User Guide

Prerequisite
It is strongly recommended to upgrade to the latest Conext XW+/SW firmware. To find the
latest firmware, go to
https://solar.schneider-electric.com/products/inverterchargers/ >your
product > DOWNLOADS > Firmware.
CAUTION
RISK OF INJURY AND EQUIPMENT DAMAGE
n To prevent battery damage in a micro-grid AC system, always use the latest firmware
available for your inverter.
n If Li-ion batteries are used, ensure they are Listed or certified with a built-in battery
management system (BMS).
Failure to follow these instructions can result in injury or equipment damage.
What is AC Coupling?
When a PV inverter is connected to the AC output terminal of a battery-based inverter, the
system is referred to as an AC-Coupled system. In this configuration, the PV inverter is
exposed to the AC output voltage of the battery-based inverter, which is responsible for grid
forming during off-grid/backup operation. The PV inverter injects power to the critical load
panel and the AC output of the battery-based inverter. The inverters are thus “AC-coupled”
with each other and are able to share PVsolar energy to the required loads.
Figure 1AC-Coupled System Diagram
Main AC Panel
AC Critical Load
Panel
PV Inverters
tuptuO
PVtuptuO retrevnI
W+X
Grid − AC Input 1
XW+ Inverter/Charger
An example of AC Coupling with the Conext XW+ is shown in Figure 1. The PV system is
connected to the grid through the internal relay located on the AC bus inside the Conext
XW+ inverter. This allows power to be produced and supplied or “sold” back to the grid if it
exceeds the power consumed by the critical loads.
When the grid goes out of limits, the Conext XW+ switches to back-up and powers the
critical load panel to support the loads. Thus, the Conext XW+ forms the grid to keep the PV
inverters operating. The Conext XW+ switch over to back-up is almost instantaneous. In
some cases, the PV inverter does not detect the transition and continues to operate without
interruption. If the PV inverter detects the switch over, it will disconnect and will wait 5
minutes before producing power.
976-0240-01-01 Revision G This document is intended for use by qualified personnel 5
Conext XW+/SW Battery Inverters and PV Solutions Guide