Method for controlling medium-voltage inverter and system comprising the same

• US 10,425,016 B2
• Filed: 01/09/2018
• Issued: 09/24/2019
• Est. Priority Date: 04/27/2017
• Status: Active Grant

• Current Assignee: LSIS Co. Ltd. (LS Corporation)
• Original Assignee: LSIS Co. Ltd. (LS Corporation)
• Inventors: Kim, Kyoung-Sue
• Primary Examiner(s): Dinh, Thai T
• Application Number:
  US15/866,021
• Publication Number:
  US 20180316278A1
• Time in Patent Office: 623 Days
• CPC Class Codes: H02M 7/49 Combination of the output voltage waveforms of a plurality of converters
• CPC Class Codes: H02P 1/04 Means for controlling progress of starting sequence in dependence upon time or upon current, speed, or other motor parameter
• CPC Class Codes: H02P 1/426 by using a specially adapted frequency converter
• CPC Class Codes: H02P 1/54 for starting two or more dynamo-electric motors
• CPC Class Codes: H02P 21/24 Vector control not involving the use of rotor position or rotor speed sensors
• CPC Class Codes: H02P 21/34 Arrangements for starting
• CPC Class Codes: H02P 2207/01 Asynchronous machines
• CPC Class Codes: H02P 23/07 Polyphase or monophase asynchronous induction motors
• CPC Class Codes: H02P 27/085 wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency

Abstract

Disclosed herein are a method for controlling a medium-voltage inverter, and a system including the same. The system includes a motor, a medium-voltage inverter driving the motor, a control unit configured to control an output voltage from the medium-voltage inverter, and an output voltage measuring unit configured to measure counter electromotive force data of the motor including a voltage and a frequency of the counter electromotive force, and transmitting it to the control unit. The control unit generates the output voltage based on the measured counter electromotive force data to re-drive the motor when the output voltage measuring unit completes the measurement of the counter electromotive force data.

Claims

1. A system for controlling a medium-voltage inverter, wherein the system comprises:

a motor;

a medium-voltage inverter driving the motor;

a control unit configured to control an output voltage from the medium-voltage inverter; and

an output voltage measuring unit configured to measure counter electromotive force data of the motor comprising a voltage and a frequency of the counter electromotive force, and transmitting the counter electromotive force data to the control unit,

wherein the control unit generates the output voltage based on the measured counter electromotive force data to re-drive the motor when the output voltage measuring unit completes the measurement of the counter electromotive force data,

wherein when the output voltage measuring unit completes the measurement of the counter electromotive force data, the control unit generates the output voltage based on the measured counter electromotive force data to re-drive the motor, and

wherein the output voltage has a magnitude and a frequency equal to the voltage and the frequency, respectively, and is generated in the same phase as the counter electromotive force.

2. The system of claim 1, wherein the output voltage measuring unit measures the counter electromotive force data from the counter electromotive force of the motor generated in the motor.

3. The system of claim 1, wherein the output frequency is maintained while the magnitude of the output voltage increases until it reaches a predetermined ratio of an output voltage to an output frequency.

4. A method for controlling a medium-voltage inverter performed in a system comprising a motor and a medium-voltage inverter driving the motor, the method comprising:

measuring, by an output voltage measuring unit electrically connected to the motor, counter electromotive force data of the motor comprising a voltage and a frequency of the counter electromotive force;

re-driving, by the medium-voltage inverter, the motor based on the measured counter electromotive force data when the measurement of the counter electromotive force data is completed; and

increasing the magnitude of the output voltage from the medium-voltage inverter,

wherein in the measuring the counter electromotive force of the motor, the output voltage has a magnitude and a frequency equal to the voltage and the frequency, respectively, and is generated in the same phase as the counter electromotive force.

5. The method of claim 4, wherein the measuring the counter electromotive force of the motor comprises

measuring, by the output voltage measuring unit, the counter electromotive force data from the counter electromotive force of the motor generated in the motor.

6. The method of claim 4, wherein the increasing the magnitude of the output voltage of the medium-voltage inverter comprises increasing the magnitude of the output voltage until it reaches a predetermined ratio of an output voltage to an output frequency.

7. The method of claim 4, wherein the increasing the magnitude of the output voltage of the medium-voltage inverter comprises increasing the magnitude of the output voltage only while maintaining the output frequency of the medium-voltage inverter.

8. The method of claim 4, wherein the increasing the magnitude of the output voltage of the medium-voltage inverter comprises completing increasing the magnitude of the output voltage when it reaches a predetermined ratio of an output voltage to an output frequency.