EPE Association: EPE 2009 - Subtopic 17-7 - DS: 'Power Electronics in Aerospace and Space Applications and Road Vehicles'

EPE 2009 - Subtopic 17-7 - DS: 'Power Electronics in Aerospace and Space Applications and Road Vehicles'
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2009 - Conference > EPE 2009 - Topic 17: 'Electrical Systems in Aerospace, Space, Surface and Marine Transport' > EPE 2009 - Subtopic 17-7 - DS: 'Power Electronics in Aerospace and Space Applications and Road Vehicles'

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   Challenges for IGBT Modules in Hybrid Buses
By Martin HELSPER, Bernd BRENDEL [View]
[Download]

Abstract: Hybrid buses are currently enjoying a very high level of interest worldwide. For this market an inverter family was developed using the latest IGBT technology. The tough operating conditions, and especially the mission profile in hybrid drives, represent a big challenge for IGBT modules. Electrical, thermal and lifetime limitations reduce the level to which they can be exploited. New IGBT developments have been investigated, which indicate ways of how to reduce these drawbacks but not eliminate them. A high level of system know-how is important to guarantee the optimal and reliable solution.

   Control of a Multi-Level Active Shunt Power Filter for More Electric Aircraft
By milijana ODAVIC, pericle ZANCHETTA [View]
[Download]

Abstract: The proposed increase of power electronic subsystems for More Electrical Aircraft (MEA) brings severe challenges to aircraft power distribution. Current aircraft power systems work at a fundamental frequency of 400Hz while proposed AC MEA power networks for next generation aircrafts will have a fundamental frequency which varies most probably between 360 and 900 Hz. An active shunt filter (ASF) is recognized as an effective device for reducing harmonic pollution. However for the AC aircraft power system, harmonics for a 400 Hz fundamental (an in the future up to 900Hz) should be controlled. A five-level active shunt filter with a high-bandwidth current controller combined together with an enhanced pulse-width modulation algorithm is proposed. The effective reference tracking of the proposed modulation combined with the employed current control approach is experimentally verified for frequencies of up to 2.8 kHz (corresponding to the 7th harmonic component when a fundamental frequency of 400 Hz is employed) with a device switching frequency of just up to 5 kHz. The proposed active filtering system therefore is suitable for more electric aircraft applications on current aircraft and can evolve to a viable solution also for the next generation aircrafts with a higher and variable supply frequency.

   Detailed Power Converter Design for a 30kW Switched Reluctance Starter/Generator Used in Aircraft
By Shoujun SONG, Weiguo LIU, Uwe SCHAEFER [View]
[Download]

Abstract: Some general considerations for the design of the power converter used in an undergoing 30kW switched reluctance starter/generator system are presented. The most suitable converter topology and power semiconductor are found firstly based on features of the application and comparisons among many possibilities. Then, the frequency stress, voltage ratings, peak and rms current ratings of the power semiconductor are calculated analytically and verified by the simulation results with PC-SRD. Finally, detailed thermal analysis of the converter is presented to check the applicability of the adopted power semiconductor products and select feasible heatsink.

   Drive train design for medium-sized zero emission electric vehicles
By Philipp MORRISON, Andreas BINDER, Bogdan FUNIERU, Chip Rinaldi SABIRIN [View]
[Download]

Abstract: Zero-emission vehicles are defined as cars with no gaseous emissions, such as NOx, CO, HC and particulate matter. In this paper, the design of the electrical drive train of a zero-emission vehicle, comparable with the smart fortwo car, is given. The design of the drive train is evaluated by MATLAB/Simulink simulation according to the calculated mass and losses of the drive train components. The loss calculation models for the main electrical and mechanical components are presented in detail. The obtained simulation results are represented by the car range and the acceleration of the car.

   Experimental Comparison of Rectifiers for Lundell Automotive Alternators
By Ruben IVANKOVIC, Jerome CROS, Philippe VIAROUGE [View]
[Download]

Abstract: This paper presents a comparative analysis of rectifiers by experimental approach, to improve output power and efficiency of a Lundell alternator without any geometry modification. Different topologies of rectifiers are considered using PWM or series/parallel reconfigurations of diode rectifier and simple control methods. An interleaving technique is also applied to minimize the output current high-frequency ripple generated by pulse modulation. To improve performances, this method must be associated to special multiple 3-phase winding configuration to minimize magnetic coupling. The proposed solution almost double the peak output power at 8000rpm (from 1602W to 3038W) and keeps alternator losses constant.

   Fault Tolerant Power Converter Topologies for PMSM Drives in Aerospace Applications
By SUDARAT KHWAN-ON, LILIANA DE LILLO, Lee EMPRINGHAM, PAT WHEELER, JON CLARE, CHRIS GERADA, MD NAZRI OTHMAN, Omar JASIM [View]
[Download]

Abstract: This paper proposes two fault tolerant power converter permanent magnet synchronous motor (PMSM) drive topologies. A reconfigured conventional DC link/two-level VSI converter and a reconfigured conventional matrix converter are presented to improve the reliability of the drive system under open phase fault operating condition. Additional phase redundancy and its control technique are included. Simulation and experimental results are shown to verify the effectiveness of the proposed topologies.

   High Temperature Electronics for Future Hybrid Drive Systems
By Folker RENKEN [View]
[Download]

Abstract: More and more, automakers are using hybrid drives and their advantages. Key components of these systems are an electrical machine and a converter, consisting of many electronic parts. This converter normally is arranged apart from the electrical machine in a separate housing. Thus the electronic components can be operated at moderate temperatures, in order to use the full potential of the hybrid system. But further developments of the electronic components in the last years make solutions tangible, which can provide high power with high environmental and coolant temperatures and are able to work reliably over the specified life time of the vehicle. The high temperature electronics make variable mounting spaces possible, so the modularity of the hybrid components can be increased and the systems can be assembled in a more compact manner. In this document the environmental conditions and the necessary requirements for the electronics are described.

   Integrated Battery Charger for Electric Scooter.
By Gianmario PELLEGRINO, Eric ARMANDO, Paolo GUGLIELMI [View]
[Download]

Abstract: The paper deals with a battery charger integrated into the traction hardware of an electric scooter, for recharging the scooter batteries by means of a single-phase AC source. A mechanical switch and a rectifier bridge are the only additional components required to transform the electric scooter powetrain into a PFC battery charger, suitable for current-controlled or voltage-controlled recharge. The AC current is controlled at unitary power factor with no harmonic distortion. Switching harmonics are also drastically reduced by means of phase-interleaving. The battery charge is regulated according to the requests of the Battery Monitor System (BMS) that is embedded into the battery packs. The effectiveness of the integrated battery charger is demonstrated here on an electric scooter with high voltage Li-Ion battery (260V) and DC/DC/AC power conversion scheme. The integrated PFC charger concept is also valid for electric vehicles with AC traction drives based on a direct DC/AC conversion scheme, as demonstrated throughout the paper.

   Modeling and testing of RFI filter for trolleybus transistor inverter
By Waldemar ZAJAC, Wojciech CZUCHRA, Wojciech MYSINSKI [View]
[Download]

Abstract: This article discusses issues related to the design and simulation of an RFI filter for a trolleybus. Due to passenger safety requirements, Cy capacitors used in the filter must not have high capacity. That is why a special filter which meets those requirements has to be designed. Also presented in this paper are the laboratory and onboard tests of a prototype filter. Furthermore, a comparison is provided between the simulations and test results.

