alternative energy in power electronics pdf

The Kyoto agreement on global reduction of greenhouse gas emissions has
prompted renewed interest in renewable energy systems worldwide. Many
renewable energy technologies today are well developed, reliable, and cost
competitive with the conventional fuel generators.

The cost of renewable energy technologies is on a falling trend and is expected to fall further as demand and production increases. There are many renewable energy sources (RES) such as biomass, solar, wind, mini hydro and tidal power. However, solar and wind energy systems make use of advanced power electronics technologies and, therefore the focus in this chapter will be on solar photovoltaic and wind power.

One of the advantages offered by (RES) is their potential to provide sustainable electricity in areas not served by the conventional power grid. The growing market for renewable energy technologies has resulted in a rapid growth in the need of power electronics. Most of the renewable energy technologies produce DC power and hence power electronics and control equipment are required to
convert the DC into AC power.

Inverters are used to convert DC to AC. There are two types of inverters:
(a) stand-alone or (b) grid-connected. Both types have several similarities but are different in terms of control functions. A stand-alone inverter is used in off-grid applications with battery storage. With back-up diesel generators (such as photovoltaic (PV)/diesel/hybrid power systems), the inverters may have additional control functions such as operating in parallel with diesel generators
and bi-directional operation (battery charging and inverting).

Grid interactive inverters must follow the voltage and frequency characteristics of the utility generated power presented on the distribution line. For both types of inverters, the conversion efficiency is a very important consideration. Details of standalone and grid-connected inverters for PV and wind applications are discussed in this chapter.