APPARATUS AND METHOD FOR CONTROLLING MEDIUM VOLTAGE INVERTER

• US 20130020976A1
• Filed: 07/17/2012
• Published: 01/24/2013
• 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
• Granted Patent: US 9,093,892 B2
• Time in Patent Office: Days
• US Class Current: 318/453
• 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 a medium voltage inverter, the medium voltage inverter including a plurality of serially connected single-phase inverters and outputting a medium voltage to drive a motor, the apparatus comprising:

an outage detector detecting whether an outage occurs or whether power is recovered; and

a controller fixing a frequency of AC (Alternating Current) power generated by the medium voltage inverter to a frequency at the time of detection of outage by the outage detector, reducing a voltage level of the AC power generated by the medium voltage inverter in response to a predetermined reduction slope, and outputting the reduced voltage level.

2. The apparatus of claim 1, wherein the controller pre-sets the reduction slope configured to reduce an output voltage of the medium voltage inverter, in a case the outage occurs.

3. The apparatus of claim 1, wherein the controller controls the medium voltage inverter in response to status of the medium voltage inverter prior to occurrence of the outage, in a case the outage detector detects the power restoration prior to lapse of a predetermined time.

4. The apparatus of claim 3, wherein the controller pre-sets an acceleration slope configured to increase an output voltage of the medium voltage inverter, in a case the power is restored within the predetermined time.

5. The apparatus of claim 4, wherein the medium voltage inverter drives a motor in any one mode of a fixed speed operation prior to occurrence of outage, an acceleration operation and a deceleration operation.

6. The apparatus of claim 5, wherein the controller increases the output voltage of the medium voltage inverter in response to the acceleration slope, in a case the medium voltage inverter runs at a fixed speed operation prior to occurrence of outage, and in a case the power restoration is detected prior to lapse of the predetermined time.

7. The apparatus of claim 5, wherein the controller increases the output voltage of the medium voltage inverter in response to the acceleration slope, in a case the medium voltage inverter runs at the acceleration operation prior to occurrence of outage, and in a case the power restoration is detected prior to lapse of the predetermined time, and increase an output frequency of the medium voltage inverter and the output voltage to a target frequency and a target voltage, in a case the output voltage of the medium voltage inverter is restored to an output voltage prior to the occurrence of outage.

8. The apparatus of claim 5, wherein the controller decreases the output voltage of the medium voltage inverter in response to the deceleration slope, in a case the medium voltage inverter runs at the deceleration operation prior to occurrence of outage, and in a case the power restoration is detected prior to lapse of the predetermined time, and decrease an output frequency of the medium voltage inverter and the output voltage to a target frequency and a target voltage, in a case the output voltage of the medium voltage inverter is restored to an output voltage prior to the occurrence of outage.