   Modeling of the Hybrid Electric Drive with an Electric Power Splitter and Simulation of the Fuel Efficiency
By Pavel MINDL, Dobri CUNDEV, Zdenek CEROVSKY [View]
[Download]

Abstract: This paper presents the results of the modeling of the HEV with an electric power splitter (EPS) and simulation of the fuel efficiency of this type of vehicle. The new innovative technological approach is presented by using the special type of synchronous machine that splits the mechanical power on two separate power transmission pats and therefore it is called electric power splitter. EPS is based on a double rotor synchronous permanent magnet generator. It is consisted of two rotating parts, a classic permanent magnet rotor and a rotating stator. The rotor is firmly coupled to the drive shaft of the internal combustion engine of the vehicle (ICE). The rotating stator, which structurally is typical AC machine stator, is firmly coupled to the transmission of the vehicle that leads to the car wheels. This technical solution enables the ICE to operate on the most optimal revolutions during the entire driving schedule. Two distinguish approaches has bean realized in order this new innovative technological solution to be confirmed as eligible. First approach is creation the mathematical model of the entire system, taking into account all the necessary preconditions, environment influences, machine and component characteristics. The results have been obtained by using this precisely determined mathematical model and by simulating the characteristics of all essential values for the entire drive, which gives clear view of the capabilities and potentials of this new HEV system. The second approach is based on experimental verification. In order to be performed the laboratory tests on this HEV concept, an experimental working stand was se up in the laboratory. ICE and the traction load are simulated with controlled AC induction motors. The entire working stand presents complex machine, measure and control system for realization of this task.

   New power centre and power electronics sharing in aircraft
By Lucien PRISSE [View]
[Download]

Abstract: The rationalization of the power sources in aircraft has led to the replacement of conventional systems by electrical ones. These new architectures have given rise to new technological needs. Indeed, power electronics is necessary to control the electrical motors. The loads are mainly the compressors for the Environmental Control System that manages the pressurization and the cooling of the aircraft cabin, the pumps (fuel and hydraulic), the fans, the starting of the engineâ€¦ One optimization axis is the power electronics sharing to control these loads. This paper presents a power centre mock-up that includes 8 similar power modules.

   Optimized 70kW power inverter dedicated to future aircraft applications
By Rodolphe DE MAGLIE, Gaetan OSVALD, Juergen ENGSTLER, Alfred ENGLER, Jean-Pierre CARAYON [View]
[Download]

Abstract: This paper presents the 70kW inverter dedicated for future aeronautical applications in the frame of the MOET program, a FP6 European Integrated Project [1]. Design considerations, principle of operation and experimental results will be presented hereunder. For DC to AC conversion, technologies improvements and specific integration allow reducing weight and volume and increase the power density up to 5kW per kilogram.

   Power Processing Unit for the Next Generation Satellite
By Hiroyuki OSUGA, Fujio KUROKAWA [View]
[Download]

Abstract: The preliminary design of the Power Processing Unit (PPU) for the next generation satellite is presented. In the future, the next generation satellite will progress to higher thrust level, to wider thrust control range and to quick response. The Hall thruster is one of the promising candidates in the electrical propulsion system for this satellite. However, it is difficult to control the Hall thruster in a way that enables a stable operation for a wide operating range. We study the PPU using a new design approach of the controlling wider thrust range for a Hall thruster. By synchronously controlling three power supplies, the discharge current oscillation and inrush current at ignition can be suppressed. As a result, the PPU uses new control logic for the wider thrust range. The new control method is the pulse width modulation that achieves to operating requirements for reducing the consumption of propellant gas. The control logic realizes the quick ignition and smooth operation in a wider thrust range.

   Power System for Electrical Propulsion in space applications
By Esteban SANCHIS, Enrique MASET, Agustin FERRERES, Juan B. EJEA, Jose M. BLANES, Ausias GARRIGOS, Jose JORDAN, VICENTE ESTEVE [View]
[Download]

