Method for determination of the risk to disturbance-free operation of a frequency converter
First Claim
1. A method for determining a risk to a disturbance-free operation of a frequency converter connected to a mains power supply, comprising the steps of:
- during operation of the frequency converter, continuously measuring an intermediate-circuit voltage and a mains-side intermediate-circuit current;
comparing the measured intermediate-circuit voltage and measured mains-side intermediate-circuit current with preset operating values of the intermediate-circuit voltage and the mains-side intermediate-circuit current for the frequency converter;
recording overshoots and undershoots of the measured intermediate-circuit voltage and measured mains-side intermediate-circuit current determined in the comparison;
computing a frequency with which the overshoots and undershoots occur; and
converting the computed frequency to a characteristic quality factor of the mains power supply.
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Abstract
The invention relates to a method for determining the chance of a disturbance-free operation of a frequency converter (2) connected to a feeding network (18). According to the invention, during the operation of said frequency converter (2), an intermediate circuit voltage (UZK) is continuously measured and a network-side intermediate circuit current (iZKmains) is continuously determined; these measuring quantities are compared with pre-determined operating values of the frequency converter (2), and quantities which are higher or lower than said values are respectively stored; and the frequency (Hij) of said higher and lower measuring quantities is determined and converted into a characteristic number for the quality of the feeding network (18). As said characteristic number decreases, the chance of a disturbance-free operation of the frequency converter (2) increases. In this way, a frequency converter (2) is able to detect the risk of appliance disturbance or failure as a result of network disturbances before the operation is interrupted.
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Citations
14 Claims
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1. A method for determining a risk to a disturbance-free operation of a frequency converter connected to a mains power supply, comprising the steps of:
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during operation of the frequency converter, continuously measuring an intermediate-circuit voltage and a mains-side intermediate-circuit current; comparing the measured intermediate-circuit voltage and measured mains-side intermediate-circuit current with preset operating values of the intermediate-circuit voltage and the mains-side intermediate-circuit current for the frequency converter; recording overshoots and undershoots of the measured intermediate-circuit voltage and measured mains-side intermediate-circuit current determined in the comparison; computing a frequency with which the overshoots and undershoots occur; and converting the computed frequency to a characteristic quality factor of the mains power supply. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for determining a risk to a disturbance-free operation of a frequency converter connected to a mains power supply, comprising the steps of:
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during operation of the frequency converter, continuously measuring an intermediate-circuit voltage and a mains-side intermediate-circuit current; applying a non-linear weighting factor to the measured intermediate-circuit voltage and mains-side intermediate-circuit current; integrating the non-linearly weighted intermediate-circuit voltage and mains-side intermediate-circuit current; and adding the integrated, non-linearly weighted intermediate-circuit voltage and the integrated, non-linearly weighted mains-side intermediate-circuit current to produce a characteristic quality factor of the mains power supply. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification