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ROYAL MILITARY COLLEGE OF CANADADEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING

Detailed Design Document

(EEE455-DID-07)

for

Improving the Self-Sufficiency of an E-Bike

NCdt Ryan Ward-Hall

OCdtBen Frans

Project /455/12/03

Supervisor: Dr. Mohammed Tarbouchi

15 March 2012


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TABLE OF CONTENTS

Table of Contents ................................................................................................................................... ii

List of Figures ........................................................................................................................................ v

List of Tables ........................................................................................................................................ vi1. Introduction .................................................................................................................................... 1

1.1. Background ............................................................................................................................. 1

1.2. Aim Statement ........................................................................................................................ 2

1.3. Scope ...................................................................................................................................... 2

1.4. Document Overview ............................................................................................................... 2

2. Referenced documents ................................................................................................................... 3

3. Requirements .................................................................................................................................. 4

3.1. Functional Requirements ........................................................................................................ 4

3.1.1. Power Generation ............................................................................................................ 4

3.1.2. Generation/Drive Switch ................................................................................................. 4

3.1.3. Stationary Power Generation .......................................................................................... 4

3.1.4. Backup Braking System .................................................................................................. 4

3.2. Design Requirements .............................................................................................................. 5

3.2.1. Prototyping ...................................................................................................................... 5

3.2.2. Data collection ................................................................................................................ 5

3.3. Simulation Requirements........................................................................................................ 5

3.3.1. Computer simulation ....................................................................................................... 5

3.3.2. Laboratory Testing Platform ........................................................................................... 5

3.3.2.1.Controlled Environment Testing Platform ............................................................................. 5

3.3.2.2.Field Testing........................................................................................................................... 5

3.3.4.Schedule Restrictions ................................................................................................................ 5

4. Architectural design ....................................................................................................................... 5

5. Detailed design ............................................................................................................................... 7

5.1. Overview ................................................................................................................................ 7

5.2. Limitations .............................................................................................................................. 7

5.3. Module Descriptions ............................................................................................................... 7

5.3.1. Microcontroller Software ................................................................................................ 7


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5.3.1.1. Control Signal .......................................................................................................... 7

5.3.1.2. Feedback .................................................................................................................. 7

5.3.1.3. Operating states ....................................................................................................... 8

5.3.2. Battery ............................................................................................................................. 8

5.3.2.1. BatteryDesign Specification and Constraints .......................................................... 8

5.3.2.2. BatteryDesign .......................................................................................................... 8

5.3.3. DC-DC ConverterBuck ............................................................................................... 8

5.3.3.1. DC-DC Converter - Buck Design Specification and Constraints............................ 8

5.3.3.2. DC-DC ConverterBuck Design ........................................................................... 9

5.3.4. DC-DC ConverterBoost ............................................................................................ 10

5.3.4.1. DC-DC ConverterBoost Design Specification and Constraints ........................ 10

5.3.4.2. DC-DC ConverterBoost Design ........................................................................ 105.3.5. Ultra-Capacitor .............................................................................................................. 12

5.3.5.1. Ultra-Capacitor Design and Specification and Constraints ................................... 12

5.3.5.2. Ultra-Capacitor Design .......................................................................................... 12

5.3.6. High-Power DC-DC Converter ..................................................................................... 13

5.3.6.1. High-Power DC-DC Converter Design Specification and Constraints ................. 13

5.3.6.2. High-Power DC-DC Converter Design ................................................................. 14

5.3.7. Brake Handle................................................................................................................. 16

5.3.7.1. Brake HandleDesign Specification and Constraints .............................................. 16

5.3.8. Motor and OTS E-Bike Controller ................................................................................ 16

5.3.8.1. Motor Design Specification ................................................................................... 16

5.3.8.2. OTS E-Bike Controller Design Specification ....................................................... 16

5.4. Interface Descriptions ........................................................................................................... 17

5.4.1. Charger Interface ........................................................................................................... 17

5.4.1.1. Battery Bus ............................................................................................................ 17

5.4.1.2. Ultra-Capacitor Bus ............................................................................................... 17

5.4.2. High-Power DC-DC Converter ..................................................................................... 17

5.4.2.1. Ultra-Capacitor Bus ............................................................................................... 17

5.4.2.2. OTS E-Bike Controller Bus................................................................................... 17

5.4.3. OTS E-Bike Controller ................................................................................................. 18

5.4.3.1. High-Power DC-DC Converter Bus ...................................................................... 18


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5.4.3.2. Regeneration Control Circuit Bus ......................................................................... 18

5.4.3.3. Motor Bus .............................................................................................................. 18

5.4.3.4. Battery Bus ............................................................................................................ 18

6. Equipment Identification .............................................................................................................. 18

7. Results .......................................................................................................................................... 19

7.1. Testing .................................................................................................................................. 19

7.1.1. Computer Simulation Test ............................................................................................ 19

7.1.2. Laboratory Testing ........................................................................................................ 19

7.1.3. Controlled Environment Testing ................................................................................... 20

7.1.4. Field Testing ................................................................................................................. 20

7.2. Results .................................................................................................................................. 20

7.2.1. Boost Circuit Voltage Output ....................................................................................... 207.2.1.1. Discussion of Buck Circuit Results ....................................................................... 21

7.2.2. Buck Circuit Output ...................................................................................................... 21

7.2.2.1. Discussion of Buck Circuit Results ....................................................................... 21

8. Summary ...................................................................................................................................... 21

9. Conclusion .................................................................................................................................... 22

10. Discussion................................................................................................................................. 22

10.1. Simulation Software ......................................................................................................... 22

10.2. Power circuit design .......................................................................................................... 22

10.3. DC-DC control circuitry ................................................................................................... 23

10.4. Isolation ............................................................................................................................ 23

10.5. Efficiency and Component Reuse ..................................................................................... 23

10.6. Trade-offs .......................................................................................................................... 23

10.6.1. High Power DC-DC Converter ..................................................................................... 23

10.6.2. Low Power DC-DC Converter ...................................................................................... 23

10.6.3. Microcontroller ............................................................................................................. 23

11. Future Work.............................................................................................................................. 24

12. EnclUsures ................................................................................................................................ 24

Appendix A Test Matrixes ................................................................................................................... 25

Appendix B Abbreivations .................................................................................................................. 26


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LIST OF FIGURES

Figure 1High Level Architectural Design .............................................................................................. 6

Figure 2Buck circuit .............................................................................................................................. 9Figure 3 Boost circuit ........................................................................................................................... 11

