Guntram Scheible

Analysis of wireless power supplies for industrial automation systems

Abundant sensors used in non-stationary, maintenance-free industrial environments with high sensor densities are preferably powered by a wireless power system. For most industrial applications this is possible with a magnetic supply principle, based on unconventional transformers with large air-gaps. This paper presents an analytical description of the magnetic components of a wireless power supply system based on the magnetic coupling of multiple spatially separated coils. The power transfer through the large air-gap transformer is accurately predicted using a coupling model.

Power supply for very high insulation requirements in IGBT gate-drives

A power supply concept for very high insulation requirements in gate-drives has been developed. The power supply concept is described, layout decisions are explained and simulations and measurements are presented. The power supply has been tested and is already operating in different industrial products. Very high efficiencies of 80% and power levels of 10 W have been achieved over a wide input voltage range. The zero voltage switching, multiresonant converter ZVS-MRC concept with the control concept used here, can deliver multiple output voltages with few components. Together with the high switching frequency and an optimized transformer construction, the concept used is well suited for integration into the gate drives of modern semiconductor switches like IGBTs or IGCTs. With a range of 20 US

Comparison of switching devices in scalable switch concept for medium voltage medium frequency power conversion

, the total cost are very low. Currently they are used for IGBT converters for up to 4500 V operation voltage, but they can be adapted easily to higher power and different insulation voltage levels.

Power supply with high insulation capability to feed electronics on the high potential side in power distribution networks

This paper provides a comparison of switch concepts for medium frequency (MF) medium voltage (MV) applications in the lower power range (<500 kW). An introduction briefly reviews recent switch and converter developments and points out example applications which will benefit from a MF-MV-scalable switch concept. Different semiconductor switching devices are compared, in scalable concepts using the series connection, for MV-suited switches/converters, with a special focus on medium frequency applications (>> 1 kHz). The comparison is based on measurements of actual discrete switches for hard-switched and ZVS forward topologies. It is shown that standard low power IGBTs in a scalable switch can be used to obtain the lowest losses and cost with the additional benefit of significantly higher possible switching frequencies.

System for wirelessly supplying a large number of actuators of a machine with electrical power

Intelligent measurement systems, communication or control equipment on the high potential side of power distribution networks require power supplies with very high insulation capability and low power level. To end up with a low volume, low costs and a high efficiency of the complete system, a resonant switch mode power supply with a special transformer design was selected, designed and built up. The power supply is designed to transfer 2.5 W, guarantees a partial discharge free insulation voltage of more than 50 kV and an insulation test voltages of more than 80 kV. The power supply is based on a class-E converter to utilize the dominating parasitic elements of the high frequency transformer as resonant elements.