Transcript Precision Variable Frequency Drive

Precision Variable Frequency Drive
Group May07-13
Jason Kilzer
Nick Nation
Dave Reinhardt
Matt Shriver
Client: Jim Walker
Faculty Advisor: Professor Ajjarapu
Precision Variable Frequency Drive
• Nick – Uses and Constraints
• Jason – Technology and Overall Design
• Matt – Detailed Design
• Dave – Requirements, Schedules, Conclusions
Problem Statement
The problem is the ability of a record player to keep a specific speed.
The synchronous motor used on a record player is supposed to play
the record at a specific speed. However, the motor does not always
run at the specified speed which causes the record to sound out of
pitch. A precision variable frequency drive will provide a constant
frequency to the synchronous motor which in turn will maintain a
constant speed of the record table.
Executive Summary
Synchronous motors are motors that run at a specific speed. A
customer may want to run the motor at different speeds, like for a
record player that needs to operate at 45 and 33 1/3 rpm. A
precision variable frequency drive is a way to speed up or slow
down the motor by changing the frequency of the input voltage.
This product will be designed to adjust the frequency between 58 to
62 hertz by the turning of a dial. The digital display will be
accurate up to the thousandth of a hertz. In addition, a strobe light
will allow the user to observe the rpm of the motor. The precision
variable frequency drive will have a long term drift that requires a
gradual decrease/increase of speed that allows for more accurate
tuning.
Operating Environment
• Indoors
• No extreme dust
• No extreme temperatures
Intended Users and Uses
• Users
– Avid music listener
– Lay person
• Uses
– Adjust the frequency of the turn-table
– With other synchronous motors
Assumptions
• Constant linkage – the belt connecting the motor to the turntable is
constant over a short time period. Basically, an increase in motor speed
by a certain factor will result in an increase in the speed of the
turntable by the same factor.
• Plug – the plug from the record player can plug into a standard three
pronged outlet.
Limitations
• Precision – the precision variable frequency drive will be accurate to .1
Hertz.
• Price – the total end product cost must be less than $1,000.
• Frequency Range – 58 to 62 Hertz with step of 0.1 Hertz.
• Nominal Voltage – 120 VAC.
• Stability – the precision variable frequency drive must be stable. Short
term stability of less that +/- 0.01%. It shall not be affected by
fluctuations in incoming voltage or frequency.
• Power Output – 75 W minimum.
• Input Voltage – the input voltage will be a standard household outlet of
120 V at 60 Hz. single phase
Design Considerations
• Maximum weight and size
• Minimum power output
• Minimum operating frequency
Functional Requirements
•
•
•
•
Synchronous motor frequency controller
Knob controller to adjust frequency
Digital read-out of frequency
Portable strobe system
Technology Considerations
• Pulse Width Modulation
• Crystal Oscillator
Technology Approach Considerations
1.
2.
3.
4.
5.
6.
An AC/DC converter was needed to change the input of AC voltage to DC
voltage.
The pulse width modulator will allow the user to change the frequency of the
voltage.
A low pass filter would change the DC signal back into an AC signal at the
desired frequency.
A amplifier would be needed to step the voltage up to an appropriate level to
feed the turn-table.
A frequency counter would be used to display the frequency output of the
low pass filter.
A strobe light system would be used to measure the RPM of the motor.
Testing Considerations
• Pulse-width modulator
• Strobe system
• Complete system
Product Design
Power Source
• 110-120 VAC
• 60 Hz nominal frequency
• Standard wall outlet
AC to DC Converter
The AC to DC converter will take in 120 VAC and
produce 25 Volt DC. The project team will purchase
this component. The group is going to purchase a
converter of the same type that a cell phone charger
would use. The converter is around $20 to purchase.
After the power has been changed into DC pulse width
modulation can take place.
Circuit Simulation via Simulink
Pulse Width Modulator (PWM)
Circuit Design of PWM
Triangle Waveform Generator Circuit
-VCC
2
C1
OS 1
OUT
V3
1n
12 .5k
-
3
0V d c
V+
R5
V-
4
U2
+
OS 2
uA 7 41
1
R4
6
5
1k
7
Z4
-VCC
V
U1
+V CC
4
-
V-
2
OS 1
+
OS 2
uA 7 41
1
R2
R3
20 k
10 k
6
5
Z3
-VCC
+V CC
Ze ne r_ di od e
7
3
V+
OUT
Ze ne r_ di od e
0
V2
V1
-10 Vd c
10 V dc
0
+V CC
0
0
0
Triangle Waveform
Comparator Circuit
+V CC
3
+
V+
7
U1
uA 7 41
OS 2
-
OS 1
1
Q2N39 04
V
4
2
V-
V4
Q1
6
OUT
10 V ac
5
+V CC
0
V T RI
R4
-VCC
20
+V CC
0
0
Q2
+V CC
Q2N39 04
-VCC
V1
10 V dc
V2
-10 Vd c
R5
20
0
0
0
Waveform after PWM
Low Pass Filter
Waveform After Low-Pass Filter
Transformer
Waveform After Transformer
Frequency Counter
A frequency counter will connect to the circuit after the low
pass filter and measure the frequency of the AC signal being
outputted to the voltage amplifier. This device will display
the frequency of the power it is sampling on a LCD screen.
Figure 8 shows a picture of the frequency counter that will
be purchased.
Product Design
Strobe Light System
Figure 11: The strobe light shinning
on the special disc. (Vinyl Engine)
Figure 10: Strobe Light Schematic (Vinyl Engine)
The strobe system will be used to measure the the RPM
of the turn-table. As the picture shows, there are three
different circles for the three rates, 33 1/3, 45, and 78.
Personal Requirements
Name
Task 1
Task 2
Task 3
Task 4
Task 5
Task 6
Task 7
Task 8
Totals
Reinhardt, Dave
1
7
40
6
5
4
5
24
92
Kilzer, Jason
1
10
42
3
5
2
5
18
86
Nation, Nick
1
7
40
3
5
6
5
18
85
Shriver, Matt
1.5
6
40
3
5
6
5
20
86.5
Total (hours)
4.5
30
162
15
20
18
20
80
349.5
Other Resource Requirements
Item
Team Hours
Other Hours
Cost
Miscellaneous Parts & Materials
0
0
$20.00
Device Components
2
0
$65.94
Project/Poster Printing
5
0
$0.00
Total
7
0
$85.94
Financial Requirements
Item
W/O Labor
With Labor
Miscellaneous Parts & Materials
$20.00
$20.00
Device Components
$65.94
$65.94
$0.00
$40.00
$85.94
$125.94
Project/Poster Printing
Subtotal
Labor at $15.00 per hour:
Reinhardt, Dave
$1,380.00
Kilzer, Jason
$1,290.00
Nation, Nick
$1,275.00
Shriver, Matt
$1,297.50
Subtotal
Total
$5,242.50
$85.94
$5,368.44
Schedule
Deadline Chart
Design Evaluation
Relative
Evaluation Resultant
Functionality
Importance
Score
Score
Stablility of frequency
15%
80%
12.00%
Adjustable frequency between 58-62 Hz
25%
100%
25.00%
Accurate strobe light system
5%
60%
3.00%
Safety
15%
100%
15.00%
Precision of .1 Hz
20%
100%
20.00%
User friendly
5%
90%
4.50%
LED display of output frequency
5%
70%
3.50%
Output at least 75W
10%
50%
5.00%
Score
88.00%
Summary
Upon review of the detailed project design, it has
been decided to continue the project as planned. It
will be continued as scheduled because the
detailed design has meet the functional
requirements of the precision variable frequency
drive.
Questions?