Kate Gleason College of EngineeringMultidisciplinary Senior Design

Detailed Design ReviewP12408

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DDR Agenda

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Meeting Timeline

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Project Summary

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Customer Needs

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Engineering Specifications

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System Block Diagram

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MPPT and Battery Charger

Solar Panel Battery

Load

SpecificationsSolar Panel MPPT and Battery Charger Battery

Pmax (W) 24 Rated Panel Power (W) 65 Vmp (V) 16.7 Float Voltage (V) 12.5 Peak Voltage (V) 12.6

Imp (A) 1.45 Rated Output Current (A) 5 Charging Current (A) 2Voc (V) 24.6 Rated Panel Voc(V) 0 - 27

Isc (A) 1.68 Disconnect Load Voltage (V) 9.3 Max Discharge Current (A) 10.4

Reconnect Load Voltage (V) 10.5 Capacity (Ah) 10.4 Nominal Voltage (V) 11.1

Solar PanelMPPT and Battery

Charger Battery

Part Number WSLE-0240-024 GV-5-Li-12.5V

AT: Tenergy Li-Ion 18650 11.1V 10400mAh Rechargeable Battery Pack w/ PCB Protection (DGR-A)

Units Used

watt (W) is a unit of power in the International System of Units.

Joule (J) is a unit of energy or work in the International System of Units.

watt hour () represents energy scaled to one hour. Providing a convenient way to quantify energy supply and demand throughout a 24 hour day.

Ampere (A) is the SI unit of electric current.

Coulomb (C) is the SI unit of electric charge.

electrons

Ampere hour (A*hr) represents charge scaled to one hour.

Power RequirementsLOAD POWER REQUIREMENTS (EXTERNAL)

Required Power(W)

Voltage Supplied

(V)

Current Supplied

(A) Light hours Dark Hours Total Hours W-hr A-hr2 12 0.167 10 14 24 47.8 3.985 12 0.417 10 14 24 0.5 0.0417

Light Minutes

Dark Minutes Total Minutes

Total W-hr Total A-hr

600 840 1440 48.3 4.025

      Total WTotal mA-

hr2.0125 4025

External Power Needs (W) Internal Power Needs (W)Total Power Needs

without Efficiencies (W)Total Power Needs

with Efficiencies (W)

2.0125 0.564 2.58 3.391

Requirements Power (W) Energy (W-hr) Charge (A-hrs) Avg Current (A)

Battery 3.39 81.38 6.78 0.28

Solar panels 8.66 86.57 N/A 0.72

Power Capture EquationLabel Value Description

Solar Constant (w/ ) 1,360 Solar Constant at top of atmosphere at perpendicular incidence

Panel Area ( ) 0.32835 Area of WSLE-0240-024

Summer 0.9 90% compared to perpendicular (Earth tilt of 23 degree towards sun)

Equinox 0.7 70% compared to perpendicular. Rochester Latitude: 43°N

Winter 0.4 40% compared to perpendicular (Earth tilt of 23 degree away from sun)

Amorphous Silicon (a-si) 0.06 6% efficient

Power Captured = Solar Constant x Panel Area x (% from perpendicular solar incidence) x Solar Panel Efficiency

Incidence at Solar Noon (12:00) Summer Power (W) Equinox Power (W) Winter Power (W)90 ° 24.11 18.76 10.72

Hourly Power and Daily Energy Capture

Solar Time Degree Radian Sin(Radian) Summer (W) Equinox (W) Winter (W)

6:00 0 0 0 0.00 0.00 0.00

7:00 15 0.261799388 0.258819045 6.24 4.86 2.77

8:00 30 0.523598775 0.499999999 12.05 9.38 5.36

9:00 45 0.785398163 0.707106781 17.05 13.27 7.58

10:00 60 1.04719755 0.866025403 20.88 16.25 9.28

11:00 75 1.308996938 0.965925826 23.29 18.12 10.35

12:00 90 1.570796325 1 24.11 18.76 10.72

13:00 75 1.308996938 0.965925826 23.29 18.12 10.35

14:00 60 1.04719755 0.866025403 20.88 16.25 9.28

15:00 45 0.785398163 0.707106781 17.05 13.27 7.58

16:00 30 0.523598775 0.499999999 12.05 9.38 5.36

17:00 15 0.261799388 0.258819045 6.24 4.86 2.77

18:00 0 0 0 0.00 0.00 0.00

Daily Energy Collected (W*hr): 183.13 142.50 81.43

Graphical Representation of Hourly Power

Lindsey, R. (2009, January 14). Climate and earth’s energy budget. Retrieved from http://earthobservatory.nasa.gov/Features/EnergyBalance/printall.php

