Table 1.5 Estimation of PV module parameters under change in irradiance and temperature using NR method.
| PV Modules | G (W/m2) | T(°C) | A | Rse (Ω) | Rsh (Ω) | Ilg (A) | Isat (A) | Vmpp (V) | Impp (A) | Pmpp (W) |
| KD245GX | 1000 | 70 | 1.3184 | 0.1562 | 623 | 8.9123 | 4.68E-07 | 29.7962 | 8.2304 | 245.2376 |
| 1000 | 50 | 1.3184 | 0.1562 | 623.2256 | 8.9123 | 4.68E-07 | 29.799 | 8.2304 | 245.2596 | |
| 1000 | 30 | 1.3184 | 0.1562 | 623.2331 | 8.9122 | 5.85E-07 | 29.8017 | 8.2304 | 240.538 | |
| 800 | 25 | 1.4485 | 0.125 | 779.0438 | 7.1291 | 5.84E-07 | 29.6937 | 6.5839 | 195.496 | |
| 600 | 25 | 1.4758 | 0.0937 | 1040 | 5.3465 | 7.84E-07 | 29.3463 | 4.9321 | 144.7091 | |
| Shell SP70 | 1000 | 25 | 1.5536 | 0.3242 | 321.2234 | 4.7047 | 1.57E-06 | 16.4975 | 4.2498 | 70.1122 |
| 800 | 25 | 1.577 | 0.2594 | 401.5293 | 3.7624 | 1.96E-06 | 16.5814 | 3.4061 | 56.4832 | |
| 600 | 25 | 1.6082 | 0.1945 | 535.3723 | 2.821 | 2.59E-06 | 16.4755 | 2.5542 | 42.0926 | |
| 400 | 25 | 1.6588 | 0.1297 | 803 | 1.8803 | 3.89E-06 | 16.0935 | 1.6979 | 27.3231 | |
| 200 | 25 | 1.7483 | 0.0648 | 1610 | 0.94 | 7.27E-06 | 15.1603 | 0.8415 | 12.7591 |
Figures 1.4 and 1.5 represent the P-V and I-V characteristics of solar PV panels such as KD245GX and SHELL SP70 under varying irradiance from 200 to 1000 W/m2 and temperature of 25 to 50°C, repectively. The results have shown that the decrease in the solar irradiance reduces the maximum power output from the PV panel and increases the power loss due to increase in the shunt resistance. However, the increase in temperature has minimum effect on shunt resistance and almost maintains the output power from the panel. On comparing the results obtained from both N-R and G-S methods, the maximum power exhibits excellent agreement with good accuracy by the NR approach under varying irradiance and temperature.
1.4.2 Experimental Results
An experimental setup was made to test the effectiveness of NR technique to estimate the parameters of PV module under dynamic environmental conditions. The experimental setup uses HST60FXXXP, 250 W PV panel with the following specification given in Table