Figure 4 Internal Structureof the Ultra-Capacitor ................................................................................ 12

Figure 5a, 5b High-Power Boost Converter(Top), High Power Buck Converter (Bottom) ................ 15


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LIST OF TABLES

Table 1 Ultra-Capacitor Data Specification ......................................................................................... 12

Table 2 Equipment Identification ........................................................................................................ 18Table 3Test Matrix, Input Voltage vs Duty Cycle Testing on Boost Converter with Load of 3 Ohms

.............................................................................................................................................................. 19

Table 4 Test Matrix, Input Voltage vs Duty Cycle Testing on Buck Converter with Load of 10 Ohms

.............................................................................................................................................................. 25


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1. INTRODUCTION

1.1. Background

Electrical vehicles are increasing in popularity; there is a worldwide push for more

sustainable sources of energy, there is an increased demand for alternatives to theautomobile. Bicycles have always been a good alternative, but the effort required to bicycle

every day as a commuter vehicle is inconvenient. Recently In-Hub BLDC motors have

become practical as an upgrade to conventional bicycles. A modification system usually

consists of three main components: The motor, Controller and Battery. Of the three, the

battery is the most expensive and has the shortest lifecycle. This exact problem exists in all

electrical vehicles.

For electrical bicycles, hub motors also open up some interesting possibilities when it comes

to getting back some of the energy that is wasted when cycling. Not only can braking power

be converted to energy for locomotion, but human power can be used to charge a battery foruse elsewhere. New controllers have the ability to take advantage of the reverse emf when the

motor is acting like a generator when not driven by the battery i.e. when going downhill or

braking. This regenerative function of the controller has an important drawback. Lead-Acid

Batteries are severely limited when charging at a high rate, and discharging at a high rate also

lowers the cycle life of a battery.

Therefore, the controllers regenerative function cannot take full advantage of the power that

is generated. This is because the chemical reaction makes it necessary that battery is charged

at a low current (1A) over the course of over 2 hours.

When using the hub motor as a generator in this way, the currents that are created canfluctuate wildly, anywhere from 1-40 Amps.The current capability of a lead-acid battery

makes it necessary that the current is limited below 15 Amps to prevent damaging the charge

life of the battery. Even so, this charges the battery very inefficiently, where 20% of this

energy is actually stored. The kind of sporadic charging that is seen here needs to be

smoothed out by a very large capacitor.

A very large capacitor behaves much like a battery. An important difference is that the

capacitors reaction is electrostatic rather than electrochemical which allows the capacitor to

operate much like an ideal battery. A capacitor charged to 36Volts in the range of tens of

Farads would also be able to deliver enough power to drive the motor for a few seconds. The

boost that the capacitor provides will be able to take the stress off of the battery for initial

acceleration of the vehicle.

It is believes that a very large capacitor could be incorporated into the charging/discharging

system with a lead acid battery to improve the efficiency of the lead acid battery, the most

commonly available and inexpensive of batteries.


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1.2. Aim Statement

This project aims to modify the current power supply system used on most E-Bikes and

replace it with another system which will improve the self-sufficiency of the E-Bike. There

are four functions that are desired from this system:

Power E-Bike from Ultra-CapacitorThe Ultra-Capacitor when charged to full capacity shallhave the ability to accelerate the E-bike from a dead stop, until completely discharged

Recharge Ultra-Capacitor from E-Bike regenerative braking The Hub motor, while acting asa generator, shall be able charge the Ultra-Capacitor to full capacity.

Ultra-Capacitor and Battery working in tandemWhen the capacitor is discharged the battery

will take over powering the bicycle.

Trickle Charge Circuitry The Battery shall have the ability to charge the capacitor at a current

of below 3A to allow the ultra-capacitor to have enough charge for the next acceleration from

a standing start. This will occur when the trickle charge circuitry senses that the Ultra-Capacitor is below the required level to accelerate the E-Bike. The other portion of the trickle

charge circuitry will occur during the regenerative phase of the E-Bike. During this phase if

the Ultra-Capacitor has been fully charged it will engage this circuitry allowing the excess

current to flow into the battery, charging it.

1.3. Scope

The system to be designed is meant to be an add-on to the kind of E-bike systems that are

available as a modification of a conventional pedal bike. The system does not alter the off the

shelf (OTS) components that are part of the current system.

Regenerative functions are already provided by the OTS controller; therefore the system tobe designed must behave exactly as if it were a battery, able to handle the very large currents

otherwise not practical with a lead acid battery.

The Ultra-Capacitor consists of 6 series connected capacitors, and charge balancing is

already provided, therefore can be treated as one unit.

1.4. Document Overview

The purpose of this document is to explain the project design, the requirements and the

results from testing the design. This document is broken down into multiple sections with

each section detailing a different aspect of the project. The breakdown for the sections is as

follows:

1: Introduction.This section is used to introduce the project and briefly explain the overall

design, limitations, and aim of the project itself.

2: Referenced Documents.This section will have a list of all documents used in this

project aswell as a description of each document.


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3: Requirements.This section will define the requirements that the project needs to meet

and be tested against.

4: Architectural Design.This section is used to present a high level view of our design as

well as a description of the architecture used within this project.

5: Detailed Design.This section will provided a detailed description of the design used in

this project. It will have a description of all modules, components, and interfaces used in this

project

6: Equipment Identification.This section will have a list of all components designed and

bought Off-the-Shelf(OTS) used for this project as well as a description and explanation of

each component.

7: Results.This section will contain all the results obtained from testing the project as well

as how it was tested.

8: Summary.This section will summarize the project as a whole and also contain an

overview of the design, testing, and results of the project.

9: Conclusion.The conclusion will contain whether or not the project has fulfilled the

requirements laid out in Section 3.

10: Discussion.This section will explain the issues, difficulties, and observations which

occurred since the beginning of the project.

11: Future Work.This section will explain what other groups or companies will be able to

do with our project as well as future projects would could come from continuing the projectas a whole or by utilizing components of the project.

12: Enclosures.This section will contain all data sheets and product specifications which

could not be placed into another section.

2. REFERENCED DOCUMENTS

List of all documents referenced in this DDD.

[1] Mazidi& Causey HCS12 Microcontroller And Embedded Systems Using Assembly and

C with CodeWarrior 1st Edition

http://www.microdigitaled.com/HCS12/Hardware/Dragon12/CodeWarrior/

This document provided a template for use of the PWM on the Dragon1 HCS12

prototyping board.

