Method of estimating voltage of input terminal of inverter and motor control method using the same

Patent metadata

Field	Value
Publication number	US-9350277-B2
Application number	US-201414522201-A
Country	US
Kind code	B2
Filing date	Oct 23, 2014
Priority date	Jun 2, 2014
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

A method for estimating a voltage of an input terminal of an inverter includes checking three-phase currents flowing from an inverter to a motor. A voltage of an input terminal of the inverter is calculated based on a plurality of design parameters, the three-phase currents, and PWM duties for determining switching operations of a plurality of switching elements of the inverter.

First claim

What is claimed is:

1. A method for estimating a voltage of an input terminal of an inverter, comprising steps of:
checking three-phase currents flowing from an inverter to a motor; and
calculating a voltage of an input terminal of the inverter based on a plurality of design parameters, the three-phase currents, and PWM duties for determining switching operations of a plurality of switching elements of the inverter.

2. The method of claim 1 , wherein
the step of calculating the voltage of the input terminal of the inverter includes calculating estimated three-phase voltages based on the plurality of design parameters and the three-phase currents, wherein
a voltage V dc _ Est of the input terminal of the inverter is calculated from an equation of V dc _ Est =V n _ Est ×(PWMduty n −0.5),
where V n _ Est and PWMduty n are values corresponding to the same phase, V n _ Est is one of the estimated three-phase voltages, and PWMduty n is one of the PWM duties.

3. The method of claim 2 , wherein
the step of calculating the estimated three-phase voltages includes steps of:
converting the three-phase currents into a D-axis current and a Q-axis current that correspond to a fixed coordinate system;
converting the D-axis current and the Q-axis current into a d-axis feedback current and a q-axis feedback current that correspond to a synchronous coordinate system;
calculating a d-axis estimated voltage and a q-axis estimated voltage based on the d-axis feedback current and the q-axis feedback current;
converting the d-axis estimated voltage and the q-axis estimated voltage into a D-axis estimated voltage and a Q-axis estimated voltage that correspond to the fixed coordinate system; and
converting the D-axis estimated voltage and the Q-axis estimated voltage into estimated three-phase voltages that correspond to a three-phase coordinate system.

4. The method of claim 3 , wherein
the d-axis estimated voltage V d _ Est and the q-axis estimated voltage V q _ Est are calculated from equations of

V
d_Est

=

R
s

⁢

I
d_feedback

+

L
d

⁢

ⅆ

ⅆ
t

⁢

I
d_feedback

-

ω
e

⁢

L
q

⁢

I
q_feedback

V
q_Est

=

R
s

⁢

I
q_feedback

+

L
q

⁢

ⅆ

ⅆ
t

⁢

I
q_feedback

+

ω
e

⁢

L
d

⁢

I
d_feedback

+

ω
e

⁢

⁢

Ψ
f

,

where I d _ feedback is a d-axis feedback current, I q _ feedback is a q-axis feedback current, R s is a coil resistance of a motor armature, L d is a d-axis inductance, ω e is an electrical angular velocity, L q is a q-axis inductance, and Ψ f is a magnetic flux interlinkage of the motor armature.

5. The method of claim 4 , wherein
only the ω e Ψ f is calculated to calculate the q-axis estimated voltage when the I d _ feedback , the I q _ feedback , the R s , the L d , the ω e , and the L q are smaller than respectively set reference values.

6. The method of claim 4 , wherein
the estimated three-phase voltages are calculated from a relationship map of the electrical angular velocity, the three-phase currents, and the three-phase voltage commands if the estimated three-phase voltages calculated from the equations of

V
d_Est

=

R
s

⁢

I
d_feedback

+

L
d

⁢

ⅆ

ⅆ
t

⁢

I
d_feedback

-

ω
e

⁢

L
q

⁢

I
q_feedback

V
q_Est

=

R
s

⁢

I
q_feedback

+

L
q

⁢

ⅆ

Assignees

• Hyundai Motor Co Ltd

Inventors

• Lee Dong Hun
• Kim Sungdo
• Ryu Chang Seok

Classifications

• G01R19/2503

  for measuring voltage only, e.g. digital volt meters (DVM's) (G01R19/2506 - G01R19/257 take precedence) · CPC title

• G01R19/0084

  Measuring voltage only · CPC title

• H02P6/001 Primary

  Electricity · mapped topic

• H02P21/06 Primary

  Rotor flux based control involving the use of rotor position or rotor speed sensors · CPC title

• H02P21/14

  Estimation or adaptation of machine parameters, e.g. flux, current or voltage · CPC title