APPARATUS AND METHOD FOR RESTARTING MEDIUM VOLTAGE INVERTER
First Claim
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1. An apparatus for restarting a medium voltage inverter, the apparatus comprising:
- a measurement unit configured to measure an input voltage of a motor;
an estimation unit configured to estimate a rotor frequency of the motor using the input voltage; and
a controller configured to controllably change an output voltage or an output frequency of the inverter in response to a first ratio corresponding to a frequency relative to a predetermined voltage using the input voltage and the rotor frequency, whereinthe estimation unit includes,a generation unit configured to generate a first voltage applied to the motor by the inverter and a second voltage substantially lagging by 90°
in phase from the first voltage,a determination unit configured to determine a control bandwidth for determining a frequency of the output voltage of the motor, anda second detection unit configured to determine the rotor frequency based on the control bandwidth.
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Abstract
An apparatus for restarting a medium voltage inverter is disclosed, wherein the medium voltage inverter can be restarted by estimating a rotor speed when an input power returns from an instantaneous defective state to a normal state, whereby a time to restart the medium voltage inverter can be reduced by a simple configuration to dispense with the need to wait until the rotor speed reaches zero speed.
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Citations
11 Claims
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1. An apparatus for restarting a medium voltage inverter, the apparatus comprising:
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a measurement unit configured to measure an input voltage of a motor; an estimation unit configured to estimate a rotor frequency of the motor using the input voltage; and a controller configured to controllably change an output voltage or an output frequency of the inverter in response to a first ratio corresponding to a frequency relative to a predetermined voltage using the input voltage and the rotor frequency, wherein the estimation unit includes, a generation unit configured to generate a first voltage applied to the motor by the inverter and a second voltage substantially lagging by 90°
in phase from the first voltage,a determination unit configured to determine a control bandwidth for determining a frequency of the output voltage of the motor, and a second detection unit configured to determine the rotor frequency based on the control bandwidth. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for restarting a medium voltage inverter, the method comprising:
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generating a first voltage applied from an input voltage of a motor to the motor and a second voltage substantially lagging by 90°
in phase from the first voltage;determining a control bandwidth to determine a frequency of an output voltage of the motor; and estimating a rotor frequency of the motor based on the control bandwidth. - View Dependent Claims (8, 9, 10, 11)
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Specification