The basic principle of PV power optimizer is that each PV module is connected to the power optimizer, and each module is an independent whole in relation to the PV array, and its output power is not affected by any other modules, and it always outputs the maximum power value under the current environmental conditions.

The power optimizer, together with a string inverter with multiple MPPT, is very effective in reducing power loss when the modules are blocked by shadows, but in a single MPPT centralized inverter, the effect is not as obvious as in a string inverter with multiple MPPT. The module-level optimizer can also be set to match the inverter in real time and communicate to distribute the voltage according to the optimal power point of the inverter. This way the output of the optimizer connected to each module is influenced by the inverter and works at maximum efficiency at all times by following the inverter’s instructions while ensuring consistent current.

For the traditional string design scheme, when one of the components of a string is shaded, the voltage is generally unchanged and the current drops. If one of the modules is shaded, the current drops to 3.2A and the current of the whole circuit drops (the series circuit current is equal everywhere), the total power becomes 2048W, a drop of about 62%.

When the optimizer is added, the shaded component no longer affects the power generation of other components, and the DC-DC control circuit of the small transformer inside the optimizer changes the output current of the component to match the current of other components (of course, the optimizer needs to monitor the output current of other components on the same string and adjust its own output current size only after finding inconsistencies), the current of the component The module current is increased from 3.2A to 8.4A, and the voltage is reduced from 32V to 12.5V, so the actual power output is 270*19+102=5232W, i.e. the actual power loss is 3%.

Because the position of the sun changes with the seasons and time of day, and the potential shade around it changes over time, people who have experience with PV plant installations understand one thing: shadows are hard to predict, and shadows are hard to avoid completely. Many times, PV power plants are only found to actually have shadows blocking them after construction is complete!

Sand, dust, stains, trees and leaves, bird droppings, flag poles, water heaters, daughter walls, power lines, surrounding buildings, and various rooftop facilities can all produce diverse shadows. As the position of the sun moves, the shape of the shadows will change as well.

Measurements show that the minuscule amount of shade and wire shadows present in a PV system can result in about 20-30% lower power generation for the entire plant!