IRJET- Analysis of 3-Phase Induction Motor with High Step-Up PWM DC-DC Conver...
Computer modeling-simulation&examples1
1. Computer Modelling/Simulation in Modern Design
and Engineering
Dr.Jian Shen
Date: August 17, 2006
Location: Video Conference Room, LCS
2. 2
Contents
Computer modeling and simulation
tools
Train performance simulation (overall operations simulation)
Frequency domain simulation (filter design, power
electronics thermal design input etc)
Time domain simulation tools (dynamic performance
simulations)
Matlab/Simulink model of Innovia
control system
3. 3
Advantages of computer modeling and
simulation
It helps to design and test a complex
system in its full dynamic range before
building it;
It helps to diagnose problems and find
solutions;
It helps to reduce costs and shorten period
of product development or trouble shoot;
Computer modeling and simulation have
become a standard method of any modern
industry design
4. 4
Requirements for a good computer modeling
of the real systems
Good understanding of each of the parts of
the physical system, its operation
mechanism;
Correct mathematics modeling of the
system and the control sequence;
It helps understanding of the system
dynamics –so a good model of the system
can be a teaching tool for junior engineers.
5. 5
Simulation tools in a electric drive system design---application
examples
Train performance simulations ---TPS (TPSAIM, TOM etc);
Frequency domain simulations--- FDM inverter etc;
Time domain simulations--- SABER, Simplorer, PSPICE,
Matlab/Simulink etc
6. 6
Why so many different simulation models?—for
different applications
Train Performance Simulation
(TPS) for overall system
evaluation and sizing the main
system components (tender
design, quick turn around);
0 500 1000 1500 2000 2500 3000 3500
0
20
40
60
80
100
speed(mph)
time (Sec)
0 500 1000 1500 2000 2500 3000 3500
0
50
100
150
200
250
300
BART Daly city to East Dublin Run Aw2 J.S. 8-22-01
Iphase(rms_amps)
0 20 40 60 80 100 120
0
10
20
30
40
50
60
Pittsburgh LRV Level tangent run @AW2 weight at low line voltage 525V
Speed(mph)
time (s)
0 20 40 60 80 100 120
-800
-600
-400
-200
0
200
400
600
800
Pittsburgh LRV Level tangent run @AW2 weight at low line voltage 525V
Motortorque(ft-lbs)
time(s)
One Acc./Dec. cycle
One trip
9. 9
BART TM rotor failure mechanism diagnose---photo
curtsey of Mr. Peter Pritchard
10. 10
Time domain simulation tools
SABER
PSIPCE
Simplorer
Simulink
Real Time Simulations, hardware in
the loop (HIL) and software in the loop
(SIL) etc.
11. 11
SABER model examples
Saber model of a 4-QS power
and control system (50Hz VS. 60Hz)
SFAA ground loss detection (report #1600) avoided
expensive development, used in all the APM projects
since including both Innovia and CX100 types.
16. 16
SPICE model of the grounding circuit of MARTA---
current carrying brush disturbance caused voltage spikes
17. 17
Real time HIL simulation dSPACE or hardware---
powerful tool for control hardware and embedded software debugging
SMSC line 7/8 inverter drive stability problem due to a
Small rotor parameter change from line 4
•SMSC line 4 inverter drive stability no problem
but the TM slightly overheating
18. 18
A more detailed introduction of Matlab/Simulink simulation
Probably the most widely used
platform;
Both TDM and FDM
calculations;
Industry standard, ease of
exchange models;
Ease of implementing both HIL
and SIL simulations;
Modeling languages using
powerful s-functions;
Unlike circuit simulators need
to write your own equations;
Interface with many other
platforms as well as real
hardware instruments
20. 20
Main issue
A low frequency (3-5Hz) oscillation in all the speed
range affecting ride quality and components life
cycle
- ATC speed regulation cycle --- rate command every 32ms.
- TCC transports & converts the command to propulsion &
friction braking in 150-270ms (random delay ).
- Propulsion to achieve the required tractive & braking effort in
20-30ms when received the command from TCC.
- A measurement showed the mechanical structure has a
natural frequency of around 4Hz.
- The above electrical delay added up to 3.3---5Hz.
- Any mechanical disturbance is coupled through the speed
sensor into the electrical system and causing the resonance.
21. 21
A low frequency oscillation 3-5Hz in all the speed range (from
the Barn), ATC mode without filter
22. 22
No low frequency oscillation 3-5Hz in all the speed range (from
the Barn), manual mode
23. 23
Possible solutions proposed
Add a P-signal generator (about $800,000 budgeted).
