EPE Association: EPE 2013 - DS2f: Energy Efficiency, Energy Savings Issues

EPE 2013 - DS2f: Energy Efficiency, Energy Savings Issues
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 13: Energy efficiency, energy saving issues in system components > EPE 2013 - DS2f: Energy Efficiency, Energy Savings Issues

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   A New Technique for Photovoltaic Energy Management System
By Natchpong HATTI, Surasak NUILERS, Jirayut PHONTIP [View]
[Download]

Abstract: This paper proposes the new technique for stand-alone PV (Photovoltaic) energy management system. The proposed technique utilizes the voltage controlled MPPT (Maximum Power Point Tracking) and the level-shifted PWM modulation. The MPPT tracks the maximum power point (MPP) of the PV by tracking the PV voltage. Then the output signal of the voltage controlled MPPT is modulated by the level-shifted PWM modulation. Each level of the level-shifted PWM is used for a particular energy storage element, for example, the highest level is used for charging the battery, whereas the lowest level is used for discharging the battery. The proposed technique makes the PV produce the power at its MPP while the load can draw the power from the system without interruption. The proposed system would have higher reliability, higher efficiency, and longer battery life-time than the conventional system. The design technique is presented in this paper. Then the proposed idea is verified by a 120-W experimental system.

   An Energy Saver for Tramway Networks using Double Active Bridge and Super-capacitors
By Julien MORAND, Dominique BERGOGNE, Pascal BEVILACQUA, Ali SARI, Pascal VENET [View]
[Download]

Abstract: An industrial energy saver system for transportation networks is designed using analytical models and simulation. This off-board energy saver uses the high power capabilities of supercapacitors and an innovative soft switching topology with a nanocrystalline insulation transformer. A laboratory demonstrator is presented, life expectancy of the storage unit is estimated. Field measurements on the industrial product demonstrates the concept.

   Analysis and Improvement of High Efficiency and Low Cost Drive System based on Direct Torque Control
By Wei XIE, Gurakuq DJAKU, Xiaocan WANG, Dieter GERLING, Ralph KENNEL [View]
[Download]

Abstract: In this paper, an optimal reference stator flux strategy is proposed to improve the drive system efficiency under direct torque control (DTC). A novel low cost interior permanent magnet synchronous machine (IPMSM) is introduced and used. Based on the easily implementable loss model (LM), the controllable electrical losses which consist of copper loss and iron loss have been minimized under optimal stator flux. Based on finite element method (FEM), the harmonics which is produced by inverter is injected into FEM model; the nonlinear machine parameters and its influence to LMC are also considered. The drive performance’s effectiveness of the proposed scheme is validated in experiment.

   Component selection tool to maximize overall energy conversion efficiency in a pumping system
By Jussi TAMMINEN, Antti KOSONEN, Tero AHONEN, Jero AHOLA, Annette MUETZE, Paula IMMONEN, Jukka TOLVANEN [View]
[Download]

Abstract: Often, the components of a pumping system are not selected from the perspective of the total system, as the individual components are selected using different programs. In this paper, a selection tool that optimizes the energy conversion efficiency of a pumping system according to actual process requirements is introduced. The tool requires only the catalog data of the components. Its application to an industrial pump system sizing, and thereby, to a component selection problem is demonstrated.

   DC Collector Grid Configurations for Large Photovoltaic Parks
By Hafiz Abu Bakar SIDDIQUE, Syed Mansoor ALI, Rik W. DE DONCKER [View]
[Download]

Abstract: This paper presents a theoretical efficiency comparison among the conventional ac collector grid configuration and two proposed dc collector grid configurations (one with string-pair-level maximum power point (MPP) tracking and one without) in large photovoltaic (PV) parks. A typical sunny day in September is used as a test case to determine the PV array yield. An already validated PV array performance model is used to estimate the expected yield of the PV array for the given environmental and connection conditions. Loss mechanisms in different grid components in the three configurations are discussed and simplified loss models are developed without compromising the accuracy. These components include the inverters, transformers, ac/dc cables and dc-dc converters. The chosen figure of merit is the total efficiency of the components lying between the PV array and the MV/HV transformer that feeds power in the HV grid. A comparison of the total losses helps to identify the configuration that has the potential to operate at higher efficiency and hence, generate more revenues.

