EPE Association: EPE 2016 - DS3j: Converters and Drives for Electric Vehicles

EPE 2016 - DS3j: Converters and Drives for Electric Vehicles
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2016 ECCE Europe - Conference > EPE 2016 - Topic 08: e-Mobility > EPE 2016 - DS3j: Converters and Drives for Electric Vehicles

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   Comparing 650 V and 900 V SiC MOSFETs for the Application in an Automotive Inverter
By Teresa BERTELSHOFER [View]
[Download]

Abstract: This paper researches the performance benefits of replacing the Si IGBTs and diodes in a power module for automotive drives with either 650 V or 900 V SiC MOSFETs. Evaluating the mean conduction and switching losses in a load profile allows a comparison of both voltage classes in order to show which class offers the lower overall losses in the given application. Furthermore, the influence on the switching losses of different gate driving methods and stray inductance of the commutation loops is investigated. It can be found that 900 V chips offer lower overall losses in combination with standard packages (middle to high commutation loop inductance) and standard gate driving methods (using only the gate resistance to control the switching speed). 650 V chips, however, profit from low inductive setups and smarter gate driving strategies, while at the same time displaying less oscillations during switching.

   DC-DC Converter Design for Power Distribution Systems in Electric Vehicles using Calorimetric Loss Measurements
By Sven BOLTE [View]
[Download]

Abstract: In this contribution, a uni-directional converter is proposed which supplies the EV's safety-low voltage grid of 14 V DC directly from the drive battery voltage level of 250 … 370 V. The converter consists of two power stages which are a hard-switching SiC boost converter and a soft-switching resonant converter. Special attention is paid to the accurate loss modelling of the converter, where frequency-depending winding losses, magnetic core losses, and semiconductor switching losses are considered. The core and winding losses were validated by calorimetric measurements, which results are in good accordance with the simulations. As final result, a converter peak efficiency of 98.2\% was achieved.

   Design of a Full SiC Voltage Source Inverter for Electric Vehicle Applications
By Alexander BUCHER [View]
[Download]

Abstract: Taking into account typical power and temperature requirements of electric vehicle applications, siliconcarbide based semiconductor devices seem to be the most promising candidates for future highpower density traction inverter applications. Therefore, the design of a three-phase DC-AC inverterbased on SiC MOSFETs under automotive constraints is discussed in this paper. In order to fully utilizethe performance offered by these superior power semiconductors, the electrical design of a highpower module in combination with a low inductance DC-link design is presented. The switching behaviorof this prototype module is presented, emphasizing the significant improvements SiC powerdevices offer in terms of performance over state-of-the art silicon IGBTs. For EV applications, theobtained low switching losses in combination with the purely Ohmic output characteristics of thesedevices result in substantial efficiency improvements which are determined by means of drive cyclesimulations. First test bench measurements are presented with the full SiC inverter operating at aswitching frequency of 40 kHz. Overall, SiC MOSFETs offer the possibility to significantly increasethe performance, power density and efficiency of the electric drive system.

   Efficiency analysis of three-level NPC and T-Type voltage source inverter for various operation modes optimizing the overall drive train efficiency by an operat
By Martin STEMPFLE [View]
[Download]

Abstract: For drive train efficiency estimation, three-level inverters are analyzed regarding different modulation techniques and switching frequencies. In this paper an optimized operating mode selector is proposed to choose a loss optimal modulation technique and switching frequency for each operating point. Energy savings due to the operating mode selector are validated on a driving cycle.

   Estimation of Losses in Permanent Magnet Synchronous Machines Caused by Inverter Voltage Harmonics in Driving Cycle Operation
By Johannes HESEDING [View]
[Download]

Abstract: This paper presents a method to measure the frequency dependent impedance of an electric machine tocalculate the additional losses caused by inverter output voltage harmonics. These losses are calculatedby combining the calculated inverter output voltage spectrum and the measured frequency dependentimpedance of the machine.