Abstract: Ion engines, also known as electrical propulsion, are used more and more in space applications due to its higher power density and its lower contamination risk than with chemical propulsion. One of its characteristics is that it needs a very stable power supply. This paper proposes a solution for the BepiColombo mission to Mercury. Electrical propulsion increases the electrical power demand of the spacecraft (in the range of 8 kW up to 14 kW for the BepiColombo Mission), generating new research opportunities on selecting the best Solar Array Regulator topology. Other missions now under study and looking for the future are Lunar Exploration. Solar electric propulsion (SEP) is used during the cruise period from Earth to Mercury in the BepiColombo mission. The Solar Array (SA) power increases with time and its associated propulsion unit has to take the maximum available power from the SA to use in the ion drive motor in order to reach Mercury within a reasonable time. Ion Thrust is not required in eclipse and therefore a Power System was designed that did not require a Battery and therefore a considerable mass could be saved. The paper describes a solution for the Mercury Transfer Module (MTM) Power Conditioning and Distribution Unit (PCDU) of the Solar Electric Propulsion Module (SEPM). The new conception is a Sequential Switching Shunt Maximum Power Regulator (S3MPR) consisting in a Sequential Switching Shunt Regulator (S3R), to keep the SA voltage at its Maximum Power Point (MPP) followed by a Boost regulator to produce a constant 100 V to supply the Electronic Propulsion (EP). A scaled-down Power Subsystem of 1 kW output power has been built and tested.

   Stability Assessment of Electric Power Systems for â€˜More Electricâ€™ Aircraft
By Antonio GRIFFO, Jiabin WANG [View]
[Download]

Abstract: This paper presents a comprehensive assessment of small-signal stability for a â€œmore-electricâ€ aircraft power system consisting of a synchronous variable-frequency generator which supplies several power electronic controlled loads via an 18-pulse autotransformer rectifier unit (ATRU) for AC-DC conversion. Functional models for key power system components and loads are derived. Numerical tools employed for the automatic calculation of linearized equations and operating points are described, and the influence of leading design and operational parameter on system stability is evaluated.

   State-space average modelling of synchronous generator fed 18-pulse diode rectifier
By Antonio GRIFFO, Jiabin WANG [View]
[Download]

Abstract: The paper derives an analytical state-space average-value model of the direct symmetric topology of an 18-pulse AC-DC rectifier. The dynamic characteristics of the rectifier are fully represented while the model is time invariant and computationally efficient. The developed model, validated with comparison of the resultant transient and steady state behaviors with those obtained from detailed simulations of a test system including synchronous generator and DC loads can, therefore, be used for stability assessment of electric power systems with diode rectifiers, multiple power electronic converter-controlled loads and electrical drives.

EPE 2009 - Subtopic 17-7 - DS: 'Power Electronics in Aerospace and Space Applications and Road Vehicles'
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2009 - Conference > EPE 2009 - Topic 17: 'Electrical Systems in Aerospace, Space, Surface and Marine Transport' > EPE 2009 - Subtopic 17-7 - DS: 'Power Electronics in Aerospace and Space Applications and Road Vehicles'
	[return to parent folder]

	Challenges for IGBT Modules in Hybrid Buses By Martin HELSPER, Bernd BRENDEL	[View] [Download]
Abstract: Hybrid buses are currently enjoying a very high level of interest worldwide. For this market an inverter family was developed using the latest IGBT technology. The tough operating conditions, and especially the mission profile in hybrid drives, represent a big challenge for IGBT modules. Electrical, thermal and lifetime limitations reduce the level to which they can be exploited. New IGBT developments have been investigated, which indicate ways of how to reduce these drawbacks but not eliminate them. A high level of system know-how is important to guarantee the optimal and reliable solution.

	Control of a Multi-Level Active Shunt Power Filter for More Electric Aircraft By milijana ODAVIC, pericle ZANCHETTA	[View] [Download]
Abstract: The proposed increase of power electronic subsystems for More Electrical Aircraft (MEA) brings severe challenges to aircraft power distribution. Current aircraft power systems work at a fundamental frequency of 400Hz while proposed AC MEA power networks for next generation aircrafts will have a fundamental frequency which varies most probably between 360 and 900 Hz. An active shunt filter (ASF) is recognized as an effective device for reducing harmonic pollution. However for the AC aircraft power system, harmonics for a 400 Hz fundamental (an in the future up to 900Hz) should be controlled. A five-level active shunt filter with a high-bandwidth current controller combined together with an enhanced pulse-width modulation algorithm is proposed. The effective reference tracking of the proposed modulation combined with the employed current control approach is experimentally verified for frequencies of up to 2.8 kHz (corresponding to the 7th harmonic component when a fundamental frequency of 400 Hz is employed) with a device switching frequency of just up to 5 kHz. The proposed active filtering system therefore is suitable for more electric aircraft applications on current aircraft and can evolve to a viable solution also for the next generation aircrafts with a higher and variable supply frequency.

