Apparatus, system and method of fault diagnosis for permanent magnet motor

Patent metadata

Field	Value
Publication number	US-2018294751-A1
Application number	US-201715660140-A
Country	US
Kind code	A1
Filing date	Jul 26, 2017
Priority date	Apr 6, 2017
Publication date	Oct 11, 2018
Grant date	—

Abstract

Disclosed are an apparatus, system and method for detecting, based on a mathematical model, a fault of a permanent magnet motor driven by a square wave. A fault diagnosis apparatus for the permanent magnet motor includes a current voltage measurement unit, a phase shift time calculation unit, and a control unit.

First claim

What is claimed is:

1 . A fault diagnosis apparatus for a permanent magnet motor, the apparatus comprising:
a current voltage measurement unit configured to measure an input current and an input voltage of an inverter connected to the permanent magnet motor driven by a square wave; a phase shift time calculation unit configured to calculate a phase shift time between start and end of a phase shift in the permanent magnet motor; and a control unit configured to calculate an inductance of each phase with respect to a stator of the permanent magnet motor by using the input current and the input voltage measured by the current voltage measurement unit and the phase shift time calculated by the phase shift time calculation unit, to compare the calculated inductance of each phase with a reference inductance of each phase, and to determine whether a fault occurs in the permanent magnet motor.

2 . The apparatus of claim 1 , wherein the control unit includes:
an inductance calculation unit configured to calculate the inductance of each phase with respect to the stator by using a voltage equation of the permanent magnet motor, based on the input current, the input voltage and the phase shift time; and a fault diagnosis unit configured to calculate an error value by comparing the inductance of each phase calculated by the inductance calculation unit with the reference inductance, and if the calculated error value is not included in a normal range, to determine that a coil wound in the corresponding phase is short-circuited.

3 . The apparatus of claim 2 , wherein the voltage equation used by the inductance calculation unit is obtained as Equation 1:

{

v
us

=

Ri
u

+

L
1



di
u

dt

+

e
u

v
vs

=

Ri
v

+

L
2



di
v

dt

+

e
v

v
ws

=

Ri
w

+

L
3



di
w

dt

+

e
w

[

Equation



1

]

where v us , v vs , and v ws denote a u-phase voltage, a v-phase voltage, and a w-phase voltage of the permanent magnet motor, respectively, where i u , i v , and i w denote a u-phase current, a v-phase current, and a w-phase current of the permanent magnet motor, respectively, where L 1 , L 2 , and L 3 denote a u-phase inductance, a v-phase inductance, and a w-phase inductance of the permanent magnet motor, respectively, where e u , e v , and e w denote a u-phase back electromotive force, a v-phase back electromotive force, and a w-phase back electromotive force of the permanent magnet motor, respectively, and where R denotes a resistance of the permanent magnet motor.

4 . The apparatus of claim 3 , wherein the inductance calculation unit is further configured to calculate the inductance of each phase by using Equation 2 derived from Equation 1:

L
1

=

(

t
2

-

t
1

)



(

DV

d


Assignees

• Korea Electronics Technology

Inventors

• Park Joonsung
• Kim Jinhong
• Hyon Byongjo
• Choi Junhyuk

Classifications

• H02P29/0241

  the fault being an overvoltage · CPC title

• H02P6/18

  without separate position detecting elements · CPC title

• H02P6/12 Primary

  Monitoring commutation; Providing indication of commutation failure · CPC title

• H02K11/20

  for measuring, monitoring, testing, protecting or switching (rectifiers H02K11/04; power electronics H02K11/33) · CPC title

• H02P6/085 Primary

  in a bridge configuration · CPC title