Determining a phase and a frequency of an electric quantity of an operating electrical device
AssigneeSiemens Aktiengesellschaft
InventorHeng Deng
Life of this patent
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Abstract
A method and an apparatus for determining a phase and a frequency of an electric quantity being associated with an operation of an electrical device are described. The method comprises extracting a fundamental component of the electric quantity, calculating a positive sequence component of the electric quantity based on the extracted fundamental component, and determining the phase and the frequency of the electric quantity based on the calculated positive sequence component.
Claims11
A method for determining a phase and a frequency of an electric quantity being associated with an operation of an electrical device, the method comprising:
- providing an electric machine or a power grid;
- providing an AC-to-DC stage for converting a first AC power signal being generated by the electric power machine into a DC power signal;
- providing a DC-to-AC stage for converting the DC power signal into a second AC power signal being received from the power grid;
- extracting a fundamental component of the electric quantity from the electric machine or power grid, wherein the electric quantity is a counter electromotive force;
- calculating a positive sequence component of the counter electromotive force based on the extracted fundamental component of the electric machine or power grid;
- determining the phase and the frequency or oscillation of the counter electromotive force based on the calculated positive sequence component of the electric machine or power grid;
- providing a feedback loop providing the determining unit and the calculating unit with the determined frequency so as to improve an accuracy of the determined phase, frequency or oscillation;
- and
- performing a change in the phase, the frequency or the oscillation of the electric machine or power grid based upon the determined phase, frequency, or oscillation.
An apparatus for determining a phase and a frequency of an electric quantity being associated with an operation of an electrical device, the apparatus comprising:
- an extracting unit configured for extracting a fundamental component of the electric quantity;
- a calculating unit configured for calculating a positive sequence component of the electric quantity based on the extracted fundamental component;
- a determining unit configured for determining the phase and the frequency of the electric quantity based on the calculated positive sequence component;
- an AC-to-DC stage for converting a first AC power signal being generated by an electric power generating machine into a DC power signal;
- a DC-to-AC stage for converting the DC power signal into a second AC power signal being received from a power grid;
- and
- a feedback loop providing the determining unit and the calculating unit with the determined frequency so as to improve an accuracy of the determined phase and frequency.
Dependencies are inferred from the claim text.