[2] Application Note AN-978, http://www.irf.com/technical-info/appnotes/an-978.pdf


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This document provided information and example application circuits on correctly

connecting the Mosfet driver.

[3] Dale Eagar AN73-1 LT1339 Design Manual Designing the Power Converter, February

1999

This document provided information and example application circuits on correctly

connecting the Mosfet driver for the Linear Technologies LT1339 buck/boost chip

[4] 12Volt Battery Specification

The discharge rate vs. battery life graph was used to judge where the appropriate top

charge and discharge rate of the lead acid battery would be.

http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

[4] 25F/ 16.2V Ultra-Capacitor specification

http://www.tecategroup.com/capacitors/datasheets/powerburst/PBL_16.2.pdf

3. REQUIREMENTS

3.1. Functional Requirements

3.1.1. Power Generation

The motor must be able to, when acting as a generator, charge up the Ultra-Capacitor or

Battery via regenerative breaking, freewheeling, or stationary human pedal input.

3.1.2. Generation/Drive Switch

To allow for stationary power generation and experimentation, the system was designed with

3 switch settings so that the user would be able to choose when to engage the power

generation or motoring. The user will also be able turn off the system completely

3.1.3. Stationary Power Generation

There is a mechanical requirement that the bike will have the ability to raise the back wheel

off the ground was added to increase the utility of the bike. In this case a battery can be

charged, and then removed to do useful work elsewhere. This means that the operator must

be able to manually apply motive power through pedal power. Therefore the system must be

based on a conventional bicycle pedal system to be effective.

3.1.4. Backup Braking SystemFor safety, conventional bicycle brakes were also included in the system. It was found that

the E-Bike system could go to about 25 km/h on the flats, This was pushing the battery

beyond the recommended specification. To be effective, our system must achieve this same

speed, but without pushing the battery beyond its recommended discharge rate. An

additional spec of 10 km/h on a 7% grade was added to test the system at varied loads.
http://www.tecategroup.com/capacitors/datasheets/powerburst/PBL_16.2.pdfhttp://www.tecategroup.com/capacitors/datasheets/powerburst/PBL_16.2.pdfhttp://www.tecategroup.com/capacitors/datasheets/powerburst/PBL_16.2.pdf


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3.2. Design Requirements

3.2.1. Prototyping

The project cell shall first construct a simulation of the circuitry to ensure that the circuits

will work in theory. After this initial build the project cell will build the circuits on bread-

boards to ensure that each circuit is realizable by the components which were ordered. Eachcircuit will be tested first to ensure the circuit is able to complete its required task, either

boosting or bucking the voltage, at a lower level before moving up to the levels needed and

testing the components to ensure they do not break.

3.2.2. Data collection

The project cell shall collect data on the power output capability of a human being to be able

to customize the power generation circuit for optimal performance.

3.3. Simulation Requirements

3.3.1. Computer simulationProject modules will be simulated using the LTSpice circuit simulation software before

implementation.

3.3.2. Laboratory Testing Platform

The motor will be initially tested in a lab under the following conditions:with the motor

mounted on a frame using laboratory power sourcesin normal room temperature (18-25oC)

3.3.2.1.Controlled Environment Testing Platform

This phase of testing will implement the bike under the following conditions. The motor will

mounted on a frame tested under load (200 lb operator) outdoors in a paved parking lot in

lower ambient temperature (5-15o

C)

3.3.2.2.Field Testing

The system will be tested in real-world conditions outdoors. These tests will include the

following performance tests and data collection speed test at various grades, charging of

battery, battery capacity, human power generation, freewheeling power generation Varying

weights and load analysis.

3.3.4.Schedule Restrictions

Our schedule has been slightly modified because of reasons beyond our control, specifically

knowledge gaps existed between the implementation of the circuit that was originally

planned and reality.

4. ARCHITECTURAL DESIGN

The first blocks which will be explained for the architectural design will be the Power

Sources, as seen in Figure 1. In this block will be the different means by which power is able

to be generated for use by the bike or to charge the Ultra-Capacitor or battery. The Ultra-


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Capacitor is a 16 V power source which will be used to power the E-Bike by being boosted

up to the required voltage via the Boost Circuitry, pass through the E-Bike Controller to drive

the motor. The Battery will be used to take the load once the bike has reached its cruising

speed and will pass from the E-Bike controller to the motor to drive the E-Bike. The

Pedals/Gravity portion of the Power Sources block is for when the user switches the bike into

power generation mode and either being to pedal or freewheel down a decline to drive the

generator and charge, through the E-Bike controller and Buck Circuit, the Ultra-Capacitor.

The Boost Circuit in Figure 1 is there to boost the voltage coming from the Ultra-

Capacitor(16 V), and bring it up to 36V. It will then have this voltage go through the E-Bike

controller to drive the motor.

The Buck Circuit will be used to take the regenerative forces, either breaking, stationary

pedaling, or freewheeling, and convert the 36 volts down to 16 volts to charge the Ultra-

Capacitor.

The E-Bike controller is a commercially available controller which will handle the

computations needed by the E-Bike motor. The E-Bike controller will be able to use the

voltage coming from the external power sources to drive the motor. It will also be able to

take the regenerative forces coming from the motor acting as a generator and send it to

charge the Ultra-Capacitor.

Figure 1High Level Architectural Design


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5. DETAILED DESIGN

5.1. Overview

In this project the power supply system was redesigned to improve the self-sufficiency of the

system as a whole. The battery was altered to include an ultra-capacitor in parallel with it to

better allow for the regenerative power coming from the motor to be used. The system wasdesigned so that the regenerative power could be down-converted through the DC-DC

converter to be able to be used by the ultra-capacitor. When the ultra-capacitor is fully

charged it will begin charging the battery through the charger circuit. The other reason for the

ultra-capacitor being added in parallel to the battery is that it has high power density in

comparison and so is able to accelerate the motor much faster than the battery, making it

more efficient. The battery will be used to power the motor once the E-Bike has achieved a

cruising speed or the ultra-capacitor has dropped below a certain voltage and will then

trickle-charge the ultra-capacitor at the same time as powering the motor.

5.2. LimitationsThe main feature on the project which will limit how affective the project will be is using the

microcontroller to create the Pulse-Width-Modulation (PWM), reading the output voltage of

the converters, and using it for the Single-Pull-Double-Throw (SPDT) circuit. After extensive

research with regards to using the microcontroller for these features it was decided that

though the microcontroller is a good tool to learn how each of these modules work; in

practice the microcontroller limits the effectiveness of the circuits being built and will

produce more errors then readily available integrated solutions.

Another limitation for the project will be the ability to create prototypes for the converters.

The bread-boards which are available for the use of this project are unable to handle the

currents needed to properly test the converters. This limits the project testing which can be

completed before the final circuits are to be built and so there will be uncertainty as to what

each circuit is able to handle.

5.3. Module Descriptions

5.3.1. Microcontroller Software

5.3.1.1. Control Signal

The programming of the microcontroller is written and debugged on freescale Codewarrior.

The microcontroller uses PWM as the control signal for the buck and boost circuitry.

5.3.1.2. Feedback

The DC-DC controller voltage is expressed as a PWM signal and fed back to the

microcontroller, which adjusts the duty cycle of the PWM control signal to raise or lower the

voltage.


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5.3.1.3. Operating states

A port on the Controller senses the output of the SPDT (Brake Handle) switch. The controller

can then adjust its control signal for DC-DC conversion in charging or discharging states.

5.3.2. Battery

5.3.2.1. BatteryDesign Specification and Constraints

The battery will be used to provide power to the motor after the ultra-capacitor has brought

the motor past the acceleration phase, it will provide the power needed to the motor through

the OTS E-Bike controller. The battery will also have direct contact with the charger circuit

to be able to trickle-charge the ultra-capacitor or charge itself from the ultra-capacitor once

the ultra-capacitor has reached maximum capacity during the regeneration phase.

5.3.2.2. BatteryDesign

5.3.2.2.1. Internal Structure of the Battery

The battery used for this project is a common AGM lead-acid battery which has a largecharge time and low power density compared to the ultra-capacitor used in this project. The

battery is limited to a current of 7.5 amps and therefore unable to take the regenerative power

generated by the motor acting as a generator.

5.3.2.2.2. Interrupts and Signals

The signals which the battery will interact with are the output from the battery itself and the

charge coming from the charge circuitry. The output signal from the battery will be a

constant 36 volt signal which will be provided to the battery and the charge circuit to charge

the ultra-capacitor. The other signal it will see, the charge signal, will be a 36 volt input

coming from the ultra-capacitor once the ultra-capacitor has been fully charged through theregenerative cycle.

5.3.2.2.3. Description of Operation

The battery will operate by supplying a 36 volt signal through the OTS E-Bike controller to

the motor once the ultra-capacitor has brought the motor past the acceleration phase. The

battery will also interact with the charge circuit, more specifically the DC-DC converter

buck, at this time to also trickle-charge the ultra-capacitor while powering the motor. The

battery will also interact with the charge circuit, more specifically the DC-DC converter

boost, to be charged by the ultra-capacitor once the ultra-capacitor has reached its maximum

storage capacity during the regeneration phase.

5.3.3. DC-DC Converter Buck

5.3.3.1. DC-DC Converter - Buck Design Specification and Constraints

This component has been designed to convert the voltage coming from the battery, 36 Volts,

to 16 Volts so that it can trickle-charge the ultra-capacitor. The buck circuit is one of the two

components which are part of the charger circuit in Figure 1. This converter is limited to 16


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Volts as this is the rated voltage for the ultra-capacitor and going over this voltage will

damage it.

5.3.3.2. DC-DC Converter Buck Design

5.3.3.2.1. InternalStructure of the DC-DC Converter

Buck

Figure 2Buck circuit


This converter will take a 36 volt input signal and it will down-convert this signal to a 16 volt

output. It will ensure that it stays at a 16 volt output by using a micro-controller to regulate

the Pulse-Width-Modulation(PWM) going to the mosfet which will regulate the voltage.


This module will interact with three other components while it is operating. The first

component it will interact with will be the battery. The DC-DC converter Buck will takethe 36 volts coming from the batter and down-convert it to 16 volts so that the ultra-capacitor

is able to be charged. The way it down-converts the voltage is by making the voltage from

the battery go through a mosfet which will regulate the voltage allowed into the circuit via a

PWM sent from the micro-controller. After this it will pass through an inductor and capacitor

which will regulate the peak-to-peak voltage and current levels which will pass through the

ultra-capacitor at the output.


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5.3.3.2.4. ErrorHandling

The main error that will arise with the buck converter will have to detect and fix will be

ensuring the output voltage of the converter will remain around 16 volts without surpassing

this level. It will regulate the voltage output by having the micro-controller read the current

voltage output and either increase or decrease the PWM sent to the mosfet depending on the

output.

5.3.3.2.5. Limitations

The Buck Circuit must be designed carefully, with as close to the rated 16.2V as possible,

since the ultra-capacitors rated voltage of 16.2VDC continuous cannot be exceeded. On the

other hand, a voltage which is slightly lower does not fully utilize the ultra-capacitors

boosting power.

5.3.4. DC-DC Converter Boost

5.3.4.1. DC-DC Converter Boost Design Specification and Constraints

This component has been designed to converter the 16 volt input from the ultra-capacitor to a

36 volt output to charge the battery when the ultra-capacitor has been fully charged. The

boost circuit is the second of the two components which are part of the charger circuit in

Figure 1. The main constraint is that this converter cannot surpass the rated voltage for the

batteries(36 volts) as this will cause damage to the batteries.

5.3.4.2. DC-DC Converter Boost Design

5.3.4.2.1. Internal Structure of the DC-DC Converter Boost

Figure 3 shows a schematic diagram of the boost circuit. A square wave generator is used to

represent the control signal to the power mosfet. Three inductors are assembled in parallellsince this lowers the resistance and increases the ability of the circuit to handle higher

currents. A load of 3 ohms was chosen to represent the 500W, 36v motor at full load.


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Figure 3 Boost circuit


This converter will take a 16 volt input signal and it will boost this signal to a 36 volt output.

It will ensure that it stays at a 36 volt output by using a micro-controller to regulate the PWM

going to the mosfet which will regulate the voltage through the circuit.


This module will interact with three other components while it is operating. The first

component it will interact with will be the ultra-capacitor. The DC-DC converterboost will

take the 16 volts coming from the ultra-capacitor and boost the signal to 36 volts so that the

battery is able to be charged. It will do this by putting the voltage signal from the ultra-

capacitor first through an inductor and capacitor so that the peak-to-peak voltage and current

can be regulated and partially boosted before passing through the mosfet. When it passes

through the mosfet the micro-controller will send a PWM to the mosfet to ensure the output

of the converter stays at 36 volts. The micro-controller will alter its PWM to ensure a proper

output is maintained.

