Consider a PV module with the following parameters as measured at STC (Standard Testing Conditions):

Voc = 55 V;

Isc = 5 A;

Impp = 4.7 A;

Fill Factor = FF = 75% ;

Efficiency = 19.75%.

Suppose that under normal operation at STC conditions, the module is not connected to an MPPT device, and is instead directly connected to a purely resistive, variable load 'R'. The load R can be tuned to give a resistance between 0 to 1kΩ.

What value of resistance will you keep the load at, if you wish to derive maximum power from the PV module under STC conditions?

1)R = 9.34Ω.
2)R = 11Ω.
3)R = 11.71Ω.
4)R = 5Ω.
5)Irrespective of the value R takes, the module can never be made to deliver maximum power under STC.

it's the first one - 9.34

3)11.71¥Ø

Thanks Onix and sat

Thanks sat it´s correct the first one

To determine the value of resistance at which the PV module will deliver maximum power under STC conditions, we can use the concept of maximum power point tracking (MPPT). The maximum power point (MPP) is the combination of voltage and current at which the module delivers maximum power.

The MPP can be determined using the equation: P = V * I, where P is the power, V is the voltage, and I is the current.

First, we need to calculate the maximum power (Pmax) that the PV module can deliver. We can use the following formula:

Pmax = Voc * Isc * FF,

where Voc is the open-circuit voltage, Isc is the short-circuit current, and FF is the fill factor.

Given that Voc = 55 V, Isc = 5 A, and FF = 75%, we can calculate:

Pmax = 55 V * 5 A * 0.75 = 206.25 W.

Next, we need to find the resistance value (R) that will allow the PV module to operate at its maximum power point. The maximum power point usually occurs when the load resistance (R) is equal to the module's internal resistance (Ri).

To calculate the internal resistance, we can use the formula:

Ri = (Voc - Vmpp) / Impp,

where Vmpp is the voltage at the maximum power point and Impp is the current at the maximum power point.

Given that Impp = 4.7 A, we need to find Vmpp.

The efficiency (η) of the PV module can be calculated using the formula:

η = P / (Pincident * 100),

where Pincident is the incident power on the module.

Since P is the maximum power, we can rearrange the formula to solve for Pincident:

Pincident = P / (η * 100).

Given that efficiency (η) = 19.75%, we can use the value of Pmax calculated earlier:

Pincident = 206.25 W / (0.1975 * 100) = 1042.22 W.

Now, we can calculate Vmpp using the formula:

Vmpp = Voc - (Impp * Ri).

Rearranging the formula, we can solve for Ri:

Ri = (Voc - Vmpp) / Impp = (Voc * FF - (Pincident / Impp)) / Impp.

By substituting the given values, we get:

Ri = (55 V * 0.75 - (1042.22 W / 4.7 A)) / 4.7 A = 9.34 Ω.

Therefore, the value of resistance (R) at which the PV module will deliver maximum power under STC conditions is R = 9.34 Ω.

Hence, the correct option is 1) R = 9.34 Ω.