Electric Two-Wheeler

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Sponsors Dr.Herb Hess & Dr.Joseph Law
Team Name King of the Hills
Duration Spring 2019 - Fall 2019
Mentor
  • Dr.Herb Hess
  • Dr.Joseph Law
Team Members
  • Val Wold
  • Armando Solis
  • Hai Huang

The goal of the project is to design a controller for an alternator being used as a motor. As proof of concept, the entire system will be mounted on a bicycle to assess its performance in the rolling terrain of the Palouse.



Problem Definition[edit]

Design a motor controller that will test the limits of an alternator as a motor; compare its motor capabilities to its generator capabilities.

The first proof of concept is a DC generator load for fine control of steady state power output. The second proof of concept is an Electric Vehicle load to test our controller under heavy transients.

Specifications[edit]

Alternators have good power density and cost-effectiveness as generators. These power values will give us the specifications for our performance standards when running our alternator as a motor. The controller design will have to be determined through capable modeling and experimentation.

However, the only initial requirement is that the system performs. That is, by any means available the controller should be able to start and reliably power the alternator under load. From here, we will be able to improve our design, bringing the performance values closer to those of the generator.

Project Learning[edit]

Implementation in c
Scheduling, fastest to slowest:

  • PWM counter (ใ€–๐‘“๐‘Ÿ๐‘’๐‘žใ€—_๐‘ ๐‘ค=80๐‘€๐ป๐‘ง/(๐‘๐‘œ๐‘ข๐‘›๐‘ก๐‘  ๐‘๐‘’๐‘Ÿ ๐‘‘๐‘ข๐‘ก๐‘ฆ ๐‘๐‘ฆ๐‘๐‘™๐‘’))
  • Space Vector PWM updater (๐‘“๐‘ข๐‘›๐‘‘๐‘Ž๐‘š๐‘’๐‘›๐‘ก๐‘Ž๐‘™/๐‘Ÿ๐‘’๐‘ ๐‘œ๐‘™๐‘ข๐‘ก๐‘–๐‘œ๐‘›)
    ๐‘Ÿ๐‘’๐‘ ๐‘œ๐‘™๐‘ข๐‘ก๐‘–๐‘œ๐‘›=(๐‘ ๐‘š๐‘Ž๐‘™๐‘™๐‘’๐‘ ๐‘ก ๐‘ ๐‘ก๐‘’๐‘ ๐‘–๐‘› ๐‘‘๐‘’๐‘”๐‘Ÿ๐‘’๐‘’๐‘ )/360
    Example: 50Hz fundamental (1500 RPM), 3 degree smallest step, 6 kHz updates
  • Frequency updater
    Change the fundamental frequency
    Change the fundamental frequency
    Example: 50 Hz to 60 Hz using a push-button

Fixed point multiplication

  • Example: divide 50 by pi
  • First, express ๐œ‹^(โˆ’1) as a multiple of 2^(โˆ’11)
    1/๐œ‹โ‰…652โˆ—2^(โˆ’11)
    50/๐œ‹โ‰…50โˆ—652โˆ—2^(โˆ’11)=(50โˆ—652)โ‰ซ11=15.918
    Actual answer: 50/๐œ‹=15.9155
    Dividing by powers of 2 is simply a right shift
  • Maximizing resolution
    16-bit architecture
    Q-number format
    Moving the point to where as many fractional bits are assigned as possible but no more

Final Design[edit]

Picture Info
Foc.png
Source: Microchipยฎ, Sensorless Field Oriented control of a PMSM


Foc2.jpg
Source: Microchipยฎ, Sensorless Field Oriented control of a PMSM
FOC in two minutes
  • Control is actually quite simple
  • Objective: make rotor field orthogonal to stator field
  • AC machines are quite nonlinear if controlled in a stationary, three phase, reference frame
  • Some reference-frame shifting can yield not only steady state DC values but the dynamics are actually decoupled.
Data flow diagram.png

Data flow diagram
Svpwm.png

Space Vector Theory
  • Not phasors:

Phasors: Describe a single sinusoidal output, with the same frequency as the reference, but with variable magnitude and phase
SpaceVectors: Describes three sinusoidal output, all with the same phase relation, but with variable magnitude and position

  • Switching states:

Each possible combination of the switching states is a unit vector in voltage space (for a voltage regulator) or current space (for a current regulator)
Using switching times to weight these states allows for precise control over the position of the three-phase signal

Validation[edit]

Method Result
Python SVM Simulation
Verification3.png
67degrees
Verification4.png
145degrees
MPLAB
Verification5.jpg
67degrees
Verification6.jpg
145degrees
Oscilloscope
Verification7.png
67degrees
Verification8.png
145degrees
Compare Three Methods
Verification1.jpg
67degrees
Verification2.jpg
145degrees

Team Members[edit]

Picture Info
Vol Wold.jpeg
Vol_Wold
  • Major: Elecrtical Engineering
  • Hometown: Coeur d'Alene, ID
  • Responsibility: Leader
  • Email: wold0156@vandals.uidaho.edu
Armando Solis.jpeg
Armando_Solis
  • Major: Elecrtical Engineering
  • Hometown: Caldwell,ID
  • Responsibility: Budgeter
  • Email: soli8592@vandals.uidaho.edu
Hai Huang.jpeg
Hai_Huang
  • Major: Elecrtical Engineering
  • Hometown: China
  • Responsibility: Wikipage supervisor
  • Email: huan2458@vandals.uidaho.edu

Additional Documentation[edit]

Meeting Minutes

File:2-27-2019 Minutes.pdf
File:3-6-2019Minutes.pdf
File:3-20-2019Minutes.pdf
File:3-27-2019Minutes.pdf
File:4-3-2019Minutes.pdf
File:4-10-2019Minutes.pdf
File:4-24-2019Minutes.pdf

Tech Presentation
File:Tech presentation.pdf

Machine Test[edit]

Picture Name Description
Machine test2.png

Machine Test Magnetization Curve Test

Procedure: Turn the machine at constant speed and record Ea as a function of If. Results: gives data to the constant relationship between Ea and ฯ‰ for all pre-saturation values of If. Rotor and Stator Tests Procedure: Place AC and DC on rotor or stator and use the resulting current outputs to determine Ls, Lr, Rs, and Rr.

Simulation[edit]

Picture Name Description
Simulink.png

simulink Matlab, simulating different synchronous machines to observe date of machine. The purpose is to help us to build control system.
Space vector.jpg

simulink
  • Rotating Space Vector
  • Stationary Space Vector
F-M.jpg

simulink
  • Phases B and C should be shifted by -120 degrees and 120 degrees, respectively
  • PWM is a form of frequency modulation, thus the fft of the PWM signal should resemble FM spectral characteristics
  • If these yield the correct results, we can conclude that the SVM algorithm generates correct switching times

Microcontroller[edit]

Picture Name Description
Microcontroller.png

Microcontroller Model: dSPIC33EV

Application: Motor control via the PWM Module

Features: 16-Bit Architecture Pin Count: 28 Six Pulse-Width Modulation Outputs

Snapshot[edit]

File:SnapshotBudget.pdf

Snapshot.jpeg



KOH Poster.jpeg