Apparatus and method for controlling medium voltage inverter

• US 9,093,892 B2
• Filed: 07/17/2012
• Issued: 07/28/2015
• Est. Priority Date: 07/20/2011
• Status: Active Grant

• Current Assignee: LSIS Co. Ltd. (LS Corporation)
• Original Assignee: LSIS Co. Ltd. (LS Corporation)
• Inventors: Jeon, Jae Hyun
• Primary Examiner(s): Duda, Rina
• Assistant Examiner(s): Dhakal, Bickey
• Application Number:
  US13/551,388
• Publication Number:
  US 20130020976A1
• Time in Patent Office: 1,106 Days
• Field of Search: 318/599, 318/811, 318/434, 363/55, 363/56.01, 363/56.07, 363/56.08, 363/56.1, 363/56.11
• US Class Current: 1/1
• CPC Class Codes: H02M 5/00 Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
• CPC Class Codes: H02M 7/49 Combination of the output voltage waveforms of a plurality of converters

Abstract

Provided is an apparatus and method for controlling medium voltage inverter, whereby a frequency outputted by the medium voltage inverter is fixed, in a case an instantaneous power interrupt occurs while the medium voltage inverter drives a motor, and a voltage level of an AC power generated by the medium voltage inverter is reduced and outputted in response to a predetermined deceleration slope to control the medium voltage inverter.

Claims

1. An apparatus for controlling an inverter, the apparatus comprising:

a detector configured to detect whether power to the inverter fails or the power to the inverter is recovered; and

a controller configured to;

maintain an output frequency of the inverter at a frequency at a time of the power failure;

decrease an output voltage of the inverter according to time while maintaining the output frequency, the voltage decrease being constant;

control the inverter according to an operation status of the inverter at the time of the power failure when the detector detects the power recovery prior to lapse of a predetermined period, the operation status a fixed speed operation, an acceleration operation or a deceleration operation;

increase the output voltage according to time while maintaining the output frequency when the operation status prior to the power failure is the acceleration operation; and

increase the output voltage to a target voltage and increase the output frequency to a target frequency, the target voltage being a voltage of the inverter at the time of the power failure.

2. The apparatus of claim 1, wherein the controller is further configured to pre-set the voltage decrease according to time.

3. The apparatus of claim 1, wherein the controller is further configured to pre-set the voltage increase according to time, the voltage increase being constant.

4. The apparatus of claim 1, wherein the controller is further configured to:

increase the output voltage according to a voltage increase according to time while maintaining the output frequency when the operation status prior to the power failure is the fixed speed operation.

5. The apparatus of claim 1, wherein the controller is further configured to:

increase the output voltage according to time while maintaining the output frequency when the operation status prior to the power failure is the deceleration operation; and

decrease the output voltage to a target voltage and decrease the output frequency to a target frequency, the target voltage being a voltage of the inverter at the time of the power failure.