EPE Association: EPE 2013 - DS2h: Electric Propulsion Systems for Road Vehicles, Converters and Control Strategies

EPE 2013 - DS2h: Electric Propulsion Systems for Road Vehicles, Converters and Control Strategies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 18: Electrical systems in road vehicles > EPE 2013 - DS2h: Electric Propulsion Systems for Road Vehicles, Converters and Control Strategies

   [return to parent folder]

   A Current Source Inverter for Battery Electric Vehicles
By Sicong LIU, Kay HAMEYER [View]
[Download]

Abstract: This paper deals with the approach of integrating a CSI into the power train of a BEV using a nouveau control strategy. The proposed control strategy for CSI provides a better harmonic performance of the electrical machine and is therefore a beneficial advantage for the system performance. Using a test setup especially designed for experimental validation of CSI the introduced control strategy is proved with experimental results. Based on the control strategy a system simulation of an IPMSM drive with CSI is implemented. A direct comparison of the impacts on system performance between VSI and CSI is conducted.

   A Novel Direct Water and Double-Sided Cooled Power Module and a Compact Inverter for Electrified Vehicles
By Kinya NAKATSU, Atsuo NISHIHARA, Koji SASAKI, Ryuichi SAITO [View]
[Download]

Abstract: Direct Water and Double-Sided Cooled Power Modules (DWDSCPM) are especially attractive due to high thermal performances. The DWDSCPM was able to reduce the thermal resistance by 50\% and increase power density of the traction inverter by 70\% in comparison with a conventional power module.

   A Series or Parallel Changeover System Using Battery with EDLC for EV
By Katsuhiro HATA, Naoya WATANABE, Kyungmin SUNG [View]
[Download]

Abstract: This paper focuses on the way to use the EDLC bank in a small electric vehicle (EV). In a recent study of an EV, a supercapacitor (EDLC; Electric Double Layer Capacitor) is adopted into an energy storage system to improve energy efficiency. Generally, the EDLC bank consists of a large number of cells because the EDLC bank cell voltage is very small compared with the battery terminal voltage, which is a DC bus voltage in the motor drive system. On the other hand, a small EV cannot be equipped with the large size EDLC bank because of the restriction of a cost and a space. Therefore, the energy storage system demands the small size EDLC bank more efficiently. Usually, the conventional system of an EV cannot utilize the full voltage range of an EDLC bank because the operating voltage range is limited by the ratio of step-up voltage between the DC bus and the terminal of the EDLC bank in bidirectional DC/DC converter. In this paper, due to improve the operating voltage range of the EDLC bank, a series or parallel changeover system using a battery with an EDLC is proposed. In addition, simulations and experimental results are presented to verify that the proposed system can expand the operating voltage range of the EDLC bank. As a result, the small bank of few EDLC cells is applied for small EV as a power assistance system.

   Application of a Decoupling Method Based on Online Filtering Technique for Multi-Source Electric Vehicles
By Mario SILVA, Joao Pedro TROVAO, Paulo PEREIRINHA, Humberto JORGE [View]
[Download]

Abstract: In this paper, an online filtering technique advantage is presented to improve the decoupling methodalready used on energy management for electric vehicles and hybrid electric vehicles. The most widelyused power sources in electric vehicles and hybrid electric vehicles are batteries, super-capacitors andfuel cells. Several studies have been made on these type of power sources and concludes that its complement is very beneficent for a big variety of applications. Based on this complement between sources, a new scenario on electric vehicles energy storage is being taken seriously, the electric vehicles with hybrid electric storage systems. A multi-source electric vehicles with hybrid electric storage systems as well as the sources frequency distribution used in hybridization concept are presented. The traditional DC-DC decoupling method control and its improvement with the online filtering technique are fully addressed. The two methods are compared using several simulation based on Matlab/Simulink under different load steps. The new technique presents a good behaviour including for unknown loads.

   Development and Analysis of a Multiple Phase Bidirectional DC/DC Converter for ripple reduction and inductor optimization
By Sebastian GORDES, Heiko PRECKWINKEL, Johanna MYRZIK [View]
[Download]

Abstract: Multiple phase bidirectional DC/DC converters are developed and analyzed for optimal inductoroperation, high efficiency and a low current ripple. Partial-load operational mode is investigated aswell. The different opportunities to degrease the size of the inductors and current ripple and to increasethe efficiency are discussed.

   Electric Vehicle Driving and Fast Charging System based on Configurable Modular Multilevel Converter (CMMC)
By Martel TSIRINOMENY, Alfred RUFER [View]
[Download]

Abstract: Electric Vehicles (EVs) owners are challenged by the limited flexibility of the actual EVs on-boardcharger according to the available charging station. This paper proposes a new concept of a UnifiedConverter (UC) for EVs based on the Configurable Modular Multilevel Converter (CMMC), which usesonly one converter for fast charging and for driving system. In fact, the motor winding is used as filterduring charging operation and the battery pack is split into submodules in order to modularize the batterysubsystem. The concept enables an adaptation of the on-board standalone fast charger for differentkinds of power sources (AC or DC, normal or fast). In addition, the CMMC itself can play the roleof ancillary services during the interconnection with the Distributed Generation (DG). Furthermore, itsimplementation is pratically simple because it is based on well-known threephase control. However,the CMMC requires an open-end AC machine with common middle points.

   Experimental Large-signal Characterization of Power Inductors in Bidirectional Electric Vehicle DC-DC Converters for Simulation Analysis
By Marina S. PERDIGAO, Joao Pedro TROVAO, Jose Marcos ALONSO, Paulo PEREIRINHA, Eduardo S. SARAIVA [View]
[Download]

Abstract: This paper presents an experimental large-signal characterization procedure for power inductors in EV applications as well as method to obtain an inductance reference value for the power inductor in bidirectional dc-dc converters. It also discusses the importance of the inductor design project, by describing important constraints, such as core size and saturation. This paper shows that an appropriated large-signal inductance model increases the reliability of simulation studies of the system performance.

   FC/Battery Power Management for Electric Vehicle Based Interleaved dc-dc Boost Converter Topology
By Farid KHOUCHA, Abdeldjabar BENRABAH [View]
[Download]

Abstract: Due to the fact that the environmental issues have become more serious recently, interest in renewableenergy systems, such as, fuel-cells (FCs) has increased steadfastly. Among many types of FCs, protonexchange membrane FC (PEMFC) is one of the most promising power sources due to its advantages,such as, low operation temperature, high power density and low emission. However, using onlyPEMFC for electric vehicle may not be feasible to satisfy the peak demand changes especially duringaccelerations and braking. So, hybridizing PEMFC and an energy storage system (ESS) decreases theFC cost and improves its performance and life. Battery (B) appears to be the most powerful candidateto hybridize with PEMFC for vehicular applications. Therefore, the performance of PEMFC/Bhybridization is limited considerably by the performance of the converter. Thus, a suitable dc-dcconverter topology is required. Various isolated and nonisolated converter topologies for FCapplications have been proposed in literature. The objective of this study is to design and simulate afuel cell - interleaved boost dc-dc converter (FC-IBC) for hybrid power systems in electric vehicleapplication, in order to decrease the FC current ripple. Therefore Energetic efficiency can also beimproved. A control strategy capable of determining the desired FC power and keeps the dc voltagearound its nominal value by supplying propulsion power and recuperating braking energy is designedand tested with an urbane electric vehicle model.

   FOUR QUADRANT FULLY CONTROLLED MECHANICAL LOAD SIMULATOR
By Stylianos SYRIGOS, Ioannis KARATZAFERIS, Emmanuel TATAKIS [View]
[Download]

Abstract: Mechanical load simulators are useful in various cases, where we wish to test an electromechanical system. A mechanical load simulator can be used to emulate a wide variety of loads, such as industrial loads, electric vehicle drivetrain, etc. In this paper, a load simulator build for the testing of various electromotion systems, with the capability of four quadrant operation (positive or negative torque, positive or negative rotational speed) and very good transient behavior is presented. The four quadrant operation allows bidirectional power flow, thus enables the study of energy recovery braking. The overall system will be investigated, the control method will be analyzed and finally, simulation and experimental results will be presented.

