Hans-Christian Reuss

Predictive motion cueing algorithm for development of interactive assistance systems

Enhanced tools for simulation and test of vehicle components enable to carry out many steps of the vehicle development process in a virtual environment. Driving simulators close the gap between virtual development and on-road test drives. They offer the possibility to experience future powertrain, chassis or aerodynamic components in an early stage of development and allow a virtual evaluation of variants. Due to their steady, on-going development, moving base driving simulators are increasingly integrated into the development process.

Real-time thermal monitoring of power semiconductors in power electronics using linear parameter-varying models for variable coolant flow situations

Real-time thermal monitoring of power-semiconductor temperatures is an important task to establish thermal protection within a water-cooled power-electronic inverter unit. A model-based method is presented, which estimates the junction temperatures. Via feedback of measured temperature signals, the observer system is also able to estimate the coolant temperature. However, if the module is cooled by variable coolant flow rates, the heat transfer coefficient from heat sink to coolant changes. Consequently, the estimated coolant temperature of the observer system based on a static thermal model becomes inaccurate. This paper proposes a method to adapt the thermal model dependent on the current coolant flow rate using a parameter-varying system design.

Real-time coolant temperature monitoring in power electronics using linear parameter-varying models for variable coolant flow situations

In power converters of (hybrid) electric vehicles, the power losses within the semiconductors (diodes and IGBTs) lead to strong self-heating. Therefore, methods for online monitoring of the relevant temperatures are a very important topic regarding thermal self-protection. In order to reduce the number of sensors (and costs) it can be advantageous to use fewer sensors than the number of relevant temperatures and to use a model-based method to reconstruct/estimate the non-measureable temperatures. However, the accuracy of such models in water cooled systems is affected if the coolant flow rate deviates from nominal (constant) flow rate. This paper presents a method to estimate the junction temperatures of the semiconductors and the coolant inlet and outlet temperature of a 3 phase voltage inverter for automotive usage. It proposes a linear parameter-varying model to cope with variable coolant flow situations. Eventually, the method is verified by measurements.

Electric Vehicle Positioning for Inductive Charging Purposes Using Magnetic Field Distortion Elimination in High-Permeability Environments

This paper presents a novel method to position electric vehicles for inductive charging purposes. The approach is to get position information by measuring the magnetic flux density caused by the charging coil located in the ground of the parking place. However, the sensors are mounted at the high-permeable undersurface of the vehicle, which leads to field distortions and, consequently, to high measurement errors. In this paper, these distortions were investigated by means of the finite-element method. Thereby, the vehicle was designed as finite expanded cuboid of high permeability. From these results, a simple mathematical model was derived, which maps the original field to the distorted one. In the following, this model and its validity constraints are discussed more in detail.

Modular modeling of a PEM fuel cell system for automotive applications

The promising potentials of fuel cell systems attract more and more interest in science and industry for the application in alternative drive concepts. Their ability to convert hydrogen into electrical energy in a clean, highly durable and reliable way offers solutions to some of the fundamental challenges of modern drive development. From a wide variety of available technologies, proton exchange membrane fuel cells PEMFC seem to be appropriate for automotive applications and are therefore a very active field of research and development. Today, first large-scale field tests of fuel cell electrical vehicles FCEV’s indicate the increasing maturity and competitiveness as a result of continuous improvements in life cycle and efficiency as well as the reductions of cost and weight. Equivalent to the ongoing development of conventional combustion engines, advancements in controller design, on-board diagnostics and the optimization of operating strategies are crucial for exploiting the technological possibilities. The basis is a fuel cell system model that takes the demands for automotive application into account.

Identification and evaluation of the real temperature loading of steering electronics

Within a few years, electric power steering (EPS) almost completely replaced hydraulic steering assistance in all vehicle segments. This is largely due to a more compact design – because the hydraulic unit is no longer needed – and a significant reduction in fuel consumption for the end customer. [1]

Framework for interactive testing and development of highly automated driving functions

With the emergence of autonomous driving, a rapidly increasing number of new vehicle functions is needed, which must be checked by numerous vehicle tests regarding their functionality. Due to the increasing complexity of these systems, this requires an expanded use of virtual developmental and test methods. Therefore, software environments that enable the generation and implementation of various test cases are needed.

High performance powertrain of a four-wheel drive racecar with an oil-cooled battery

The most recent GreenTeam race car, the E0711-7, has been designed and built to set a new level of high performance race cars made by GreenTeam. This paper investigates the E0711-7s high performance powertrain design process, powertrain structure and the unique oil-cooled battery pack. Experimental results from test bench measurements and race data have been reported to illustrate the powertrain performance and to point out the behavior of the oil-cooled battery pack.

A model-driven approach for the development of safety-critical functions using modified architecture description language (ADL)

Safety is becoming more and more important with the ever increasing level of safety related E/E Systems built into the cars. Increasing functionality of vehicle systems through electrification of power train and autonomous driving leads to complexity in designing system, software and safety architecture. ISO 26262 aims to reduce the complexity and to approve the traceability of the different safety activities. An approach, how the engineers deal with these challenges in an efficient and effective way, offers model-driven system, software and safety development. This makes it possible to describe, analyze and verify the system, software and safety architecture with models in order to detect the design and systematic errors before implementation. This paper presents an approach about model-based development of system, software and safety. In particular, we briefly discuss how the main activities from ISO 26262 such as hazard analysis and risk assessment, functional safety concept, technical safety concept, safety analysis, etc. can be developed model-driven and how it can be merged with system and software development. The state-of-art is also provided and compared with the proposed approach.

Electric drivetrain modular layout based on range specifications

After many years with low number of units, sales figures for electric vehicles (EVs) start rising. This leads to diversified specifications in range and drive power for EVs of the next generations. Single EV models are likely to be sold not only with different drive powers (like with combustion drivetrains) but also with different battery sizes (and thus ranges). Specific layout tools are necessary for this way of modularization, to identify optimal solutions not only for a single drivetrain but for a whole portfolio.