Perturb and Observe MPPT algorithm with a current controller based on the sliding mode

Maximum power point tracking in PV systems based on adaptive control and sliding mode control

“…Accounting for a previously measured power level, if the present power is higher, then the algorithm performs the next perturbation in the same direction of the previous one; but if the power decreases, the algorithm performs the next perturbation in the opposite direction [6]. The flowchart of the P&O algorithm is shown in Figure 4.…”

“…The objective of MRAC is to provide a pre-established dynamic response to ensure a constant settling time (t s ) to the PV voltage. Such a characteristic is required to calculate the sampling time (T a ) of the P&O algorithm, which is an important feature since t s < T a must be ensured to guarantee the stability of the system as demonstrated in [6]. In this manner, the selection of T a is a tradeoff between stability and tracking speed of the MPP.…”

“…In this manner, the selection of T a is a tradeoff between stability and tracking speed of the MPP. In the case of classical controllers, T a is set to the worst case (longest sampling time) to ensure system stability [6], but such a condition introduces power losses since the tracking speed of the MPP decreases, i.e. the PV system is far from the optimal operation condition for a longer time in comparison with a system driven by a shorter T a .…”

Sliding-Mode Controller for Maximum Power Point Tracking in Grid-Connected Photovoltaic Systems

“…This constraint puts at risk the system performance since the operating point changes with the unpredictable and unavoidable environmental perturbations. To address this problem, the work in [16] uses a sliding mode controller (SMC) to regulate the inductor current of a boost converter associated to the PV module, which enables to guarantee global system stability at any operating point. The solution proposed in that work considers three controllers in cascade as follows: the SMC that generates the activation signal for the MOSFET, a PI controller designed to provide the SMC reference depending on the command provided by a P & O algorithm, which is in charge of optimizing the power.…”

“…Similarly, the work in [17] uses a SMC to regulate the input capacitor current of the boost converter. This solution has a major advantage over the work reported in [16]: the solution in [17] does not require a linearized model since the transfer function between the capacitor current and voltage is linear and it does not depend on the irradiance or temperature conditions. Therefore, such a solution is able to guarantee the desired performance in all the operating range.…”