Distributed inverter and intelligent gateway

Abstract

A system and method for converting DC from one or more sources to AC power utilizing a novel partitioning scheme are disclosed. This partitioning scheme is particularly well suited for photovoltaic (PV) microinverter applications. The primary goals are to make installation, operation and maintenance of the system safe and simple. Secondary goals are to improve reliability and lifetime of the converter in a cost effective manner. In one embodiment, the microinverters are placed in one-to-one proximity with the photovoltaic modules, each proximate microinverter incorporating a reduced number of functions and components. Remaining common functions and controls are implemented separately.

Description

[0001]The present application relates to and claims the benefit of priority to U.S. Provisional Patent Application No. 60 / 938,663 filed May 17, 2007, which is hereby incorporated by reference in its entirety for all purposes as if fully set forth herein. The present application is further related to co-pending U.S. patent application Ser. No. LAR004 entitled, “Photovoltaic AC Inverter Mount and Interconnect” and U.S. patent application Ser. No. LAR003 entitled “Photovoltaic Module-Mounted AC Inverter”, both of which are hereby incorporated by this reference in their entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to power conversion including direct current (DC) to alternating current (AC) and, more particularly, to photovoltaic module output power conversion to AC.[0004]2. Discussion of the Related Art[0005]In coming years, distributed generation of electricity is likely to become a larger and larger part of the energy sourced to utili...

AI Technical Summary

Benefits of technology

[0020]An advantage of the invention is to provide a system and method of installation, operation, and maintenance of the a power conversion system that is simple and safe.

[0021]Another advantage of the invention is to provide a high degree of reliability and a long lifetime to the microinverter.

[0022]Yet another advantage of the invention is to provide upgradeability of the system during the lifetime of the system.

Problems solved by technology

Residential rooftops present a special challenge for the placement and interconnection of photovoltaic modules, due to the presence of gables, multiple roof angles, and other such obstructions.

Such rooftops often do not expose a sufficiently large, commonly directed surface to the sun for photovoltaic modules to be positioned to harvest maximum power.

This degrades the AC power harvest from the entire array.

Commercial buildings and larger installations present slightly different challenges.

In commercial buildings, large, commonly directed surfaces are generally available, but even then, obstructions, such as HVAC components must be dealt with as the components may block solar radiation.

Additionally, since such installations often consist of thousands of PV modules, monitoring, operation and maintenance can be time consuming and expensive.

Yet, the use of microinverters continues to be negligible due to their inferior reliability and efficiency as well as their high cost as compared to conventional inverters.

When microinverters are placed in proximity to PV modules, the hostile outdoor environment exacerbates the design challenge for achieving high reliability, high efficiency and low cost.

Similarly, servicing and replacing microinverters on a rooftop is potentially more challenging and labor intensive than servicing and replacing centralized inverters.

Early versions of related art for microinverters utilized electrolytic capacitors, having a lifespan susceptible to degradation at high temperatures.

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