   Impact of Developing Semiconductor Technologies on Two- and Three-Level Converters for Electric Vehicle Applications
By Theodore SOONG [View]
[Download]

Abstract: New semiconductor technologies, like SiC, are being integrated into electric vehicles (EVs). These semiconductors reduce losses to improve the driving range of EVs, and higher switching frequencies minimize harmonic losses. This work presents a framework to quickly assess different topologies and semiconductor technologies where both two- and three- level converters are scrutinized.

   Impact of the Automotive Energy Net Impedance on the Voltage-Stabilization Performance of a Floating Capacitor H-Bridge Converter
By Matthias HIERMEIER [View]
[Download]

Abstract: A floating capacitor H-Bridge converter is proposed to stabilize the automotive energy net against undesired voltage spikes and to limit the voltage range for the electrical loads. In comparison to classical converter topologies the proposed floating H-Bridge converter with integrated energy storage device provides lower switch-voltage stress and allows therefore the implementation of high-current low-voltage switching devices with lowest on-state resistance and very simple drive circuits. In this publication the impact of the energy net impedance on the voltage stabilization performance and on the stability of the system is analyzed. Analyses are performed, a control method is proposed and results of a full-size prototype converter are shown to prove the converter performance for the given application. Theoretical predictions are in good correlation with experimental results.

   Inversion-Based Control Of Modular High Frequency Inverters
By Marcel LUTZE [View]
[Download]

Abstract: Inversion-based control for modular high frequency (MHF) inverters in a two-degree-of-freedom structure is presented in this paper. This establishes a state-space average model of MHF inverters. The results of this paper are illustrated using simulation and experiment based on an MHF3P inverter with four submodules.

   Investigation of Discontinuous PWM as Additional Optimization Parameter in an Active Thermal Control
By Dennis KACZOROWSKI [View]
[Download]

Abstract: For AC converters in electric vehicles, the opportunity to change space vector modulation to discontinuousPWM during operation is investigated and added to an active thermal control, which already variesthe switching frequency and the current limit to achieve lower junction temperature swings and improvethe reliability. Simulated start-up processes of the vehicle show the potential of this approach. The onlinepower loss model and the thermal temporal behaviour is validated by measurements.

   Model based Thermal Evaluation of a Modular Power Inverter System
By Manuel BROSE [View]
[Download]

Abstract: Modular power inverter systems for auxiliary drives in utility vehicles can meet various differentcustomer requirements. A model based approach can be used for validating the thermal design of thosesystems in any suitable modular configuration. This contribution is focused on an equivalent lumpedthermal network model for a modular inverter system on a given heat sink concept. The proposednetwork representation is based on spatial splitting of the heat sink geometry whereby the lumpednetwork elements are parametrized by means of the heat sink geometry. Since the proposed network iseasy and straightforward, a minimum of variables are introduced to adjust the temperature resultsempirically with FEM results on certain reference operation points. Furthermore, modularity isconsidered due to the coolant and therefore, customer specific placement of modules can beinvestigated. Finally, the proposed model is compared with FEM results of a worst case systemconfiguration, the influence of the introduced adjustment variables is shown and further validationresults with thermal measurements and FEM results of different system configurations are given.

   Modular Multilevel Battery (M2B) for Electric Vehicles
By Florian HELLING [View]
[Download]

Abstract: Electromobility is expected to successfully compete with conventional propulsion technology in thenear future and thus creates new challenges for the automotive industry. Major issues with state of theart electric vehicles (EVs) include limited range due to insufficient energy density and heavy weight ofexisting battery storage systems, unsatisfactory charging duration as well as comparatively high costs.A leap in power electronics technology might meet these challenges, as the aforementionedcharacteristics are predominantly determined by existing EV system architectures and powerconverters. This paper presents a novel modular multilevel parallel converter-based split batterysystem for electric vehicles, enabling dynamic switching of battery cells in parallel and in series. Eachindividual battery cell may be interconnected to its neighbours according to operational needs, e.g. toprovide optimum source resistance, lowest state-of-charge (SOC) cycling, and balanced aging,rendering separate battery management systems (BMS) unnecessary. Applying the proposedtechnology in EVs may fundamentally change existing powertrain architectures and chargertopologies, as it merges the battery storage system and the power converter. This forms the basis for ahighly integrated power electronics unit that includes traction converter, battery charger, and BMS.