5.3.4.2.4. Error Handling

The main error which will be present with this component will be ensuring that the circuit is

able to maintain a 36 volt output. This component will ensure that the required output is

maintained by having the micro-controller read the current voltage output of the circuit andadjust the PWM to the mosfet accordingly to increase or decrease the voltage output.

5.3.4.2.5. Limitations

The current at the low voltage side of the boost circuit must be very high, this current is not a

problem for the ultra-capacitor, but the surrounding circuitry must be re-enforced with higher

gauge wire for transmission, and resistances of all the components involved must be very low

to keep from dissipating very much power.


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5.3.5. Ultra-Capacitor

5.3.5.1. Ultra-Capacitor Design and Specification and Constraints

The ultra-capacitor module is essentially a bank of Maxwell powerboost capacitors

assembled with charge balance circuitry by tecate group(trademarked). The capacitor has

stable operating specifications from -40 to +65 degrees Celsius.

Table 1 Ultra-Capacitor Data Specification

Item Performance

Rated Voltage 16.2VDC

Surge Voltage 17.1VDC

Capacitance 25 Farads +-20%

Internal resistance DC .01 ohm +-50%

Life 500k cycles or 10 yrs

5.3.5.2. Ultra-Capacitor Design

5.3.5.2.1. Internal Structure of the Ultra-Capacitor

Figure 4 Internal Structureof the Ultra-Capacitor

In contrast to conventional capacitor designs, which create an electrostatic field between two

flat plates, the ultra-capacitor utilizes a very rough and porous surface to store charge. This

effectively increases surface area of the negative and positively charged regions, enablingincreased capacitance.

5.3.5.2.2. Expected Capacitor Charging/Discharge Times

The ultra-capacitor is expected to be able to discharge completely over the course of about 5

seconds while accelerating and to be able to charge in a similar amount of time, This cycle is


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expected to occur sporadically every minute or however long it takes until a stoplight is

encountered in normal commuter traffic.


5.3.5.2.3.1.ChargingCharge is provided to the ultra-capacitor while operating in two separate states. Either the

capacitor is being charged by the battery or the capacitor is being charged by regenerative

braking.

In trickle charging mode, the battery voltage is DC-DC converted and the current is limited to

provide a constant power charging to allow the ultra-capacitor to be charged over some time

without overtaxing the battery.

In regenerative braking mode, the capacitor is charged by the DC-DC converted voltage from

the bicycle hub motor acting as a generator.

5.3.5.2.3.2.Discharging

Like charging, the discharging ultra-capacitor operates in two separate states. The ultra-

capacitor charges the battery or provides power to the controller through boost circuitry.

The ultra-capacitor will provide a power boost to the motor when starting from a stop, or in

transit when the capacitor has been charged by the battery. In both cases the voltage from the

ultra-capacitor is regulated through smps circuitry.

The ultra-capacitor may be put into a state where it charges the battery. This may be desired

when using the bike in a stationary mode of operation, where the sole purpose is to charge the

battery, or when the ultra-capacitor is charged, but the bike is no longer being used (as whenarriving at the users destination.)

5.3.5.2.4. Error-Handling

The controller is a changing load; therefore the voltage must be regulated. The level of the

voltage is regulated by taking the current level, putting it through an ADC

5.3.6. High-Power DC-DC Converter

5.3.6.1. High-Power DC-DC Converter Design Specification and Constraints

The high-power DC-DC converter will be used in two parts in this project. First it will be

used to boost the 16 volts coming from the ultra-capacitor and boost it to 36 volts so that the

motor is able to use this affectively. Secondly it will be used to down-convert the 36 volts

coming from the motor during regeneration phase to 16 volts so that it can charge the ultra-

capacitor. This converter is considered different from the previous converters as it will be

dealing with a higher current flow through the entire system and will need a larger heat sync

to ensure the circuit does not break. This converter must be able to handle a minimum of 15


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amps as this is the expected current flow to and from the motor which the controller can

safely 1`

5.3.6.2. High-Power DC-DC Converter Design

5.3.6.2.1. Interrupts and SignalsThe high-power DC-DC converter will be interacting with the input voltages coming from

either the OTS E-Bike controller or ultra-capacitor, the output signal which it will produce,

and also the PWM from a micro-controller passing through the HSLS driver which will help

to regulate the voltages. The converter will have to regulate its output signals depending on

which way power is flowing. If it is outputting towards the controller side then it will need to

keep a constant voltage of 36 volts. This voltage will be kept regulated by the features

present in the HSLS driver which will keep the output voltage coming from the driver at the

same level. It will do this by altering the PWM coming into it from the microcontroller once

it is in the HSLS driver to increase or decrease the output voltage. If it the converter is

outputting towards the ultra-capacitor it will need to keeps an output voltage of no more than16 volts using the same system.


The high-power DC-DC converters are shown in figure 5 will operate by either boosting or

down-converting the voltage coming into the converter so that it can be used to either power

the motor or charge the ultra-capacitor. If the input into the converter is the ultra-capacitor

then the converter will take the 16 volts from the ultra-capacitor and boost it to 36 volts. It

will do this in the same way that the previous boost converter does, reference 5.3.3., except

that this converter will be dealing with higher current and the driver will be regulated by the

LT1339 chip driver instead of the microcontroller. Refer to 5.3.6.2.1. (LT1339 Design

Guide) for how the LT1339 driver is able to regulate the voltage output.

Both the Buck and Boost circuit are based on a typical application circuit from the LT1339

design guide. Important modifications and components to note are that the voltage divider of

R1 and R2 choose the output voltage. Both circuits contain a 0.002 ohm sensing resistor

which converts the high current to a voltage for detection and regulation of the LT1339.

Feedback is taken care of by the chip, and gate driving is done with the help of a 1uF

capacitor to enable the boost output to hold the voltage at a higher level than the input and

drive the high side N-channel mosfet gate.


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5a

5b

Figure 5a, 5b High-Power Boost Converter(Top), High Power Buck Converter (Bottom)


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If the input of the converter is coming from the motor during the regeneration phase of the E-

Bike then the converter will be operation similar to the DC-DC- buck converter previously

discussed, reference 5.3.2.. During this time the converter will take the 36 volts coming from

the motor and down-converting it to 16 volts, ensuring that the voltage does not go past 16

volts as this has the potential to damage the ultra-capacitor.

