Precision Variable Frequency Drive by gegeshandong


									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
       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

• 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.
• Precision – the precision variable frequency drive will be accurate to .1
• 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.    An AC/DC converter was needed to change the input of AC voltage to DC
2.    The pulse width modulator will allow the user to change the frequency of the
3.    A low pass filter would change the DC signal back into an AC signal at the
     desired frequency.
4.    A amplifier would be needed to step the voltage up to an appropriate level to
     feed the turn-table.
5.   A frequency counter would be used to display the frequency output of the
     low pass filter.
6.   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
                                                                         -V CC

                                                                 2                           1

R5              C1                                                   -            OS1                 R4
                                                      V3                         OUT
                1n                                                                                    1k
12.5k                                     0Vdc                   3                           5

                                                                     +            OS2

                     -V CC                                                                                     Zener_diode
                                          V           0

            2                    1

                -          OS1                R2                                        R3
                                              20k                                       10k
            3                    5                                                                             Z3

                +          OS2                      +VCC             -V CC

                                                           V1                V2
                                              10Vdc             -10Vdc
        0            +VCC

                                                           0                 0
Triangle Waveform
             Comparator Circuit
                                                U1         +VCC

                        3                       5

                            +         OS2                Q1
10Vac                   2                       1             Q2N3904

                            -         OS1


             VTRI                                                    R4
        0                       -V CC
                    0               Q2                        +VCC                 -V CC

                                                                          V1               V2
                                                         10Vdc                 -10Vdc

                                                20                        0                0
Waveform after PWM
Low Pass Filter
Waveform After Low-Pass Filter
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
Project/Poster Printing                                  $0.00                $40.00
                                  Subtotal           $85.94               $125.94
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                              $5,242.50
                                    Total            $85.94             $5,368.44
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%

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

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