Abb Schweiz Ag

Abb Technology Ag

John Eckerle

Mats Larsson

Matthias Schult

Christian Schlegel

Dominik Flum

A method for determining a converter Thevenin equivalent model for a converter system, includes: receiving measurement values of a coupling point voltage and a coupling point current measured at a point of common coupling between a grid emulator system and the converter system, wherein the grid emulator system supplies the converter system with a supply voltage; and determining a converter Thevenin impedance and a converter Thevenin voltage source of the converter Thevenin equivalent model by inputting the measurement values of the coupling point voltage and of the coupling point current into a coupled system model, which includes equations modelling the converter system and the grid emulator system and from which the converter Thevenin impedance and a converter Thevenin voltage source are calculated.

Determining Thevenin equivalent model for a converter system

A method is provided for connecting a main converter, e.g. for use in a power plant for regenerative energy having a generator, to a power grid. The method includes providing energy from the pre-charge unit to at least one of at least two converter paths. The at least one converter path is pre-charged using the energy provided from the pre-charge unit. At least one further converter path of the at least two converter paths is pre-charged using the energy provided from the pre-charge unit via the at least one converter path through the grid side converter of the at least one converter path and the grid side converter of the at least one further converter path. The main converter is connected to the power grid by closing the grid breaker.

Power converter

A method and an apparatus are described for determining a field current through a field winding in an electrical machine with a stator and a rotor. The electrical machine includes a field-circuit transformer to produce, by induction of an electrical current on the rotor side, field current with which a field winding is energized in order to generate an excitation magnetic field. The method includes driving the primary side of the field-circuit transformer to produce a field current in the rotor, which is derived from the current induced on the secondary side in the field-circuit transformer; measuring one or more phase currents in one or more primary-side phases of the field-circuit transformer; determining a maximum value depending on the one or more measured phase currents; determining the field current through the field winding depending on the determined maximum value.

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Basel, Switzerland

John Eckerle