Transcript M6_C3_Lesson 1_System Developmentx

AVTC Model Based Design
Curriculum Development
Project
Lesson 1: System Development
Outline
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Electric drives
Introduction to Power Electronics
Rectifiers
Inverters
Simulink Models
Simscape Models
Failure Modes
Electric Drives
• What is an Electric Drive?
– Conditions power to motor, responds to driver request and provides
feedback loop from motor to controller logic
•
Monitors characteristics of the electric motor such as temperature,
torque, speed and angular position
Source: www.uqm.com
Electric Drive
• Why is it needed?
– To provide appropriate voltage and frequency for desired speed
– In order to change speed we need a variable frequency 3-φ source
• 𝑁𝑠 ∝ 𝑓, where 𝑁𝑠 is synchronous speed and 𝑓 is electrical frequency
Electric Drive
3-φ output voltage
Electric Motor
DC input voltage
Source: www.uqm.com
Block Diagram of the Drive
• Basic functionality of the drive
Input
Inverter
Electric Motor
Electric Drive
Controller
Introduction to Power Electronic Devices
Four Quadrant Operation
of Electric Drive
http://acdcdrives.blogspot.com/
Illustrated by: Shrikanthv
2-Step and 3-Step Waveform
2-Step Waveform
0
3-Step Waveform
0
t
t
5- Step Waveform
0
t
Three-Step 3-φ Waveform
Phase A
0
t
Phase B
0
t
Phase C
0
t
Comparison Between
Different Waveforms
Waveform
Signal
Transitions
per Period
System
Description
Total Harmonic
Distortion
2
2-level square
wave
45%
4
3-level square
wave
>24%
8
5-level square
wave
>7%
Regeneration
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When the motor is operated as a generator, the power is fed
back to the batteries through rectifiers
Basic Principle of Rectifiers
• It converts alternating current (AC), which periodically
reverses direction, to direct current (DC), which flows in only
one direction
1-φ AC
Simulink Model of Basic Rectifiers
Half-wave rectifier:
Full-wave rectifier:
3-φ Full-Wave Rectifier
• The output response of a 3-φ full-wave rectifier is shown
below:
Inverter
• The DC power from the batteries is converted to AC power by
Inverters to supply 3-φ motor
i
Basic Principle of Inverters
• It converts DC voltage to AC voltages
• We will demonstrate:
– DC to 1-φ AC
– DC to 3-φ AC
Direct Current
Inverter
Alternating Current
• There are different types of conversion techniques among
them Space Vector Modulation is prominent
Basic Principle of
Space Vector Modulation
• The principle of space vector modulation is based on the
application as shown below in the hexagon
• As the transistors in the basic 3-φ inverter are switched on and
off, six possible active switching vectors V1 through V6 are
actualized
Source: http://electrotech4u.blogspot.com/2011/07/implementation-of-space-vector.html
Space Vector Timing Diagram
• The timing sequence and the resulting switching
waveform for Symmetric Sequence SVM in sector 1 is
shown below
Source: http://electrotech4u.blogspot.com/2011/07/implementation-of-space-vector.html
2- Step Inverter
3-Step Inverter
5- Step Inverter
3-Step 3-φ Inverter
Simscape Model of 3-φ Inverter
Simscape Response of
3-φ Inverter
Specifications Used with
Simscape Models
AC Motor Drive
DC Motor Drive
Stator Resistance: 1.48 mΩ
Rotor Resistance: 9.29 mΩ
Inductance: 0.303 mH
Moment of Inertia: 10 kg-m2
Friction Coefficient: 0.08 N-m-s
Armature:
• Resistance: 56 mΩ
• Inductance: 0.15 mH
Field:
• Resistance: 150 Ω
• Inductance: 113 H
• DC Source: 150 V
Moment of Inertia: 10 kg-m2
Friction Coefficient: 0.272 N-m-s
Smoothing Inductance: 0.5 mH
Simscape Model of
Two Quadrant DC Motor Drive
Speed and Torque Response of Two
Quadrant DC Motor Drive
Simscape Model of
Induction Motor Drive
Speed and Torque Response of
AC Motor Drive
Failure Modes – DFMEA
Potential
Effects of
Failure
Line
No:
Function of
Part
Potential
Failure Mode
Uncontrolled
Motor
behavior
Loss of
torque
1
Inverter:
Motor must
operate with
in specified
RPM/Torque
ranges
Inverter:
Inverter pack
must operate
within
specified
temperature
range
Inverter over
temperature
Inverter
unable to
supply
motor
with
adequate
power
2
S
E
V
8
7
Potential
Cause
Inverter
electronic
malfunction
Temp sensor
malfunction/
coolant
leak/
inverter
malfunction
O
C
C
Current Design
Controls
Prevention
Current Design
Controls
Detection
None
CAN messages
/ Motor RPM
monitoring
2
7
Proper hose/
fitting selector/
respond to
increase in
temp. before
undesirable
operation
happens
Detect pump
impeller speed
/ monitor and
verify temp/
monitor
inverter
temperature
D
E
T
RPN
2
32
2
98
Test and Review
1.
What is the function of an Inverter?
1. Converts AC to DC
2. Converts AC to AC
3. Converts DC to DC
4. Converts DC to AC
2. What is the acronym MOSFET?
a. Metal Oxide Semi-inductor Field Effect Transistor
b. Metal Organized Semiconductor Field Efficient Transistor
c. Metal Oxide Semiconductor Field Effect Transistor
3. What is the relation between 𝑁𝑠 𝑎𝑛𝑑 𝑓, where 𝑁𝑠 is synchronous speed
and 𝑓 is frequency.
a. Directly proportional
b. Inversely proportional
c. Not related
References
• “A Guide to Electric Drives and DC Motor Control, Published by Ohio
Electric Motors,” http://www.ohioelectricmotors.com/a-guide-toelectric-drives-and-dc-motor-control-688#ixzz2t4v60h6B, Aug. 2011.
• Boglietti, G. Griva, Pastorelli, M., Profumo, F., and Adam, T.,
“Different PWM Modulation Techniques Indexes Performance
Evaluation,” IEEE Technical Paper, 0-7803-1227-9, 1993.
• Hughes, Austin, and Bill Drury, “Electric Motors and Drives:
Fundamentals, Types and Applications,” Oxford: Newnes, 978-0-08098332-5, 73-111, 113-140 2013.
• Kumar, R. R., Kumar, S., and Yadav, A., “Comparison of PWM
Techniques and Inverter Performance,” IOSR-JEEE, ISSN: 2278-1676,
Volume 4, Issue 1, PP 18-22, Jan. - Feb. 2013.
• “Motor Drive & Control,”
http://www.ti.com/lsds/ti/apps/motor/brushless_dc/overview.page,
2014.