on frequency domain analysis it allows to win computer time and memory. It is applied to the single phase full bridge rectifier operating in CCM with a PWM control strategy. The method is validated with time domain simulations and practical results. Its interest is emphasised with a filter design procedure.

   Positive Line Inductance Effects on the Harmonic Content Limiting the Single-Phase Thyristor Rectifier Adoptability in the Respect of the Low Frequency EMC Stan
By Luca Ferraris; G. Griva [View]
[Download]

Abstract: In this paper, the problem of Low Frequency harmonic currents generated by single-phase SCR rectifiers, supplying a resistive load, is analyzed. In particular, the attention is focused on the constraints in the utilization of such converters due to the respect of the EMC Standards, taking into account the effects of the line inductance. The results presented in the paper show that the presence of the line inductance increases significantly the power that can be transferred to the load, without exceeding the harmonic current limits prescribed by the EN 61000-3-2 Standard.

   Reduction of Magnetic Field Strength Generated by an SMPS
By M. Albach; G. Sauerländer [View]
[Download]

Abstract: The replacement of the 50Hz transformer in audio sets by a switched mode power supply requires that the magnetic field strength generated by the high frequency operated converter becomes extremely low, especially in the LW and MW frequency range. In this paper the noise sources are analytically characterized and measures for the noise level reduction are described. Considerable improvements are achieved by the proper design of the magnetic components and by means of a new pcb technology (Buried Jumper Technology).

   Reduction of Radiated Emissions from Power Electronics Converters
By M. Youssef; J. Roudet; Y. Marechal [View]
[Download]

Abstract: The present paper deals with the problem of reduction electromagnetic interference of power converters. The radiated field is proportional to the current slope (di/dt) during switching. Presence of a ground plane under the power circuit and using soft switching mode reduce di/dt and consequently the radiated field. The purpose of this paper is to evaluate this decreasment. For all configurations comparisons of measured and computed fields are reported.

   Separating Common Mode and Differential Mode Noise in EMI Measurements
By A. Nagel; R. W. De Doncker [View]
[Download]

Abstract: The separation of differential mode and common mode noise in EMI analysis is a well known procedure which is usefull especially for the analysis and the understanding of interference phenomena of power converters. However, seperating both components is rarely done during measurements. Therefore, two different approaches are developed and evaluated in this paper to realize seperated common mode and differential mode measurements.

   Simulation of Conducted Electromagnetic Interference of Inverter-Fed Induction Motors
By E. Hoene; W. John; H. Reichl [View]
[Download]

Abstract: The present paper deals with the development of a simulation method for conducted electromagnetic interference produced by inverter-fed induction motors. Power electronic systems generate impulse currents through the power leads causing serious electromagnetic interference problems. In the proposed approach simplified models for high frequency behaviour of active and passive components are introduced and the parameterization of the models is described. A new measurement method is presented, which allows to characterize the properties of passive networks and components. The measurement setup enables potential free measurements in the circuit without significant influence on the device under test up to the frequency of 30MHz. The measurement results are used to generate simulation models of the examined system. With these models the effect of different filter components can be evaluated in the simulator. Experimental measurements are compared with simulation results and discussed.

EPE 1999 - Topic 10a: EMC
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1999 - Conference > EPE 1999 - Topic 10: SYSTEMS ENGINEERING > EPE 1999 - Topic 10a: EMC
	[return to parent folder]

	An Innovative Gate Drive to Control Electromagnetic Perturbations... By F. Costa; E. Labouré; F. Wilmot; F. Forest	[View] [Download]
Abstract: The high frequency electromagnetic perturbations emitted by a static converter can be reduced by different methods : adding filters and shieldings is the most common one, decreasing dV/dt and dI/dt with soft switching techniques [1] is another solution. Gate drive control is also a valuable solution [2], [3]. The focus of this paper concerns this late point. It has been noticed that high frequency perturbations (range 1-30MHz) are entirely determined by the switching transients [4]. So an improved gate drive has been developed to control accurately the current shape during switching, in order to get a hardly decreasing perturbation spectrum.

	Conducted EMI Optimization by Variable Frequency PWM Techniques By M. Cacciato; A. Consoli; G. Scarcella; A. Testa	[View] [Download]
Abstract: A common problem to face in designing any electric motor drive today consists in forcing the generated electromagnetic emissions to stay inside the boundaries stated by recently introduced electromagnetic compatibility standards. Conventional design approaches cope with such a problem by adding suitable filters on standard power stages. Alternatively, specific power stage design techniques can be applied allowing to obtain better results in terms of power converter costs, reliability and sizes. Along this way, a viable alternative to the EMC filters approach consists in exploiting optimized PWM strategies, allowing to reduce the generated electromagnetic pollution. The present paper points out the advantages in using Variable Frequency Pulsewidth Modulation Techniques instead of conventional, fixed frequency approaches, in terms of generated high frequency stray current components, that are the main responsible of conducted electromagnetic emissions. Particularly, an experimental comparative evaluation is presented between conventional modulation techniques and different variable frequency approaches.

