Hybrid Go-Kart University of Connecticut Department of Electrical - - PowerPoint PPT Presentation

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Hybrid Go-Kart University of Connecticut Department of Electrical - - PowerPoint PPT Presentation

Oct 20, 2023 242 likes •490 views

Hybrid Go-Kart University of Connecticut Department of Electrical Engineering Team Members: Jonathan Blake (EE), Nathan Butterfield (EE), Joshua Calkins (EE), Anupam Ojha (EE) Advisor: Prof. Sung-Yeul Park 4/18/2014 1 Outline System

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SLIDE 1

Hybrid Go-Kart

University of Connecticut Department of Electrical Engineering

Team Members: Jonathan Blake (EE), Nathan Butterfield (EE), Joshua Calkins (EE), Anupam Ojha (EE) Advisor: Prof. Sung-Yeul Park

4/18/2014

1

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SLIDE 2

Outline

  • System Overview
  • Flyback Results
  • PCB Revision
  • Software
  • Boost Converter
  • Budget
  • Problems Occurred
  • Final Steps

2

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SLIDE 3

What is Our Project?

  • Design a power electronics system to

combine three separate power sources in

  • rder to drive an electric go-kart.

3

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SLIDE 4

The Power Sources

  • We will use three power sources:
  • A 30V Lead Acid battery
  • Four ultra-capacitors, wired in

series, at 14V across bank

  • Photovoltaic Panel, 8->40V
  • utput, 200W

4

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SLIDE 5

System Overview

5

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SLIDE 6

System Layout

6

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SLIDE 7

Flyback Schematic

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SLIDE 8

Flyback Specifications

  • High current caused for multiple design alterations.
  • 4:7 turns ratio
  • Voltage Primary 8V-40V. Secondary Voltage 14V.
  • 16.7% to 50% Duty cycle
  • Current max 5A in 14.3A
  • Inductance on primary 20μH
  • 100KHz switching frequency
  • CCM
  • Selection of core geometry and material.
  • Toroid, E I core with gap
  • Kool mμ, ferromagnetic material, MPP

8

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SLIDE 9

Flyback Results

9

5 10 15 20 25 10 20 30 40 50 Vout Vin

Flyback 25% Duty Cycle 10Ω Load

Load Power In Power Out Efficiency 10Ω 2.96W 2.3W 77.70% 10Ω 12.2W 10.1W 82.80% 22Ω 15.6W 14.2W 91% 22Ω 35.1W 34.87W 99.30% 10Ω 47.3W 40W 84.50% 11Ω 97.7W 68.3W 60.90% 5.5Ω 102W 55.9W 54.80%

  • Windings
  • DCM
  • Snubber circuit
  • High Power
  • 30.01Vin 17.5Vout 97.2%

𝑊

𝑝𝑣𝑢 = 𝑊 𝑗𝑜(

𝐸 1 − 𝐸)(𝑂𝑡 𝑂𝑄 )

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SLIDE 10

Magnetics

10

  • 𝐶𝑁𝑏𝑦 =

𝑊𝑞𝑙 𝑢𝑝𝑜 𝑦108 𝑂𝐵𝑓

Gauss

  • Core loss due to eddy

currents and hysteresis

  • 𝑋𝑏𝑢𝑢

𝑙𝑕 = 𝑙𝑔 𝑛𝐶𝑁𝑏𝑦 𝑜

  • Core 585 𝐵𝑀 = 79𝑜𝐼/𝑈2
  • 𝐵𝑓 = 46.6𝑛𝑛 25𝑕
  • Saturation 1.05Tesla
  • 𝐶𝑁𝑏𝑦=.107Tesla
  • Power Loss =3.4W
  • Wire Loss=2.8W
  • For 102W input 6.1%
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SLIDE 11

Power Board Layout

11

  • Four layer board with 1oz copper with top and bottom layers devoted

to low voltage signals.

  • Combines Flyback converter along with sensing and gate drive

circuits for boost converter.

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SLIDE 12

12

Control Board Layout

  • Texas Instruments DSP

TMS320F28335.

  • Allows up to 6

independently controlled PWM signals.

  • 8 ADC channels allows

for multiple converters to be controlled by single DSP.

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SLIDE 13

13

Power Board Revision

  • Buck Converter
  • Non-isolated

Output

  • Flyback

Discontinuous mode

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SLIDE 14

Software Design

  • Software being written with Texas

Instruments Code Composer v5 to interface with TI DSP.

  • Software must read the voltage and current

values from sensors.

  • This information will determine the duty ratios

for the power converters.

  • Generate gate switching signal.

14

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SLIDE 15

Control Loop

15

  • Current mode control for Boost Converter
  • PI w/ PV Power Reference for Buck Converter
  • Danger conditionals
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SLIDE 16

ePWM and ADC

  • ePWM currently active with five signals

switching at arbitrary duty ratios at variable frequency.

  • Due to nature of control board (2 signals per

module), interleaving of boost controller limited to two channels always switching at the same

  • time. Cannot interleave four power stages.
  • ADC and control coding in progress. Awaiting

new power board revision to begin debugging.

16

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SLIDE 17

Boost Converter Design

  • The design of our boost converter has

changed drastically.

  • The driving factor of these changes

has been the input current.

  • Current design is rated for 120A input,

with an expected maximum input of 90A.

17

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SLIDE 18

Boost Power-Stage Platform

  • High-current sections of a boost

converter placed on separate platform, connected by cables.

  • Current and voltage sensor output to

microcontroller.

  • Gate switching would determined by

microcontroller, sent through gate drive circuit.

18

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SLIDE 19

Boost Power-Stage Platform (cont.)

19

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SLIDE 20

Budget

  • PCB $400 X 2 = $800
  • Parts = $550
  • Magnetics = $200
  • Mechanical = $30
  • Total Spent = $1580
  • Total allotted money =$1500
  • Over Budget = $-80

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  • Reasons:
  • Power electronics parts

more expense by nature

  • PCBs have to handle large

amounts of current

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SLIDE 21

Problems Encountered

21

  • Flyback Efficiency
  • Large voltage spikes across MOSFETs
  • Magnetics
  • Programming took longer than

expected

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SLIDE 22

Final Steps

  • Assemble and test Buck Converter
  • Implement Control Loop Algorithm
  • Assemble PV Structure

22

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SLIDE 23

Questions?

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