Abb Schweiz Ag

Abb Research Ltd.

Pedro Rodriguez

Cajetan Pinto

Subrat Sahoo

Ghanshyam Shrestha

Chenjie Lin

Mehanathan Pathmanathan

Tuomas Janhunen

Jianping Wang

Zoran Gajic

Rolf Disselnkötter

Maciej Orman

Michal Orkisz

James Ottewill

Rahul Kanchan

Antonis Marinopoulos

Jan Mikael Westerlund

Omer Ikram Ul Haq

Reza Rajabi Moghaddam

Pawel Rzeszucinski

Jahirul Islam

Eino Silander

Mustafa Ibrahim

Klaus Vänskä

Matti Kivioja

Ulf Ahrend

Ingo Stroka

Qimao Liu

Pasi Paloheimo

Susanna Bäckström-Andersson

Janne Holla

Tapio Rauhala

Ilari Karkkainen

Liwei Wang

Ilari KÄRKKÄINEN

Juliette Soulard

Ziwei Li

A field of electric drive devices and electric machines, such as electric motors and electric generators for industrial applications and more particularly to a method and an arrangement for controlling vibration of a variable frequency drive controlled electric machine. In the method for controlling vibration of a variable frequency drive controlled electric machine, the resonance frequency/frequencies and the stiffness are determined in a ramp up/ramp down test; amount of damping is determined in an impulse test; a mechanical transfer function is determined in a steady drive test; a vibration control model is determined utilizing said resonance frequency/frequencies, said stiffness, the amount of damping and the mechanical transfer function; and vibration is controlled utilizing the vibration control model.

Method and an arrangement for controlling vibration of a variable frequency drive controlled electric machine

A method of identifying a fault in a synchronous reluctance electric machine, the method including carrying out a first vibration measurement on a stator in a first radial direction of the stator; carrying out a second vibration measurement on the stator in a second radial direction of the stator; determining, on the basis of at least one of the first vibration measurement and the second vibration measurement, a first vibration frequency; determining, on the basis of the first vibration measurement and the second vibration measurement, a mode shape of the vibration at the first vibration frequency; and determining, on the basis that the first vibration frequency fand the mode shape m fulfil the following barrier fault conditions:f=f, and m=where fis a rotation frequency of a rotor, that a flux barrier of the rotor is defect.

Method of identifying fault in synchronous reluctance electric machine, monitoring system and synchronous reluctance electric machine

A method and device of determining a fault condition in a synchronous motor including a rotor provided with damper bars and an end ring to which the damper bars are mechanically connected thereby forming a damper cage, wherein the method includes: obtaining a first measurement of an end ring current from a first location along the end ring, processing the first measurement to thereby obtain a processing result, and determining whether a fault condition is present in the synchronous motor based on the processing result.

Method and a diagnostics device for determining a fault condition in a synchronous motor

A method for preventing a frequency component of a voltage from occurring in an electrical machine including the steps of: obtaining, either by measuring a voltage signal or a current signal from the electrical machine in time domain and transforming the measured signal into frequency domain, by simulating or deducing a first frequency component present in the electrical machine in absence of a grounding, the first frequency component representing a first undesired frequency higher than a limit frequency of 500 Hz; and providing the electrical machine with a first grounding at a grounding location, the first grounding including a resonant circuit resonating at the first undesired frequency. In order to get rid of harmful shaft voltages in the form of sharp voltage peaks at high frequencies, it is first necessary to determine at which undesired frequency or frequencies these voltage peaks occur. Only thereafter can a low impedance grounding be provided that works satisfactorily at the undesired frequency or frequencies.

Electrical machine with an active grounding

A method for detecting a fault in an AC/AC exciter having an exciter rotor and an exciter stator. A signal reflecting the current or voltage, is obtained at an exciter rotor winding or at an exciter stator winding. A frequency analysis is applied and on the basis of a presence of a frequency component, a rotor current or voltage signal, at a first frequency f*(2&#x2212;s), where fis a supply frequency of the exciter stator and s is an exciter slip, it is determined whether the exciter suffers from an inter-turn short circuit in an exciter stator winding or not. On the basis of a presence of a frequency component, in the case of a stator current signal or a stator voltage signal, at a second frequency f*(1&#x2212;2*s), it is determined whether the exciter suffers from an inter-turn short circuit in an exciter rotor winding or not. Presence of frequency components at the first and/or second frequencies in windings of an AC/AC exciter indicate the mentioned fault conditions.

Method for detecting a fault in an electrical machine

Unique systems, methods, techniques and apparatuses of exciterless synchronous machines are disclosed. One exemplary embodiment is a fractional slot synchronous machine comprising a rotor including a first pole pair including a first pole including a first plurality of slots having a first center point and arranged on a first outer surface in a slot pattern; a second pole pair including a second pole including a second plurality of slots having a second center point and arranged on a second outer surface in the slot pattern; energy harvest windings arranged in a winding pattern within a portion of the first plurality of slots and arranged in the same winding pattern within a portion of the second plurality of slots, the energy harvest winding being structured to receive a harmonic power from the stator; and a rectifier structured to receive the harmonic power from the energy harvest winding.