	Design for EMC in Switched-Mode Power Supplies By P. Vallittu; T. Laurinen; I. Nisonen; S. Ritamäki	[View] [Download]
Abstract: Our paper gives some design guidelines for efficient EMC design in a typical switched-mode power supply configuration. In practice, trial-and-error is inevitable during EMC design process. In this paper, instead of only presenting some basic EMC design rules we also present some good design tips which have been learned as a result of trial-and-error. An AC/DC rectifier having a typical medium power level topology, is used as a practical case example.

	Determination of DI/DT Allowing to a Solid Switch to Commute on t... By F. Guitton; D. Magnon	[View] [Download]
Abstract: all applications using solid switches to commute the mains require the addition of input filters to limit the EMI within the standard level. We will present a theoretical study of the di/dt on linear, exponential and sine waveforms, so that conducted EMI do not exceed the standard, without any mains filter. The results are then applied successfully, for the NF EN 55014 standard, to an ASDÆË cell built around a ¡§normally-on¡¨ GTO.

	Effectiveness of Supply Decoupling Capacitors for Digital Circuits By J. Balcells; J. Gago; D. González	[View] [Download]
Abstract: A model to assess EMI decoupling effectiveness of capacitors used in the supply of digital circuits is obtained and validated. Experimental results show that the optimal value for the decoupling capacitor depends on the series inductance of the decoupling circuit and also of the internal capacitance of the digital device.

	Electromagnetic and Acoustic Emissions From a Digitally Controlle... By L. Xu; Z.Q. Zhu; D. Howe	[View] [Download]
Abstract: The electromagnetic interference and the radiated acoustic noise from a microprocessor-controlled induction machine are investigated, with particular reference to comparing the influence of PWM strategies, viz. space vector and random PWM, with direct torque control. In contrast to space vector PWM which results in concentrated harmonic spectrum and tonal acoustic noise emission, random PWM and direct torque control strategy result in similar wideband harmonic spectra and indeed less irritating atonal acoustic noise. However, they produce almost identical conducted and radiated EMI spectra, on which it was found that there exist dominant discrete peaks due to the energy concentrated into discrete bands by the action of periodic signals on the external and internal buses of the microprocessor system. A technique, referred to as software waiting loop length control (SWLLC), is proposed to reduce the radiated EMI from digital PWM drive system. By randomly changing the length of the software waiting loops, discrete EMI components can be spread across a larger frequency range. Using this technique, significant reduction of radiated interference levels has been achieved in a typical PWM drive system.

	EMC Filter to Suppress Travelling Waves on Inverter-Motor Power Lines Between Inverter and Motor By P. Feuerstack; B. Orlik	[View] [Download]
Abstract: Power converters for motor drives with fast switching semiconductors and a high pulse frequency allow motors of almost ideal sinusoidal shape, but the voltage applied to the motor contains a lot of harmonics. Besides the resulting EMC problems it comes to an additional stress on the coil isolation due to the high du/dt of the motor voltage. There is an intensification of this effect, if the motor is connected to the inverter with an electrical long (e.g. 100 m.) power line, because the voltage blocks generated by the converter are reflected on both ends of the line. The result is an HF oscillation on the line after each switching activity of one of the power semiconductors, fading away in a slow balancing process. A second effect of the reflections are overvoltage peaks at the motor terminals of up to the double of the dc-link voltage. This paper deals with EMC filters to avoid the reflections at at least one end of the inverter motor power line. The filters work as a transmission line termination according to the HF-TEM theory, the aim is to transfer the voltage blocks to the motor with only a minimum of deformation, and to reduce the overvoltage at the motor terminals.

	EMI Suppression Techniques Comparison in a AC/DC PWM Switching Converter with PFC to be used in Linear Power Systems By F. P. Ridao; J. M. Carrasco; L. G. Franquelo	[View] [Download]
Abstract: A special low EMI switching power supply has been designed and mounted in this paper to be used in a Linear Power Amplifier. Conducted EMI interference has been measured and compared with a typical not regulated power supply. New interference suppression techniques have been included in this prototype based on a special power circuit design, filtering and shielding, that show excellent performance in the suppression of EMI interference.

