*3.2.1. Constant Voltage*

In addition, notice that temperature changes may directly affect the tracking quality: com‐ monly, PV systems are designed considering its operation on the SCT, i.e., *T* =25° , howev‐ er, when PV modules are exposed to the solar radiation, its real temperature of operation encreases and, as consequence, the voltage associated to MPP is moved to the left. This be‐ havior is critical for buck converter, as per Figure 19 (a), since its non tracking region is also

Although boost converter also presents a non tracking region, in this case it presents a prop‐ er tracking behavior, once temperature increasing replaces the MPP to left, toward to the

Finally, buck-boost converter (and similars) can track the MPP independent on its position on the I-V pan, as is shown on Figure 19 (c). Furthemore, these converters are also indicated

The tracking algorithm performance is fundamental for an efficient tracking response. Usu‐ ally, the algorithm receives the PV module voltage and current as input data and defines the dc-dc converter duty cycle that establishes the system operating point on the MPP, as de‐

As the radiation and temperature are dynamic variables, and the MPP depends on both of them, the algorithm must practically work in real time, updating the duty cycle for a fast

On the literature, there are several proposed algorithms for improving the tracking speed, accuracy or both, but the algorithm efficiency is directly associated to the complexity of im‐

In this section, based on the PV curves understanding, a new tracking method is developed, whose main characteristics are: simplicity, excellent tracking dynamic, accuracy, stability in

for tracking applications, when constant voltage loads are employed.

on left of *V bus*.

106 Sustainable Energy - Recent Studies

picts Figure 20.

and accurate tracking.

plementation.

tracking region, in according to Figure 19 (b).

**3.2. MPPT from the tracking algorithm point of view**

**Figure 20.** Typical input and output data related to MPPT algorithms.

steady-state (no oscillations), and low cost.

This method is achieved in or to impose the voltage across the PV terminals clamped at a fixed value, normally specified to ensure the maximum power transfer on the STC [4]. Once a single voltage sensor is needed, it is featured by simplicy of implementation and low cost, but for any temperature change, the PV operating point is set out of the MPP.
