Implementation of a Temperature Control System

1Cluj-Napoca, 20.06.2016

2Cluj-Napoca, 20.06.2016

Close control loop

Fuzzy regulator

Fuzzy logic system: 9 rules

Temperature Sensor

One Wire Digital Temperature Sensor - DS18B20

Heating element

Thermal resistor 2Ω, supplied in ac (12V peak value)

Heating power control

Phase control of a SCR (thyristor) – TCA 785

System structure

3Cluj-Napoca, 20.06.2016

Arduino development board

• “Brain” of the entire system

• Read current temperature

• Compute error and change-of-error

• Run fuzzy logic system

• Determine digital value of control signal

DAC - MCP4725, I2C interface

Provide analog value of control signal

Phase control board

Analog amplifier for control voltage – AD820

TCA 785 – phase control IC

System implementation

Block diagram

5

Functional diagram

6

ARDUINO UNO development board

7

Programmable Resolution 1-Wire Digital Temperature Sensor

9-bit to 12-bit Celsius temperature measurements

Unique 1-Wire® Interface Requires Only One Port Pin for

Communication

Allows multiple DS18B20s to function on the same 1-Wire bus

8

12-Bit Resolution

On-Board Non-Volatile Memory (EEPROM)

External Voltage Reference (VDD)

Rail-to-Rail Output

Single-Supply Operation: 2.7V to 5.5V •

I2C Interface

Eight Available Addresses

DAC MCP4725

9

Phase control TCA 785

Control thyristors, triacs, and transistors.

The trigger pulses can be shifted within a

phase angle between 0 ˚ and 180 ˚

10

TCA 785

11

Thermal enclosure Phase control board

12

16 x 2 LCD

13

Experimental setup

14

Experimental setup

15

Fuzzy logic system

16

-1 -0.5 0 0.5 10

0.2

0.4

0.6

0.8

1

err; cerr

Neg

Zero

Pos

-1 -0.5 0 0.5 10

0.2

0.4

0.6

0.8

1

du

N

Z

P

Input fuzzy sets

Output fuzzy sets

Control surface

errFls

cerrFlsNeg Zero Pos

Neg N N Z

Zero N Z P

Pos Z P P

Rule base

1

2

3

4

5

6

7

8

9

18

0 500 1000 1500 2000 250025

30

35

40

45

50

time [s]

tem

pera

ture

[C

]

Tref

T

Experimental results, Tref = 45oC

19

0 500 1000 1500 2000 250020

40

60

tem

p

0 500 1000 1500 2000 2500-20

0

20

err

0 500 1000 1500 2000 2500-20

0

20

cerr

0 500 1000 1500 2000 2500-1000

0

1000

du

0 500 1000 1500 2000 25000

2000

4000

u

Experimental results, Tref = 45oC

0 500 1000 1500 2000 250020

40

60te

mp

0 500 1000 1500 2000 2500-1000

0

1000

du

0 500 1000 1500 2000 25000

2000

4000

u

0 500 1000 1500 2000 25000

2

4

con

tr.

vo

ltag

e

Experimental results, Tref = 45oC

Experimental results, Tref = 37oC

0 100 200 300 400 500 600 700 800 90026

28

30

32

34

36

38

time [s]

tem

pera

ture

[C

]

Tref

T

Experimental results, Tref = 34oC from 37oC

0 200 400 600 800 1000 120033.5

34

34.5

35

35.5

36

36.5

37

time [s]

tem

pera

ture

[C

]

Tref

T

0 200 400 600 800 1000 120030

35

40te

mp

0 200 400 600 800 1000 1200-1000

0

1000

du

0 200 400 600 800 1000 12002000

4000

6000

u

0 200 400 600 800 1000 12002

3

4

con

tr.

vo

ltag

e

Experimental results, Tref = 34oC from 37oC