2. 1-Three phase induction motor.
Advantages Problems
It is the center of majority of
the industrial production
process.
Cheap.
Small size.
Easy maintenance.
Mechinical parts is less than
other machines.
3. Problems in stator
Grounding.
occures resulting
breakdown insulation
between phase and ground
,this lead to short circuit.
I=V/R
Isolation.
Isolation
Benfits problems
4. Benfits.
It aims current loop.
Ia=Ib=Ic
R=ρL/A
At constant(ρ,A)
RαL
Th=(Rh/Rc)(K+Tc)-
k
RαT
T L R
Problem of isolation.
Break down
insulation
Reasons Types
Increasing
voltage
Increasing
current
8. where:
p=d/dt Ls=Lls+Lm Lr=Llr+Lm
r
r
s
s
r
r
r
r
e
m
m
r
e
r
r
e
r
r
m
r
e
m
m
m
e
s
s
s
e
m
e
m
s
e
s
s
s
s
i
i
i
i
p
L
R
L
p
L
L
L
p
L
R
L
p
L
p
L
L
p
L
R
L
L
p
L
L
p
L
R
V
V
0
0
)
(
2
3
r
s
r
s
m
p
e i
i
i
i
L
P
T
m
m
m
m
l
e f
dt
d
J
T
T
p
r
m
P
10. Solving
At occurs
breakdown
isolation .
L R I
We can from
mointoring current
and voltage for
protection of motor.
2-Maintenance.
Maintenance
Predictive
maintenance
Corrective
maintenance
Preventive
maintenance
11. Corrective maintenance Preventive maintenance
Concept
Repair of equipment to back
to original operation
condition.
It occurs after problem.
Concept.
Regular examination of
equipment for defects by
means of PM checklist and
sensory perception.
Examples:
1-Lubrication.
2-Filters.
3-Testing.
12. Predicative maintenance
Concept.
Regular examination of
equipment to determine
what corrective actions
should be performed with
best timing.
OR
Predictive maintenance
monitors the performance
and condition of equipment
and condition of
equipment or system to
detect degradation.
Examples
Vibration mointoring.
Oil analysis.
Signature analysis of
voltage and current.
Performance testing.
Visual inspection.
Predicative maintenance is
the best method
14. Concept
This method is used to
mointoring parameters of
machine and its performance
.
Types of paramrters:
1-Electrical parameters.
Rs,Ls,Lm,Rr,Lr,Rcore
2-Mechinical parameters
Moment of inertia.
Real-time parameter
estimation.
This type is used to tune the
controllers of induction motor
drive.
This requires real-time
parameter estimation
technique.
Using simplified I.M models.
this is fast enough to
continuously update.
15. Parameter calculation
from motor construction
data.
This method requires
adetailes knowledge of the
machines construction ,
such as
material parameters.
It is the most accurate.
It is the most cost.
It based on field
calculation method.
Such as: the finite element
method
Parameter estimation
based on steady-state
motor model.
This method requires
available data(V,I,speed).
This method based on I.M
steady-state equations.
This is the most common
type of parameter estimation
.
Such as:
1- RLS
2-MRAS
16. Frequency –domain
parameter estimation.
This method based on
measurements that are
performed at stand still.
In facts ,stand still tests
are not common
industry practice.
Time-domain parameter
estimation.
This method performed
and modl parameters are
adjusted to match the
measurements.
Not all parameters can
be observed using
measurements
quantities
This method is costly.
The required data not
available.
17. 4-Parameters estimation using RLS Algorithm
Advantages:
Requirements data is available.
Stator voltages , Stator currents, speed.
Can determination full parameters at the same
time.
Good accurty.
Fast response.
18. Mathematical model of RLS Algorithm.
From dynamic model of I.M Vαr=0 Vβr=0
We will operate at constant speed w=0
r
r
s
s
r
r
r
r
m
m
r
r
r
r
r
m
r
m
m
s
s
m
s
s
s
s
i
i
i
i
p
L
R
L
p
L
L
L
p
L
R
L
p
L
p
L
p
L
R
p
L
p
L
R
V
V
0
0
0
0
0
0
19. Mathmatical model of RLS Algorithm
Stator
• Vαs=(Rs+ p Ls) iαs + p Lm iαr (5)
• Vβs=(Rs+ p Ls) iβs +p Lm iβr (6)
Rotor:
• 0=Lm p iαs+wr Lm iβs +(Rr+Lr p) iαr+wr Lr iβr (7)
• 0= -wr Lmiαs +Lm p iβs-wr Lr iαr+(Rr+Lr p) iβr (8)
Where:
P=d/dt Ls=Lls+Lm Lr=Llr+Lm
20. a
R L R L
j
a
L R
T
j
b
L
b
L
T
j
s r r s
s
r
o
r s
s r
r
r
s
o
r
s r
r
1
1
1
1
Where:
Ls = Lm + Lls and Lr = Lm + Llr
s = Ls Lr - Lm
2
is a leakage coefficient.