5.3.6.2.3. Error-Handling

The error-handling of the high-power DC-DC converter will be done primarily through the

HSLS driver. This driver automatically regulates the voltages which are outputted from the

driver as well as the PWM which is coming to it from the microcontroller. The HSLS driver

will also alter the PWM which is inputted into it to try and keep the voltage output at the

same level as it started. This way the high-power DC-DC converter will have a more reliable

error-handling process then the other converters will be using. This is in place as the

amperage used for this converter is much more dangerous and the project cell does not want

injure the user or severely damage the components used.

5.3.7. Brake Handle

5.3.7.1. Brake HandleDesign Specification and Constraints

The brake handle provides a means to enable the regenerative braking function. The brake

handle contains a switch that is used to activate a relay to switch between charging and

discharging modes, this is accomplished by a SPDT switch. This brake handle was chosen to

be the switch to change between discharging and charging modes as this brake handle has

already been designed to work with the OTS E-Bike controller used in this project.

5.3.8. Motor and OTS E-Bike Controller

5.3.8.1. Motor Design Specification

The motor used for this project is a 500 Watt motor which takes a 36 Volt three-phase input

to make the motor work. This motor can only take a three-phase input meaning that all

voltages and currents which are being sent to power the motor must first be converted from

single-phase to three-phase via the OTS E-Bike controller. This motor was chosen for the

project as it does not require as much power to run the E-Bike and therefore it would be

easier to design the power system required to run the motor.

5.3.8.2. OTS E-Bike Controller Design Specification

The OTS E-Bike controller was purchased for use on this project for the ease of use in thesystem as a whole. This controller does all the conversions needed to convert the single-

phase voltages coming from the power supply and converting it to three-phase voltage so that

the motor is able to use it. The controller also does all the computations for the motors three-

phases to keep the motor running when the user wants the E-Bike to move.


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5.4. Interface Descriptions

5.4.1. Charger Interface

5.4.1.1. Battery Bus

The battery interacts with the charger module in two ways. One way it interacts is bysupplying 36 volts to the charger so that the charger can down-convert it to 16 volts via the

DC-DC converter-buck sub-module. The purpose behind this interaction is so that the ultra-

capacitor can be charged by the battery after the battery takes over powering the motor.

Secondly the battery will interact with the charger module by receiving the boosted voltage,

via the DC-DC converter-boost sub-module, from the ultra-capacitor during the regeneration

phase once the ultra-capacitor has been fully charged.

5.4.1.2. Ultra-Capacitor Bus

The ultra-capacitor interacts with the charger module in two ways. One way it interacts with

the charger module is by supplying 16 volts to the charger circuit to be boosted to 36 volts

via the DC-DC converter-boost sub-module to recharge the battery once the ultra-capacitor

has been fully charged. Secondly it will interact with the charger module by receiving the 16

volt down-converted voltage from the battery via the DC-DC converterbuck sub-module.

This interaction will occur once the battery has taken over powering the motor.

5.4.2. High-Power DC-DC Converter

5.4.2.1. Ultra-Capacitor Bus

The ultra-capacitor will interact with the high-power DC-DC converter during two phases. In

the first phase it will interact with the converter by supplying 16 volts to be boosted to 36

volts to power the motor. This phase will be the acceleration phase of the motor and will alsobe requiring a large amount of current through the system. During the second phase, the

regeneration phase, it will interact with the converter by taking the voltage generated by the

motor during this phase and down-converting it to 16 volts to charge the ultra-capacitor.

During this phase there will be a large current flow with the possibility of currents reaching

in excess of 20 amps.

5.4.2.2. OTS E-Bike Controller Bus

The OTS E-Bike controller will interact with the high-power DC-DC converter during two

phases. In the first phase it will interact with the converter by taking the boosted 36 volts

received from the ultra-capacitor and converting it to a three-phase voltage before sending

this voltage to power the motor. During the second phase of the interaction the OTS E-Bike

controller will convert the voltage and current coming from the motor during the regeneration

phase from three-phase to single phase so that the ultra-capacitor may be able to use it. After

the controller has finished converting the voltage and current to single phase the voltage will

be passed through the high-powered DC-DC converter and down-converted to 16 volts to

charge the ultra-capacitor.


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5.4.3. OTS E-Bike Controller

5.4.3.1. High-Power DC-DC Converter Bus

Refer to 4.4.2.2.

5.4.3.2. Regeneration Control Circuit BusThe regeneration control circuit will interact with the E-Bike controller by sending a signal to

the controller to initialize the regeneration phase of the motor. It will do this by the user

pressing the break handle which will send the correct signal to the E-Bike controller. This

signal will allow the motor to turn into a generator and use its current momentum to generate

power which will recharge the ultra-capacitor.

5.4.3.3. Motor Bus

The motor bus interacts with the E-Bike controller in two ways. One way the motor interacts

with the controller is by having the voltage needed to power the motor sent to the controller

and having the controller convert the original single-phase voltage to three-phase voltage.

Once this conversion has been done the motor is then able to use this voltage and will be able

to move the E-Bike. The second way that the motor interacts with the controller is during the

regeneration phase of the E-Bike. During this phase the motor will begin to generate power

which will then flow through the controller where it will be converted from three-phase to

single-phase. After this conversion the voltage will be passed on to the high-powered DC-DC

converter to boost the voltage and then it will charge the ultra-capacitor.

5.4.3.4. Battery Bus

The battery will interact with the E-Bike controller by supplying it with voltage once the

acceleration phase of the motor has been completed. The controller will then convert the

voltage supplied by the battery and convert it from single-phase to three-phase to power themotor.

