1 Introduction

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.