2 Perturb And Observe

Perturb and observe works by periodically adjusting the operating voltage of the solar panel (perturb) and measuring the resulting change in input power (observe). This allows the system to dynamically track the MPP of the panel in real-time.

The P&O algorithm incrementally converges towards the maximum power point by using a simple comparison logic to step up or down the PV operating point. If power increases, then the system continues to increase the PV operating point in the same direction. If power decreases, then the direction is reversed. Once near the MPP, the system naturally ends up oscillating slightly around the peak power point, because the system must keep perturbing to stay close to the maximum power point.

The size of the perturbation step (Δ) can be adjusted to fit the needs of the system. A smaller step causes finer fluctuations with less deviation from the MPP, but the controller can take longer to reach the MPP under rapidly changing conditions, while a larger step causes faster changes but larger swings in power.