Method for voltage dip compensation of inverter
First Claim
1. A method for voltage dip compensation of inverter, the method comprising:
- performing a momentary voltage dip test for grasping a load characteristic of a load installed at a field site with a basic set point to cope with a momentary voltage dip;
determining whether a relevant load is a load that requires an additional current control in response to the grasped load characteristic;
setting the relevant load as a current control subject when it is determined that the relevant load is the current control subject as a result of determination, and setting the relevant load as not a current control subject when it is determined that the relevant load is not the current control subject as a result of determination;
setting to perform a momentary voltage dip compensation using voltage and current control on a relevant inverter when a momentary power failure occurs to a load set as the current control subject during inverter operation;
reducing an output frequency of an inverter to obtain a regenerative energy when it is determined that power failure has occurred during the inverter operation;
adjusting increase/decrease of inverter output frequency in response to size of exceeding current and voltage based on an output current and DC-link voltage of the inverter;
increasing the inverter output frequency in order to prevent excessive current flow when power restoration occurs at a power failure state; and
returning to a speed prior to the momentary voltage dip by gradually increasing the inverter output frequency in a state where the inverter output frequency does not exceed an over-current limit by monitoring the inverter output frequency.
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Abstract
Disclosed is a method for voltage dip compensation of inverter, the method including reducing an output frequency of an inverter to obtain a regenerative energy when it is determined that power failure has occurred during the inverter operation, adjusting increase/decrease of inverter output frequency in response to size of exceeding current and voltage based on an output current and DC-link voltage of the inverter, increasing the inverter output frequency in order to prevent excessive current flow when power restoration occurs at a power failure state, and returning to a speed prior to the momentary voltage dip by gradually increasing the inverter output frequency in a state where the inverter output frequency does not exceed an over-current limit by monitoring the inverter output frequency.
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Citations
9 Claims
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1. A method for voltage dip compensation of inverter, the method comprising:
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performing a momentary voltage dip test for grasping a load characteristic of a load installed at a field site with a basic set point to cope with a momentary voltage dip; determining whether a relevant load is a load that requires an additional current control in response to the grasped load characteristic; setting the relevant load as a current control subject when it is determined that the relevant load is the current control subject as a result of determination, and setting the relevant load as not a current control subject when it is determined that the relevant load is not the current control subject as a result of determination; setting to perform a momentary voltage dip compensation using voltage and current control on a relevant inverter when a momentary power failure occurs to a load set as the current control subject during inverter operation; reducing an output frequency of an inverter to obtain a regenerative energy when it is determined that power failure has occurred during the inverter operation; adjusting increase/decrease of inverter output frequency in response to size of exceeding current and voltage based on an output current and DC-link voltage of the inverter; increasing the inverter output frequency in order to prevent excessive current flow when power restoration occurs at a power failure state; and returning to a speed prior to the momentary voltage dip by gradually increasing the inverter output frequency in a state where the inverter output frequency does not exceed an over-current limit by monitoring the inverter output frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification