Group 18 Lucas Chokanis Daniel Ramirez Lloyd Harrison Philip Teten.
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Transcript of Group 18 Lucas Chokanis Daniel Ramirez Lloyd Harrison Philip Teten.
Experimental Engineering Thermal Control System
(EETCS)Group 18
Lucas ChokanisDaniel RamirezLloyd Harrison
Philip Teten
A Proposal from Researchers to Implement Their Algorithms
Design an Experimental Thermostat to Control a Vehicle’s Heating, Ventilation, and Air Conditioning (HVAC) Systems
Provide a Control System that is Feasible to adapt for Future Modifications
Motivation
Ability to Detect Input:◦ Temperature of the Vehicles Interior◦ Temperature of the Blower Motor◦ Extra Temperature Sensor for Researchers Use
Control Output:◦ Speed of the Blower Motor (High, Med, & Low)◦ Speed Command of the PMSM Motor◦ Condenser Fan◦ Clutch Control
Implement a User Interface◦ LCD Screen and LED’s for Feedback◦ Push Buttons for User Control
Objectives
Electrically Noisy Environment:◦ Use of Parts that Meet Automotive Requirements
15 ft Transmission Lines:◦ PMSM Motor Control◦ Two Remote Temperature Sensors
Highly Intuitive Programming:◦ Giving Researchers Ease of Understanding◦ Communicating Multiple Temperature Readings
Via SPI Bus
Challenges
Voltage Received: ◦ 12 to 15 VDC
Output to Motors: ◦ 12 VDC Three Speed Blower Motor Control
High, Medium, Low◦ 12 VDC Condenser Fan◦ 12 VDC Clutch Control◦ Linear 0 to 2.63 VDC “Step” Speed Command
Relays:◦ Four 15 Amp Relays◦ One 30 Amp Relay◦ Coil Voltage of 12 VDC
Microcontroller◦ MSP430 or C2000
Specifications and Requirements
Parametrics MSP430F2274-Q1
TMS320F28030
LM4F110B2QR
Architecture 16-bit 32-bit 32-bitFlash (KB) 32 32 32Frequency
(MHZ)16 60 80
RAM (KB) 1 12 12GPIO 32 44 43I2C 1 1 4
UART 1 1 8SPI/SSI 1 2 4
ADC 10-Bit/12 channels 12-bit/16 channels 12-bit/12 channelsRating Automotive Standard Standard
Microcontroller
The chosen microcontroller is the MSP430F2274-Q1 for the following reasons: Ultra-Low power Code Composer Studio IDE Qualified for Automotive Applications Sponsor provided the MSP430 Target board
and USB programmer
Microcontroller
Ambient temperature Sensor:◦ Housed on main thermostat circuit board.◦ Provides feedback to the user via LCD screen
Blower Motor Temperature Sensor:◦ Remote sensor location. ◦ 15ft away from main board as required by the
customer. Its purpose is to keep track of the rate at which the blower motor is cooling.
Auxiliary Temperature Sensor:◦ Remote sensor location (<15ft away from main board).
Temperature Sensors
Model Manufacturer
Accuracy
Temp. Range
Current Draw
Output Price $
LM35A Texas Instruments
±0.25ºC -40ºC to 110ºC
60µA Linear Voltage
5.60
LM35CA Texas Instruments
±0.25ºC -40ºC to 110ºC
60µA Linear Voltage
14.61
ADT7420
Analog Devices
±0.25ºC -40ºC to 125ºC
265µA 16-Bit 4.87
ADT7320
Analog Devices
±0.25ºC -40ºC to 125ºC
265µA 16-BitSPI
4.87
ADT7310
Analog Devices
±0.50ºC -40ºC to 125ºC
265µA 16-BitSPI
4.87
TMP100 Texas Instruments
±3ºC -55ºC to 125ºC
45µA 2.15
Temperature Sensors
The chosen temperature sensors were the ADT7320 for the following reasons: Very high accuracy rating on a wide
temperature scale. We can expect reliable temperature
readings in a cold environment such as the evaporator.
User programmable with multiple features Temperature resolution up to 16-bits.
Temperature Sensors
Extending The SPI Bus for Long Distance Communication:◦ For the remote sensors, it is possible that propagation
delay could be significant enough to hinder data transmission.
◦ Once we attempt to conduct SPI communications at distances greater than 15 feet, we will know if propagation delay will require a hardware solution.
◦ If this turns out to be the case, dual differential transceivers will be used to refresh the clock signal protect the data transfer from noise.
◦ If the signal is fed back to the master from the slave, data transmissions between the master and slave will occur at the same delayed clock signal.
Temperature Sensors Communication
Although the ADT7320 sensor performed above our expectations, we realized that an initialization subroutine was required for it to function reliably.