	Detailed Power Converter Design for a 30kW Switched Reluctance Starter/Generator Used in Aircraft By Shoujun SONG, Weiguo LIU, Uwe SCHAEFER	[View] [Download]
Abstract: Some general considerations for the design of the power converter used in an undergoing 30kW switched reluctance starter/generator system are presented. The most suitable converter topology and power semiconductor are found firstly based on features of the application and comparisons among many possibilities. Then, the frequency stress, voltage ratings, peak and rms current ratings of the power semiconductor are calculated analytically and verified by the simulation results with PC-SRD. Finally, detailed thermal analysis of the converter is presented to check the applicability of the adopted power semiconductor products and select feasible heatsink.

	Drive train design for medium-sized zero emission electric vehicles By Philipp MORRISON, Andreas BINDER, Bogdan FUNIERU, Chip Rinaldi SABIRIN	[View] [Download]
Abstract: Zero-emission vehicles are defined as cars with no gaseous emissions, such as NOx, CO, HC and particulate matter. In this paper, the design of the electrical drive train of a zero-emission vehicle, comparable with the smart fortwo car, is given. The design of the drive train is evaluated by MATLAB/Simulink simulation according to the calculated mass and losses of the drive train components. The loss calculation models for the main electrical and mechanical components are presented in detail. The obtained simulation results are represented by the car range and the acceleration of the car.

	Experimental Comparison of Rectifiers for Lundell Automotive Alternators By Ruben IVANKOVIC, Jerome CROS, Philippe VIAROUGE	[View] [Download]
Abstract: This paper presents a comparative analysis of rectifiers by experimental approach, to improve output power and efficiency of a Lundell alternator without any geometry modification. Different topologies of rectifiers are considered using PWM or series/parallel reconfigurations of diode rectifier and simple control methods. An interleaving technique is also applied to minimize the output current high-frequency ripple generated by pulse modulation. To improve performances, this method must be associated to special multiple 3-phase winding configuration to minimize magnetic coupling. The proposed solution almost double the peak output power at 8000rpm (from 1602W to 3038W) and keeps alternator losses constant.

	Fault Tolerant Power Converter Topologies for PMSM Drives in Aerospace Applications By SUDARAT KHWAN-ON, LILIANA DE LILLO, Lee EMPRINGHAM, PAT WHEELER, JON CLARE, CHRIS GERADA, MD NAZRI OTHMAN, Omar JASIM	[View] [Download]
Abstract: This paper proposes two fault tolerant power converter permanent magnet synchronous motor (PMSM) drive topologies. A reconfigured conventional DC link/two-level VSI converter and a reconfigured conventional matrix converter are presented to improve the reliability of the drive system under open phase fault operating condition. Additional phase redundancy and its control technique are included. Simulation and experimental results are shown to verify the effectiveness of the proposed topologies.

	High Temperature Electronics for Future Hybrid Drive Systems By Folker RENKEN	[View] [Download]
Abstract: More and more, automakers are using hybrid drives and their advantages. Key components of these systems are an electrical machine and a converter, consisting of many electronic parts. This converter normally is arranged apart from the electrical machine in a separate housing. Thus the electronic components can be operated at moderate temperatures, in order to use the full potential of the hybrid system. But further developments of the electronic components in the last years make solutions tangible, which can provide high power with high environmental and coolant temperatures and are able to work reliably over the specified life time of the vehicle. The high temperature electronics make variable mounting spaces possible, so the modularity of the hybrid components can be increased and the systems can be assembled in a more compact manner. In this document the environmental conditions and the necessary requirements for the electronics are described.

