Mellivora: A Battery Experiment Overview Team Introduction - - PowerPoint PPT Presentation

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Mellivora: A Battery Experiment Overview Team Introduction - - PowerPoint PPT Presentation

Dec 11, 2022 353 likes •751 views

Mellivora: A Battery Experiment Overview Team Introduction Problem Our Approach Technological Innovations Design Alternatives Design Specifications Block Diagram Individual Subsystems MDR Deliverables

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Mellivora:

A Battery Experiment

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Overview

▪ Team Introduction ▪ Problem ▪ Our Approach ▪ Technological Innovations ▪ Design Alternatives ▪ Design Specifications ▪ Block Diagram ▪ Individual Subsystems ▪ MDR Deliverables ▪ Questions

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Team Introduction

Nathan Ball EE Derek Wang CSE Derek Clougherty EE Lubin Jian EE

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The Problem

▪ Inefficiencies of conventional cars ▪ Lost power from braking ▪ Long charge times ▪ Chemical batteries are not environmentally friendly

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Our Approach

▪ Demonstrate effectiveness of supercapacitor technology ▪ Demonstrate recharging capabilities with regenerative braking ▪ Use Brushless DC motor to turn a single wheel ▪ Physical wheel controls to accelerator and brake wheel ▪ Android App that displays RPM, Speed, and Capacitor Bank Charge Level

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Regenerative Braking

▪ Recover kinetic energy from braking instead of converting to heat ▪ Back EMF slows motor ▪ Braking speed is controlled via brake pedal input

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Why Supercapacitors?

▪ Advantages

  • Rapid charge/discharge cycles
  • No degradation over vehicle life
  • Future technology will drastically reduce cost, size, and weight

while significantly increasing charge density

▪ Disadvantages

  • Advanced technology not yet

commercially released

  • High discharge rate requires

special cautions and consideration

  • Fewer applications in the

automotive industry compared to batteries, need custom solutions

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Capacitor Banks Usages

▪ Regulates reactive power (AC power correction)

▪ Computers, buses, trains, cars, generators,

transformers, etc.

▪ Can supply huge bursts of current

▪ Pulsed lasers, fusion research, particle accelerators,

nuclear detonators, railguns etc.

▪ As a power supply

▪ Due to size, weight, cost, and charge density issues,

has not been done

▪ Tesla has expressed interest in this technology ▪ EEstor claimed in 2007 to have created a car battery

equivalent capacitor bank. Has not demonstrated it.

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Final Product and Specification

▪ One wheel concept to show advantages of capacitor bank power technology

  • Accelerated charging capabilities with capacitor bank

power supply

  • On board Central Control Module program
  • Controlled with multiple inputs - Pedals, Android App

▪ Requirements

  • Top speed of 30MPH
  • Efficiency of system must be above 70%
  • Full stop from 30 MPH within 3 seconds
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Block Diagram

Nathan Ball Lubin Jian Derek Wang Derek Clougherty

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Central Control Module

▪ Derek Wang

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Central Control Module (CCM)

▪ Microprocessor: TI Sitara ARM Cortex A9 MPU Main Tasks ▪ Input processing ▪ Android App Interfacing ▪ Power Control ▪ Drive Control ▪ Also deals with error handling

  • Ex. Braking and accelerating simultaneously.

Derek Wang

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Input Processing

▪ By Gamepad Pedal

  • Interpret gamepad voltage signals as wheel speed

demands and power mode changes

  • A/D Converter

▪ By Android App

  • Interpret bluetooth signals from Android app to

modulate wheel speed

Derek Wang

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Sensor Data and Android App Interfacing

▪ Processes Sensor Data

  • Hall Sensor feedback in wheel
  • Power supply voltage from Power Control
  • Current and voltage to and from power supply
  • Power mode (drive, braking, freewheel, and charging)

▪ Sends Sensor Data to Android App via Bluetooth

  • Wheel speed and RPM
  • Power remaining in power supply
  • Rate of power consumption and generation
  • Power control mode

▪ Communicates via bluetooth

Derek Wang

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Power Control and Drive Control

▪ Power Control

  • Mode changes (Drive, braking, freewheel, and charging)

▪ Drive Control

  • Control variable motor speed using pulsed signal
  • Control variable regenerative braking with pulsed signal
  • Select forward/backward using directional signal
  • Calculate what pulsed signal is needed based on

gamepad pedal or Android input and wheel speed sensor data

Derek Wang

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MDR Deliverables

▪ CCM program calls correct functions in simulation and outputs correct dummy signals based on simulated inputs Challenges: ▪ Get microprocessor mounted and with a working program ▪ CCM on chip can recognise and give the correct

  • utput to signals from gamepad pedal input

Derek Wang

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Controller Inputs and Display

▪ Lubin Jian

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Pedals as Analog Inputs

Drive Pedals

▪ In order to replicate a real driving experience ▪ Adapt gaming pedals in order to connect to CCM ▪ Simplifies android application

