Sensorless motor drive vector control

Patent metadata

Field	Value
Publication number	US-9490738-B2
Application number	US-201615053273-A
Country	US
Kind code	B2
Filing date	Feb 25, 2016
Priority date	Jan 16, 2013
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

Disclosed examples include methods, computer readable mediums and motor drive power conversion systems for sensorless speed control of a motor driven by an inverter through an intervening filter, a transformer and a motor cable, in which sensorless vector control is used to regulate the motor speed based on a speed feedback value computed according to voltage or current values associated with the motor drive using an observer having formulas and impedance parameters of the filter, the transformer, the motor cable and the motor.

First claim

The following is claimed:

1. A power conversion system, comprising:
an inverter comprising a DC input, an AC output, and a plurality of switching devices coupled between the DC input and the AC output and operative according to inverter switching control signals to convert DC electrical power received at the DC input to provide AC electrical output power at the AC output to drive a motor through an intervening filter, a transformer and a motor cable; and
a controller configured to compute a speed feedback value representing a rotational speed of the motor according to at least one voltage or current value associated with the power conversion system, and to provide the inverter switching control signals to control the inverter to regulate the rotational speed of the motor at least partially according to the inverter speed feedback value using vector control;
wherein the controller is configured to compute the speed feedback value according to the at least one voltage or current value associated with the power conversion system using an observer that includes impedance parameters of the filter, the transformer, the motor cable and the motor.

2. The power conversion system of claim 1 , wherein the controller is configured to compute the speed feedback value by:
computing an estimated motor position value, representing an angular position associated with the motor load according to the at least one voltage or current value associated with the power conversion system using a position observer that includes impedance parameters of the filter, the transformer, the motor cable and the motor; and
computing the speed feedback value according to the estimated motor position value.

3. The power conversion system of claim 2 , wherein the controller is configured to compute the estimated motor position value using the following equation:

θ
=

tan

-
1

⁡

(

λ
β
′

λ
α
′

)

;

wherein:

[

λ
α
′

λ
β
′

]

=

[

-

i
α

·

L
sys

-

i
β

·

L
sys

]

+

∫

[

v
α

-

i
α

·

R
sys

v
β

-

i
β

·

R
sys

]

·

ⅆ
t

;

wherein:

R
sys

=

R
motor
′

+

R
cable
′

+

R
filter

+

R
Xmfr
′

=

(

N
p

N
s

)

Assignees

• Rockwell Automation Tech Inc

Inventors

• Nondahl Thomas A
• Liu Jingbo
• Royak Semyon
• Schmidt Peter B
• Al-Nabi Ehsan
• Dai Jingya

Classifications

• H02P27/06

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

• H02P21/24 Primary

  Vector control not involving the use of rotor position or rotor speed sensors · CPC title

• H02P6/08

  Arrangements for controlling the speed or torque of a single motor (H02P6/10, H02P6/28 take precedence) · CPC title

• H02M1/126

  using passive filters · CPC title

• H02P21/13

  Observer control, e.g. using Luenberger observers or Kalman filters · CPC title