- May not work, not knowing now what delays the system can tolerate. May need another
kind of device depending on stability needs.
- Ref: B.Paluf, P-Signal Decision Mitigation Plan, B70” 10-11-2001
- Extra cost of hardware.
Model the vehicle with combined ATC--TCC--Propulsion/friction brake, to
understand the dynamics of the system and find solutions through a
systematic investigation (president Ray Betler set up a special budget for the
modeling work).
- Considered necessary for the total system adjustment not partial adjustment which
may cause new problems.
- All the subsystems are proven design and none thought their problem. Without
modeling, any change to the system (motor, inverter, TCC etc) is unknown how it will
impact system operation.
- It is related to if the Innovia control system design is valid ---impact on this
and future projects.
24. 24
Approach to tackle the issue
Understand the three main parts of the system.
Model the system in Matlab/Simulink (no Simulink model for
each of the components, yet)
Validate the model by comparing the test results from the
prototype train.
Try to find a stable solution and optimize on the model.
Implement the solution.
25. 25
MATLAB/Simulink model of Innovia control system---a software
in the loop approach (SIL)
rate_req
V_ATO
Innovia ATO-TCC-Propulsion System Simulation Model
Click Here
To Load
Parameters
TCC
Train Commu. & Control
Reference
Reference1
P&C
Propulsion System
ClickHere
for Overview
VATO_CTM
A_speed
BE_fric
A_acc
Dist_ft
prop/brk
speed_mph
TE(lbs)
TE_dilved
26. 26
Modeling of the ATO controller (software in the loop
“SIL” approach VATO_CTM block)
The ATO model (implementing the actual C code “control train
motion” in a Matlab S-function)
2
prop/brkstate
1
rate_request(mphps)
ref_vel
com_speed
rate_req
Pro_brk_state
dis_2_station
tar_acc
sta_tar_speed
com_acc
vato_ctm
S-Function
Mux
Mux
Demux
Demux
3
Distance(feet)
2
actual_acc(mphps)
1
actual_speed(mph)
27. 27
Modeling of the TCC controller (below the TCC block)
TCC is modeled in behavioral level
Train Communication and Control Simulation Model
2
BE_fric
1
TE_prop
rate_gwex rate_wtb
wtb_dly
rate_comc rate_v cu1
vcu1_dly
rate_req2
rate_wtb rate_gwin
gwin_dly
rate_v cu1 rate_gwex
gwex_dly
rate_atc rate_comc
comc_dly
rate_gwin
TE_dilv ed
mph
pwr_brk_req
TE_prop
BE_f ric
VCU-dly2
2.236936292e-4
Gain
4
pwr_brk_req
3
mph
2
TE-dilved
1
rate_ATC
28. 28
Modeling of the propulsion control (below the P&C
block)
Propulsion control is also modeled in behavioral level with
necessary details
Propulsion Simulation Model
<Xus2>
<Xomega_m>
2
TE_dilved
1
mph
WAVE_G
wave
VSI
pwm2
torq_nm
omega_m
mph
TE_dilv ed(lbs)
Train Model
ws
is3
torq
Reference
Reference1
Controller
Orion_mod
Observer
Orion
Obs
Measure
Ts varying.
Measurement
Board4
Traction
Motor
Gamma-Model
Ud
DC-link
2
BE_fric
1
TE_require
<Xpsis_k+1>
<Xpsis_k+1>
<Xpsis2>
<Xpsis2>
<F>
<F>
<delta_ref >
<delta_ref >
<pwm6>
<is3>
<is3>
<is3>
<Xis_k+1>
<Xis_k+1>
<>
<f lux_ref >
<psis2>
<Xis2>
<us3>
<us3>
<ctrl_f act2>
<torque>
<Xtorque>
<Xtorque>
<psir2>
<Xpsir2>
omega_us
29. 29
Reproduce the low frequency oscillation problem on the
simulation model
0 5 10 15 20 25 30 35 40 45 50
0
5
10
15
20
25
30
vehiclespeed(blue)
speedsensorsignal
(red)
02-05-2002S.J.
time(s)
(mph)
15 16 17 18 19 20 21 22 23 24 25
26.5
27
27.5
28
28.5
vehiclespeed(blue)
speedsensorsignal
(red) 02-05-2002S.J.
