Hybrid inverter power control system for PV string, battery, grid and back-up loads

摘要

A string inverter for use with a photovoltaic array includes a string-level DC input channel for receiving DC power from a photovoltaic array. The input channel performs channel-level maximum power point tracking. An input-output channel connects the string inverter to a battery pack. A DC to DC buck-boost circuit between the at least one DC input channel and the at least one input-output channel prevents more than a predetermined amount of DC voltage from reaching the battery pack. A DC to AC inverter circuit having an AC output serving as an output of the string inverter. A revenue grade power meter is configured to measure the AC output of the string inverter.

主权项

1. A string inverter for use with a photovoltaic array and configured to supply power to one or more back-up loads, the string inverter comprising:
at least one string-level DC input channel for receiving DC power from a photovoltaic array, wherein the at least one input channel performs maximum power point tracking; at least one input-output channel for connecting the string inverter to a battery pack; a DC to DC buck-boost circuit coupled between the at least one string-level DC input channel and the at least one input-output channel for preventing more than a predetermined amount of DC voltage from reaching the battery pack; a DC to AC inverter circuit having an output terminal; a revenue grade power meter configured to measure an AC output of the string inverter provided on the output terminal; and a switch controlling a flow of power from the string inverter to the one or more back-up loads, the switch being a three-position switch, wherein in a first position, AC power is permitted to flow from the string inverter to a load side of a customer utility meter and the one or more back-up loads, in a second position, power is permitted to flow from the load side of a customer utility meter to the one or more back-up loads bypassing the string inverter with inverter output disabled, and in a third position, all circuits tied to the string inverter's output are electrically disconnected from the string inverter.