Operating method of synchronous machine

Patent metadata

Field	Value
Publication number	US-10224850-B2
Application number	US-201615135174-A
Country	US
Kind code	B2
Filing date	Apr 21, 2016
Priority date	Jun 2, 2015
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

An operating method of a synchronous machine is provided, the operating method including: generating an MTPA (Maximum Torque Per Ampere) curve, based on a current limiting circle depending on a rated current of an inverter or a motor and a torque curve depending on a torque command; generating a voltage limiting ellipse, based on a DC-link voltage; displaying, on an X-Y plane, the current limiting circle, the torque curve, the MTPA curve, and the voltage limiting ellipse; and computing a d-axis current and a q-axis current, based on an intersection point between at least two of the current limiting circle, the torque curve, the MTPA curve, and the voltage limiting ellipse, displayed on the X-Y plane.

First claim

The invention claimed is:

1. An operating method of a synchronous machine, the method comprising:
generating an MTPA (Maximum Torque Per Ampere) curve, based on a current limiting circle depending on a rated current of an inverter or a motor and a torque curve depending on a torque command;
generating a voltage limiting ellipse based on a DC-link voltage;
displaying, on an X-Y plane the current limiting circle, the torque curve, the MTPA curve, and the voltage limiting ellipse;
computing the d-axis current and the q-axis current based on an intersection point between at least two of the current limiting circle, the torque curve, the MTPA curve, and the voltage limiting ellipse, displayed on the X-Y plane;
determining an operational mode of the motor based on a reference rotor speed depending on the intersection point, upon determining that the intersection point is a point intersecting between the current limiting circle, the torque curve, and the MTPA curve,
determining whether a rotor speed of the motor is smaller than the reference rotor speed; and
computing the d-axis current and the q-axis current corresponding to a current command for operating the motor in an MTPA operational mode, by combining the torque curve and the MTPA curve via a numerical-analytical method, upon determining that the rotor speed of the motor is smaller than the reference rotor speed,
wherein a size of the voltage limiting ellipse decreases as the rotor speed increases, and the reference rotor speed is a speed where the voltage limiting ellipse passes the MTPA maximum torque operational point, wherein the MTPA operational mode is available with respect to all torque commands when the rotor speed is smaller than the reference rotor speed; and
operating the synchronous machine to have the computed d-axis current and q-axis current.

2. The method of claim 1 , wherein the step of computing the d-axis current and the q-axis current corresponding to a current command for operating the motor in an MTPA operational mode, by combining the torque curve and the MTPA curve via a numerical-analytical method, includes:
computing the d-axis current and the q-axis current using Newton's method depending on the following equations:

F
MTPA

=

[

F
T

⁡

(

i
d

,

i
q

)

F
MTPA

⁡

(

i
d

,

i
q

)

]

J
=

[

(

L
d

-

L
q

)

⁢

i
q

λ
f

+

(

L
d

-

L
q

)

⁢

i
d

λ
f

+

2
⁢

(

L
d

-

L
q

)

⁢

i
d

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2

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(

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d

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q

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i
q

]

Assignees

• Lsis Co Ltd

Inventors

• Lee Eun Woo

Classifications

• H02P21/0017

  Model reference adaptation, e.g. MRAS or MRAC, useful for control or parameter estimation · CPC title

• H02P21/22 Primary

  Current control, e.g. using a current control loop · CPC title

• H02P21/50 Primary

  Vector control arrangements or methods not otherwise provided for in H02P21/00- H02P21/36 · CPC title

• H02P21/20

  Estimation of torque · CPC title

• H02P21/0025

  implementing a off line learning phase to determine and store useful data for on-line control · CPC title