Lubin Jian

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Android Application Display

Android Display

▪ Takes in an input from the CCM ▪ Displays valuable information the summarizes

the current state of the system

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Wheel speed

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Power being drawn from capacitor bank

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How much power is left in the capacitor bank

▪ We will be able to visualize the regenerative

braking in real time

▪ Eventually implement controls to move the

wheel from the android application

Lubin Jian

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MDR Deliverables

▪ Deliverables ▪

Working pedals that can interface with the CCM

▪

User-friendly application that displays the information in a clear concise way

▪ Challenges ▪

Adapting the pedals from whatever system it was made for

Lubin Jian

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Drive Module

▪ Nathan Ball

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▪ Permanent magnets on rotor ▪ Teeth offset between rotor and stator ▪ Energize electromagnets to turn rotor

Stepper Motor

Nathan Ball

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Motor

▪ 8 Wire NEMA 34 Stepper Motor ▪ 5 Nm holding Torque ▪ $45

Nathan Ball

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Motor Driver

▪ Converts signal from controller to motor pulses

  • MA860H Driver

▪ Control regenerative braking

  • Full wave rectifier to convert AC to DC current

▪ Feedback

  • 3 Hall Sensors

Nathan Ball

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MDR Deliverables & Challenges

▪ MDR Deliverables

  • Demonstrate working drive module from test signals
  • Hall sensors for wheel speed

▪ Challenges

  • Providing clean power with regenerative braking

Nathan Ball

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Power Supply

▪

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Power Supply and Charge Controller Requirements

▪ Support 3-5 minute runtime ▪ Monitors cell voltages for fault detection and

  • vervoltage conditions

▪ Charge cells from 120V AC power supply or drive motors while in regenerative braking mode ▪ Communicate with CCM for charge level display and for switching between power and regenerative braking mode

Derek Clougherty

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Supercapacitor Power Supply

Capacitor Maxwell BCAP0350 in 6x2 series-parallel array 2.7V 350F 170A (max) Power for supercapacitor array 2[((116.7F*16.2V^2)/2)/(1Wh/3600J)] = 4.25 Wh Motor OMC 34HS38-3008S 36V 2A 5Nm 3500RPM Runtime 36V*2A = 72W [4.25WHr/72W]*60 = 3.5 minute continuous runtime

Derek Clougherty

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MDR Deliverables & Challenges

▪ MDR Deliverables

  • Circuit layout designed and prototyped
  • Demonstrate switching between power and charging

modes

▪ Challenge

  • Providing clean power to capacitor bank during

regenerative braking

  • Producing a suitably sized power supply that fits within

the budget

Derek Clougherty

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Conclusion

▪ Problem ▪ Our Approach ▪ Technological Innovations ▪ Design Alternatives ▪ Design Specifications ▪ Block Diagram ▪ Individual Subsystems ▪ MDR Deliverables

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Questions?

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▪ Energy in our wheels (Joules of KE) at different speeds? ▪ Energy is only dependent on mass of wheel if we pick a desired lateral velocity ▪ KE = Iw2 ▪ IWheel = ½ M (R2

inner+R2 Outer)

Research Questions

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Research Questions

▪ Braking force of regenerative braking (how fast can we stop?) ▪ Need Physical testing, braking speed does not decrease regenerative efficiency (within reason, excessively long braking distances will have additional friction losses compared to faster stops)

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Research Questions

▪ Efficiency of battery/ capacitor bank in charge/discharge from current input? ▪ Battery seems to be between 10-20% loss

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Research Questions

▪ Motor Efficiency, how many joules can we get out if we put in X amount of electric joules ▪ 3k or 3.5k RPM on standard

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Capacitor Bank Equations

Q = CV2/2 1 Wh = 3600 J Capacitance for one string of 6 capacitors in series 1/[(1/350 F)6] = 58.3 F Capacitance for two strings of six capacitors in parallel 58.3 F + 58.3 F = 116.7 F Voltage for one string of 6 capacitors in series 6(2.7 V) = 16.2 V Q = [116.7 F × (16.2 V)2 ] ÷ 2 = 15,309 J (1 Wh / 3600 J)(15,309 J) = 4.25 Wh

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Wheel Speed Calculations

7.75” radius to tread of wheel Circumference of wheel = 2πr 2 × π × 7.75 = 48.7” Wheel speed to achieve 30MPH Speed (MPH) × 1 Hr/60 min × 63360 in/mile ÷ circumference of wheel = RPM 30MPH × 1 Hr/60 min × 6360 in/mi ÷ 48.7 in/revolution = 65.3 RPM Reduction ratio Motor speed ÷ wheel speed 3500 RPM ÷ 65.3 RPM = 53.8:1 Torque delivered to the wheel Motor torque × Reduction ratio 5Nm × 53.8 = 269 Nm

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Motor Conections