	Integrated Battery Charger for Electric Scooter. By Gianmario PELLEGRINO, Eric ARMANDO, Paolo GUGLIELMI	[View] [Download]
Abstract: The paper deals with a battery charger integrated into the traction hardware of an electric scooter, for recharging the scooter batteries by means of a single-phase AC source. A mechanical switch and a rectifier bridge are the only additional components required to transform the electric scooter powetrain into a PFC battery charger, suitable for current-controlled or voltage-controlled recharge. The AC current is controlled at unitary power factor with no harmonic distortion. Switching harmonics are also drastically reduced by means of phase-interleaving. The battery charge is regulated according to the requests of the Battery Monitor System (BMS) that is embedded into the battery packs. The effectiveness of the integrated battery charger is demonstrated here on an electric scooter with high voltage Li-Ion battery (260V) and DC/DC/AC power conversion scheme. The integrated PFC charger concept is also valid for electric vehicles with AC traction drives based on a direct DC/AC conversion scheme, as demonstrated throughout the paper.

	Modeling and testing of RFI filter for trolleybus transistor inverter By Waldemar ZAJAC, Wojciech CZUCHRA, Wojciech MYSINSKI	[View] [Download]
Abstract: This article discusses issues related to the design and simulation of an RFI filter for a trolleybus. Due to passenger safety requirements, Cy capacitors used in the filter must not have high capacity. That is why a special filter which meets those requirements has to be designed. Also presented in this paper are the laboratory and onboard tests of a prototype filter. Furthermore, a comparison is provided between the simulations and test results.

	Modeling of the Hybrid Electric Drive with an Electric Power Splitter and Simulation of the Fuel Efficiency By Pavel MINDL, Dobri CUNDEV, Zdenek CEROVSKY	[View] [Download]
Abstract: This paper presents the results of the modeling of the HEV with an electric power splitter (EPS) and simulation of the fuel efficiency of this type of vehicle. The new innovative technological approach is presented by using the special type of synchronous machine that splits the mechanical power on two separate power transmission pats and therefore it is called electric power splitter. EPS is based on a double rotor synchronous permanent magnet generator. It is consisted of two rotating parts, a classic permanent magnet rotor and a rotating stator. The rotor is firmly coupled to the drive shaft of the internal combustion engine of the vehicle (ICE). The rotating stator, which structurally is typical AC machine stator, is firmly coupled to the transmission of the vehicle that leads to the car wheels. This technical solution enables the ICE to operate on the most optimal revolutions during the entire driving schedule. Two distinguish approaches has bean realized in order this new innovative technological solution to be confirmed as eligible. First approach is creation the mathematical model of the entire system, taking into account all the necessary preconditions, environment influences, machine and component characteristics. The results have been obtained by using this precisely determined mathematical model and by simulating the characteristics of all essential values for the entire drive, which gives clear view of the capabilities and potentials of this new HEV system. The second approach is based on experimental verification. In order to be performed the laboratory tests on this HEV concept, an experimental working stand was se up in the laboratory. ICE and the traction load are simulated with controlled AC induction motors. The entire working stand presents complex machine, measure and control system for realization of this task.

	New power centre and power electronics sharing in aircraft By Lucien PRISSE	[View] [Download]
Abstract: The rationalization of the power sources in aircraft has led to the replacement of conventional systems by electrical ones. These new architectures have given rise to new technological needs. Indeed, power electronics is necessary to control the electrical motors. The loads are mainly the compressors for the Environmental Control System that manages the pressurization and the cooling of the aircraft cabin, the pumps (fuel and hydraulic), the fans, the starting of the engineâ€¦ One optimization axis is the power electronics sharing to control these loads. This paper presents a power centre mock-up that includes 8 similar power modules.

	Optimized 70kW power inverter dedicated to future aircraft applications By Rodolphe DE MAGLIE, Gaetan OSVALD, Juergen ENGSTLER, Alfred ENGLER, Jean-Pierre CARAYON	[View] [Download]
Abstract: This paper presents the 70kW inverter dedicated for future aeronautical applications in the frame of the MOET program, a FP6 European Integrated Project [1]. Design considerations, principle of operation and experimental results will be presented hereunder. For DC to AC conversion, technologies improvements and specific integration allow reducing weight and volume and increase the power density up to 5kW per kilogram.

