S. Jeschke

HiL simulation of electric vehicles in different usage scenarios

This paper describes the simulation of an electric vehicle drive train via a hardware in the loop (HiL) setup in combination with an interactive driving simulator based on MATLAB/Simulink. This setup provides the possibility to test the suitability of electric vehicles in different usage scenarios using a laboratory environment. Another aspect is that by a comprehensive analysis of the measurement data, system components of the drive train can be tested under realistic conditions and further developed in order to improve the efficiency of such vehicles.

Investigations on the Impact of Different Electric Vehicle Traction Systems in Urban Traffic

Currently electric vehicles are introduced in e.g. public transport and individual traffic in order to reduce i.a. the green house gas emissions. The main disadvantage of electric vehicles compared to vehicles with conventional drive is the shorter operating distance. In contrast this disadvantage is partially negligible in urban usage scenarios, like e.g. taxi or delivery services. This paper focuses on the simulation of electric vehicle propulsion systems using a Hardware in the Loop (HiL) model. The model consisting of components used in actual electric vehicles is scaled using Buckinghams Pi-Theorem in order to analyze the impact of different electric traction systems on the vehicles energy consumption. Thus the available operating distance of such vehicles can be optimized in urban traffic.

Latest development of the national and international EMC-standards for electric vehicles and their charging infrastructure

For a long term success of electric mobility, its definitely necessary to provide safe charging infrastructures in addition to marketable vehicles. Since safety and functionality requirements on every electric mobility product are extremely high, the interoperability between charging infrastructure and vehicle, as well as the interaction of both systems under every possible environmental condition and parameter variations are significant. In addition to climatic and mechanical influences, electromagnetic influence, e.g. broadcast transmitter, mobile phones, the disturbances caused by the systems themselves and the sensibility to each other, belongs also to environmental requirement. Focusing on the Electromagnetic Compatibility (EMC) of the charging infrastructure of these vehicles, the normative standards have to be adapted to these new circumstances. In this paper, several critical issues, especially the controversial discussed aspects regarding EMC in the draft version of IEC 61851-21-2, which is an EMC standard for conductive charging infrastructure, are demonstrated according to the diverse charging modes and the special interfaces to energy supply networks.

Examination of the low voltage system in the frequency range up to 500 kHz with regard to data transmission by powerline communication

In the common energy supply network the energy is transferred from the high voltage level to the medium voltage grid and further via the low voltage grid to the end customer. This general principle of the power distribution grid and its planning is currently changed especially by means of the increasing number of peripheral producers on the low voltage network. Furthermore, the grids rising complexity causes a connection between the power supply grid and the information and communication technology. The extreme power fluctuation shows, that greater efforts have to be made to plan and control modern grids. As a result of these variations, voltage may rise above tolerance limit at load reversal. Due to the increase of hardly predictable regenerative energy generation the number of critical operating conditions and grid overload is constantly rising. There is an increase of regenerative energy generation as well as of the use of efficient electronic power switching (e.g. switch-mode power supply) in the low voltage grid. This leads to an increase of harmonics and the necessity to know the exact system status of the low voltage system.

EMI measurement on electric vehicle drive inverters using a passive motor impedance network

As a result of the power train electrification in electric and hybrid vehicles the electromagnetic compatibility of these vehicles is comprehensively affected. Especially the power electronic components operated at battery voltages of around 400V produce broadband EMI inside the vehicle. To prove compliance with the normative requirements considering the vehicles inner EMC, EMI measurements on component level are used. As testing a drive inverter requires an electric motor as load which has to be mechanically loaded by another inverter driven system possibly affecting the measurement, the load torque has to be generated outside the shielded chamber. As the mechanical connection of the two drives through the chambers wall has to be shielded, it is quite difficult to realize. Thus in this work a passive load is developed, modeling the impedance behavior of an existing motor. Thus no bushing and no setup for load torque generation has to be used for drive inverters test setup according to CISPR 25. This circuit is realized to model the load for drive inverters typically used in electric vehicles. Finally the results of the EMI measurements at the passive network and at the modeled drive are compared.

Investigations on the shaft currents of an electric vehicle traction system in dynamic operation

As a result of the power train electrification in electric and hybrid vehicles the electromagnetic compatibility of these vehicles is comprehensively affected. To ensure the electromagnetic compatibility of these vehicles the traction system is built up completely shielded and isolated from the vehicle chassis. Considering the shielding of the propulsion system the shaft of the traction drive represents a weak point. Due to stray capacitances of the drives bearings the high frequent portions of the stator current can couple onto the shaft. These currents can flow through the gear box in direction of the wheels and possibly affect sensors of the 12V system. For EMC testing on component level, normally the common mode current on the cables between the inverter and the drive and between the inverter and the propulsion battery is considered. For the disturbances occurring on the battery cables alternatively the unsymmetrical voltage is measured using a high voltage coupling network. Considering the actual standard, a measurement of the shaft currents is actually not provided. Another point is that the measurements are normally tested in constant operating points, not representing the typical operation of a vehicle. Thus in this paper the shaft currents occurring in the traction system of an electric vehicle are investigated for constant and dynamic operation. For the investigation, a Hardware in the Loop (HiL) setup of an electric vehicle traction system with the ability to variably simulate dynamic drive scenarios is used. For the detection of the shaft currents, an inductive measurement transducer is used. The occurring EMI are measured using a Time Domain EMI Measurement system to analyze the EMI behavior and to indentify critical operating points during the dynamic operation of an electric vehicle.