Ralph Teichmann

A comparison of three-level converters versus two-level converters for low-voltage drives, traction, and utility applications

This paper evaluates three-level topologies as alternatives to two-level topologies in converters for low-voltage applications. Topologies, semiconductor losses, filter aspects, part count, initial cost, and life-cycle cost are compared for a grid interface, a conventional drive application, and a high-speed drive application.

Design and loss comparison of matrix converters, and voltage-source converters for modern AC drives

This paper compares a matrix converter (MC) and a DC-voltage link converter with an active front end for a 7.5 kW, 460 V induction motor drive. Part count, semiconductor losses, input filter design, and protection aspects are discussed. It is shown that the matrix converters semiconductor losses are smaller only at full load operation for the same silicon area in both converters. A 33% reduction of the device current rating of the MC is possible, resulting in comparable thermal device stress. The overall passive component count and rating is only slightly better for the MC.

Evaluation of three-level rectifiers for low-voltage utility applications

This paper evaluates the benefits of three-level topologies as alternatives to two-level topologies in low-voltage converters primarily operated in rectifier mode. The main evaluation aspects are input filter size, semiconductor losses, maximum switching frequency, part count, initial cost, and life cycle cost. Semiconductor loss characteristics of various three-level topologies are discussed. A detailed converter comparison is based on a 100-kW 400-V/sub rms/ rectifier using commercially available Si insulated gate bipolar transistor modules.

Comparison of high-power IGBT's and hard-driven GTO's for high-power inverters

This paper compares hard-driven gate-turn-off thyristors (IGCTs) and high-power insulated gate bipolar transistor (IGBT) modules in a two-level pulsewidth modulation inverter. The structure, fundamental operation and specific characteristics of the considered devices are shown. Simulations enable a loss comparison of IGCTs and IGBTs in a 1.14 MVA inverter at switching frequencies of f/sub s/=250 Hz/500 Hz. The evaluation of device characteristics is the basis for a derivation of potential applications.

Evaluation of a high power ARCP voltage source inverter with IGCTs

An evaluation and comparison of a two-level conventional voltage source inverter (VSI) and an auxiliary resonant commutated pole voltage source inverter (ARCPVSI) featuring IGCTs for a 3 MVA application is presented. Design issues of both topologies are addressed. The IGCT loss approximations are based on extensive measurements of the devices under hard and soft switching conditions. The results show that the ARCPVSI with IGCTs is a highly competitive alternative to conventional VSIs in this power range.

Three-level topologies for low voltage power converters in drives, traction and utility applications

This paper evaluates three-level topologies as alternative to two-level topologies in converters for low voltage applications. Topologies, semiconductor losses, filter aspects, part count, initial cost and cost over life-cycle are compared for a grid interface, a conventional drive application, and a high speed drive application.

Magnetic field generation in an inductively coupled radio-frequency power transmission system

This paper discusses various methods for the generation of an omni-directional magnetic field suitable for use in an inductively coupled power transmission system. The field characteristics are evaluated with a focus on minimizing undesired shielding effects while remaining within the boundaries set by international standards for occupational exposure to magnetic fields. The dynamic requirements of load resonant converters that allow a minimum disruption in the magnetic field are derived. Various topologies are analyzed and the theoretical results are verified using a test set-up.

A redundant electrical braking system for wind turbine generators

Mechanical brake is typically used in wind turbine, which typically suffers from frequent wear-out, more trip opportunities and high maintenance cost. To addressing this issue, a redundant electrical braking system is proposed in this paper. It comprises a conventional dynamic brake connected to the converter DC link and a fully controllable resistive load connected to the generator terminals. The resistive load can be engaged by an active power semiconductor and a NC(normally closed) contactor.