   Optimized design of DC-DC converter LC output filter for EV battery charging applications in terms of defined battery current and voltage ripple as well as over
By Marco JUNG [View]
[Download]

Abstract: This paper presents an optimization strategy for DC-DC converters. The goal is to find the optimum design for the LC output filter in terms of the defined battery voltage and current ripple limits as well as the overall system efficiency (battery and converter).

   Spectral Synthesis of Switching Distortion in Automotive Drive Inverters
By Stefan GOETZ [View]
[Download]

Abstract: Conventional inverters rely on switching modulation to generate the alternating current (AC) output required by many loads, such as electric machines. Particularly in mass-produced electric vehicles (EV), inverters exclusively use pulse-width modulation (PWM) with fixed switching rates, resulting in strong though con_ned peaks in the output spectrum at the switching frequency, as well as its overtones. These peaks conflict with electromagnetic compatibility and interference (EMC/EMI) regulations due to their large spectral power concentration, and interfere with other electronic components such as\_most obvious to the passengers\_the entertainment electronics. We present a modulator for commercial EV inverters that shapes the spectral content of the unavoidable distortion of switching modulation according to given constraints such that load requirements, regulatory limits, and constraints provided by other automotive components can be balanced. We will further present how the modulator can, unlike in known methods, balance switching loss and distortion. A gallium nitride (GaN) inverter demonstrates the high potential for motor-drive applications. The spectral density of the switching harmonics in the experimental inverter could be reduced more than three-fold compared to conventional PWM.

   Z-source with Rectangular wave Modulation Inverter for Hybrid / Electric Vehicles
By Thilak SENANAYAKE [View]
[Download]

Abstract: An improved circuit topology of Z-source inverter is presented that will meet the requirements and features of the Hybrid / Electric vehicle power control system. It is able to perform rectangular wave modulation for motor drive control depending on the drive condition of a motor which cannot be achieved from the conventional Z-source inverter.

EPE 2016 - DS3j: Converters and Drives for Electric Vehicles
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2016 ECCE Europe - Conference > EPE 2016 - Topic 08: e-Mobility > EPE 2016 - DS3j: Converters and Drives for Electric Vehicles
	[return to parent folder]

	Comparing 650 V and 900 V SiC MOSFETs for the Application in an Automotive Inverter By Teresa BERTELSHOFER	[View] [Download]
Abstract: This paper researches the performance benefits of replacing the Si IGBTs and diodes in a power module for automotive drives with either 650 V or 900 V SiC MOSFETs. Evaluating the mean conduction and switching losses in a load profile allows a comparison of both voltage classes in order to show which class offers the lower overall losses in the given application. Furthermore, the influence on the switching losses of different gate driving methods and stray inductance of the commutation loops is investigated. It can be found that 900 V chips offer lower overall losses in combination with standard packages (middle to high commutation loop inductance) and standard gate driving methods (using only the gate resistance to control the switching speed). 650 V chips, however, profit from low inductive setups and smarter gate driving strategies, while at the same time displaying less oscillations during switching.

	DC-DC Converter Design for Power Distribution Systems in Electric Vehicles using Calorimetric Loss Measurements By Sven BOLTE	[View] [Download]
Abstract: In this contribution, a uni-directional converter is proposed which supplies the EV's safety-low voltage grid of 14 V DC directly from the drive battery voltage level of 250 … 370 V. The converter consists of two power stages which are a hard-switching SiC boost converter and a soft-switching resonant converter. Special attention is paid to the accurate loss modelling of the converter, where frequency-depending winding losses, magnetic core losses, and semiconductor switching losses are considered. The core and winding losses were validated by calorimetric measurements, which results are in good accordance with the simulations. As final result, a converter peak efficiency of 98.2\% was achieved.

