Detection of an AC input phase-loss on a multi-phase AC servo drive
AssigneeRockwell Automation Technologies, Inc.
InventorsJeffery J. Pankau, Robert Harris Schmidt
Life of this patent
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Abstract
Systems and methods that detect a phase loss condition in a three-phase electrical power source are presented. The system includes a detection component that measures and/or monitors a magnitude and frequency of a voltage of a power source, and a controller component that compares measured and/or monitored voltage characteristics to characteristics associated with phase loss.
Claims17
A system that detects phase loss comprising:
- a three-phase rectifier component that converts three-phase AC power to DC power;
- a DC bus that provides DC power to one or more three-phase load devices;
- a detection component that measures a magnitude and a frequency of a three-phase AC voltage and measures a magnitude and frequency of a ripple voltage associated with a converted three-phase DC voltage;
- a converter component that converts an analog ripple voltage signal to a digital ripple voltage signal;
- a digital filter component that applies a Fast Fourier transform filter to the digital ripple voltage signal to isolate voltage components caused by single-phase operation from voltage components caused by standard operation of a three-phase load device;
- a firmware controller component that compares the magnitude and the frequency of the AC voltage to predetermined voltage characteristics indicative of a phase loss and compares the magnitude and frequency of the DC ripple voltage to predetermined voltage characteristics indicative of a phase loss and compares and compares the filtered digital ripple voltage signal to predetermined voltage characteristics indicative of a phase loss.
A method to detect a phase loss condition in a three-phase power supply comprising:
- converting AC power to DC power;
- providing DC power to one or more three-phase load devices;
- measuring a magnitude and frequency of a three-phase voltage of an AC power source, a DC power source and DC ripple voltage;
- converting an analog ripple voltage signal to a digital ripple voltage signal;
- applying a Fast Fourier Transform filter to the digital ripple voltage signal;
- and
- comparing the measured magnitude and frequency to a magnitude and frequency associated with phase loss for the measured AC voltage, DC voltage and the filtered digital DC ripple voltage, the comparison performed wholly by firmware.
A method to detect a phase loss condition in a three-phase electrical system comprising:
- monitoring a magnitude and frequency of a ripple voltage associated with a DC bus;
- converting an analog ripple voltage signal to a digital ripple voltage signal;
- applying a Fast Fourier Transform filter to the digital ripple voltage signal;
- and
- comparing the monitored magnitude and frequency to a magnitude and frequency associated with phase loss for the measured DC voltage and the filtered digital DC ripple voltage, the comparison performed wholly by firmware.
A system that detects phase loss in an industrial network comprising:
- supplying means for supplying predetermined operation requirements to a motor drive system;
- means for measuring ripple voltage characteristics of a DC voltage bus in conjunction with the supplying means;
- means for converting the analog ripple voltage to a digital ripple voltage;
- means for applying a fast Fourier Transform filter to the digital ripple voltage;
- and
- firmware comparing means that compares the voltage characteristics of the filtered DC ripple voltage to predetermined voltage characteristics associated with a phase loss.
Dependencies are inferred from the claim text.