Electrical engineering, Electronics
– Power electronics
ELECTRICAL ENGINEERING, ELECTRONICS // KILN AND FURNACE ENGINEERING// ON- AND OFFSHORE ENGINEERING // POWER ELECTRONICS // MEASURING SYSTEMS // CONTROL SYSTEMS // WAFER PRODUCTION // ELECTRIC MOTORS // TELECOMMUNICATIONS // LIGHTING SYSTEMS // PHYSICAL RESEARCH // ELECTRONICS – GENERAL
Typical ceramic components in power electronics are casings for vacuum switching tubes, diodes and thyristors as well as highly resilient electric feedthroughs and surge arresters.
The casing and feedthroughs usually consist of high-vacuum-tight ceramic–metal composites produced by means of brazing with ≥ 94 % pure Al2O3 as the ceramic and Ni based alloys like, for example, 1.3917 resp. 1.3981 and/or OF-copper as the metallic partner. The tightness of the composites reaches the He leakage rates of less than 10-9 mbar*L/s usual for the application of this technology and composite strengths of 200 MPa and more measured with standard test specimens.
These components that have proven effective over decades are used widely because of their high reliability and lifetime in stationary and mobile applications, in recent years, for example, in wind power plants and in electrically powered vehicles.
The switching of currents with several 1.000 A is not a problem for vacuum switching tubes, not even at high switching frequencies. Another advantage is that additional cooling is not necessary and accordingly small component sizes can be realized. As the switching elements are in high-vacuum-tight housing, no oxidation processes take place that can reduce the switch power.