Enhanced Efficient Thermal Control System

(EETCS)Group 18

Lucas ChokanisDaniel RamirezLloyd Harrison

Philip Teten

A Proposal from Researchers to Implement Their Algorithms

Design a Power Efficient Thermostat to Control a Vehicle’s Heating, Ventilation, and Air Conditioning (HVAC) Systems

Create a Control System That will Significantly Extend the Life-Cycle of a Vehicle’s Battery

Provide a Control System that is Feasible to adapt for Future Additions

Motivation

Ability to Detect Input:◦ Temperature of the Vehicles Interior◦ Temperature of the Evaporator◦ 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◦ Remote Temperature Sensors

Highly Intuitive Programming:◦ Giving Researchers Ease of Understanding

Challenges

Voltage Recieved: ◦ 12 VDC to 15 VDC

Output to Motors: ◦ 12 VDC Three Speed with Separate Hi, Med, Low input◦ 12 VDC On/OFF 12VDC motor.◦ Linear 0-3.3V “ramp” speed command

Relays:◦ Coil Voltage of 12 VDC

Microcontroller◦ MSP430◦ C2000

Specifications and Requirements

The Proposed System

Microcontroller

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 Temperature sensor

Microcontroller

Temperature Sensors

Ambient temperature Sensor:◦ Housed on main thermostat circuit board.◦ Provides feedback to the user via LCD screen

Evaporator 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 evaporator is cooling.◦ Prevents the evaporator from freezing over.◦ Feeds data back to the MCU to be that will be used to improve

efficiency.

Auxiliary Temperature Sensor:◦ Remote sensor location (<15ft away from main board).◦ Feeds data back the MCU to be used to improve efficiency.

Temperature Sensors

Model Manufacturer Accuracy Temp. Range

Current Draw

Output Price $

LM35A Texas Instruments

±0.2ºC -40ºC to 110ºC

60µA Linear Voltage

5.60

LM35CA Texas Instruments

±0.2ºC -40ºC to 110ºC

60µA Linear Voltage

14.61

ADT7420 Analog Devices ±0.2ºC -40ºC to 125ºC

265µA 16-Bit 4.87

ADT7320 Analog Devices ±0.2ºC -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

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

Temperature Sensors Communication

User Interface

User Interface

User Interface 4 Digits 1 Decimal Accuracy

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 A1 0 1 1 b1 1 0 0 C1 1 0 1 d1 1 1 0 E1 1 1 1 F

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

LCD Display and Driver

User Interface 4 Digits 1 Decimal Accuracy

User Interface View Changing: Scroll Through

User Interface Temperature Set for Nominal Setting

User Interface Setting the Blower Motor State

PMSM Communication

PMSM Communication

PMSM Communication

Analog Out0.165V to 2.13510 Settings

PMSM Communication

PWM Input

PMSM Communication

Lowpass FilterEliminates High Frequency ComponentsMaintains Analog DC Valuew0 = 1/RC = 1kHz

PMSM Communication

Dual Differential DriverTo Drive the 15’ of CableBetter Noise ImmunityDO+1=DI1/2DO-1 = -DI1/2

PMSM Communication

Shielded Twisted PairHigher Noise ImmunityNoise Cancels

PMSM Communication

Dual Differential RecieverR2OUT2 = (RIN2+) – (RIN2-)

PMSM Communication

Analog Out0.165V to 2.13510 Settings

Power and Motor Control

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.

Motor Control

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: 10.8 mA 50 uADesign current limit:

10 mA 1 mA

P/S efficiency: 91 % 84 %

Power

Current Draw

Power

3.3V P/S EFFICIENCY 5V P/S EFFICIENCY

Power

Load

SupplyVoltage

(V)

SupplyCurrent

(mA)3.3V OutputCurrent (mA)

5V OutputCurrent (mA)

Efficiency (%)

Minimum 12 13 11.3 9.77 55.215 12 11.3 9.83 48.0

Medium 12 11 12.2 6.39 54.715 10 12.2 6.39 48.1

Maximum 12 12 12.8 6.81 53.015 11 12.8 6.81 46.2

Power

Power

The Proposed System

Administrative ContentItem Price

Quantitiy

Paid Total

Microcontroller - MSP430F2274-Q1 Free Sample 1 Yes -Temperature Sensors - ADT7320 $ 4.87 3 No $ 14.61 PCB by 4PCB.com $ 33.00 1 No $ 33.00 LCD Display - Lumex LCD-S401C39TF Free Sample 1 Yes -LED for User Interface Owned 8 Yes -Push Buttons for User Interface $ 0.19 5 No $ 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 $ 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 $ 182.95

Research

Design

Fabrication

Coding

Testing

Parts Ordered

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Progress

Noise from motors induced into MCU◦ Possible Solutions: Filters, bypass capacitors,

optocouplers Multiple Temperature Sensors Sharing One

SPI Interface.

Concerns

Questions?