	Design of a Full SiC Voltage Source Inverter for Electric Vehicle Applications By Alexander BUCHER	[View] [Download]
Abstract: Taking into account typical power and temperature requirements of electric vehicle applications, siliconcarbide based semiconductor devices seem to be the most promising candidates for future highpower density traction inverter applications. Therefore, the design of a three-phase DC-AC inverterbased on SiC MOSFETs under automotive constraints is discussed in this paper. In order to fully utilizethe performance offered by these superior power semiconductors, the electrical design of a highpower module in combination with a low inductance DC-link design is presented. The switching behaviorof this prototype module is presented, emphasizing the significant improvements SiC powerdevices offer in terms of performance over state-of-the art silicon IGBTs. For EV applications, theobtained low switching losses in combination with the purely Ohmic output characteristics of thesedevices result in substantial efficiency improvements which are determined by means of drive cyclesimulations. First test bench measurements are presented with the full SiC inverter operating at aswitching frequency of 40 kHz. Overall, SiC MOSFETs offer the possibility to significantly increasethe performance, power density and efficiency of the electric drive system.

	Efficiency analysis of three-level NPC and T-Type voltage source inverter for various operation modes optimizing the overall drive train efficiency by an operat By Martin STEMPFLE	[View] [Download]
Abstract: For drive train efficiency estimation, three-level inverters are analyzed regarding different modulation techniques and switching frequencies. In this paper an optimized operating mode selector is proposed to choose a loss optimal modulation technique and switching frequency for each operating point. Energy savings due to the operating mode selector are validated on a driving cycle.

	Estimation of Losses in Permanent Magnet Synchronous Machines Caused by Inverter Voltage Harmonics in Driving Cycle Operation By Johannes HESEDING	[View] [Download]
Abstract: This paper presents a method to measure the frequency dependent impedance of an electric machine tocalculate the additional losses caused by inverter output voltage harmonics. These losses are calculatedby combining the calculated inverter output voltage spectrum and the measured frequency dependentimpedance of the machine.

	Impact of Developing Semiconductor Technologies on Two- and Three-Level Converters for Electric Vehicle Applications By Theodore SOONG	[View] [Download]
Abstract: New semiconductor technologies, like SiC, are being integrated into electric vehicles (EVs). These semiconductors reduce losses to improve the driving range of EVs, and higher switching frequencies minimize harmonic losses. This work presents a framework to quickly assess different topologies and semiconductor technologies where both two- and three- level converters are scrutinized.

	Impact of the Automotive Energy Net Impedance on the Voltage-Stabilization Performance of a Floating Capacitor H-Bridge Converter By Matthias HIERMEIER	[View] [Download]
Abstract: A floating capacitor H-Bridge converter is proposed to stabilize the automotive energy net against undesired voltage spikes and to limit the voltage range for the electrical loads. In comparison to classical converter topologies the proposed floating H-Bridge converter with integrated energy storage device provides lower switch-voltage stress and allows therefore the implementation of high-current low-voltage switching devices with lowest on-state resistance and very simple drive circuits. In this publication the impact of the energy net impedance on the voltage stabilization performance and on the stability of the system is analyzed. Analyses are performed, a control method is proposed and results of a full-size prototype converter are shown to prove the converter performance for the given application. Theoretical predictions are in good correlation with experimental results.

	Inversion-Based Control Of Modular High Frequency Inverters By Marcel LUTZE	[View] [Download]
Abstract: Inversion-based control for modular high frequency (MHF) inverters in a two-degree-of-freedom structure is presented in this paper. This establishes a state-space average model of MHF inverters. The results of this paper are illustrated using simulation and experiment based on an MHF3P inverter with four submodules.

	Investigation of Discontinuous PWM as Additional Optimization Parameter in an Active Thermal Control By Dennis KACZOROWSKI	[View] [Download]
Abstract: For AC converters in electric vehicles, the opportunity to change space vector modulation to discontinuousPWM during operation is investigated and added to an active thermal control, which already variesthe switching frequency and the current limit to achieve lower junction temperature swings and improvethe reliability. Simulated start-up processes of the vehicle show the potential of this approach. The onlinepower loss model and the thermal temporal behaviour is validated by measurements.

