7/29/2019 The Global Electrical Energy Consumption is Rising and There is an Urgent Demand to Increase the Power Capacity

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The global electrical energy consumption is rising and there is an urgen

demand to increase the power capacity. It is expected that the powe

capacity has to be doubled within 20 years. The production, distribution an

use of energy should be as efficient as possible and incentives to sav

energy at the end-user should also be set up. Deregulation of energy has

the past lowered the investment in larger power plants, which means th

need for new electrical power sources will be high in the near future. Tw

major technologies will play important roles to solve the future problem

One is to change the electrical power production sources from th

conventional, fossil (and short term) based energy sources to renewab

energy resources. The other is to use high efficient power electronics i

power generation, power transmission/distribution and end-user applicatio

This paper discuss the most emerging renewable energy sources, win

energy, which by means of power electronics are changing from being

minor energy source to be acting as an important power source in th

energy system. Power electronics is the enabling technology and th

presentation will cover the development in wind turbine technology from kW

to MW, discuss which power electronic solutions are most feasible and use

today. In classical power systems, large power generation plants located a

adequate geographical places produce most of the power, which is the

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transferred towards large consumption centers over long distanc

transmission lines. The system control centers monitor and regulate th

power system continuously to ensure the quality of the power, name

frequency and voltage. However, now the overall power system is changing

a large number of dispersed generation (DG) units, including bot

renewable and non-renewable sources such as wind turbines, wav

generators, photovoltaic (PV) generators, small hydro, fuel cells an

gas/steam powered Combined Heat and Power (CHP) stations, are bein

developed and installed. A wide-spread use of renewable energy sources

distribution networks and a high penetration level will be seen in the nea

future in many places. For instance Denmark has a high power capacit

penetration (> 20%) of wind energy in major areas of the country and toda

18% of the whole electrical energy consumption is covered by wind energy

The main advantages of using renewable energy sources are the eliminatio

of harmful emissions and inexhaustible resources of the primary energy

The availability of renewable energy sources has strong daily and season

patterns and the power demand by the consumers could have a ver

different characteristic. Therefore, it is difficult to operate a power system

installed with only renewable generation units due to the characterist

differences and the high uncertainty in the availability of the renewab

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energy sources. This is further strengthened as no real large energy storag

systems exist. The wind turbine technology is one of the most emergin

renewable energy technologies. It started in the 1980es with a few tens o

kW power capacity to today with multi-MW size wind turbines that are bein

installed. It also means that wind power production in the beginning did no

have any impact on the power system control but now due to their size the

have to play an active part in the grid. The technology used in wind turbine

was in the beginning based on a squirrel cage induction generato

connected directly to the grid. By that power pulsations in the wind ar

almost directly transferred to the electrical grid. Furthermore there is n

control of the active and reactive power, which typically are importan

control parameters to regulate the frequency and the voltage. As the powe

range of the turbines increases those control parameters become mor

important and it is necessary to introduce power electronics [3] as a

interface between the wind turbine and the grid. The power electronics

changing the basic characteristic of the wind turbine from being an energ

source to be an active power source. The electrical technology used in win

turbines is not new. It has been discussed for several years [8]-[98] but no

the price pr. produced kWh is so low, that solutions with power electronic

are very attractive. This paper will first discuss the basic development

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power electronics and power electronic conversion. Then different win

turbine configurations will be explained both aerodynamically an

electrically. Also different control methods will be shown for a wind turbin

They are also now installed in remote areas with good wind conditions (of

shore, on-shore) and different possible configurations are shown an

compared. Finally, a general technology status of the wind power

presented demonstrating still more efficient and attractive power source fo

the future.