DC-DC Converters

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TDK-LAMBDA Part NO. CC3-1203SFRECOM Part NO. RPP20-2412SWBoth are through-hole devices

*Will use the internal switch of the 12VDC converter to shut off the output

*Will need to test

ConverterInput Voltage

(VDC)Output Voltage

(VDC) Max Output Current (A) Efficiency(%)

CC3-1203SF-E 9-18 3.3 ± 0.09 0.8 74RPP20-2412SW 9-36 12 ± 0.18 1.67 86

ConverterMax Output Power

(W)Output Noise

(mV p-p) Case Material PottedCC3-1203SF-E 2.64 120 Aluminum NoRPP20-2412SW 20 100 Aluminum Yes (Silicone)

Output FuseFuse to be placed at the output of the 12V DC-DC Converter Bourns Part NO. MF-MSMF050-2 , SMT DeviceTrip Current = 1A , Hold Current = 0.5A , Resistance =0.15Ω

• Polymeric Positive Temperature Coefficient (PPTC)/ resettable fuse

• A non-linear thermistor acting as a circuit breaker at trip current

• The device enters a high-resistance mode while passing a small value of current

• When the current is decreased below the trip current value, the device resumes normal operation

• The “hold current” value is the nominal operating current value of the PPTC

*Will need to test16

Energy Collection and Storage

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Voltage Converting

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Control and Communication

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Microcontroller and Firmware

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MSP430F2234

• 3.3 V Supply• Max Clock: 16 MHz• 16-Bit RISC Architecture• 8KB Flash Memory• 512 B RAM• 12 Channel 10-bit ADC• UART Interface• 38 pin TSSOP

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Operation Modes

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Timers

• Sensor Evaluation Loop is controlled by a 1-second timer interrupt. This timer uses an external 32 kHz crystal.

• Communication timeouts are handled by a 208-µS timer interrupt. This timer uses the internal DCO.

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Sensor Operation

• The internal and external temperature sensors uses two ADC channels each.

• Solar panel sensing uses one ADC channel for current and one channel for voltage and one channel for an external negative reference.

• Battery sensing uses two ADC channels for current and one for voltage.

• Output sensing uses one ADC channel for current and one channel for voltage.

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Fault Handling

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Fault Handling

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Communication

• The NSSPCM uses a modified MODBUS protocol.

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Start Address Function Data CRC END

3.5 c 8 bits 8 bits n * 8 bits 8 bits 3.5 c

Functions

Code Name Description0x01 GET_SOLAR Get Solar Panel Voltage and Current0x02 GET_BATT Get Battery Voltage and Current0x03 GET_OUTPUT Get Output Voltage and Current0x04 GET_INT_TEMP Get Internal Temperature0x05 GET_EXT_TEMP Get External Temperature0x06 GET_STATUS Returns Status of Module0x07 RESET_OUTPUT Toggles the Power Output0x08 INT_TEMP_WARN Internal Temperature Warning0x09 INT_TEMP_CRITICAL Internal Temperature Critical0x0A BATT_LOW Battery Level is Low0x0B PING Sends a ping

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ExceptionsCode Name Description

0x01 ILLEGAL_FUNCTION The function code received in the request is not an allowable action.

0x02 ILLEGAL_DATA_ADDRESS The data received in the address field is out of range.

0x03 ILLEGAL_DATA_VALUE A value in the data field is not allowable.

0x04 SLAVE_DEVICE_FAILURE An unrecoverable error occurred while the slave was attempting to process the request.

0x05 ACKNOWLEDGE The slave has accepted the request and is processing it but it will take longer than the timeout to process.

0x06 SLAVE_DEVICE_BUSY The slave node is busy processing a long duration request.

0x07 NEGATIVE_ACKNOWLEDGE That slave node cannot perform the request.