	Model based Thermal Evaluation of a Modular Power Inverter System By Manuel BROSE	[View] [Download]
Abstract: Modular power inverter systems for auxiliary drives in utility vehicles can meet various differentcustomer requirements. A model based approach can be used for validating the thermal design of thosesystems in any suitable modular configuration. This contribution is focused on an equivalent lumpedthermal network model for a modular inverter system on a given heat sink concept. The proposednetwork representation is based on spatial splitting of the heat sink geometry whereby the lumpednetwork elements are parametrized by means of the heat sink geometry. Since the proposed network iseasy and straightforward, a minimum of variables are introduced to adjust the temperature resultsempirically with FEM results on certain reference operation points. Furthermore, modularity isconsidered due to the coolant and therefore, customer specific placement of modules can beinvestigated. Finally, the proposed model is compared with FEM results of a worst case systemconfiguration, the influence of the introduced adjustment variables is shown and further validationresults with thermal measurements and FEM results of different system configurations are given.

	Modular Multilevel Battery (M2B) for Electric Vehicles By Florian HELLING	[View] [Download]
Abstract: Electromobility is expected to successfully compete with conventional propulsion technology in thenear future and thus creates new challenges for the automotive industry. Major issues with state of theart electric vehicles (EVs) include limited range due to insufficient energy density and heavy weight ofexisting battery storage systems, unsatisfactory charging duration as well as comparatively high costs.A leap in power electronics technology might meet these challenges, as the aforementionedcharacteristics are predominantly determined by existing EV system architectures and powerconverters. This paper presents a novel modular multilevel parallel converter-based split batterysystem for electric vehicles, enabling dynamic switching of battery cells in parallel and in series. Eachindividual battery cell may be interconnected to its neighbours according to operational needs, e.g. toprovide optimum source resistance, lowest state-of-charge (SOC) cycling, and balanced aging,rendering separate battery management systems (BMS) unnecessary. Applying the proposedtechnology in EVs may fundamentally change existing powertrain architectures and chargertopologies, as it merges the battery storage system and the power converter. This forms the basis for ahighly integrated power electronics unit that includes traction converter, battery charger, and BMS.

	Optimized design of DC-DC converter LC output filter for EV battery charging applications in terms of defined battery current and voltage ripple as well as over By Marco JUNG	[View] [Download]
Abstract: This paper presents an optimization strategy for DC-DC converters. The goal is to find the optimum design for the LC output filter in terms of the defined battery voltage and current ripple limits as well as the overall system efficiency (battery and converter).

	Spectral Synthesis of Switching Distortion in Automotive Drive Inverters By Stefan GOETZ	[View] [Download]
Abstract: Conventional inverters rely on switching modulation to generate the alternating current (AC) output required by many loads, such as electric machines. Particularly in mass-produced electric vehicles (EV), inverters exclusively use pulse-width modulation (PWM) with fixed switching rates, resulting in strong though con_ned peaks in the output spectrum at the switching frequency, as well as its overtones. These peaks conflict with electromagnetic compatibility and interference (EMC/EMI) regulations due to their large spectral power concentration, and interfere with other electronic components such as\_most obvious to the passengers\_the entertainment electronics. We present a modulator for commercial EV inverters that shapes the spectral content of the unavoidable distortion of switching modulation according to given constraints such that load requirements, regulatory limits, and constraints provided by other automotive components can be balanced. We will further present how the modulator can, unlike in known methods, balance switching loss and distortion. A gallium nitride (GaN) inverter demonstrates the high potential for motor-drive applications. The spectral density of the switching harmonics in the experimental inverter could be reduced more than three-fold compared to conventional PWM.

	Z-source with Rectangular wave Modulation Inverter for Hybrid / Electric Vehicles By Thilak SENANAYAKE	[View] [Download]
Abstract: An improved circuit topology of Z-source inverter is presented that will meet the requirements and features of the Hybrid / Electric vehicle power control system. It is able to perform rectangular wave modulation for motor drive control depending on the drive condition of a motor which cannot be achieved from the conventional Z-source inverter.