	Power Processing Unit for the Next Generation Satellite By Hiroyuki OSUGA, Fujio KUROKAWA	[View] [Download]
Abstract: The preliminary design of the Power Processing Unit (PPU) for the next generation satellite is presented. In the future, the next generation satellite will progress to higher thrust level, to wider thrust control range and to quick response. The Hall thruster is one of the promising candidates in the electrical propulsion system for this satellite. However, it is difficult to control the Hall thruster in a way that enables a stable operation for a wide operating range. We study the PPU using a new design approach of the controlling wider thrust range for a Hall thruster. By synchronously controlling three power supplies, the discharge current oscillation and inrush current at ignition can be suppressed. As a result, the PPU uses new control logic for the wider thrust range. The new control method is the pulse width modulation that achieves to operating requirements for reducing the consumption of propellant gas. The control logic realizes the quick ignition and smooth operation in a wider thrust range.

	Power System for Electrical Propulsion in space applications By Esteban SANCHIS, Enrique MASET, Agustin FERRERES, Juan B. EJEA, Jose M. BLANES, Ausias GARRIGOS, Jose JORDAN, VICENTE ESTEVE	[View] [Download]
Abstract: Ion engines, also known as electrical propulsion, are used more and more in space applications due to its higher power density and its lower contamination risk than with chemical propulsion. One of its characteristics is that it needs a very stable power supply. This paper proposes a solution for the BepiColombo mission to Mercury. Electrical propulsion increases the electrical power demand of the spacecraft (in the range of 8 kW up to 14 kW for the BepiColombo Mission), generating new research opportunities on selecting the best Solar Array Regulator topology. Other missions now under study and looking for the future are Lunar Exploration. Solar electric propulsion (SEP) is used during the cruise period from Earth to Mercury in the BepiColombo mission. The Solar Array (SA) power increases with time and its associated propulsion unit has to take the maximum available power from the SA to use in the ion drive motor in order to reach Mercury within a reasonable time. Ion Thrust is not required in eclipse and therefore a Power System was designed that did not require a Battery and therefore a considerable mass could be saved. The paper describes a solution for the Mercury Transfer Module (MTM) Power Conditioning and Distribution Unit (PCDU) of the Solar Electric Propulsion Module (SEPM). The new conception is a Sequential Switching Shunt Maximum Power Regulator (S3MPR) consisting in a Sequential Switching Shunt Regulator (S3R), to keep the SA voltage at its Maximum Power Point (MPP) followed by a Boost regulator to produce a constant 100 V to supply the Electronic Propulsion (EP). A scaled-down Power Subsystem of 1 kW output power has been built and tested.

	Stability Assessment of Electric Power Systems for â€˜More Electricâ€™ Aircraft By Antonio GRIFFO, Jiabin WANG	[View] [Download]
Abstract: This paper presents a comprehensive assessment of small-signal stability for a â€œmore-electricâ€ aircraft power system consisting of a synchronous variable-frequency generator which supplies several power electronic controlled loads via an 18-pulse autotransformer rectifier unit (ATRU) for AC-DC conversion. Functional models for key power system components and loads are derived. Numerical tools employed for the automatic calculation of linearized equations and operating points are described, and the influence of leading design and operational parameter on system stability is evaluated.

	State-space average modelling of synchronous generator fed 18-pulse diode rectifier By Antonio GRIFFO, Jiabin WANG	[View] [Download]
Abstract: The paper derives an analytical state-space average-value model of the direct symmetric topology of an 18-pulse AC-DC rectifier. The dynamic characteristics of the rectifier are fully represented while the model is time invariant and computationally efficient. The developed model, validated with comparison of the resultant transient and steady state behaviors with those obtained from detailed simulations of a test system including synchronous generator and DC loads can, therefore, be used for stability assessment of electric power systems with diode rectifiers, multiple power electronic converter-controlled loads and electrical drives.