Rotor with asymmetric energy harvest windings

A rotor bar fault in a rotor of an electrical machine having a plurality of rotor bars and an end ring configured to short circuit the rotor bars. The method includes the steps of measuring a first temperature at a first end ring location, and measuring a second temperature at a second end ring location, the second end ring location being different from the first end ring location. As broken rotor bars cause a non-uniform temperature distribution in the end ring, the detection of rotor bar faults can be based on monitored temperatures at different end ring locations.

Method for detecting a rotor bar fault

Unique systems, methods, techniques and apparatuses of an exciterless synchronous generator are disclosed. One exemplary embodiment is an exciterless synchronous generator comprising a stator, a rotor, and a startup excitation system. The stator includes a set of stator windings. The rotor includes an energy harvest winding, a DC power supply including a DC bus and coupled to the energy harvest winding, and a field winding coupled to the DC power supply. The startup excitation system comprises one of a magnetic field generation system structured to generate a magnetic field received by the energy harvest winding in response to a rotation of the rotor, wherein the magnetic field is converted to DC power with the DC power supply and transmitted to the field winding; or a rotor DC power source including and diode coupled in series across the DC bus.

Apparatuses, methods, and systems for starting an exciterless synchronous generator

Unique systems, methods, techniques and apparatuses of a rotating DC power supply are disclosed. One exemplary embodiment includes a first and second DC bus rail, a first and second leg, and a discharge resistor. The first leg includes a first semiconductor device and a second semiconductor device coupled in series at a first midpoint connection, the first semiconductor device being coupled to a first point on the first DC bus rail and the first midpoint connection being coupled to a field winding. The second leg includes a third semiconductor device and a fourth semiconductor device coupled in series at a second midpoint connection, the third semiconductor device being coupled to a second point on the first DC bus rail and the second midpoint connection being coupled to the field winding. The discharge resistor is operatively coupled to the first DC bus rail between the first point and the second point.

Rotating direct current power supply for synchronous machines

A method for identifying a fault condition in an electrical machine in which at least a stator or a rotor has parallel winding branches is disclosed. A measurement is carried out for obtaining a set of circulating current values between two parallel winding branches of which each winding branch includes a single coil. A frequency analysis is applied on the set of circulating current values to obtain at least one frequency component. A fault condition of the electrical machine is determined on the basis of the at least one frequency component.

Method for detecting a fault condition in an electrical machine

A method and system of determining an electro-mechanical fault condition in a synchronous machine having a stator, a rotor, and exciter. The method includes: a) obtaining an exciter current signal which is a measurement of an exciter current through stationary windings of the exciter, b) transforming the exciter current signal to obtain an exciter current frequency spectrum, and c) determining whether an electro-mechanical fault condition is present, and a type of the electro-mechanical fault condition, based on harmonic content related to the frequency of the stator, of the exciter current frequency spectrum.

Method and system for determining a synchronous machine fault condition

A method of determining a fault condition in a synchronous machine. The method includes a) obtaining a field current signal and a shaft voltage signal of the synchronous machine, b) transforming the field current signal and the shaft voltage signal to obtain a field current frequency spectrum and a shaft voltage frequency spectrum, and c) determining whether a fault condition is present, and in case a fault condition is present identifying a type of the fault condition, based on harmonic content of the field current frequency spectrum and harmonic content of the shaft voltage frequency spectrum, wherein c) includes comparing the harmonic content of the field current frequency spectrum with fault condition field current signature spectra and comparing the harmonic content of the shaft voltage frequency spectrum with fault condition shaft voltage signature spectra.

A method for discovering demagnetisation faults of a permanent magnet synchronous generator, such as a wind power generator. The method is performed during operation of the synchronous generator and includes measuring the vibration of the stator, performing a frequency analysis of the vibration, and deducing whether the generator suffers from demagnetization of a permanent magnet, from the vibration analysis. Moreover, geometric eccentricity faults and electric short circuit faults may also be detected from the vibration.

Method for monitoring demagnetization

For identifying a fault in an electrical machine vibration is measured in a plurality of radial directions of the stator. On the basis of the vibration measurements a vibration frequency and a mode shape of the vibration at this frequency is determined. Characteristics of the vibration in terms of both the vibration frequency and the mode shape are used to identify a fault condition of the electrical machine.

Method for identifying a fault in an electrical machine

A missing stator slot wedge in an electrical machine can be detected by analyzing a current spectrum of the machine in a high frequency area. A current spectrum is provided from a current measurement, and values of the current spectrum in the high frequency area used to determine whether a stator slot wedge is missing or not. The conclusion can be based on values of a relative current amplitude Ior on presence of certain harmonics in the high frequency area.

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Västerås, Sweden

Pedro Rodriguez