   Design and Operation Optimization of a Hybrid Railway Power Substation
By Petronela PANKOVITS, Julien POUGET, Stephane BRISSET, Dhaker ABBES, Benoit ROBYNS [View]
[Download]

Abstract: Railway traffic increases and electricity market liberalization constrain the railway actors to considernew solutions to handle the energy consumption. Hence, a technology change in the railway electricalsystems is considered through the integration of renewable energy sources and storage units. In thiscontext, a relevant methodology is proposed here for optimal design and operation analysis of railwayhybrid power substations. This method is useful for the analysis and improvement of future railwaypower network efficiency.

   ENERGY EFFICIENCY OF THE NEW HOUSEHOLD APPLIANCES
By Ljupcho ARSOV, Slobodan MIRCHEVSKI, Iljaz ILJAZI, Ivana ARSOVA, Marija CUNDEVA [View]
[Download]

Abstract: The paper deals with the influence on the power quality of various new technologies of householdappliances and measurement of their energy efficiency. Using a virtual power quality analyzer, whichenables measurement of all power components according the newest power models and definitions,series of measurements were performed. Details of the measurement of harmonics generation bydifferent domestic appliance technologies are presented, and the energy efficiency of various domesticappliances is estimated by the real electrical energy consumption. This more realistic approach to theenergy efficiency estimation by real power effects may be generalized to other devices, sources ofharmonics.

   Energy-efficient control of induction machines with variable rotor flux
By Rudolf MECKE [View]
[Download]

Abstract: The paper presents the energy saving potential of induction machines by using variable rotor flux instead of commonly used constant flux. The efficiency optimized rotor flux depends on the actual load and speed of the motor. At low load it has to be decreased with reference to a pre-calculated look-up table. This table can be included in a field oriented speed control structure as reference value of the rotor flux. The calculation of optimal rotor flux curves includes the non-linear main inductance, the frequency-dependent rotor resistance and rotor leakage inductance, the speed-dependent iron, friction and windage losses and the motor frequency. This distinguishes this paper from former scientific works. The calculations and measurements are carried out at an 11 kW high-efficiency (efficiency classification IE2) asynchronous machine with 2 pole pairs. An increase in efficiency can be reached below 2/3 of rated torque. The maximum increase is about 35 \% in motor and 45 \% in generator operation mode. The average efficiency improvement is 4,5 \% in motor and 6,0 \% in generator mode. Additionally, the power factor can be improved over the whole load range and the current consumption can be reduced. Energy saving with variable rotor flux is possible in the whole speed range from 10 to 100 Hz.

   High efficiency battery converter with SiC devices for Residential PV systems
By Pham CAM, Teodorescu REMUS, Kerekes TAMAS, Mathe LASZLO [View]
[Download]

Abstract: The demand for high efficiency and higher power density is a challenge for Si-based semiconductorsdue to the physical characteristics of material. These can be overcome by employing wide-band-gapmaterials like SiC. This paper compares a second generator SiC MOSFETs against a normally-onTrench JFETs and theirs performances in a high efficiency battery converter for residentialphotovoltaic systems. The prototypes are 3 kW converters with more than 98\% efficiency and highsimplicity and power density.

   High Efficient Low Harmonic Drives with Integrated Active Filters
By Sergej KALASCHNIKOW [View]
[Download]

Abstract: Energy saving technology for electrical drives becomes high attention. Low harmonic drives reduce losses in the power supply. However, compare to the conventional drives, these have lower efficiency. In this paper the different kinds of adjustable speed low harmonic drives are compared. A new low harmonic drive with an integrated active filter is presented, which shows strengths of the harmonic mitigation technique for electrical drives, based on active filters.

   HYBRID SWITCH USE FOR LIGHT LOAD EFFICIENCY IMPROVEMENT OF A POWER INVETER FOR STAND-ALONE RESIDENTIAL RENEWABLE ENERGY SYSTEM
By Ugur Savas SELAMOGULLARI, Hakan AKCA [View]
[Download]

Abstract: In stand-alone residential renewable energy systems (such as solar and/or fuel cell powered), thepower inverter used for DC-AC transformation will operate at light loads, where its efficiency islower, most of the time during a day. Thus, improving the inverter efficiency at light loads will resultin more efficient use of renewable energy sources. In this study, the use of a parallel IGBT-MOSFETswitch combination and its unique control is analyzed for efficiency improvement at light loadconditions. Experimental results are provided for a half bridge inverter with and without hybridswitch. It is shown that the light load efficiency can be improved with the proposed hybrid switch use.As the use of renewable energy sources is on the rise, even the slightest increase in the inverterefficiency will mean large energy savings overall.

