A Simple Bipolar Transistor-Based Bypass Approach for Photovoltaic Modules

Abstract

This paper presents a novel bypass approach for photovoltaic panels relying on a bipolar transistor operated in saturation, the activation of which is handled automatically by a circuit comprising a pair of MOS transistors only. The functioning principle of the proposed system is explained and the improvements in terms of reliability of the bypassed subpanel and power produced by the string in comparison with a traditional diode-based scheme are quantified. The analysis is corroborated by dc/transient measurements and tailored PSPICE simulations.Index Terms-Active bypass, bypass diode, one-diode equivalent circuit, hot spot, photovoltaic (PV) panel, shading.

Accurate Maximum Power Tracking in Photovoltaic Systems Affected by Partial Shading

“…Equation (2), however, does not account for the voltage drop across conducting bypass diodes [15,16]. In the previous example, indeed, the actual MPP2 is lower than the one given by (2) with the forward voltage across the conducting bypass diode (about 0.7 V), must be considered.…”

Single-Panel Voltage Zeroing System for Safe Access on PV Plants

“…First, the bypass power diode D [22] allows continuous flowing of the string current even when the MOSFET is OFF (conversely, it is reverse biased when the MOSFET is ON); hence, continuous power delivering from the string is guaranteed when, for some reasons (for example, because the solar panel has been recognized as malfunctioning or for reconfiguration purposes), just one solar panel requires disconnection. Second, as already said, the harvesting circuit, providing power supply for all sections of the electronic board, is connected to the internal terminals of the For applications to safety the correct operation of the disconnection MOSFET is of paramount importance; its reliable behavior is evidenced in Fig.…”

A wireless controlled circuit for PV panel disconnection in case of fire

“…The MOSFET is driven by a microcontroller which receives remote commands sent via a WiFi network. During normal operation the MOSFET is in the on state and offers a series resistance of only few milli Ohms [4], thus conduction losses are fully negligible. When an alarm signal is sent the MOSFET is pushed in an open circuit condition while the relays is short circuited.…”

“…Active by pass devices [4,5], which are three terminal electronic devices that can be used instead of the conventional two terminal by-pass diodes, to reduce dissipated power, could be used as well but require special driving schemes. In a recent paper [6] features which should be accomplished by a reliable firefighter safety system have been revised and discussed according to the German Association for Electrical, Electronic & Information Technologies (VDE) application guide "VDE-AR-E 2100-712:2013-05 [7].…”