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Abb Research Ltd.

Pieder Jörg

Thomas Besselmann

Christian Stulz

Stefan Almer

Halina Burzanowska

Thomas Berner

Christoph Eichler

Erich Suter

Martin Bruha

Adrian Zuckerberger

Petteri Sario

A thyristor bridge of an electrical converter is connected to at least one DC link and including at least one phase leg for each output phase and each phase leg being composed of two series-connected thyristor arms. The thyristor arms of a thyristor bridge are cyclically switched by: determining an upper bound for a firing angle of a thyristor arm, wherein the upper bound is determined from voltage and current measurements; and determining a firing angle for the thyristor bridge, which firing angle determines a switching time of the thyristor arm, wherein the firing angle is determined, such that it is less or equal to the upper bound.

Current source converter with dynamical firing angle determination

An electrical converter with at least two output phases includes a rectifier and a thyristor-based inverter interconnected by a DC link with an inductor, wherein the thyristor-based inverter includes a half-bridge with at least two half-bridge arms for each output phase of the electrical converter and each arm being provided by a thyristor. A method for switching the electrical converter includes: cyclically switching the thyristors of the inverter, such that at least one time instant, two thyristors of different half-bridge arms are switched on simultaneously, such that a pulse number, which determines at how many time instants thyristors of the inverter are switched during one stator voltage period, is lower than the number of half-bridge arms of the inverter.

Switching an electrical voltage source converter

A method and apparatus are provided for operation of a three-phase rotating electrical machine which has at least two stator winding sets and each stator winding set has three phase windings connected in star, and the star circuits of the stator winding sets have a phase shift of 30 degrees electrical with respect to one another, and an associated converting unit is respectively provided for each stator winding set, in which method the respective stator winding set is fed by the associated converter unit, and a respectively associated regulation device is provided for each converter unit, and each converter unit is driven by means of a drive signal from the associated regulation device independently of regulation devices of the respective other converter units.

Method for operation of a three-phase rotating electrical machine, and an apparatus for carrying out the method

A polyphase converter circuit having p&#x2267;3 phases (R, Y, B) and a converter circuit element provided for each phase (R, Y, B) is specified, each converter circuit element having a rectifier unit, a DC voltage circuit which is connected to the rectifier unit and an inverter unit which is connected to the DC voltage circuit. In addition, a first AC voltage output of each inverter unit forms a phase connection, and second AC voltage outputs of the inverter units are star-connected. In order to produce harmonics which are as low as possible with respect to the fundamental of the voltage and the current of an electrical AC voltage system which is connected on the input side to the converter circuit, n transformers are provided, each having a primary winding and m three-phase secondary windings, where n&#x2267;2 and m&#x2267;3. Furthermore, p sets of secondary windings are provided, each set of secondary windings being formed by in each case three-phase secondary windings of each transformer, and each set of secondary windings with the associated secondary windings being connected to the rectifier unit of a respective converter circuit element.

Low-harmonics, polyphase converter circuit

A method for the turn-on regulation of an IGBT and an apparatus for carrying out the method are specified. In contrast to the prior art, the gate current is used as controlled variable rather than the gate voltage. Said gate current acts on the gate electrode according to a desired-actual comparison of an actual voltage value present at the gate electrode and of a corresponding desired value. The regulation guides the load current on a predetermined trajectory during the switching operation. Nevertheless, no current detection is necessary on the load side. Instead, use is made of the fact that, during the turn-on of the MOSFETs in the IGBT, the behavior of the latter predominates. It can be shown that there is a quadratic relationship between the gate voltage and the load current as soon as the gate voltage is greater than the threshold voltage. This is true until the full load current flows. Regulation of the gate voltage to a specific trajectory from the off state to the on state enables the load current to rise quadratically proportionally thereto. Conversely, the gate voltage profile can easily be calculated to a desired load current profile. The fact that no measuring apparatuses on the load side are required is also particularly advantageous.

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