   Highly Integrated Power Electronics for a 48 V Hybrid Drive Application
By Andreas SCHMIDHOFER, Janko HORVAT, Thomas GABRIEL, Heinz LANZENBERGER, Daniel PRIX, Markus BICHLER [View]
[Download]

Abstract: This paper represents the prototype inverter, which is designed for 48 V belt-drive unit with enhanced hybrid functionalities. A pure electric drive mode for low speed range is possible in addition to the classical hybrid operation modes like internal combustion engine start, recuperation and boosting. Electric machine and inverter are combined in a compact drive unit where the inverter is axially attached to the electrical machine. The entire unit is intended to be installed into the engine compartment and integrated in the combustion engine cooling circuit. The paper is focused on thermal design of the inverter which was constructed using standard electronic components and materials. Furthermore first experimental results of the thermal behavior of the inverter prototype are introduced.

   Loss Minimization of Boost Mode Dual Inverter Drive System
By Thomas GERRITS, Korneel WIJNANDS, Johan PAULIDES, Jorge DUARTE [View]
[Download]

Abstract: A dual inverter drive system is proposed, which is capable of boosting the phase voltages applied to an open-winding electric machine. A zero sequence current at the third harmonic of the intended output frequency is added to increase the supply voltage of one inverter, thereby extending the operating range of the machine. The need for a reactive current to weaken the machine field is avoided as a result.A method is introduced for simultaneously optimizing the inverter voltages and minimizing the required boost current, to maximize the overall system efficiency. The analysis is explained and verified by simulation.

   Multiphase integrated on-board battery chargers for electrical vehicles
By Ivan SUBOTIC, Emil LEVI, Martin JONES, Dushan GRAOVAC [View]
[Download]

Abstract: The paper considers on-board battery charging of electrical vehicles (EVs) using a multiphase voltagesource and a multiphase propulsion motor. The multiphase inverter and the multiphase machine are fullyintegrated into the charging process. The proposed integrated on-board battery charger has an advantage of unity power factor operation with no torque production in the machine during the charging mode. The principle of the charging mode operation is based on the additional degrees of freedom that exist in multiphase machines. It is shown that they can be conveniently utilised to achieve charging through the machine’s stator winding with zero electromagnetic torque. Detailed theoretical analysis is reported for a five-phase system, with a subsequent generalization to other multiphase systems with other higher odd numbers of phases. A mathematical model of a multiphase voltage source rectifier (VSR) is developed, its control in the charging mode is discussed, and the concept is validated by simulation.

   Power and Balancing Control Considerations on Modular Multilevel Converters for Battery Electric Vehicles
By Pietro TRICOLI, Salvatore D'ARCO, Luigi PIEGARI [View]
[Download]

Abstract: Modular multilevel converters with embedded battery cells are suitable candidates to improve the energy conversion efficiency of battery electric vehicles. In this new topology, the series connection of the battery cells is obtained by means of H-bridge modules, allowing the highest flexibility for the discharge and recharge of each individual battery cell. This objective can be achieved in practice only when a suitable control algorithm is designed to control at the same time the generation of the desired output voltages and the state of charge of cells. This paper discusses some aspects of the balancing algorithm of the battery cells including the cross-balancing between the converter’s arms and the design of the control loop for symmetric three-phase output voltages. Simulations results applied to a city car confirm the theoretical considerations and illustrate the main features of the proposed control algorithm.

