Apparatus for controlling induction motor

Patent metadata

Field	Value
Publication number	US-9379658-B2
Application number	US-201414533952-A
Country	US
Kind code	B2
Filing date	Nov 5, 2014
Priority date	Nov 29, 2013
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

An apparatus for controlling an induction machine is disclosed, wherein a magnitude of a current outputted to the induction machine to an inverter is determined by the apparatus to determine a voltage amount that compensates the command voltage in response to the magnitude of the current, and a voltage compensation amount is added to a command voltage determined from a voltage-frequency relationship according to a relevant voltage compensation amount to output a final command voltage.

First claim

What is claimed is:

1. An apparatus for controlling an induction machine in a system including a first determination unit configured to determine a command voltage in response to a command frequency from a predetermined voltage-frequency relationship, and an inverter configured to drive an induction motor in response to the command voltage, the apparatus comprising:
a second determination unit configured to determine the magnitude of a current outputted from the inverter to the induction motor; and
a third determination unit configured to determine a voltage compensation amount for compensating (offsetting) the command voltage in response to the magnitude of a current outputted from the inverter to the induction motor, wherein the first determination unit outputs a final command voltage in which the command voltage determined by the voltage-frequency relationship in response to the voltage compensation (offset) amount received from the third determination unit is added by the voltage compensation amount.

2. The apparatus of claim 1 , further comprising a first conversion unit configured to provide an output voltage of the first determination unit to the inverter by converting the output voltage of the first determination unit to a voltage on a stationary coordinate system.

3. The apparatus of claim 1 , further comprising a current detection unit configured to detect a magnitude of a current outputted from the inverter to the induction motor.

4. The apparatus of claim 3 , further comprising a second conversion unit configured to convert an output of the current detection unit to d axis and q axis currents on a synchronous coordinate system.

5. The apparatus of claim 4 , wherein the second determination unit provides a magnitude of a current outputted from the inverter to the induction motor and a magnitude of a q axis current to the third determination unit.

6. The apparatus of claim 5 , wherein the third determination unit includes, an error generation unit configured to determine a difference between a magnitude of the q axis current and a value in which a rated current of the inverter or the induction motor is multiplied by a first gain,
a comparison unit configured to output ‘1’ when an output of the error generation unit is greater than zero (0) and to output zero (0) when the output of the error generation unit is smaller than zero (0),
a division unit configured to output a value in which a magnitude of a current outputted from the inverter to the induction motor is divided by a rated current of the inverter or the induction motor multiplied by a second gain,
a first multiplication unit configured to multiply the output of the division unit by the output of the comparison unit,
an amplification unit configured to output a value by multiplying the output of the first multiplication unit by a third gain,
an addition unit configured to add the output of the amplification unit to a preset offset voltage, and
a second multiplication unit configured to determine a code of a final output in response to a code of a command frequency of the first determination unit.

7. The apparatus of claim 6 , wherein the third determination unit further includes a low-pass filter unit arranged between the first multiplication unit and the amplification unit to low-pass-filter an output of the first multiplication unit.

8. The apparatus of claim 6 , wherein the third determination unit further includes a first limitation unit arranged between the amplification unit and the addition unit to limit an output of the amplification unit using a predetermined minimum value and maximum value.

9. The apparatus of claim 6 , wherein the third determination unit further includes a second limitation unit arranged between the addition unit and the second multiplication unit to limit an output of the addition unit using a predetermined minimum value and maximum value.

10. The apparatus of claim 6 , wherein the second multiplication unit multiplies a code of the command frequency by an output of the addition unit.

Assignees

• Lsis Co Ltd

Inventors

• Yoo Anno

Classifications

• H02P27/047

  V/F converter, wherein the voltage is controlled proportionally with the frequency · CPC title

• H02K17/12

  for multi-phase current · CPC title

• H02P23/14

  Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage · CPC title

• H02P27/024 Primary

  using AC supply for only the rotor circuit or only the stator circuit · CPC title

• H02P27/06 Primary

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title