0x08 MEMORY_PARITY_ERROR The slave attempted to read extended memory but detected a parity error.

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Timing

8N2 at 19200 baud

3.5 char marker is 1.458 mS1.5 char marker is 0.625 mS

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Time

Address Function 2 Data Bytes CRC

Notes: Not to ScaleValues are for 19200 baud

1.458 mS 416.67 uS 416.67 uS 833.33 uS 416.67 uS 1.458 mS

4.999 mS

<IDLE> <IDLE>

MAX3483

• 3.3 V Supply• 250 kbps• RS-485• 1.1 mA Supply Current• Half duplex

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Mechanical Overview

Structural Design

Overall DimensionsLength: 1 meterWidth: 0.383 metersHeight: 0.252 metersWeight: 0.6027 kg

Front View:

Top View:

Material Selection – Aluminum 6061-T6*Selected for low density, high strength and availability

6061-T6 Material Properties:Density: 2700 kg/m3

Modulus of Elasticity: 68.9 GpaPoisson’s Ratio: 0.33Shear Strength: 207 MPa

Material Needed (T x W x L, qty):1/16” x 3/4” x 12’1/16” x 3/4” x 10’1/16” x 1/2” x 10’

Source: www.matweb.com

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X

YZ

FEB 22 201213:01:08

ELEMENTS

FNFORNMOM

Structural Analysis

Anticipated Loading on Ascent:Average Speed of Rise: 6.71 m/s (15 mph)Peak Speeds: 22 m/s (50 mph)

Force due to Rise: 4.55 N

Solar Panel Area: 0.0825 m2

Structural Analysis - Deflection

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MN

MX

X

YZ

-.007767-.006904

-.006041-.005178

-.004315-.003452

-.002589-.001726

-.863E-030

FEB 22 201212:54:10

NODAL SOLUTION

STEP=1SUB =1TIME=1UZ (AVG)RSYS=0DMX =.007767SMN =-.007767

Maximum Deflection:

7.7 mm

Modeled using Average rise speed (6.71 m/s)

1

MN

MX

X

YZ

.172E-07

.339E+07.678E+07

.102E+08.136E+08

.169E+08.203E+08

.237E+08.271E+08

.305E+08

FEB 22 201213:18:52

NODAL SOLUTION

STEP=1SUB =1TIME=1SEQV (AVG)DMX =.007767SMN =.172E-07SMX =.305E+08

Structural Analysis – Shear Stress

Allowable Shear Stress:

207 MPa

Maximum Shear Stress Experienced:

30.5 MPa

Thermal Analysis – Enclosure

Expanded Polystyrene:

Thickness: 0.035 m

Density: 15 kg/m3

Thermal Conductivity:0.027 W/m-K

Thermal Analysis - Enclosure

Thermal Analysis - Enclosure

Thermal Analysis - Conduction

Heat Conditions:Maximum = 2.996 WattsMinimum = 0.3036 WattsAverage = 1.02 Watts

Weight Estimation

Aluminum = 0.6027 kgEnclosure = 0.195 kgSolar Panel = 0.65 kgBattery = 0.589 kgMPPT = 0.04 kgPCB = 0.09 kgFrame Hardware = 0.25 kg

Total = 2.42 kg

Specification = 2.5 kg

PCB Layout

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Board Dimensions203.20mm x 152.40mm8.0”(L) x 6.0”(W)

Electronic Component PCB Area

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2-Layer Board: Through-hole and surface-mount components

Component Dimensions (L x W x H):

A=1.59 x 1.0 x 0.46 B=0.90 x 0.65 x 0.33 C= 0.19 x 0.24 x 0.06D=0.49 x 0.31 x 0.04 E=0.59 x 0.59 x ? F=0.39 x 0.39 x ?G=0.23 x 0.078 x ? H=1.03 x 0.37 x 0.50 I=0.21 x 0.37 x 0.50J=0.54 x 0.37 x 0.49*See DDR Document Package for Component Descriptions*Not an exact layout of PCB

Board Section Dimensions2.5(L) x 6.0 (W)

*Dimensions in Inches

Connections To Payload

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Preliminary Test Plan

• Will present from Edge

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Preliminary MSDII Plan

• Beginning of MSDII (weeks 1-3) • Will view on external document

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Risk Management

• Will present from EDGE

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