   Power flow control with bidirectional dual active bridge battery charger in low-voltage microgrids
By Luis M. MIRANDA, Diogo VARAJÃO, Bruno L. SANTOS, Rui ARAUJO, Carlos MOREIRA, Joao P. LOPES [View]
[Download]

Abstract: This paper describes a power conversion system that implements bidirectional power flow between the electric grid and a battery, based on a full bridge inverter associated with a dual active bridge. A method for power flow control based on the agreement between battery pack and low voltage grid requirements has been developed to allow the large penetration of both, electric vehicles (EV) and renewable microgeneration. A laboratory prototype containing all functions required to implement a vehicle-to-grid (V2G) power interface has been built. The hardware implementation is reported, including control scheme and high-frequency transformer design details. Converter key waveforms are presented to evaluate the power quality on batteries and grid, as well as its dynamic behavior. An experimental laboratory setup is described and results are shown to demonstrate the technical benefits for low-voltage (LV) microgrids, if electric vehicle charger includes a power flow control based on frequency-voltage droop concept.

   Prediction of device temperatures in an electric vehicle battery charger system by analysis of device thermal cross-coupling
By Jonathan DAVIDSON, David STONE, Martin FOSTER, Christopher GOULD [View]
[Download]

Abstract: This paper presents a practical implementation of the measurement and use of thermal cross-coupling data. Thermal cross-coupling, the thermal transfer impedance between the heat generation of one power device and the temperature of another, is characterised using pseudo-random binary sequences for a typical H-bridge arrangement. Knowledge of the cross-coupling between each pair of devices allows temperature profiles to be predicted for arbitrary input power waveforms. The technique is verified by applying arbitrary power waveforms to all devices in the experimental arrangement and measuring the temperature response. Good agreement is shown between predicted and practical device temperature waveforms, demonstrating the viability of the technique.

   Voltage Support from Electric Vehicles in Distribution Grid
By Shaojun HUANG, Jayakrishnan R. PILLAI, Paul THØGERSEN, Birgitte BAK-JENSEN [View]
[Download]

Abstract: The paper evaluates the voltage support functions from electric vehicles (EVs) on a typical Danish distribution grid with high EV penetration. In addition to the popular voltage control modes, such as voltage droop charging (low voltage level leads to low charging power) and reactive power support, the combination of these two methods is also examined for controlled EV charging. Simulation results show that the combination of the two individual supporting methods has the best performance in terms of voltage regulation as well as improving EV penetration level at weak distribution grids.

EPE 2013 - DS2h: Electric Propulsion Systems for Road Vehicles, Converters and Control Strategies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 18: Electrical systems in road vehicles > EPE 2013 - DS2h: Electric Propulsion Systems for Road Vehicles, Converters and Control Strategies
	[return to parent folder]

	A Current Source Inverter for Battery Electric Vehicles By Sicong LIU, Kay HAMEYER	[View] [Download]
Abstract: This paper deals with the approach of integrating a CSI into the power train of a BEV using a nouveau control strategy. The proposed control strategy for CSI provides a better harmonic performance of the electrical machine and is therefore a beneficial advantage for the system performance. Using a test setup especially designed for experimental validation of CSI the introduced control strategy is proved with experimental results. Based on the control strategy a system simulation of an IPMSM drive with CSI is implemented. A direct comparison of the impacts on system performance between VSI and CSI is conducted.

	A Novel Direct Water and Double-Sided Cooled Power Module and a Compact Inverter for Electrified Vehicles By Kinya NAKATSU, Atsuo NISHIHARA, Koji SASAKI, Ryuichi SAITO	[View] [Download]
Abstract: Direct Water and Double-Sided Cooled Power Modules (DWDSCPM) are especially attractive due to high thermal performances. The DWDSCPM was able to reduce the thermal resistance by 50\% and increase power density of the traction inverter by 70\% in comparison with a conventional power module.

