1. Synchronous Motor Drive Control System with Prescribed Closed-Loop Speed Dynamics
Dodds, J., Stephen*, Vittek, Ján**
*University of East London, School of Computing & Technology, UK
**University of Žilina, Faculty of Electrical Engineering,
Dept. of Power Electrical Systems, SK

2. Model of Permanent Magnet Synchronous Motor
Non-linear differential equations formulated in the magnetic field-fixed d,q co-ordinate system describe the permanent magnet synchronous motor and form the basis of the control system development.

3. Control System Structure For PM Synchronous Motor
outer loop sub-plant
inner loop sub-plant
Master
control
law
estimator
and
observers
slave I U
inner loop
outer
loop
Idem
SJD

4. Complete control structure of electric drive with synchronous motor
Transf.
dq / a_b
and
a,b / a,b,c
Master
control law
SMPM
Slave control law
abc / a b
a,b / d,q
Angular velocity Extractor
Discrete
two phase
oscillator
Mg. flux
calculator
Sliding mode Observer
Filtering observer iq id ud uq
ua,b,c
vd_ekv
vq_ekv ia ib ua ub uc
ib_dem
ia_dem
ic_dem
id_dem
iq_dem ic
POWER
electronics

5. Discrete Time Two-Phase Oscillator
The discrete time two-phase oscillator produces the transformation matrix elements, needed for the transformation blocks.
where the new transformation matrix elements
are equal to and

6. Master Control Law linearising function motor equation
demanded dynamic
linearising function
vector control terms
demanded values of the current components
motor equation

7. Acceleration Demands for Three Various Dynamics
First Order Dynamic
Second Order Dynamic
Constant Acceleration

8. Slave Control Law
Proportional High Gain Slave Control Law
Bang-Bang Slave Control Law
A High Gain Proportional Control Law with Voltage Saturation Limits was used for simulation
Bang-Bang Control Law Operating in the Sliding Mode (switching strategy for two-phase version is satisfactory determined).

9. The Sliding Mode Observer and Angular Velocity Extractor
The basic stator current vector pseudo sliding-mode observer is given by:
The required estimates is equivalent values
where is high a gain
unfiltered angular velocity estimate can be extracted
For the purpose of producing a useful formula for perfect constant parameter estimates may be assumed:

10. The Filtering Observer
Filtered values of and are produced by the observer based on Kalman filter VJ
where:
needs adjustment of the one parameter only.

11. Current sensors are as follows:- LEM LTA 50P/SPI.
EXPERIMENTAL RESULTS
Electric drive with synchronous motor consists of synchronous machine with nominal parameters:
, , P = 4 , , , .
Parameters of IGBT FUJI 6MBI-060 are as follows:- nominal voltage: 600 [V] , nominal current: 6x10 [A].
Current sensors are as follows:- LEM LTA 50P/SPI.

12. Measured Results for Synchronous Motor with Constant Acceleration
Complex Current
Current v. t 2 2 -2 -2 -2
Complex Mg. Flux 2
Mg. Flux v. t
0.5
0.2
0.2
-0.2
-0.2
-0.2
Observed Values
0.2
Rotor Speed
0.5
100
100 50 50
-50
0.5 1
-0.5
0.5 1
T1 = 0.1 s , wd = 60 rad/s

13. 1 - angular velocity, 2 - current in phase A
Measured Results for Synchronous Motor with Constant Acceleration - osciloscope screen
1 - angular velocity, 2 - current in phase A
T1 = 0.1 s , wd = 60 rad/s

14. Experimental results for idle running synchronous motor and first order speed demand .-5 5
Complex Current
0.4
Current v. t
-0.2
0.2
Complex Mg. Flux
Mg. Flux v. t
0.5 1
-50 50
100
Observed Values
-0.5
Rotor Speed
T1 = 0.05 s , wd = 80 rad/s

15. 1 - angular velocity, 2 - current in phase A
Experimental results for idle running synchronous motor and second order speed demand - osciloscope screen
1 - angular velocity, 2 - current in phase A
Tset = 0.15 s , wd = 80 rad/s

16. Experimental results for idle running synchronous motor and second order speed demand-5 5
Complex Current
0.4
Current v. t
-0.2
0.2
Complex Mg. Flux
Mg. Flux v. t
0.5 1
-50 50
100
Observed Values
-0.5
Rotor Speed
Tset = 0.15 s , wd = 80 rad/s

17. 1 - angular velocity, 2 - current in phase A
Experimental results for idle running synchronous motor and first order speed demand - osciloscope screen
1 - angular velocity, 2 - current in phase A
T1 = 0.05 s , wd = 80 rad/s

18. Experiments with 2nd Order Dynamic for Various Damping
-0.2
0.2
0.4
0.6
0.8 60
-10 10 20 30 40 50
z=0.5
z=2
z=1
Tsettl=0.3 s , wd = 40 rad/s

19. Experimental Results for Synchronous Motor Drive
Constant Acceleration
First Order Dynamic
Second Order Dynamic
wd=
600 rpm,
Tramp=
0.05 s
800 rpm,
Tsettl=
0.3 s
Zilina
1998
Control of the angle between rotor flux and stator current vectors

20. Conclusions and Recommendations
A new approach to the control of electric drives with permanent magnet synchronous motors, based on feedback linearisation has been developed and experimentally proven.
Three various prescribed dynamics to speed demands were achieved.
Further research will focus on the application of the new approach to enhancement of control system for outer loop based on MRAC or SMC to improve precision of control.