Rolls-Royce Corporation

Sivakumar Nadarajan

Amit Kumar Gupta

Vaiyapuri Viswanathan

Chandana Jayampathi Gajanayake

Chandana Jayamapathi Gajanayake

Shantha Dharmasiri Gamini Jayasinghe

Ellis F H Chong

Chao Bi

Subash Chandar Athikessavan

Sanjib Kumar Panda

Nay Lin Htun Aung

Mohamed Halick Mohamed Sathik

Jiang Quan

Bikramjit Bhangu

Viswanathan Vaiyapuri

A method of classifying a stator winding fault in a brushless synchronous generator includes measuring an electrical parameter of the stator winding and classifying the fault by calculating positive or negative sequence harmonics of the parameter and comparing one or more harmonic component to a threshold.

Brushless synchronous generator stator winding fault

A method of assessing a condition of a multi-phase power system comprises the steps of: acquiring a voltage signal and a current signal for each phase of the multi-phase power system; calculating a product of the voltage signal for each phase of the multi-phase power system with one of the current signals such that the product is between a voltage signal for one phase and a current signal for a different phase for at least two of the products; summing the calculated products; and identifying the possible existence of a fault in the multi-phase power system based on a frequency analysis of the summed calculated products.

Assessment method

A method for diagnosing a fault condition in an electric machine includes measuring at least one physical parameter generated during operation of the electric machine; analyzing the or each measured parameter in a frequency domain; and determining whether the electric machine has a stator or rotor winding fault based on a comparison of an amplitude of the or each analyzed parameter at a first predetermined frequency and a first threshold amplitude for the first frequency. The at least one physical parameter includes a sound generated by the electric machine.

Method and apparatus for diagnosing a fault condition in an electric machine

A fault condition is diagnosed in an electric machine that includes a rotor and a plurality of permanent magnets. To do so, the rotor is rotated so that each of the plurality of permanent magnets passes a magnetic flux density sensor, and the values of magnetic flux density are measured using the magnetic flux density sensor at a plurality of positions of the rotor. The measured values of magnetic flux density are analyzed and a magnitude of a peak amplitude is compared in a time or frequency domain with a reference value. If the peak amplitude is below the reference value, the electric machine is determined to have a fault condition.

A method of detecting a fault in an induction machine having one or more windings arranged to draw current at a supply frequency, the method including: performing a process of judging whether a respective sideband of one or more selected harmonics of the supply frequency exists at a predetermined fault frequency in a signal in the one or more windings; and determining that a fault has occurred if the judgement is positive; wherein in the judging process each of the selected harmonics of the supply frequency is a harmonic frequency of the supply frequency other than the supply frequency itself.

Fault detection in induction machines

A rectifier diode failure detection apparatus for an electrical machine (), the electrical machine () comprising an exciter armature winding (-), a rotor main field winding () and first and second rectifiers () arranged in parallel, each rectifier () comprising at least first and second diodes (), each rectifier being configured to independently supply the rotor main field winding () with DC electrical current, the failure detection apparatus comprising: a controller () comprising at least two current sensors (), each current sensor () being configured to measure output current (I, I) of a respective one of the rectifiers (), and the controller () being configured to determine a harmonic of the measured rectifier output currents; the controller () being further configured to determine a ratio of the magnitude of the first rectifier () output current harmonic to the magnitude of the second rectifier () output current harmonic, wherein the controller () is configured to determine that a fault has occurred in one of the rectifier diodes () where the ratio exceeds a threshold value.

Electrical machine component failure detection apparatus and method

An axial flux permanent magnet machine including a pair of axially spaced first components. A second component positioned axially between and equidistant from the first components. Either the pair of first components or the second component is arranged to rotate about a shaft. A translation mechanism coupled to each of the first components. The translation mechanism configured to translate the first components axially away from the second component. Also a method of controlling an axial flux permanent magnet machine.

Axial flux permanent magnet machine

A method of open-switch fault detection in a two-level voltage source power converter comprises the steps of:

Open switch fault detection and identification in a two-level voltage source power converter

A method of detecting a diode fault in an AC signal rectifier circuit, the AC signal rectifier circuit including a plurality of diodes, and being arranged to supply a rectified output voltage to a load, wherein the method includes the steps of deriving an operating value indicative of the ratio of the voltage magnitudes of a first harmonic frequency and another harmonic frequency of the rectified output voltage across the load; and determining whether a fault has occurred in one or more diodes on the basis of the derived operating value. The first harmonic frequency is preferably the fundamental harmonic frequency, and/or the another harmonic frequency is preferably the 6harmonic frequency.

Rectifier diode fault detection in brushless exciters

A method for detecting a fault in an exciter circuit, suitable for use in a brushless generator, the exciter circuit including (a) an exciter armature winding, having a plurality of armatures, arranged to generate a multiphase AC signal, each armature of the plurality of armatures providing a respective sub-signal component of the multiphase AC signal, and (b) a rectifier circuit for receiving the sub-signals via the respective armatures, the rectifier circuit comprising a plurality of components arranged to rectify the sub-signals to provide a rectified output signal, wherein the method includes the steps of: acquiring a respective operational sub-value for a first characteristic of each of at least two of the respective sub-signals; deriving an operational value indicative of a relationship between the acquired respective operational sub-values; determining whether a fault has occurred in the exciter circuit on the basis of the derived operational value.

Fault detection in brushless exciters

A thermal controller for driving a gate control unit of a gate-driven semiconductor switching device, the thermal controller comprising a junction temperature estimation module for generating an estimated junction temperature for the switching device, a gate voltage control module for modifying a gate voltage of the switching device, a switching frequency control module for modifying a switching frequency of the switching device, and a duty cycle control module for modifying the duty cycle of the switching device. In use, the thermal controller is adapted to activate one of the gate voltage control module, switching frequency control module and duty cycle control module dependent upon the estimated junction temperature in order to maintain the actual junction temperature below a pre-determined limit.

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Singapore, Singapore

Sivakumar Nadarajan