time(s)
(mph)
30. 30
The proposed solution- A digital notch filter ‘s characteristics
1 2 3 4 5 6 7 8 9 10
-35
-30
-25
-20
-15
-10
-5
0
frequency (Hz), (fs=32Hz)
gaininDB 4th order butterworth digitized bandstop filter (SBW 2-6Hz) frequency characteristics
32. 32
R142A project one year after in revenue service, 3 trains being
trapped under river due to a “bucking” E/M resonance problem
33. 33
Measured results---Low frequency oscillations (6.5-7Hz) in speed signal
rpm1, torque dsp T, and speed signal dsp Wls,
People say it is a mechanical problem
Due to inverter shut down & still oscillations
34. 34
The Inverter and vector control simulation model --- Using a
simplified model from DFW (no ATC and TCC)
Propulsion Simulation Model
WAVE_G
wave
ud
time
VSI
pwm2
ClickHere
To Load
Parameters
Id
Un
Ud
In
dc-link1
torq_nmomega_m
Train Mdeol
Xtorq
torq
psir2
psis2
is3
Scope7
Scope6
Scope5
Reference
Reference1
Controller
Orion_mod
Observer
Orion
Orion1
Measure
Ts varying.
Measurement
Board4
Traction
Motor
Gamma-Model
Ud
DC-link
Clock
<Xpsir2>
<Xpsir2>
<Xpsis_p2>
<Xpsis_p2>
<Xpsis2>
<Xpsis2>
Ud
Ud
<Xomega_m><Xomega_m>
<Xomega_m>
<F>
<F>
<delta_ref>
<delta_ref>
<pwm6>
omega_us
<Xtorque>
<Xtorque>
<is3>
<is3>
<is3>
<psir2>
<Xis_p2>
<Xis_p2>
<torque>
<torque_ref>
<flux_ref>
<psis2>
<Xis2>
<Xis2>
<Xus2>
<Xus2>
<us3>
<us3>
<ctrl_fact2>
35. 35
Problem run with 6.5Hz oscillations injected in the speed signal
resulted in torque oscillation and motor phase current oscillations and
inverter shutdown---1
0 0.5 1 1.5 2 2.5 3 3.5 4
-2
0
2
4
6
8
Speed, current and torq with30%mechinject.speed(mph)
0 0.5 1 1.5 2 2.5 3 3.5 4
-500
0
500
1000
1500
phaseamp&torq
J.S. 9-13-2002
time (s)
36. 36
Problem run with 6.5Hz oscillations injected in the speed signal
resulted in torque oscillation and motor phase current oscillations and
inverter shutdown---2
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
-500
-400
-300
-200
-100
0
100
200
300
400
500
Tractionmotor 3- phasecurrent with6.5Hz oscillation
37. 37
A proposed solution to stop the bucking—implemented in the
whole R142A fleet of more than 600 cars
40. 40
The Second Thought
Why a cost/effective solution to a difficult problem considered a
“Patch”?
Why some of our people so sure that it is a mechanical problem only
(similar situation in Las Vegas Monorail)?
Why this is considered by some as not a “correct” solution but liked
by the project team and the customers (KRC & NYCT)?
Why a totally unrelated DC link stability control is considered the
correct solution even measured data and tests prove to be not the
case? Do we have the same situation in other projects, i.e. when we
have a pain at the foot but the prescription is for curing the headache?
Answer, EAT more --- Education and Training.
41. 41
“Fly by wire example”
http://www.centennialofflight.gov/essay/Dictionary/fly-by-wire/DI83G1.htm
42. 42
Digital Fly By Wire (http://www.disenchanted.com/dis/technology/fly-by-wire.html)
The other reason for DFBW was to correct for
something called Pilot Induced Oscillations (PIO),
which is where the pilot over-controls the aircraft
and a sustained oscillation results. What's
interesting is that it also revealed the other hidden
advantage of DFBW: PIO wasn't accounted for on
the first flight of NASA 802, but began to show-up
on test flights of the Space Shuttle. In response,
the computer programmers wrote a filter for it and
tested it out on the F-8, making it probably the first
piece of hardware to ever be enhanced by a
software upgrade.
44. 44
Conclusion:
Computer modeling and simulation is an effective way of diagnose
for existing systems.
Solutions can be found and optimized on the model once it is
established without expensive Lab time and on site tests.
The better way is to prevent the kind of problems by systematic
modeling in the design stage but often due to budget or time
constrains it is not done.
In projects where it is done and problems being prevented, it is not
always appreciated. Management need to understand this and
allocate the resource to carry out the task where ever and when ever
possible.
A detailed engineering report has been written (#1815)