Aeolus Kite Generator

Project Description Team:

Brad Nardone Caden Sowers

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Table of Contents Introduction 3 Electrical Specifications 3 Project Specifications 3 Power Requirements 3 Special Environment Requirements 3 System Description 4 Hardware 4 Schematic Block Diagrams 4 MCU 5 Peripherals 5 Software 6 PCB Details 6 User Interface 7 Development Plan 8 Features 8

Development Sequence 8 Development Tools 9 Demonstration 9 Preliminary Parts List 10 Base 10 Kite 10

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I. Introduction Aeolus is a kite generator system that harnesses wind energy to produce power. Aeolus uses an onboard control system to move the kite up and down in the wind in an oscillatory motion. While the kite is being elevated by the wind, power is being generated by pulling a string attached to a generator. While the kite is descending the slack is reeled up in preparation for the next upswing. The goal of Aeolus is to make a product that is designed to be a low cost, high output, sustainable power source for both residential and commercial use. A main focus in the design process is to make a product that can have noticeable reduction on power grid reliance but also have a much more reasonable recuperation period than most other sustainability products on the market today. Aeolus is planned to be a 20 foot kite, with an average theorized output of around 1.5-3MW hours per year. This much power output is about 15-30% of an average household’s power consumption.

II. Electrical Specifications Project Specifications

Low Power Wireless Communications - 2.4GHz band is best option a.) Range of 0-400ft b.) Best Options: Zigbee, Bluetooth, and Wifi

Altitude accuracy within ±5ft.

Measured power output accuracy of ±5%.

Power Requirements Base Power Requirements

o 12V peak for motor operation o 52.27W peak power dissipation o Expected consumption of 83.4 kWhrs/year o Rechargeable

Kite Battery Requirements o 6V peak for MCU and peripheral operation o 91.54W peak power dissipation o Expected consumption of 17.68 kWhrs/year o Rechargeable

Special Environment Requirements Temperature: Range from -20°C to 60°C

Humidity: 0% to 95%

Withstand High Wind Speeds: 30mph+

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III. System Description Hardware

System Block Diagram of Base Circuit

System Block Diagram of Kite Circuit

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MCU Base

The base MCU will require an RF transceiver, Timer, Memory, and communication resources. The RF transceiver will be used to wirelessly transmit data between the kite and base at 2.4 GHz. The 2.4GHz is needed due to high efficiency and emerging low power technologies such as BTLE and Zigbee. Both BTLE and Zigbee operate at 2.4GHz. Flex timers will be needed to generate a PWM signal. A PWM signal is required in order to control the speed of the motor. If no PWM is used there will be only two speeds for the motor, on and off. Communications module with I2C, SPI, UART, and GPIO support is needed for peripheral communications. An LCD could require SPI, UART, or parallel GPIO. A power monitor could require I2C or SPI and GPIO will be needed for button input. Memory requirements of 60kB of flash and 15kB of RAM are needed. This is needed because of wireless communications which require extra storage space.

Kite

All of the tasks the MCU must do, including Zigbee communication, will be done using Flash memory which is estimated to be less than 37kB-42kB and will operate at a bus frequency of 50MHz.

RF Transceiver will be used to send and receive data to and from the base unit. Timer module will be used to control the PWM signal of the on-board motor that help keep the

kite in the air when required, and on initial launch. Communications module will be using SPI protocol which is needed to gather data from the

barometric pressure sensor which is constantly measuring the altitude of the kite. Analog-to-Digital converter (ADC) on the MCU is required to convert the data from the barometric

pressure sensor into digital data that can be transmitted. General Purpose I/O (GPIO) will be used to communicate to the servo motor.

MCU Choice

Both the base and the kite will use the Kinetis KW24 MCU. This MCU was chosen due to the

inclusion of an RF transceiver which supports ZigBee. The KW24 also has 24 GPIO, a timer module, a 16-bit

ADC, and supports SPI, I2C, and UART. Due to the need for a development board we will be required to use

the MKW24D512VHA5 which has the most RAM (64KB) and Flash (512KB). Ideally we could get away with

the lower model, MKW21D256VHA5 which has 256KB of flash and 64KB of RAM and is about half the price. Both models are powered by the ARM Cortex M4 processor and have multiple power modes. Either option operates with a bus frequency of 50MHz.

Peripherals Base

In addition to an MCU the base will require a power monitor, LCD, generator, and a motor. The motor and generator will be separate devices so that it will be possible to use inertia to continue developing power. This makes the device more expensive but will hopefully result in better power generation.

All important data will be displayed on a 16x4 LCD screen. The LCD screen is intentionally large in order to display multiple items at once. If possible a larger LCD screen may be used, but 16x4 is the smallest allowed size.

The power monitor is needed to know how much energy is being generated by the generator. The power monitor must be able to correctly monitor the power to within ±5% as per project requirements.

