ABB Ltd

About: ABB Ltd is a company organization based out in Zurich, Switzerland. It is known for research contribution in the topics: Voltage & Signal. The organization has 6222 authors who have published 6852 publications receiving 83994 citations.

Deadbeat-direct torque & flux control motor drive over a wide speed, torque and flux operating space using a single control law

Abstract: This paper presents an implementation of deadbeat-direct torque and flux control (DB-DTFC) for AC induction machine drives that demonstrates nearly ideal properties over a wide range of flux and torque operating conditions, including deep field weakening. A key attribute of this DB-DTFC is that the control law is the same over the entire operating space, including steady-state and transient operation at the voltage limits. By comparison, field oriented control at the voltage limit is inherently compromised and requires adjustment of the current control laws. Similarly, PI control-based DTFC becomes oscillatory under voltage limit conditions. This DB-DTFC implementation requires no change to the control law under voltage limit conditions. This paper presents an implementation of DB-DTFC and experimentally demonstrates its performance over a full range of operating conditions, including operation at the voltage limit.

Method of operating a combined-cycle plant

Abstract: In a method of operating a combined-cycle plant, which essentially comprises a gas-turbine group, a waste-heat steam generator (14) and a steam cycle equipped with a steam turbine (17), the gas-turbine group being operated according to sequential combustion (4, 9), at least one steam quantity (50) proportioned by a control (C) is extracted at a suitable point in terms of pressure in order to increase the operational output of the steam turbine (17). This steam quantity (50) is then fed to the gas-turbine group at a suitable point in such a way that, to maintain the output thus induced, at least the metering (D, E) of a fuel quantity (5, 10) at at least one combustion chamber (4, 9) is influenced.

Conductor bar for a stator winding of an electric machine

Abstract: The stator winding of an electrical machine comprises conductor elements which are spaced apart from one another, are electrically insulated from one another and are surrounded over their entire length by common main insulation. The cavities, which are caused by the arrangement on both bar narrow sides of the conductor elements and the main insulation, are filled with an electrically semiconductive compound which, for its part, is covered by an electrically semiconductive strip. In order to provide a smooth bar surface, the electrically semiconductive strip is composed of a fiber-reinforced plastic, which has incisions on alternate sides of the narrow sides of the conductor bar oriented transversely with respect to the bar's longitudinal direction; these incisions are deeper than half the strip width and have a cut width which is on the order of magnitude of the strip thickness.

Prüfstand zum Testen des Antriebsstranges eines Fahrzeuges

Abstract: Bei diesem Prufstand zum Testen des Antriebsstranges eines Fahrzeuges sind mindestens zwei voneinander unabhangig momentengeregelte elektrische Belastungsmaschinen (9, 11, 13, 15) direkt an die Wellen (8, 10, 12, 14) des zu prufenden Antriebsstranges (2, 3, 4, 5, 6, 7, 8, 10, 11, 14) angeflanscht. Rollen werden nicht eingesetzt. Uber einen Simulationsrechner (24a) erfolgt eine Simulation der Fahrwiderstande, der Rader und des Fahrzeug-Beschleunigungsverhaltens ausschlieslich der real als Fahrzeugkomponenten vorhandenen Teile, wie Hauptantriebsstrang (3), Achsgetriebe (4, 7), Wellen (8, 10, 12, 14), Kupplung (15), Getriebe (2), Verbrennungsmotor (1). Es sind Simulationen einer Kurvenfahrt, von durchdrehenden Radern, von unterschliedlichen Radradien und von durchdrehenden oder blockierenden Radern moglich.

A tutorial on ferroresonance

Abstract: Ferroresonance is a widely studied phenomenon but it is still not well understood because of its complex behavior. It is “fuzzy-resonance.” A simple graphical approach using fundamental frequency phasors has been presented to elevate the readers understanding. Its occurrence and how it appears is extremely sensitive to the transformer characteristics, system parameters, transient voltages and initial conditions. More efficient transformer core material has lead to its increased occurrence and it has considerable effects on system apparatus and protection. Power system engineers should strive to recognize potential ferroresonant configurations and design solutions to prevent its occurrence.