Maximum Power Density In Passive Components



Bernhard Kalkmann, technical director at Semikron in Nuremberg

The German Ministry of Education and Research is backing a research project on the optimization of passive components with maximum energy density and the use of these components in power electronics. The project involves the partners Bosch, Semikron, Epcos, Sumida, Fraunhofer IISB, Treofan, FIT Ceramics, VIA Elektronik, as well as the Fraunhofer Institute for Ceramic Technologies and Systems IKTS. Leading passive component manufacturers such as Epcos, Sumida and Via Elektronik are joining forces with materials specialists and research institutes such as Treofan, FIT Ceramics, Bosch, Semikron, Fraunhofer IISB and Fraunhofer IKTS to work on the joint research project "Efficient passive components with maximum energy density for increased temperature range in power electronics - EPa". On the basis of the high-tech strategy of the German government, manifest in the "IT and communications technology 2020" initiative, IKT 2020, the German Ministry of Education and Research, BMBF, is providing funding of €1.669 million, the total volume is totalling €2.923 million, which is being put into the EPa project as part of the "LES: Power electronics for energy efficiency enhancement" programme. This application-oriented research project is intended to create a basis for innovations in the field of passive components - in connection with state-of-the-art power supply systems. One of the aims of IKT 2020 is to expand and bolster Germany's leading position in the field of ICT. The project will last for a period of three years and is expected to be complete by the end of May 2013. The aim if the EPa project is to enable the manufacture of far more compact - and hence resource-efficient power supply systems - by using innovative passive components. "What makes this cluster different from others is that for the first time component manufacturers and users are working together on improving the technology used in switched-mode power supply systems," explains the cluster co-ordinator Johann Winkler from SUMIDA Components & Modules GmbH. Increasing energy costs are not only a burden for private households. In fact, they are becoming an increasingly strong competitive factor among German companies. At the same time, ecological targets are driving us to be more responsible in our use of resources. Today, for example, 40% of the energy consumed worldwide is electric energy, a figure that is expected to rise to as much as 60% by 2040. As a result, the need for power electronics will grow, too. Power electronics is a sub-section of the broader field of electrical engineering and covers the conversion and the distribution of electrical energy using components and systems. Power electronics is instrumental in the efficient use of resources. The potential energy savings through the consistent use of power electronics is estimated at 20 to 35 %. As part of the framework programme IKT 2020, the German government is therefore backing multidisciplinary research and development projects under the heading "LES: Power electronics for energy efficiency enhancement". In power electronic assemblies and systems, besides power semiconductors, passive components such as coils and capacitors are key components. With the major advances achieved in the field of power semiconductors over the past 20 years, at the moment the only things standing in the way of a further reduction in the size of power electronic assemblies is the space needed for the passive components. The reason for this is that the physical boundary conditions relating to the miniaturisation of passive components are far more restrictive than, say, in the area of IT and commutations technology. In communications systems, for example, bits and bytes are being incorporated into increasingly compact systems; in contrast, the electric energy storage systems needed for power electronic processes have to meet a given minimum volume due to the material properties. For this reason, users generally regard passive components as being too large, too heavy and too costly. The focus here should therefore not only be for these components to sustain the developments in the area of power semiconductors. Rather, there should be a call for further improvements in these components as regards higher operating frequencies. As part of the EPa project, a component demonstrator is to be developed - a mobile charger for batteries used in electric vehicles - which enables both an increase in efficiency in the power electronics and energy savings in the overall system through mass and weight reductions. From an environmental point of view, this will bring about better overall results - especially in mobile applications - than a solution based solely on the reduction of electric power losses. The main aim of the EPa cluster is to develop a new generation of power electronic passive components based on innovative materials, packaging and cooling solutions - a move that will be instrumental in the increasing miniaturisation of power electronic assemblies. To achieve this, a two-pronged approach is being used: firstly, the energy storage capacity of the materials involved is to be improved and, secondly, the energy content stored in a coil, 1/2 LI², or in a capacitor, 1/2 CU², is to be transferred from the input to the output of a electronic circuit as often as possible per second. In real terms, this means a clear increase in operating frequency, which in turn generally means a significant increase in heat losses in the passive components, which then have to be limited by using innovative materials or the heat dissipated by way of suitable cooling measures. In terms of technology, the research focus will be on the improvement of base materials, the optimization of component design, and the development of a compact prototype. On the economic front, the aim is to slow down the current migration movement in the electronics industry by way of R&D work in the field of "best in class" technologies, in doing so safeguarding existing jobs in this sector. The research findings are to be protected by patents in order to guarantee sustainability for Germany as an industrial location. Products: The products range from chips, discrete semiconductors, transistor, diode and thyristor power modules to customer specific solutions and integrated power electronic systems for applications from one kilowatt into the Megawatt range. Semikron is the market leader in the field of diode/thyristor semiconductor modules, enjoying a 37% share of the worldwide market. (Source: IMS Research „The worldwide market for power semiconductor discretes and modules"2008). Applications: Semikron technology powers nearly half of the globally installed wind power capacity. According to a survey carried out by BTM Consult ApS, the total wind power capacity installed until 2009 was 122 Gigawatt. 57 Gigawatt comprises semiconductors from Semikron. "Semikron inside" has become a trademark for markets such as industrial drives, power supplies, renewable energy, battery vehicles and the rail industry. The dedication to the electric and hybrid vehicle market was further strengthened with the majority take-over of Compact Dynamics GmbH. As a significant innovator in the power electronics sector, many of Semikron's progressive developments have been accepted as industrial standards.