	A Series or Parallel Changeover System Using Battery with EDLC for EV By Katsuhiro HATA, Naoya WATANABE, Kyungmin SUNG	[View] [Download]
Abstract: This paper focuses on the way to use the EDLC bank in a small electric vehicle (EV). In a recent study of an EV, a supercapacitor (EDLC; Electric Double Layer Capacitor) is adopted into an energy storage system to improve energy efficiency. Generally, the EDLC bank consists of a large number of cells because the EDLC bank cell voltage is very small compared with the battery terminal voltage, which is a DC bus voltage in the motor drive system. On the other hand, a small EV cannot be equipped with the large size EDLC bank because of the restriction of a cost and a space. Therefore, the energy storage system demands the small size EDLC bank more efficiently. Usually, the conventional system of an EV cannot utilize the full voltage range of an EDLC bank because the operating voltage range is limited by the ratio of step-up voltage between the DC bus and the terminal of the EDLC bank in bidirectional DC/DC converter. In this paper, due to improve the operating voltage range of the EDLC bank, a series or parallel changeover system using a battery with an EDLC is proposed. In addition, simulations and experimental results are presented to verify that the proposed system can expand the operating voltage range of the EDLC bank. As a result, the small bank of few EDLC cells is applied for small EV as a power assistance system.

	Application of a Decoupling Method Based on Online Filtering Technique for Multi-Source Electric Vehicles By Mario SILVA, Joao Pedro TROVAO, Paulo PEREIRINHA, Humberto JORGE	[View] [Download]
Abstract: In this paper, an online filtering technique advantage is presented to improve the decoupling methodalready used on energy management for electric vehicles and hybrid electric vehicles. The most widelyused power sources in electric vehicles and hybrid electric vehicles are batteries, super-capacitors andfuel cells. Several studies have been made on these type of power sources and concludes that its complement is very beneficent for a big variety of applications. Based on this complement between sources, a new scenario on electric vehicles energy storage is being taken seriously, the electric vehicles with hybrid electric storage systems. A multi-source electric vehicles with hybrid electric storage systems as well as the sources frequency distribution used in hybridization concept are presented. The traditional DC-DC decoupling method control and its improvement with the online filtering technique are fully addressed. The two methods are compared using several simulation based on Matlab/Simulink under different load steps. The new technique presents a good behaviour including for unknown loads.

	Development and Analysis of a Multiple Phase Bidirectional DC/DC Converter for ripple reduction and inductor optimization By Sebastian GORDES, Heiko PRECKWINKEL, Johanna MYRZIK	[View] [Download]
Abstract: Multiple phase bidirectional DC/DC converters are developed and analyzed for optimal inductoroperation, high efficiency and a low current ripple. Partial-load operational mode is investigated aswell. The different opportunities to degrease the size of the inductors and current ripple and to increasethe efficiency are discussed.

	Electric Vehicle Driving and Fast Charging System based on Configurable Modular Multilevel Converter (CMMC) By Martel TSIRINOMENY, Alfred RUFER	[View] [Download]
Abstract: Electric Vehicles (EVs) owners are challenged by the limited flexibility of the actual EVs on-boardcharger according to the available charging station. This paper proposes a new concept of a UnifiedConverter (UC) for EVs based on the Configurable Modular Multilevel Converter (CMMC), which usesonly one converter for fast charging and for driving system. In fact, the motor winding is used as filterduring charging operation and the battery pack is split into submodules in order to modularize the batterysubsystem. The concept enables an adaptation of the on-board standalone fast charger for differentkinds of power sources (AC or DC, normal or fast). In addition, the CMMC itself can play the roleof ancillary services during the interconnection with the Distributed Generation (DG). Furthermore, itsimplementation is pratically simple because it is based on well-known threephase control. However,the CMMC requires an open-end AC machine with common middle points.

	Experimental Large-signal Characterization of Power Inductors in Bidirectional Electric Vehicle DC-DC Converters for Simulation Analysis By Marina S. PERDIGAO, Joao Pedro TROVAO, Jose Marcos ALONSO, Paulo PEREIRINHA, Eduardo S. SARAIVA	[View] [Download]
Abstract: This paper presents an experimental large-signal characterization procedure for power inductors in EV applications as well as method to obtain an inductance reference value for the power inductor in bidirectional dc-dc converters. It also discusses the importance of the inductor design project, by describing important constraints, such as core size and saturation. This paper shows that an appropriated large-signal inductance model increases the reliability of simulation studies of the system performance.