Sensor Initialization
LCD Display and Driver Driver Uses Less Pin Outs Good for Intuitive Programming
B3 B2 B1 B0 LCD Display
0 0 0 0 00 0 0 1 10 0 1 0 20 0 1 1 30 1 0 0 40 1 0 1 50 1 1 0 60 1 1 1 71 0 0 0 81 0 0 1 91 0 1 0 -1 0 1 1 E1 1 0 0 H1 1 0 1 L1 1 1 0 P1 1 1 1 (blank)
D1 D2 D3
D4 Function
0 0 0 0 No Change0 0 0 1 Store Data in Latch 4 to be Displayed in
Digit 40 0 1 0 Store Data in Latch 3 to be Displayed in
Digit 30 1 0 0 Store Data in Latch 2 to be Displayed in
Digit 21 0 0 0 Store Data in Latch 1 to be Displayed in
Digit 11 1 1 1 Store Data in All Data Latches, Display All
Solid-State Relays (SSRs) Vs. Electromechanical Relays:
Motor Control
Relay Type Pros ConsSolid-state Faster switching
times Increased lifetime (no
moving parts) Bounceless switching No sparking or arcing Silent operation
Higher ON resistance (more power dissipated)
Small OFF resistance (small reverse leakage current)
Fails “short”Electromechanical Lower ON
resistance (ohmic contacts)
Higher OFF resistance (no current flow)
Fails “open”
Noisy Shorter lifetime
(10^5 to 10^7 switching cycles)
Switch bouncing Arcing across
contacts
Motor Control: Choosing Relay Current Rating
Motor Control
DC SupplyVoltage
(V)
LO-speedCurrent
(A)
MED-speedCurrent (A)
HI-speedCurrent
(A)12.0 5.7 8.6 15.012.5 5.9 8.9 15.613.0 6.2 9.0 16.113.5 6.4 9.3 16.914.0 6.6 9.5 17.414.5 6.8 9.8 18.015.0 7.1 9.9 18.7
Blower motor current draw (low, medium, and high speeds)
Note: Highlighted values are interpolated values due to limitations in test equipment.
Motor Control: Choosing Relay Current Rating
Motor Control
Condenser Fan Motor Current Draw
DC SupplyVoltage
(V)
Motor Current
(A)
12.0 7.012.5 7.513.0 7.913.5 8.214.0 8.714.5 9.115.0 9.4
Note: Highlighted values are interpolated values due to limitations in test equipment.
P/S section: 3.3V 5V Items Drawing Current
6.5 mA – MCU 50 uA – LCD driver795 uA – Temperature sensors (3 x 265uA)
Total per section: 7.3 mA 50 uADesign current limit:
10 mA 1 mA
P/S efficiency: 91 % 84 %
Power
Current Draw
Power
Load
SupplyVoltage
(V)
SupplyCurrent
(mA)3.3V OutputCurrent (mA)
5V OutputCurrent (mA)
Efficiency (%)
Minimum 12 13 11.3 9.77 55.2
15 12 11.3 9.83 48.0
Medium 12 11 12.2 6.39 54.7
15 10 12.2 6.39 48.1
Maximum 12 12 12.8 6.81 53.0
15 11 12.8 6.81 46.2
Regulator Efficiency
Administrative ContentItem Price
Quantitiy
Paid Total
Microcontroller - MSP430F2274-Q1 Free Sample 1 Yes -
Temperature Sensors - ADT7320 $ 4.87 3 Yes $ 14.61
PCB by PCBFabrication.com $ 76.00 6 Yes $ 457.00
LCD Display - Lumex LCD Free Sample 1 Yes -
LED for User Interface Owned 8 Yes -
Push Buttons for User Interface $ 0.19 5 Yes $ 0.95
Dual Differential Driver - DS90LV027AQMA Free Sample 2 Yes -
Dual Differential Receiver - DS90LV028AQMA Free Sample 2 Yes -
Shielded Twisted Pair - C1352-100-ND $ 66.96 1 Yes $ 66.96 NPN transistor 200mA ICmax, 40V Vce(breakdown), through hole
$0.17 10Yes $ 1.74
Switching Regulator - TI LM26003 Free Sample 3 Yes -
Relay automotive SPST 12V, 15A $1.79 6 Yes $ 10.74
Relay automotive SPST 12V, 30A $5.02 2 Yes $ 10.04
Capacitors $2.50 65 Yes $ 17.47
Diode, Schottky 40V 30mA, through hole $0.66 5 Yes $ 3.30
Inductor 1mH, 10% through hole $2.79 3 Yes $ 8.37
Resistors $0.72 77 Yes $ 6.79
TSSOP-20 to DIP-20 SMT Adapter (for TI LM26003 chip) $4.49 2 Yes $ 8.98
TOTAL $ 606.86
Research
Design
Fabrication
Coding
Testing
Parts Ordered
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Progress