6. EQUIPMENT IDENTIFICATIONTable 2 Equipment Identification

Developed Items Model/Part # Arrival Date

Battery Tray 20 Oct 2011

DC-DC Converter Buck

DC-DC Converter Boost

High-Power DC-DC Converter

Driver Circuitry

SPDT Switching Circuit

140uH/20A Inductors 20 Feb 2012

Off-The-Shelf Items

LTSpice In Stock

E-Bike Controller GoldenMotor 36V/BAC 281 In Stock

Hub Motor GoldenMotor MagicPie 36 V In Stock


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Battery 12V 7.5Ah x3 In Stock

Freescale CodeWarrior In Stock

Ultra-Capacitor TecatePowerburst/PBL-25/16.2 15 Nov 2011

Opto-coupler 4N33 30 Jan 2012

Capacitor PLV1H680MDL1TD 68uF/50V 30 Jan 2012

Inductors 1130-331K-RC-ND 30 Jan 2012Diodes SR202-TP 2A/20V 10 Feb 2012

High-Side Low-Side Driver IR2110-2PBF 10 Feb 2012

Mosfets IRFU4104PBF-ND 40V/42 A 20 Feb 2012

Support Equipment

Lab Test Equipment In Stock

7. RESULTS

7.1. Testing

7.1.1. Computer Simulation Test

The first phase of testing for the project was conducted using the LTSpice software. Using

this software the converters being built for the project were tested using the parts data which

would be used in the project. For this phase of testing each converter will be tested by

changing the input voltage and varying the duty cycle with different sized loads. The

reasoning behind these testing parameters is so that the desired output can be more easily

achieved with the least amount of disturbances being seen through the system as the input

voltage decreases. If the correct load can be found to allow for minimal amount of

adjustments to the PWM then the circuitry will rely less on the microcontroller which is

intended to reduce the amount of errors produced. An example test matrix is show in Table 3

which shows test results of the output voltage for the boost converter when the duty cycle is

varied with the input voltage at a load of 3 Ohms. The other test matrixes used can be found

in Appendix A.

Table 3Test Matrix, Input Voltage vs Duty Cycle Testing on Boost Converter with Load of 3 Ohms

Voltage

Input(V)

Duty Cycle (%)

10 20 30 40 50 60 70 80 90 100

16 16.7 18.7 20.9 24.4 28.5 35.4 45.9 62.8 87.5 40

14 14.5 16.8 18.4 21.4 25.2 31.3 40.8 55.4 77.1 36.5

12 12.6 13.9 15.9 17.9 22.5 26.9 35.1 47.6 66.4 3610 10.3 11.5 12.9 14.8 17..6 22.1 29.4 39.7 55.5 30

7.1.2. Laboratory Testing

The testing conducted in the lab began by building each circuit and ensuring that each circuit

can either boost or buck the voltage going through it. Once this initial testing was completed

the voltage and current going through the system was increased until it reached the levels


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which will be used in the final design of the project. During this phase where the voltage and

current was being increased the circuit was also tested to ensure that each component used

can handle the current flowing through it without breaking; needless to say there were many

mosfets which were broken at first. During this phase of testing the micro controller isolation

circuitry was tested to ensure the microcontroller did not interact with the large voltages

being used on each circuit. The purpose behind testing both of these circuit first of the bread-

boards before building the entire circuit together were to ensure that each component first

acted as it should, and secondly to ensure that these circuits could interact together

effectively without any problems developing.

7.1.3. Controlled Environment Testing

This testing will be conducted in the laboratory to ensure that it is as controlled as possible in

case of critical system failure. This testing will involve having the fully built boost and buck

circuits tested with the E-Bike on a bike stand. This testing will be primarily to demonstrate

that that circuitry designed is able to function with the E-Bike system as the project cell

intended. It will also allow the project cell to attempt to put all the components together asone cohesive unit and ensure each component works as it should when hooked into the

system as a whole.

7.1.4. Field Testing

The field testing portion will involve testing the E-Bike on the road with a rider on it. This

testing will be used to prove that the entire circuit is working together as it should and that

the E-Bike, with the re-designed power system, is able to move under load of a user. This

testing will be completed on a variety of inclines to fully test the system as a whole. During

this testing the charging capabilities of the Ultra-Capacitor using the regenerative breaking

will be fully tested to ensure that the Ultra-Capacitor is able to be recharged enough toprovide the next phase of acceleration. This phase will also test the acceleration of the E-Bike

using the Ultra-Capacitor will be obtained and compared with the acceleration of using only

the battery to accelerate. The final portion of this testing will be to have the user ride the E-

Bike for an extended period of time with the re-designed power system and compare it to the

results obtained from using a normal battery. At this point the project cell will be able to

compare the two tests and be able to conclusively decide whether this project was a success

or not.

7.2. Results

7.2.1. Boost Circuit Voltage Output

Test results of the high power boost circuit indicate that the boost circuit operating at 6kHz

was able to convert the voltage of the Ultra-Capacitor to 33.0-38.7 volts with an input voltage

range of 1V-16V. The circuit typically fully discharges the Ultra-Capacitor in 1.5- 2.5

seconds. The maximum Current observed during discharge was 10Amps at 35V, this gives

350W output peak observed. This boost is enough to accelerate the Hub motor to a speed of


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about 10 km/h when attached to a stationary bicycle. A road test with a load of a 200lb

individual was not conducted due to time constraints.

7.2.1.1. Discussion of Buck Circuit Results

Although 350W peak power was observed, preliminary results indicated that currents even

closer to the desired 13 amps could be achieved. The higher performance results wereobtained before two diodes were added to the 16V and 36V terminals of the buck circuit.

These high power diodes were added to prevent regenerative power from accidentally

feeding into the 36V output. It is believed that these diodes contributed to about 1V drop in

voltage available from the Ultra-Capacitor. Since more energy is stored when at the higher

voltage level of the Ultra-Capacitor, losing 1V from a fully charged Ultra-Capacitor was

detrimental to the overall performance of the buck circuit in exchange for some safety.

7.2.2. Buck Circuit Output

Initial test results of the high power buck circuit showed that the circuit has 8.61V at the

output. When connected to the E-Bike controller, the buck circuit was able to charge the

Ultra-Capacitor to the desired 15.5 Volts. At this point excessive back emf was encountered.

Currents during charging were not stable, ranging from 5-7A for a leisurely pace, up to 20A

when exerting about a (qualitative) 70% effort. Buffeting was experienced when spikes of

over 30A were observed.

7.2.2.1. Discussion of Buck Circuit Results

It was originally believed that the controller would simply disable it's regen function when a

charged state was achieved, just as it does for a battery, yet the controller continues to

attempt to regen. The method that the controller uses to detect a battery attached to itsterminals is not well understood and would have to be further investigated, though the

controller is rated to 30A, therefore the buffeting of the motor that was experienced may have

been due to some current limiting by the controller.

8. SUMMARY

In this project the four aims of the project were as follows: To be able to power the E-Bike

using only the Ultra-Capacitor; to be able to recharge the Ultra-Capacitor using the E-Bike

regenerative means; to have the Ultra-Capacitor and battery work together to be able to

power the E-Bike during different phases; and to create trickle charge circuitry to be able to

recharge either the Ultra-Capacitor or the battery depending on the state the E-Bike is in

currently. The project cell was able to successfully create the first two objectives of this

project. The project cell was able to successfully power the E-Bike using the Ultra-Capacitor

by using the high-power boost circuitry to convert the 16V to 36V. The Ultra-Capacitor was

also able to be recharged via the motor acting as a generator in its regenerative states by


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passing this voltage through the buck circuitry bringing the voltage from 36V to 16V. Both of

these circuits were successfully tested in simulation and as a full build to be used with the E-

Bike.