   Inverter Improving Motor Efficiency of Switched Reluctance Motor for Electric Vehicle
By Tadayuki NONAKA, Yoshihiro NAKAZAWA, Kazuhiro OHYAMA [View]
[Download]

Abstract: This paper proposes the new inverter topology which improves the motor efficiency of switched reluctance motor (SRM) for electric vehicle (EV). The SRMs generate the regenerating power even in motoring mode, and the regenerating power flows in both directions of battery and coils. The proposed inverter I – IV can control the flows of regenerating power to improve the motor efficiency.

   OPTIMAL CONTROL OF THE HYBRID EXCITATION SYNCHRONOUS MOTOR AND ITS SUPPLY FOR ELECTRIC VEHICLE APPLICATION
By Rita MBAYED, Georges SALLOUM, Lionel VIDO, Eric MONMASSON, Mohamed GABSI [View]
[Download]

Abstract: This paper presents an optimal current control for the hybrid excitation synchronous motor in electric vehicle application. The whole electric propulsion system is modeled including the battery and converters. The control aims to meet the torque and speed requirements while insuring minimal copper and iron losses as well as inverter and chopper losses. Extended Lagrange multipliers optimization method (Kuhn-Tucker conditions) is used to elaborate analytical expressions for the optimal reference armature and field currents with respect to armature current and voltage constraints. Simulation over the New European Driving Cycle proves that the proposed optimal control leads indeed to the lowest losses.

   Size and performance optimization of filter inductors for highly efficient and compact power conversion circuits
By Thiemo KLEEB, Samuel ARAUJO, Peter ZACHARIAS [View]
[Download]

Abstract: When optimizing a power converter concerning its efficiency and overall size, all circuit elements (semiconductors, magnetic components, capacitors, cooling, etc.) need to be considered in details. The semiconductors and magnetic components are usually responsible for a major part of the system losses, while the magnetic components additionally contribute to the total converter size. The performance of these two components will be investigated in detail in this paper. With WBG devices, an increase of the switching frequency will be a major contributor for compact and efficient converters. Such development needs nevertheless to be confronted with other optimization possibilities for inductors like material choice and loss densities. This publication will address such issues making use of experimental case studies.

EPE 2013 - DS2f: Energy Efficiency, Energy Savings Issues
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 13: Energy efficiency, energy saving issues in system components > EPE 2013 - DS2f: Energy Efficiency, Energy Savings Issues
	[return to parent folder]

	A New Technique for Photovoltaic Energy Management System By Natchpong HATTI, Surasak NUILERS, Jirayut PHONTIP	[View] [Download]
Abstract: This paper proposes the new technique for stand-alone PV (Photovoltaic) energy management system. The proposed technique utilizes the voltage controlled MPPT (Maximum Power Point Tracking) and the level-shifted PWM modulation. The MPPT tracks the maximum power point (MPP) of the PV by tracking the PV voltage. Then the output signal of the voltage controlled MPPT is modulated by the level-shifted PWM modulation. Each level of the level-shifted PWM is used for a particular energy storage element, for example, the highest level is used for charging the battery, whereas the lowest level is used for discharging the battery. The proposed technique makes the PV produce the power at its MPP while the load can draw the power from the system without interruption. The proposed system would have higher reliability, higher efficiency, and longer battery life-time than the conventional system. The design technique is presented in this paper. Then the proposed idea is verified by a 120-W experimental system.

	An Energy Saver for Tramway Networks using Double Active Bridge and Super-capacitors By Julien MORAND, Dominique BERGOGNE, Pascal BEVILACQUA, Ali SARI, Pascal VENET	[View] [Download]
Abstract: An industrial energy saver system for transportation networks is designed using analytical models and simulation. This off-board energy saver uses the high power capabilities of supercapacitors and an innovative soft switching topology with a nanocrystalline insulation transformer. A laboratory demonstrator is presented, life expectancy of the storage unit is estimated. Field measurements on the industrial product demonstrates the concept.