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The battery must be able to supply 12V, have a power output of at least 52.27W, and be rechargeable. This project is a closed loop system and we will be charging the base battery for proof of concept, because of this, the battery must be rechargeable. A Lead-acid battery was chosen due to its low cost and the ability to recharge. The specific battery selected was the PS-1250 because it is a 12V, 5.0 AH lead-acid battery with a max discharge current of 50.0 Amps.

Switching voltage regulators will be used to provide step down voltages for powering the MCU, LCD, and motor.

Kite

The kite electronics, along with the MCU will include: antenna, barometric pressure sensor, servo, DC motor and motor controller, two switching regulators, comparator, and a battery.

The antenna is connected to the MCU thorough SMA and is used to transmit and receive signals to and from the base.

The battery on-board will be a 6V Nickel-metal Hydride battery which is used because the voltage output is enough to meet the specifications of the MUC and all of the peripherals. The battery type (NiMH) is used because it has a long life, is rechargeable, and is a reasonable price.

The Motor must be able to run off of a 6V battery via a motor controller and have a minimum thrust capacity of 1000 grams.

The motor controller must be able to power a 6V motor at with a maximum power output of 90W. The motor controller is to be controlled by the MUC using a PWM signal.

The servo which controls the canard, is powered by the battery through a 4.8V switching regulator and controlled by the MCU through GPIO.

The barometric pressure sensor is powered by a 2.5V switching regulator and communicates to the MCU through SPI.

The comparator must be able to compare the 6V battery output voltage to output of a 4.8V switching regulator to determine when the battery charge level is getting too low.

Software All code will be developed using C/C++. The base MCU will use µCOS-III while the kite MCU will use a combination of a time-slice event scheduler and interrupts.

PCB Initially everything will be sized in accordance with the Freescale tower development system. This

means the PCB max width will is 3.157 inches. Length has a minimum requirement of 3.543 inches. Height requirement of less than 2 inches.

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IV. User Interface The goal of the project is to make everything automated which means very little user interface.

Since the kite will be fully automated, and will be communicating to the kite, there will be no user interface

required for the kite. The only user interface are two buttons and a 16x4 LCD screen attached to the base

which will display all the data being recorded which includes: current power being generated, total

generated power, and total operating time. One button will cycle through display configurations while the

other will be a reset button that resets the operating time and total generated power.

User Interface State Diagram

16x4 LCD Transition Diagram

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V. Development Plan

Features The main features will be the synchronization of the kite oscillations with the tension motor,

correctly calculating and displaying the instantaneous power and total power generated, monitoring the

battery level on the kite, correct altitude of the kite, and retrieving the wind speed.

Future features will be a grid tie inversion system that allows the Aeolus Kite Generator to be

removed from a battery source to an AC wall outlet, a phone app that displays all current data, and

improved data monitoring. The generated power would be sent into the outlet instead of charging a

battery. The transceiver circuit of the MCU supports up to two nodes so it could be used to transmit

between the kite and another peripheral device.

Tasks and Schedule Caden will be developing all software and hardware components for the base while Brad will

develop all software and hardware components for the kite.

Development Schedule

Week Dates Caden’s Task Brad’s Task

1 11/30/14 - 12/6/14 Research and Design PCB platform for use with Kinetis KW24 Tower Board ( Want to

avoid elevator module if possible)

Research and purchase required electronics for kite

2 12/7/14 - 12/13/14

3 12/14/14 - 12/20/14

12/14/14-12/27/14 Break

Break

4 12/28/14 - 1/3/15 Design and Test I2C interface with

LTC2946 Design Comparator

5 1/4/15 - 1/10/15 Design and Test SPI interface with

LCD Test switching regulators with

battery

6 1/11/15 - 1/17/15 Design and test battery charging circuit

Test DC motor and motor controller

7 1/18/15 - 1/24/15 Test Servo and motor controller

8 1/25/15 - 1/31/15 Design and test base motor

control Build and test Comparator

10 2/1/15 - 2/7/15 Begin PCB Layout Testing Barometric Pressure

sensor

11 2/8/15 - 2/14/15 Complete and order PCB Test Switching regulators

12 2/15/15 - 2/21/15 Start programming, begin

wireless development Begin Wireless development

13 2/22/15 - 2/28/15 Continue Wireless Development Continue Wireless Development

14 3/1/15 - 3/7/15 Continue Wireless Development Continue Wireless Development

15 3/8/15 - 3/14/15 Begin UI Layout Assemble all electronics

16 3/15/15 - 3/21/15 Complete UI Layout Buy materials for kite

17 3/22/15 - 3/28/15 Begin PID of motor control Break

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18 3/29/15 - 4/4/15 Complete PID of motor control Begin programming all

electronics to work together

18 4/5/15 - 4/11/15 Begin assembling PCB's Continue Programming

19 4/12/15 - 4/18/15 Complete PCB assembly Assembly of kite

20 4/19/15 - 4/25/15 Begin assembling base structure Continue Assembly of kite

21 4/26/15 - 5/2/15 Continue assembling base

structure Testing of kite with base

22 5/3/15 - 5/9/15 Complete base structure Testing kite/Debug/evaluating

results

23 5/10/15 - 5/16/15 Test/Debug Testing kite/Debug/evaluating

results

24 5/17/15 - 5/23/15 Test/Debug Testing kite/Debug/evaluating

results

25 5/24/15 - 5/30/15 Test/Debug Testing kite/Debug/evaluating

results

26 5/31/15 – 6/6/15 Demonstration Demonstration

Development Tools The code will be developed using the Kinetis Design Studio IDE and the Beekit Wireless

