NMOS-Based Integrated Modular Bypass for Use in Solar Systems (NIMBUS): Intelligent Bypass for Reducing Partial Shading Power Loss in Solar Panel Applications

Abstract

NMOS-based Integrated Modular Bypass for Use in Solar systems (NIMBUS) is designed as a replacement for the traditional bypass diode, used in common solar panels. Because of the series connection between the individual solar cells, the power output of a photovoltaic (PV) panel will drop disproportionally under partial shading. Currently, this is solved by dividing the PV panel into substrings, each with a diode bypass placed in parallel. This allows an alternative current path. However, the diodes still have a significant voltage drop (about 350 mV), and due to the fairly large currents in a panel, the diodes are dissipating power that we would rather see at the output of the panel. The NIMBUS chip, being a low-voltage-drop switch, aims to replace these diodes and, thus, reduce that power loss. NIMBUS is a smart bypass: a completely stand-alone system that detects the failing of one or more cells and activates when necessary. It is designed for a 100-mV voltage drop under a 5-A load current. When two or more NIMBUS chips are placed in parallel, an internal synchronization circuit ensures proper operation to provide for larger load currents. This paper will elaborate on the operation, design and implementation of the NIMBUS chip, as well as on the first measurements.

Techniques to Mitigate Problem of Partial Shading and Soiling on PV Module: A Review

“…In [26], bypass diode is replaced with NMOS-based Integrated Modular Bypass (NIMBUS). NIMBUS is a smart switch that detect a failing cell when subjected to shading, and then activated upon requirement.…”

“…NIMBUS is a smart switch that detect a failing cell when subjected to shading, and then activated upon requirement. It has small losses attached to them as compared to conventional diode [26]. Such switches can be combined together in parallel in order to handle larger current than that could be handled by single NIMBUS [26].…”

“…It has small losses attached to them as compared to conventional diode [26]. Such switches can be combined together in parallel in order to handle larger current than that could be handled by single NIMBUS [26]. The optimum number of cells are grouped together, and with buck converter in place current is increased whenever there is a shade for a particular group [27].…”

Switch for the Optimization of Module Power by Reconfiguration of All Strings (SOMBRA): An Insulated Integrated Switch for a Reconfigurable Solar Panel

“…The bypass, albeit most likely a Schottky diode, will itself consume a few watts of power. This can be avoided by using a more intelligent implementation of the bypass diode: a low-ohmic switch with control logic to let it act as a bypass diode [7,8]. A second and more important shortcoming is the fact that when a substring is bypassed, any power that may be generated in this substring is completely lost.…”

The Improvement of Solar Cell Output Power Using Cooling and Reflection from Mirror

“…Figure 1 shows the schematic picture of solar cell and solar module. The solar module is a combination of several solar cells parallelysor serially connected with bypass diodes or blocking diodes [12], [13]. The shadow from trees, building, cloud, dirt and leaves may decrease the output power [14].…”