	FC/Battery Power Management for Electric Vehicle Based Interleaved dc-dc Boost Converter Topology By Farid KHOUCHA, Abdeldjabar BENRABAH	[View] [Download]
Abstract: Due to the fact that the environmental issues have become more serious recently, interest in renewableenergy systems, such as, fuel-cells (FCs) has increased steadfastly. Among many types of FCs, protonexchange membrane FC (PEMFC) is one of the most promising power sources due to its advantages,such as, low operation temperature, high power density and low emission. However, using onlyPEMFC for electric vehicle may not be feasible to satisfy the peak demand changes especially duringaccelerations and braking. So, hybridizing PEMFC and an energy storage system (ESS) decreases theFC cost and improves its performance and life. Battery (B) appears to be the most powerful candidateto hybridize with PEMFC for vehicular applications. Therefore, the performance of PEMFC/Bhybridization is limited considerably by the performance of the converter. Thus, a suitable dc-dcconverter topology is required. Various isolated and nonisolated converter topologies for FCapplications have been proposed in literature. The objective of this study is to design and simulate afuel cell - interleaved boost dc-dc converter (FC-IBC) for hybrid power systems in electric vehicleapplication, in order to decrease the FC current ripple. Therefore Energetic efficiency can also beimproved. A control strategy capable of determining the desired FC power and keeps the dc voltagearound its nominal value by supplying propulsion power and recuperating braking energy is designedand tested with an urbane electric vehicle model.

	FOUR QUADRANT FULLY CONTROLLED MECHANICAL LOAD SIMULATOR By Stylianos SYRIGOS, Ioannis KARATZAFERIS, Emmanuel TATAKIS	[View] [Download]
Abstract: Mechanical load simulators are useful in various cases, where we wish to test an electromechanical system. A mechanical load simulator can be used to emulate a wide variety of loads, such as industrial loads, electric vehicle drivetrain, etc. In this paper, a load simulator build for the testing of various electromotion systems, with the capability of four quadrant operation (positive or negative torque, positive or negative rotational speed) and very good transient behavior is presented. The four quadrant operation allows bidirectional power flow, thus enables the study of energy recovery braking. The overall system will be investigated, the control method will be analyzed and finally, simulation and experimental results will be presented.

	Highly Integrated Power Electronics for a 48 V Hybrid Drive Application By Andreas SCHMIDHOFER, Janko HORVAT, Thomas GABRIEL, Heinz LANZENBERGER, Daniel PRIX, Markus BICHLER	[View] [Download]
Abstract: This paper represents the prototype inverter, which is designed for 48 V belt-drive unit with enhanced hybrid functionalities. A pure electric drive mode for low speed range is possible in addition to the classical hybrid operation modes like internal combustion engine start, recuperation and boosting. Electric machine and inverter are combined in a compact drive unit where the inverter is axially attached to the electrical machine. The entire unit is intended to be installed into the engine compartment and integrated in the combustion engine cooling circuit. The paper is focused on thermal design of the inverter which was constructed using standard electronic components and materials. Furthermore first experimental results of the thermal behavior of the inverter prototype are introduced.

	Loss Minimization of Boost Mode Dual Inverter Drive System By Thomas GERRITS, Korneel WIJNANDS, Johan PAULIDES, Jorge DUARTE	[View] [Download]
Abstract: A dual inverter drive system is proposed, which is capable of boosting the phase voltages applied to an open-winding electric machine. A zero sequence current at the third harmonic of the intended output frequency is added to increase the supply voltage of one inverter, thereby extending the operating range of the machine. The need for a reactive current to weaken the machine field is avoided as a result.A method is introduced for simultaneously optimizing the inverter voltages and minimizing the required boost current, to maximize the overall system efficiency. The analysis is explained and verified by simulation.

