Introduction

Everyone uses some kind of electronic gadget while in their motor-home, SUV or car. You might listen to your MP3 player, check for directions on your global positioning system (GPS) or play a portable video game. These types of electronic devices can be recharged or powered by plugging them into the cigarette lighter (or power port) in your vehicle.

But what if you want to use something a little more elaborate while you're on the open road? Maybe you want to make toast, watch an LCD TV, or perhaps even write an article on your laptop computer. These devices plug into regular wall outlets, not cigarette lighters. Making sure your electronic gear gets the juice it needs while on the road isn't a simple matter of finding the right adapter. You need a power inverter.

A solar inverter, or PV inverter, converts the variable direct current (DC) output of a photovoltaic (PV) solar panel into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or used by a local, off-grid electrical network. It is a critical component in a photovoltaic system, allowing the use of ordinary commercial appliances. Solar inverters have special functions adapted for use with photovoltaic arrays, including maximum power point tracking and anti-islanding protection.

Classification

Solar inverters may be classified into tow broad types:

* Stand-alone inverters, used in isolated systems where the inverter draws its DC energy from batteries charged by photovoltaic arrays. Many stand-alone inverters also incorporate integral battery chargers to replenish the battery from an AC source, when available. Normally these do not interface in any way with the utility grid, and as such, are not required to have anti-islanding protection.

* Grid-tie inverters, which match phase with a utility-supplied sine wave. Grid-tie inverters are designed to shut down automatically upon loss of utility supply, for safety reasons. They do not provide backup power during utility outages.

Grid tied solar inverters

Solar grid-tie inverters are designed to quickly disconnect from the grid if the utility grid goes down. This is an NEC requirement that ensures that in the event of a blackout, the grid tie inverter will shut down to prevent the energy it produces from harming any line workers who are sent to fix the power grid.

Grid-tie inverters that are available on the market today use a number of different technologies. The inverters may use the newer high-frequency transformers, conventional low-frequency transformers, or no transformer. Instead of converting direct current directly to 120 or 240 volts AC, high-frequency transformers employ a computerized multi-step process that involves converting the power to high-frequency AC and then back to DC and then to the final AC output voltage.

Historically, there have been concerns about having transformerless electrical systems feed into the public utility grid. The concerns stem from the fact that there is a lack of galvanic isolation between the DC and AC circuits, which could allow the passage of dangerous DC faults to be transmitted to the AC side.

Many solar inverters are designed to be connected to a utility grid, and will not operate when they do not detect the presence of the grid. They contain special circuitry to precisely match the voltage and frequency of the grid.

Solar charge controller

A charge controller may be used to power DC equipment with solar panels. The charge controller provides a regulated DC output and stores excess energy in a battery as well as monitoring the battery voltage to prevent under/over charging. More expensive units will also perform maximum power point tracking. An inverter can be connected to the output of a charge controller to drive AC loads.

Type of Inverters

ABB offers one of widest portfolio of solar inverters ranging from small micro-inverters and three-phase string inverters up to megawatt-sized central inverters. This extensive range of solar inverters is suitable for the smallest residential photovoltaic (PV) systems right up to multi-megawatt PV power plants. The offering is complemented by various monitoring solutions as well as a global service network to maximize the return on your investment.

ABB solar inverters utilize over 40 years of experience and advances made in inverter and power converter technology that have contributed to ABB becoming the world leader in frequency converters, and also one of the largest suppliers of wind turbine converters.

When it is time for you to specify a solar inverter for your PV project, ABB, as one of the world’s leading power and automation technology companies, has very strong credentials to fulfill your requirements for years to come. This trust should help you to comfortably conclude that ABB is a truly bankable choice in solar inverters.

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