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
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