Research
Research projects at the HiPE-LAB
The following research projects use the HiPE-LAB to test the newly developed systems.
ODYSSEV
However, to achieve a mainstream adoption of fully electric vehicles (EV), main concerns from consumers must be addressed, including longer driving ranges and faster charging. High voltage systems offer the opportunity to tackle this challenge and companies around the world like Hitachi Automotive or Porsche have started now the mass production of 800V systems. However, moving from the standard 12V batteries to 800V systems and the upcoming generation of high voltage EVs implies a new set of engineering challenges such as the need for high-reliability components or to reduce the size and weight of systems while safely increasing voltages.
ODYSSEV builds on the current trend for higher voltage powertrains to develop the next generation of automotive power converters, as well as to optimize the different powertrain elements by taking advantage from the benefits of higher voltage levels and from the advanced capabilities of novel power electronic topologies. In this sense, the central development of ODYSSEV is a hybrid concept of inverter, able to benefit from both RC-IGBTs and SiC MOSFET characteristics in the different load conditions faced by the EV. In this sense, two different configurations of a quasi-level VSI combined with AHXS will be validated looking for the best techno-economic performance under different scenarios.
Linked to the inverter, ODYSSEV will optimize both the high voltage motor geometry and topology, with a specific focus on avoiding partial discharge and current harmonics issues, and the battery pack configuration. Regarding the battery pack, it has been designed as fully reconfigurable so that it can be charged at lower voltages (400-800V) but also provide 1200-1600V during traction mode. At this point it must be highlighted that ODYSSEV powertrain preliminary design aims at achieving 1200V and 100 kW, but several scenarios will be analyzed prior to making the final design, thus assessing the achievement of higher voltages.
ODYSSEV will also address innovations in the powertrain dealing with the on-board charger, the system packaging and the overall control of the powertrain, thus providing a fully functional solution with capability to maximize efficiency for different car models, driving regions, load conditions and driving styles across the entire vehicle lifecycle. The final aim of ODYSSEV is to demonstrate the novel concept of high voltage powertrain by integrating the prototype in a vehicle for its test under real driving conditions, thus providing real evidence on the lower costs, losses and weight that high voltage solutions can offer for EV manufacturers.
LimBa-Leik
As part of the planned transformation of energy systems in Germany and Europe, efficient technologies for generating, storing and converting renewable energy will be used in the future. The link to the electrical grid is usually provided by power electronics in the form of power converters, which can feed the renewable energy generated into the electrical grid extremely efficiently. Due to their design, the power semiconductor switches in the power converters are subject to high thermo-mechanical stress caused by hard switching on and off at high frequencies, high voltages and high currents. Due to the numerous different materials with sometimes very contrasting thermal parameters that are used to manufacture power semiconductor switches in modular design, the stress exerted on them also causes ageing in the structure and ultimately failure of the devices.
The aim of the proposed ‘LimBaLeik’ project is to develop, for the first time, a validatable overall model for assessing the remaining lifetime in line with industry standards and to work out the necessary measurement procedures and methods, which do not currently exist. These are to be experimentally demonstrated and derived through initial feasibility studies at the HiPE-LAB.
ReCoWind
Frequency converters are indispensable components of modern wind turbines. At the same time, they exhibit high failure rates and cause considerable repair costs and yield losses. The aim of the ReCoWind project is to further investigate the causes and mechanisms of the often premature and unforeseen failures of frequency converters in wind turbines. One focus is humidity as a failure-relevant influencing factor identified in preliminary work. Based on the results of field data, model-based and experimental investigations, measures in the field of design, operation management, maintenance as well as in the field of component testing are derived to increase the reliability of frequency converters in wind turbines.
Within the framework of ReCoWind, it was possible for the first time to measure converter modules equipped with temperature and humidity sensors in a converter system in the HiPE-Lab under combined climatic and electrical loads. To ensure application-typical, realistic test conditions, the test profiles were derived from field measurement data recorded during field measurement campaigns in the ReCoWind project, among others. The aim of the measurements is to record and better understand the microclimate in converters.
SiC-Mobil
The aim of the SiC-Mobil joint project is to make traction drives and charging systems for electric vehicles smaller, lighter and more efficient. The key to this lies in power electronics. Novel power semiconductor components based on silicon carbide (SiC) enable the realisation of high-power converters with less installation space and weight, while at the same time achieving higher efficiency than with the silicon-based switches (IGBT) used to date. Research and development work on SiC converters for electromobility is therefore still the subject of current research in the entire automotive industry worldwide. The economically successful use of SiC converters in electromobility can only be achieved if, in addition to the pure converter functionality, the parasitic lifetime and EMC effects are also included in the SiC converter development as part of an interdisciplinary development process.
Establishment of the HLE research group "High power electronics of wind turbines"
The high development speed of today's multi-megawatt wind turbines means that there can hardly be any long-term experience in terms of technical reliability during continuous power generation over the entire lifetime. Their global distribution leads to increasingly diverse and, as a result, challenging environmental conditions for the power electronics used. At the same time, cost pressure leads to a minimisation of the system air conditioning, so that the electronics are not only exposed to different load profiles, but also to changing climatic conditions. The main task of the ERDF-funded research group "High-performance electronics of wind turbines" is to investigate multimodal loads by researching the interactions between electrical, mechanical and climatic profiles. In the new competence centre, power electronic components and their behaviour based on field experience and in the entire range from individual component tests to tests with complete converters were carried out and analysed for four years. Predicting the effect of multimodal loads during the development phase is of great importance for the lifetime of components and for avoiding field failures and thus for long-term product success.
The importance of the laboratory facilities for practical reliability tests that have been created within the project can already be seen today in the demand from companies for simulation models, load measurements, further research and development cooperation and concrete investigations in the HiPE-LAB. In particular, the research group’s expertise in taking a holistic view of the areas of power electronic components, converter technology and control technology, from components to circuit modules to test benches for practical investigations of dynamic loads that the electronic components of wind turbines have to endure, comes into play here. With modern analysis and measurement systems for determining the component characteristics and by simulating component simulations, important insights can be gained both for increasing the lifetime and for increasing the efficiency of the power components.
Article from the University of Bremen on the project HLE