9. CONCLUSIONOverall this project has been a success. The main objective of this project was to improve the

self-sufficiency of the E-Bike by using the regenerative means already present on the E-Bike.

With the circuitry designed the concept that the Ultra-Capacitor is able to provide enough

power to drive the E-Bike as well be able quickly charges itself via the regenerative functions

on the E-Bike. Although not all the objectives were able to be completed, as the circuitry

required to power the E-Bike using the Ultra-Capacitor was successfully tested the main

focus of this project was a success. With the incorporation of the Ultra-Capacitor into the

design, the power loss on the system is greatly reduced as the capacitor is able to take the

current being generated by the hub-motor, acting as generator, during the regeneration phase

(higher then 10A). This demonstrates that Ultra-Capacitors provide a reliable, safe, andpromising solution for instantaneous power and instantaneous regeneration via the

regenerative breaking. These principles could be applied to solving similar problems on

future electric vehicle systems.

10. DISCUSSION

10.1. Simulation Software

The simulation software that was initially selected for schematic capture and circuit

simulation was NI Multisim. Although this software is based on the Spice language,

problems were encountered with errors in the simulation. This problem led to changing the

simulation software that we used to LTSpice, which had an equally user friendly interface

minus the simulation errors. LTSpice provides a large database of actual components from

many other companies besides the manufacturer of the software: Linear Technologies.

10.2. Power circuit design

Difficulties were encountered when attempting to simulate circuits with power that could

exceed the ratings of some of the devices whether due to improper connections or excess

heat. As circuits became more power hungry, heat became an issue. As power capabilities of

the equipment were exceed, there need to move to more robust testing equipment, andprototyping boards. Moving the circuits to a higher power level slowed the process, since the

prototypes needed to be soldered directly to prevent arcing and undue heat stress. When

finally testing the power circuits, it was found that the circuits worked inefficiently during an

open load test, yet they worked well at the very low resistances that we were expecting. This

is because the power circuits are designed to have current sensing elements that will only

work under high current conditions.


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10.3. DC-DC control circuitry

The biggest gap in knowledge existed in the design and the implementation of the control

circuitry. The design of whole subsections of the control circuitry was learned on the fly. The

circuitry needed to bias a high side mosfet for the buck converter was much more complex

than originally expected. This required that we choose and learn how to properly set up and

design a circuit using a gate Driver IC and DC-DC controller IC chips.

10.4. Isolation

The design of the isolation circuitry was not foreseen in the design, as envisioned by the

project cell, though this did not preclude their necessity. Opto-coupled isolation was used for

the isolation. It was found that opto-couplers do not provide the kind of linear response that

was desired; therefore it was necessary that the voltage levels be expressed in a pulse-width

modulation scheme.

10.5. Efficiency and Component Reuse

The design as originally envisioned was to take advantage of the split-pi topology of DC-DCconverter. This topology theoretically had very high efficiency (over 97%), can transfer

power in both directions, and maximizes the use of large inductors and capacitors. The

disadvantage of this design is that the control circuitry and the control signals are very

complex. After attempting some designs using this topology, it was determined that the boost

and buck circuits that we needed could be implemented more simply through separate

individual circuits for each direction of power transfer that was required.

10.6. Trade-offs

10.6.1. High Power DC-DC ConverterWhen Boosting the voltage held in the capacitor, we ideally wanted to have a wide input

range; As the capacitor drains, from 16V to Zero, we wish the output to stay around 36 Volts,

and 10Amps. The boost is made possible by an increased current from the source on the

lower voltage side. Although the current of the ultra-capacitor could theoretically be infinity,

the actual conductors could not handle the high currents needed. Therefore we must limit the

current and have a lower limit on the ultra-capacitor voltage; therefore we are not able to

discharge the capacitor totally.

10.6.2. Low Power DC-DC Converter

The low power DC-DC controllers current must also be limited since the battery cannot

handle currents much over 5A

10.6.3. Microcontroller

The microcontroller prototyping board that was used throughout the design was the Dragon

12P board. This board is much too bulky to be integrated into a circuit that will travel along

with the bike, therefore, a more mobile solution would be desirable. Adding the

microcontroller to a circuit board would add complexity to the design, therefore it was


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determined that a monolithic DC-DC controller chip would be a better solution for the

control circuitry. This means that the project cell would not have as much control over the

PWM and feedback of the circuit simplifying the design of the high power circuits.

11. FUTURE WORKOne of the first things which could arise as future work from this project would be to finish

the last 2 objectives of the project. Another project cell would be able to take our design for

using the Ultra-Capacitor and finish designing and building the circuitry to have the Ultra-

Capacitor and battery working together as well as the charging circuitry.

Another possibility for future work would be to continue in studying the used of the Ultra-

Capacitor. The project cell believes this to be a new and prominent field of study which many

electrical engineers will be studying in depth for all possible uses of the Ultra-Capacitor. A

possible project could include using the Ultra-Capacitor in an electrical car.

12. ENCLUSURES

The data sheets for the Ultra-Capacitor and LT1339 chip used have been include in Annex C.


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APPENDIX ATEST MATRIXES

Table 4 Test Matrix, Input Voltage vs Duty Cycle Testing on Buck Converter with Load of 10 Ohms

Voltage

Input (V)

Duty Cycle (%)

10 20 30 40 50 60 70 80 90 100

36 24.7 22.1 19.3 16.5 13.7 10.9 8.2 5.3 2.6 0.48

34 23.0 20.9 18.3 15.5 12.8 10.3 7.6 5.0 2.3 0.44

32 22.1 19.5 17.1 14.6 12.1 9.6 7.1 4.8 2.2 0.40

30 20.7 18.4 16.0 13.7 11.3 9.0 6.7 4.4 2.1 0.39


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APPENDIX BABBREIVATIONS

OTS - Off the shelf

HSLS - High-Side-Low-Side

Mosfet - Metal oxide silicone field effect transistor


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Annex C

Enclosures


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LT1339 Chip Data Sheet Located at:

http://pdf1.alldatasheet.com/datasheet-pdf/view/70412/LINER/LT1339.html