	Analysis and Improvement of High Efficiency and Low Cost Drive System based on Direct Torque Control By Wei XIE, Gurakuq DJAKU, Xiaocan WANG, Dieter GERLING, Ralph KENNEL	[View] [Download]
Abstract: In this paper, an optimal reference stator flux strategy is proposed to improve the drive system efficiency under direct torque control (DTC). A novel low cost interior permanent magnet synchronous machine (IPMSM) is introduced and used. Based on the easily implementable loss model (LM), the controllable electrical losses which consist of copper loss and iron loss have been minimized under optimal stator flux. Based on finite element method (FEM), the harmonics which is produced by inverter is injected into FEM model; the nonlinear machine parameters and its influence to LMC are also considered. The drive performance’s effectiveness of the proposed scheme is validated in experiment.

	Component selection tool to maximize overall energy conversion efficiency in a pumping system By Jussi TAMMINEN, Antti KOSONEN, Tero AHONEN, Jero AHOLA, Annette MUETZE, Paula IMMONEN, Jukka TOLVANEN	[View] [Download]
Abstract: Often, the components of a pumping system are not selected from the perspective of the total system, as the individual components are selected using different programs. In this paper, a selection tool that optimizes the energy conversion efficiency of a pumping system according to actual process requirements is introduced. The tool requires only the catalog data of the components. Its application to an industrial pump system sizing, and thereby, to a component selection problem is demonstrated.

	DC Collector Grid Configurations for Large Photovoltaic Parks By Hafiz Abu Bakar SIDDIQUE, Syed Mansoor ALI, Rik W. DE DONCKER	[View] [Download]
Abstract: This paper presents a theoretical efficiency comparison among the conventional ac collector grid configuration and two proposed dc collector grid configurations (one with string-pair-level maximum power point (MPP) tracking and one without) in large photovoltaic (PV) parks. A typical sunny day in September is used as a test case to determine the PV array yield. An already validated PV array performance model is used to estimate the expected yield of the PV array for the given environmental and connection conditions. Loss mechanisms in different grid components in the three configurations are discussed and simplified loss models are developed without compromising the accuracy. These components include the inverters, transformers, ac/dc cables and dc-dc converters. The chosen figure of merit is the total efficiency of the components lying between the PV array and the MV/HV transformer that feeds power in the HV grid. A comparison of the total losses helps to identify the configuration that has the potential to operate at higher efficiency and hence, generate more revenues.

	Design and Operation Optimization of a Hybrid Railway Power Substation By Petronela PANKOVITS, Julien POUGET, Stephane BRISSET, Dhaker ABBES, Benoit ROBYNS	[View] [Download]
Abstract: Railway traffic increases and electricity market liberalization constrain the railway actors to considernew solutions to handle the energy consumption. Hence, a technology change in the railway electricalsystems is considered through the integration of renewable energy sources and storage units. In thiscontext, a relevant methodology is proposed here for optimal design and operation analysis of railwayhybrid power substations. This method is useful for the analysis and improvement of future railwaypower network efficiency.

	ENERGY EFFICIENCY OF THE NEW HOUSEHOLD APPLIANCES By Ljupcho ARSOV, Slobodan MIRCHEVSKI, Iljaz ILJAZI, Ivana ARSOVA, Marija CUNDEVA	[View] [Download]
Abstract: The paper deals with the influence on the power quality of various new technologies of householdappliances and measurement of their energy efficiency. Using a virtual power quality analyzer, whichenables measurement of all power components according the newest power models and definitions,series of measurements were performed. Details of the measurement of harmonics generation bydifferent domestic appliance technologies are presented, and the energy efficiency of various domesticappliances is estimated by the real electrical energy consumption. This more realistic approach to theenergy efficiency estimation by real power effects may be generalized to other devices, sources ofharmonics.

	Energy-efficient control of induction machines with variable rotor flux By Rudolf MECKE	[View] [Download]
Abstract: The paper presents the energy saving potential of induction machines by using variable rotor flux instead of commonly used constant flux. The efficiency optimized rotor flux depends on the actual load and speed of the motor. At low load it has to be decreased with reference to a pre-calculated look-up table. This table can be included in a field oriented speed control structure as reference value of the rotor flux. The calculation of optimal rotor flux curves includes the non-linear main inductance, the frequency-dependent rotor resistance and rotor leakage inductance, the speed-dependent iron, friction and windage losses and the motor frequency. This distinguishes this paper from former scientific works. The calculations and measurements are carried out at an 11 kW high-efficiency (efficiency classification IE2) asynchronous machine with 2 pole pairs. An increase in efficiency can be reached below 2/3 of rated torque. The maximum increase is about 35 \% in motor and 45 \% in generator operation mode. The average efficiency improvement is 4,5 \% in motor and 6,0 \% in generator mode. Additionally, the power factor can be improved over the whole load range and the current consumption can be reduced. Energy saving with variable rotor flux is possible in the whole speed range from 10 to 100 Hz.