	Implementation of Low Cost Current Probes for Conducted EMI Interface Measure in Power Systems By F. P. Ridao; J. M. Carrasco; E. Galván; L. G. Franquelo	[View] [Download]
Abstract: In this work, three complementary low cost current probes have been designed and implemented for conducted interference measurement in the range between 3kHz and 300MHz. Current probes are specially useful in common mode and differential mode current measurement in switching power converters. In this paper, these three current probes are characterised and compared with very expensive commercial probes.

	Parasitic Currents in PWM Voltage Inverter-Fed Asynchronous Motor Drives By I. Dolezel; J. Škramlík; V. Valouch	[View] [Download]
Abstract: The paper deals with analysis of the common and differential mode currents in a system consisting of the transistor PWM inverter, a long cable and an induction motor. Several representations of the motor and the cable suitable for determining both steady state and transient responses in a wide range of frequencies (tens kHz-tens MHz) have been proposed in common with finding the transfer functions of individual parts of these models in the particular modes. The results are compared with data obtained from a lot of experiments and simulations.

	PFC Full Bridge Rectifier EMI Forecast Analysis By J. C. Crebier; M. Brunello; J. P. Ferrieux	[View] [Download]
Abstract: Switched mode power supplies must comply with EMC standards. A new forecast method is proposed to study EMI of PFC boost derived rectifiers. Based on frequency domain analysis it allows to win computer time and memory. It is applied to the single phase full bridge rectifier operating in CCM with a PWM control strategy. The method is validated with time domain simulations and practical results. Its interest is emphasised with a filter design procedure.

	Positive Line Inductance Effects on the Harmonic Content Limiting the Single-Phase Thyristor Rectifier Adoptability in the Respect of the Low Frequency EMC Stan By Luca Ferraris; G. Griva	[View] [Download]
Abstract: In this paper, the problem of Low Frequency harmonic currents generated by single-phase SCR rectifiers, supplying a resistive load, is analyzed. In particular, the attention is focused on the constraints in the utilization of such converters due to the respect of the EMC Standards, taking into account the effects of the line inductance. The results presented in the paper show that the presence of the line inductance increases significantly the power that can be transferred to the load, without exceeding the harmonic current limits prescribed by the EN 61000-3-2 Standard.

	Reduction of Magnetic Field Strength Generated by an SMPS By M. Albach; G. Sauerländer	[View] [Download]
Abstract: The replacement of the 50Hz transformer in audio sets by a switched mode power supply requires that the magnetic field strength generated by the high frequency operated converter becomes extremely low, especially in the LW and MW frequency range. In this paper the noise sources are analytically characterized and measures for the noise level reduction are described. Considerable improvements are achieved by the proper design of the magnetic components and by means of a new pcb technology (Buried Jumper Technology).

	Reduction of Radiated Emissions from Power Electronics Converters By M. Youssef; J. Roudet; Y. Marechal	[View] [Download]
Abstract: The present paper deals with the problem of reduction electromagnetic interference of power converters. The radiated field is proportional to the current slope (di/dt) during switching. Presence of a ground plane under the power circuit and using soft switching mode reduce di/dt and consequently the radiated field. The purpose of this paper is to evaluate this decreasment. For all configurations comparisons of measured and computed fields are reported.

	Separating Common Mode and Differential Mode Noise in EMI Measurements By A. Nagel; R. W. De Doncker	[View] [Download]
Abstract: The separation of differential mode and common mode noise in EMI analysis is a well known procedure which is usefull especially for the analysis and the understanding of interference phenomena of power converters. However, seperating both components is rarely done during measurements. Therefore, two different approaches are developed and evaluated in this paper to realize seperated common mode and differential mode measurements.

	Simulation of Conducted Electromagnetic Interference of Inverter-Fed Induction Motors By E. Hoene; W. John; H. Reichl	[View] [Download]
Abstract: The present paper deals with the development of a simulation method for conducted electromagnetic interference produced by inverter-fed induction motors. Power electronic systems generate impulse currents through the power leads causing serious electromagnetic interference problems. In the proposed approach simplified models for high frequency behaviour of active and passive components are introduced and the parameterization of the models is described. A new measurement method is presented, which allows to characterize the properties of passive networks and components. The measurement setup enables potential free measurements in the circuit without significant influence on the device under test up to the frequency of 30MHz. The measurement results are used to generate simulation models of the examined system. With these models the effect of different filter components can be evaluated in the simulator. Experimental measurements are compared with simulation results and discussed.