SLYT855 May 2024 AFE88101 , DAC161S997 , DAC8551 , LM74610-Q1 , TVS3301
In solar photovoltaic (PV) systems, module-level power electronics (MLPE) improve power-yield performance under certain conditions, especially in shade. Once considered a costly specialty category, MLPE is now one of the fastest-growing market segments in the solar industry. A solar power optimizer is one type of MLPE that optimizes the power output of the PV panel and increases efficiency.
Conventional solar power optimizers use a P-N junction diode or a Schottky diode for the bypass circuit. When high current flows through the diode, the high-power dissipation can cause severe thermal issues because of the diode’s relatively high forward voltage drop. An improved method uses a metal-oxide semiconductor field-effect transistor (MOSFET) with a lower voltage drop than diodes to overcome the high-power loss.
Additionally, solar optimizers can now support higher input voltages – up to 150V transient with two PV panels in series – thanks to the efficiency improvements gained by lower conduction losses for a given power level, and lower system costs. In this article, we’ll discuss a scalable bypass circuit solution using a floating-gate ideal diode controller. This circuit addresses challenges related to bypass switches with wide voltage support in solar power applications such as solar power optimizers, rapid shutdown and PV junction boxes.
Figure 1 illustrates a PV system with a solar power optimizer installed on an individual PV panel.
Think of a power optimizer as a compromise between a microinverter and a string inverter. It is installed on individual solar panels like a microinverter, but its function has nothing to do with converting DC to AC electricity. A power optimizer tracks the maximum power of each solar panel in real time and regulates the output voltage before sending it to the inverter. Therefore, the inverter can process much more electricity. The result is optimized power-yield performance for every single solar panel, regardless of orientation to the sun, shade or even damage to one or more panels. Solar systems with power optimizers installed at each PV panel can be 20% to 30% higher in efficiency compared to one without an individual panel-level optimizer.