Development Tool (ZigBee development), both of which are provided by Freescale. The hardware will

require the use of digital multi-meters, Altium, breadboards, oscilloscope, and soldering equipment. In

addition to the software and hardware tools, a wide open space outside will be required in order to test

the functionality of the entire system.

Demonstration The base station will be constructed mostly of aluminum that has been welded together. The kite

will be made of rip-stop nylon fabric and carbon rods that use connectors to interlock the rods. Both the

base and kite will be prototyped using the KW24 development board provided by Freescale. All custom

PCB’s will have the necessary parts soldered onto them.

For the demonstration, a video will be played of the kite generator in action while the base and

kite will lie partially disassembled nearby. A poster with important data received and general information

about the project will also be displayed.

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VI. Preliminary Parts List

Base

Description Manufacturer Part # Price QTY Total Cost Lead Time

Max Power Dissipation

Average Energy Dissipation/Day

MCU Freescale MKW24D512VHA5 $7.52 1 $7.52 1 Week 76.68 mW 1.24 Whrs

Power Monitor

Linear Technology

LTC2946IMS#PBF $5.52 1 $5.52 1 Week 3.5 mW 84 mWhrs

16x4 LCD Screen

Newhaven Display

NHD‐0416BZ‐FL‐YBW $14.93 1 $14.93 1 Week 14.4 mW 346 mWhrs

Mosfets Fairchild

Semiconductors RFP12N10L $0.55 4 $2.20 1 Week 480 mW 11.52 Whrs

Zener Diode Vishay

Semiconductors 1N4747A $0.07 4 $0.28 1 Week N/A N/A

Antenna Pulse W1038 $5.15 1 $5.15 1 Week 80 mW 1.92 Whrs

12V Lead Acid Battery

Power Sonic PS-1250 $17.52 1 $17.52 1 Week N/A N/A

12V DC Gear Motor

ServoCity 638280 $39.99 1 $39.99 1 Week 50 W 200 Whrs

Resistor Vishay

BCcomponents SFR16S $0.04 10 $0.40 1 Week 200 mW 4.8 Whrs

Switching Regulator

Micrel LM2576 $1.49 2 $2.98 1 Week 400 mW 9.6 Whrs

Capacitor Vishay

BCcomponents K222K10X7RF5UH5 $0.03 20 $0.60 1 Week N/A N/A

Operational Amplifier

Texas Instruments

LM324 $.10 2 $.20 1 Week 14.4mW 345.6 mWhrs

Generator Automation

Industry MTPM-P33-1L18 $163.35 1 $163.35 1 Week N/A N/A

Totals $268.79 52.57 W 229.86 Whrs

Kite

Description Manufacturer Part # Price QTY Total Cost

Lead Time

Max Power Dissipation

Average Energy Dissipation/Day

MCU Freescale MKW24D512VHA5 $7.52 1 $7.52 1 Week 70.3 mW 1.68 Whrs

Antenna Pulse W1038 $5.15 1 $5.15 1 Week 80 mW 19.2 mWhrs

Battery Tenergy 10203 $4.50 5 $22.50 1 Week N/A N/A

DC Motor Turnigy 3648 T3648-1450 $28.22 1 $28.22 1 Week 81 W 32.4 Whrs

Motor Controller

Hobby King 20ABECU $10.66 1 $10.66 1 Week 9 W 3.6 Whrs

Servo Solar Servo D227 $9.88 1 $9.88 1 Week 1.008 W 1.61 Whrs

Switching Regulator

ON Semiconductor

LM2575T-ADJG $1.58 2 $3.16 1 Week 366 mW 8.78 Whrs

Operational Amplifier

Texas Instruments

LM324 $0.10 1 $0.10 1 Week 14.4 mW 346 mWhrs

Capacitor Vishay

BCcomponents K222K10X7RF5UH5 $0.03 10 $0.30 1 Week N/A N/A

Resistor Vishay

BCcomponents SFR16S $0.04 15 $0.60 1 Week 14.1 uW 338 uWhrs

Barometric Pressure Sensor

Bosch Sensortec BPM180 $1.73 1 $1.73 1 Week 30 uW 720 uWhrs

Totals $89.82 91.54W 48.44Whrs