	Multiphase integrated on-board battery chargers for electrical vehicles By Ivan SUBOTIC, Emil LEVI, Martin JONES, Dushan GRAOVAC	[View] [Download]
Abstract: The paper considers on-board battery charging of electrical vehicles (EVs) using a multiphase voltagesource and a multiphase propulsion motor. The multiphase inverter and the multiphase machine are fullyintegrated into the charging process. The proposed integrated on-board battery charger has an advantage of unity power factor operation with no torque production in the machine during the charging mode. The principle of the charging mode operation is based on the additional degrees of freedom that exist in multiphase machines. It is shown that they can be conveniently utilised to achieve charging through the machine’s stator winding with zero electromagnetic torque. Detailed theoretical analysis is reported for a five-phase system, with a subsequent generalization to other multiphase systems with other higher odd numbers of phases. A mathematical model of a multiphase voltage source rectifier (VSR) is developed, its control in the charging mode is discussed, and the concept is validated by simulation.

	Power and Balancing Control Considerations on Modular Multilevel Converters for Battery Electric Vehicles By Pietro TRICOLI, Salvatore D'ARCO, Luigi PIEGARI	[View] [Download]
Abstract: Modular multilevel converters with embedded battery cells are suitable candidates to improve the energy conversion efficiency of battery electric vehicles. In this new topology, the series connection of the battery cells is obtained by means of H-bridge modules, allowing the highest flexibility for the discharge and recharge of each individual battery cell. This objective can be achieved in practice only when a suitable control algorithm is designed to control at the same time the generation of the desired output voltages and the state of charge of cells. This paper discusses some aspects of the balancing algorithm of the battery cells including the cross-balancing between the converter’s arms and the design of the control loop for symmetric three-phase output voltages. Simulations results applied to a city car confirm the theoretical considerations and illustrate the main features of the proposed control algorithm.

	Power flow control with bidirectional dual active bridge battery charger in low-voltage microgrids By Luis M. MIRANDA, Diogo VARAJÃO, Bruno L. SANTOS, Rui ARAUJO, Carlos MOREIRA, Joao P. LOPES	[View] [Download]
Abstract: This paper describes a power conversion system that implements bidirectional power flow between the electric grid and a battery, based on a full bridge inverter associated with a dual active bridge. A method for power flow control based on the agreement between battery pack and low voltage grid requirements has been developed to allow the large penetration of both, electric vehicles (EV) and renewable microgeneration. A laboratory prototype containing all functions required to implement a vehicle-to-grid (V2G) power interface has been built. The hardware implementation is reported, including control scheme and high-frequency transformer design details. Converter key waveforms are presented to evaluate the power quality on batteries and grid, as well as its dynamic behavior. An experimental laboratory setup is described and results are shown to demonstrate the technical benefits for low-voltage (LV) microgrids, if electric vehicle charger includes a power flow control based on frequency-voltage droop concept.

	Prediction of device temperatures in an electric vehicle battery charger system by analysis of device thermal cross-coupling By Jonathan DAVIDSON, David STONE, Martin FOSTER, Christopher GOULD	[View] [Download]
Abstract: This paper presents a practical implementation of the measurement and use of thermal cross-coupling data. Thermal cross-coupling, the thermal transfer impedance between the heat generation of one power device and the temperature of another, is characterised using pseudo-random binary sequences for a typical H-bridge arrangement. Knowledge of the cross-coupling between each pair of devices allows temperature profiles to be predicted for arbitrary input power waveforms. The technique is verified by applying arbitrary power waveforms to all devices in the experimental arrangement and measuring the temperature response. Good agreement is shown between predicted and practical device temperature waveforms, demonstrating the viability of the technique.

	Voltage Support from Electric Vehicles in Distribution Grid By Shaojun HUANG, Jayakrishnan R. PILLAI, Paul THØGERSEN, Birgitte BAK-JENSEN	[View] [Download]
Abstract: The paper evaluates the voltage support functions from electric vehicles (EVs) on a typical Danish distribution grid with high EV penetration. In addition to the popular voltage control modes, such as voltage droop charging (low voltage level leads to low charging power) and reactive power support, the combination of these two methods is also examined for controlled EV charging. Simulation results show that the combination of the two individual supporting methods has the best performance in terms of voltage regulation as well as improving EV penetration level at weak distribution grids.