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Idiomas disponibles
Idiomas disponibles
ADVANTAGES OF MPPT VS PWM TECHNOLOGY (CONTINUED)
GAINS OF A MPPT OVER PWM
The voltage of a photovoltaic solar panel varies according to its temperature: its voltage decreases as the
temperature increases and vice versa. This normative value, called the temperature coefficient, is given
with a cell temperature of 25°C.
Example: with a panel that displays +/-0.34%/°C, we must correct the Vmp voltage by -0.34% per cell
degree above 25°C.
As shown in the example below, which highlights voltage variations due to temperature and voltage drops
due to the cable, a UNIMPPT charge regulator allows an APG (Average Production Gain) of 20% in
summer and up to 40% in winter.
In addition, it is noted that the more discharged is the battery and/or high is the panel voltage, the
greater the advantage of an MPPT over a PWM is.
Solar radiation in
Winter
temperature
Sunrise
9h
12h
End of charge
16h
Solar radiation in
Summer
temperature
Sunrise
7h
10h
End of charge
14h
* Example MPPT efficiency 98%
100 W solar panel with a UNIMPPT regulator
Solar
Panel
panel
voltage
VMP
5°C
20,0 V
19,9 V
19,8 V
19,7 V
19,6 V
15°C
19,5 V
Solar
Panel
panel
voltage
VMP
30°C
18,4 V
17,2 V
17,2 V
16,6 V
16,3 V
70°C
16,0 V
Panel voltage
Voltage
with drop due
battery
to the cables
charge
(5%) (A)
(B)
19,0 V
12,2 V
18,9 V
12,5 V
18,8 V
13,0 V
18,7 V
13,5 V
18,6 V
14,0 V
18,5 V
14,6 V
Panel voltage
Voltage
with drop due
battery
to the cables
charge
(5%) (A)
(B)
17,5 V
12,2 V
16,3 V
12,5 V
16,3 V
13,0 V
15,8 V
13,5 V
15,5 V
14,0 V
15,2 V
14,6 V
www.uniteck.fr
Theoric
Theorical
al gain
gain in
=(A-B)
%
6,8 V
56%
6,4 V
51%
5,8 V
45%
5,2 V
39%
4,6 V
33%
3,9 V
27%
Medium APG
+ 40%
Theoric
Theorical
al gain
gain in
=(A-B)
%
5,3 V
43%
3,8 V
31%
3,3 V
26%
2,3 V
17%
1,5 V
11%
0,6 V
4%
Medium APG
EN
Gain
rectified
MPPT*
53%
49%
42%
37%
31%
26%
Gain
rectified
MPPT*
41%
29%
24%
16%
10%
4%
+ 20%
35
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