Single Sensor Three-Phase Permanent Magnet Synchronous Motor Drive based on Luenberger Style-Observers

Bahaa Hafez 1, A. Abdel-Khalik 2, A. M. Massoud 3, Shehab Ahmed 4, and Robert D. Lorenz 5

1 Texas A&M University, College Station TX, U.S.A, 2 Alexandria University, Alexandria, Egypt, 3 Qatar University, Doha, Qatar, 4 Texas A&M University at Qatar, Doha, Qatar

5 University of Wisconsin-Madison, WEMPEC, Madison WI, U.S.A

IEEE-ICEMS2012-Fall – Sapporo, Japan – October 22, 2012

This paper presents a technique to

estimate phase currents and rotor position

in a vector-controlled PMSM drive using

only dc-link current measurement based

on Luenberger style observers.

Abstract

Proposed Algorithm

+

idc

+

vdq s *

1

L s

r

-

^

-Esal dq

s^

idq

s

-

+

abc

ab

iabc Kio

Ro +

s ^

DC link Current Mapping

PMSM Luenberger style observer

idq

s^

DC link measurement Limitation

V5 V6

V1V4

V7100

011

110010

001 101

V0

Vcom

a

Sector 1

Sector 2

Sec

tor

3

Sector 4

Sector 5

Sec

tor

6

V2V3

SA_UP

SB_UP

SC_UP

T0/4 T0/4T0/4 T0/4

SA_LOW

SB_LOW

SC_LOW

ia iaic ic

T1/2 T2/2 T2/2 T1/2

Tpwm/2 Tpwm/2

SA_LOW SB_LOW SC_LOW

idc

ia

ib

ic

SA_UP SB_UP SC_UP

V3

V1

V2

V4

V5 V6

V0

V7

Sector boundary region

Measurable

region

Low Modulation region t (sec) tcom

tset ton tA2D

Full system and Hardware results

Performance Improvement

Motor current - full sensors

Motor current - single sensor

Conclusion

• Better “Dynamic Stiffness” and lower harmonic motor

current due to higher resolution estimated position.

• Overcome the sector boundary region limitation.

• No PWM modification needed.

• Simple algorithm which can be implemented by an

industry standard DSP (F2812).

• Controllers orientation is simple and straightforward

due the observer linearity.

• No hardware modification needed.

• 0.2 [PU] lower speed transient limit

Test setup Parameter Parameter Value

DC bus Voltage 100 V

Phase resistance 1.4489 Ohms

D,Q axis Inductance- 0.0049325 H

Flux Linkage 0.077393 V.s/rad

Pole pairs-P 6

Motor inertia-J 0.00924 kg/m2

Motor viscous friction-b 0.005 N.m/s.rad

Base current 7 A

Base voltage 57.735 V

Base mechanical speed 85 rad/s

Base Torque 4 N.m

Electrical loop freq. 5000 Hz

Mechanical loop freq. 500 Hz

CRO loop freq. 5000 Hz

Elect. loop Eigen values freq. 10 Hz,100 Hz

Mech. loop Eigen values freq. 0.1 Hz,1 Hz

BEMF est. Eigen values freq. 80 Hz,800 Hz

BEMF Tracking Observer

Eigen values freq. 1Hz,10Hz,100Hz

Speed Filter Eigen values

freq. 0.1Hz,1Hz,10Hz

Inverter

1

L s

r

Kt

1

J s

b

1

s

Ke

--

- ++

Kio

Ko +

s

++

1

J s^

+

+

1

s

P

2

j( + )

e

qr

p2

^

^

1

J s

wrm^

qrm

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qr

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Kio-2

Ko-2 +

s

bo-2

+

+

+

+^

1

J s

1

s+

+

-

- qrm

^

wrm^

wrm-2^

qrm-2

^

Cascaded Position

Observer

Back-emf Tracking

Observer

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s^

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1

L s

idq

s^

r

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-Esal dq

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idq

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+abc

ab

iabc Rio

Ro +

s

Three phase Current Reconstruction/

Back-emf State Filter

-1

^

id = 0*

Te* Ki

Kp +

s

Kt-1

iq*

id*+ j iq

* Kio-1

Ko-1 +

s

vdq s

dq

ab

*

SVM

qr^

Te* Te

*

wrm-2^

wrm*

+

-

+

-

Physical motor/inverter setupDrive Controller

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l d

q

s

vdq s

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Td +wrm

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0.5 P