A Short Introduction to Grid Tie Inverters

Jan 25
10:32

2010

Rupert Smith

Rupert Smith

  • Share this article on Facebook
  • Share this article on Twitter
  • Share this article on Linkedin

This article will supply the reader with the most important information regarding grid tie inverters, what they do, and how they can be purchased.

mediaimage

Grid tie inverters,A Short Introduction to Grid Tie Inverters Articles or GTIs, are a special type of DC to AC power inverter which are used primarily in renewable energy applications. They are often used to feed power into the utility grid which can then be sold to the electric company. For example, if during a certain month a GTI system feeds 500 kilowatt hours into the utility grid, and of these hours 100 are used, they would receive a compensation for the 400 additional hours. The policies regarding this system of ‘net metering’ differ depending on your geographical location and the jurisdictions therein.

There are actually several different types of grid tie inverters on the market today and each of them uses different types of technology. These days they may use the newest high frequency transformers, more common low frequency transformers, and some don’t use transformers at all. The high frequency models take advantage of a computerized process that contains several different steps to convert the power to high frequency AC, back to DC, and then to AC again at the required output voltage. The process by which these highly technical machines work is complicated, but with the help of a schematic drawing it can be understood.

On the other hand, grid tie inverters which do not use transformers are often more light weight and work at a higher efficiency than those that do. As a result they happen to be more popular in Europe. However, they have not witnessed the same amount of popularity in the United States. This is largely due to the fact that laws in the country required all solar powered electric systems to be negative grounded, which is a configuration that is impossible with transformerless converters. There is also a risk when feeding power created by transformerless grid tie inverters into the power grid because the energy is not as stable and could cause problems.

Before purchasing grid tie inverters, there are several issues that you must keep in mind:

• Rated output power – provided in either watts or kilowatts, this figure provides an output rating for different voltages of output. • Peak efficiency – tells you the highest level of efficiency that the device can achieve. • Maximum input current – the maximum amount of direct current that the device will use. • Start voltage – is a value that is not always listed on data sheets. It tells you the minimum DC voltage required for the device to turn on and begin working. • NEMA rating – tells you how much protection the device has against water.

When you are in the market for grid tie inverters, one company you should consider is Enphase. This company offers a wide variety of these devices, especially suited towards solar panel systems. They can be expensive, but when you shop around you are often lucky enough to find them at a discount.