Vs=Vsα+j Vsβ
is=isα+j isβ
Where:
Vsα , Vsβ are the -axis and -
axis stator voltage components
in the stationary reference frame
.
isα, isβ are the corresponding
currents.
s
o
s
s
o
s
s
V
b
dt
dV
b
i
a
dt
di
a
dt
i
d
1
1
2
2
The coefficients of above equation are
functions of the machine parameters and
the rotor speed (wr) , and given by:
From(7),(8) , we can obtion:
iαr, iβr afunction iαs, iβs.
Then the time derivatives
21. From above equations,we can obtion:
Where:
Y(t) is the measurements.
X(t) is the regression matrix.
Θ(t) is the unknown parameters.
t
t
x
t
y
)
(
s
s
r
s
s
r
s
s
s
s
r
s
s
r
s
s
s
r
s
s
r
s
V
V
dt
dV
i
i
dt
di
V
V
dt
dV
i
i
dt
di
dt
di
dt
i
d
dt
di
dt
i
d
2
2
2
2
5
4
3
2
1
22. We have two matrix:
First matrix.
Second matrix.
s
s
r
s
s
r
s
s
s
r
s
V
V
dt
dV
i
i
dt
di
dt
di
dt
i
d
2
2
s
s
r
s
s
r
s
s
s
r
s
V
V
dt
dV
i
i
dt
di
dt
di
dt
i
d
2
2
5
4
3
2
1
5
4
3
2
1
24. t
V
V e
s
s
cos
)
cos(
t
i
i e
s
s
)
sin(
t
i
i e
s
s
)
sin(
/
t
i
dt
di e
s
e
s
)
cos(
/
t
i
dt
di e
s
e
s
t
V
V e
s
s
sin
25.
5
4
3
2
1
s
s
e
r
s
r
s
s
e
s
e
r
e V
V
i
i
i
i
From the first matrix ,we can
obtion these yield.
s
e
r
e i
t
y
)
(
s
s
e
r
s
r
s
s
e V
V
i
i
i
t
x
)
(
26. Flow chart of RLS
Algorithm
start
Inputs Vs ,Is,
speed (measured)
Clarke transformation
From equatios : obtion
Y(t) x(t)
Y’(t)=x(t)*theta(t-1)
ԑ=Y(t)-Y’(t)
From equation : obtion P(t) (covariance matrix)
Theta(t) =theta(t-1)+p(t)x(m) ԑ(t)
Outputs Electrical parameters
Rs Rr Lls Lr
27. The following steps describe the RLS algorithm used
to estimate the unknown vector (θ)
Set the initial value of the estimated parameter and covariance
matrix P.
covariance matrix P is assumed to be diagonal matrix with large
postive numbers.
Compute estimate y’.
y’(k)=x(t)*θ(t-1)
Compute the estimation error of y(t).
ԑ=y(t)-y’(t)
Compute the estimation covariance matrix at t
)
(
)
1
(
)
(
)
1
(
)
(
)
(
)
1
(
)
1
(
1
)
(
t
x
t
P
t
x
t
P
t
x
t
x
t
P
t
P
t
P T
T
28. The forgetting α=0.999 is used to track the time variation of the
unknown parameters.
Compute the estimation veator θ’ at instant t.
θ’(t)=θ’(t-1)+p(t)x(t)ԑ(t)
Repeat these steps until apreset minimum error ԑ(t) is reached.
By estimating vectors θ’ ,the electrical parameters can be easily
deduced by using the following equations.
4
3
ˆ
ˆ
ˆ
s
R
4
ˆ
1
ˆ
ls
L
3
1
3
1
5
ˆ
ˆ
ˆ
ˆ
ˆ
1
ˆ
r
L
3
1
3
2
4
ˆ
ˆ
ˆ
ˆ
ˆ
1
ˆ
r
R
29. 5-Expermintial and simulation results of parameters.
The test motor was a 10 H.P, 220 V, 50 Hz, delta connected,
. The rated current per phase was 15 A at 1450 rpm.
The next table illustrates the estimated mean values of
electrical motor parameters obtained using the RLS
algorithm and those obtained experimentally (standard
tests). The third row shows the percentage error results. It
can be noted that it is possible to estimate all electrical
parameters with good precision (estimation errors between
2-5 %). These errors are small and tolerated to get good
parameters estimation.
39. Discussion 6- performance of I.M at
Steady-State operation.
From above figures, we
notice:
fast convergence time.
Small estimation errors in
steady-state.
Motor Performance include on:
Input current.
Input power.
Output power.
Losses power.
Efficiency.
Speed.
Power factor.
We compare between
motor performance
depend on :
Expermintial parameters.
Estimation parameters.
48. 7-Conclusion
An identification methodology based on the RLS algorithm was
successfully applied in this work to identify induction motor electrical
parameters, without saturation effect and skin effect ,harmonic and
temperature .
The identification algorithm should be executed when the system is in
steady state operation.
predicative maintenance includes on :
Electrical parameters
Mechinical parameters
Mechinical parameters plays important role in predicative
maintenance.
such as : estimation load torque to known Tl<Te or not.
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