	High efficiency battery converter with SiC devices for Residential PV systems By Pham CAM, Teodorescu REMUS, Kerekes TAMAS, Mathe LASZLO	[View] [Download]
Abstract: The demand for high efficiency and higher power density is a challenge for Si-based semiconductorsdue to the physical characteristics of material. These can be overcome by employing wide-band-gapmaterials like SiC. This paper compares a second generator SiC MOSFETs against a normally-onTrench JFETs and theirs performances in a high efficiency battery converter for residentialphotovoltaic systems. The prototypes are 3 kW converters with more than 98\% efficiency and highsimplicity and power density.

	High Efficient Low Harmonic Drives with Integrated Active Filters By Sergej KALASCHNIKOW	[View] [Download]
Abstract: Energy saving technology for electrical drives becomes high attention. Low harmonic drives reduce losses in the power supply. However, compare to the conventional drives, these have lower efficiency. In this paper the different kinds of adjustable speed low harmonic drives are compared. A new low harmonic drive with an integrated active filter is presented, which shows strengths of the harmonic mitigation technique for electrical drives, based on active filters.

	HYBRID SWITCH USE FOR LIGHT LOAD EFFICIENCY IMPROVEMENT OF A POWER INVETER FOR STAND-ALONE RESIDENTIAL RENEWABLE ENERGY SYSTEM By Ugur Savas SELAMOGULLARI, Hakan AKCA	[View] [Download]
Abstract: In stand-alone residential renewable energy systems (such as solar and/or fuel cell powered), thepower inverter used for DC-AC transformation will operate at light loads, where its efficiency islower, most of the time during a day. Thus, improving the inverter efficiency at light loads will resultin more efficient use of renewable energy sources. In this study, the use of a parallel IGBT-MOSFETswitch combination and its unique control is analyzed for efficiency improvement at light loadconditions. Experimental results are provided for a half bridge inverter with and without hybridswitch. It is shown that the light load efficiency can be improved with the proposed hybrid switch use.As the use of renewable energy sources is on the rise, even the slightest increase in the inverterefficiency will mean large energy savings overall.

	Inverter Improving Motor Efficiency of Switched Reluctance Motor for Electric Vehicle By Tadayuki NONAKA, Yoshihiro NAKAZAWA, Kazuhiro OHYAMA	[View] [Download]
Abstract: This paper proposes the new inverter topology which improves the motor efficiency of switched reluctance motor (SRM) for electric vehicle (EV). The SRMs generate the regenerating power even in motoring mode, and the regenerating power flows in both directions of battery and coils. The proposed inverter I – IV can control the flows of regenerating power to improve the motor efficiency.

	OPTIMAL CONTROL OF THE HYBRID EXCITATION SYNCHRONOUS MOTOR AND ITS SUPPLY FOR ELECTRIC VEHICLE APPLICATION By Rita MBAYED, Georges SALLOUM, Lionel VIDO, Eric MONMASSON, Mohamed GABSI	[View] [Download]
Abstract: This paper presents an optimal current control for the hybrid excitation synchronous motor in electric vehicle application. The whole electric propulsion system is modeled including the battery and converters. The control aims to meet the torque and speed requirements while insuring minimal copper and iron losses as well as inverter and chopper losses. Extended Lagrange multipliers optimization method (Kuhn-Tucker conditions) is used to elaborate analytical expressions for the optimal reference armature and field currents with respect to armature current and voltage constraints. Simulation over the New European Driving Cycle proves that the proposed optimal control leads indeed to the lowest losses.

	Size and performance optimization of filter inductors for highly efficient and compact power conversion circuits By Thiemo KLEEB, Samuel ARAUJO, Peter ZACHARIAS	[View] [Download]
Abstract: When optimizing a power converter concerning its efficiency and overall size, all circuit elements (semiconductors, magnetic components, capacitors, cooling, etc.) need to be considered in details. The semiconductors and magnetic components are usually responsible for a major part of the system losses, while the magnetic components additionally contribute to the total converter size. The performance of these two components will be investigated in detail in this paper. With WBG devices, an increase of the switching frequency will be a major contributor for compact and efficient converters. Such development needs nevertheless to be confronted with other optimization possibilities for inductors like material choice and loss densities. This publication will address such issues making use of experimental case studies.