Although known and exploited for a long time, wind energy was completely neglected during the industrial era, for the almost exclusive benefit, except hydroelectricity, of fossil fuels.
The kinetic energy of the wind can be directly converted into mechanical energy and be usable for example in old windmills or to operate pumps. But nowadays we transform it into electrical energy by using wind turbines.
The new interest in wind energy since the mid-1970 s is the result of two concerns: first, the protection of the environment and the resulting saving in fossil fuels. On the other hand, the evolution of technologies makes the conversion of this energy more and more profitable and therefore its use becomes economically competitive compared to traditional sources of the same power.
1-Constant speed wind turbine
Wind turbines based on variable reluctance machines also fall under this category of generators.
These mechanical multipliers have the disadvantage of requiring increased maintenance and affect the reliability of the wind turbine. However, for the generation of high power, it is the technology that is used by manufacturers for connection to a medium voltage network.
Connection to the grid
The connection of these turbines to the electrical network requires controlling the frequency of the current generated by them. And you can use Power Electronics and have a set of electronic units that control the electric current to go out with the required frequency. It can also work properly with stand-alone units, i.e. it works as an independent power plant.
Wind turbines are considered as generators of variable power. Connected on an electrical network, wind generators do not impose the amplitude of the voltage and do not regulate not the power-frequency ratio, in other words, they do not participate in system services, and so disturb the stability of networks more than their penetration rate is important. With the use of power electronics, new technologies have appeared to optimize this generation of energy.
The technology inherent in the first category of wind turbines is well mastered. Indeed, it is a technology that has demonstrated the simplicity of installation, reliability, and low cost, which allows the rapid installation of hundreds of kW of wind generation. However, with the very gradual implementation of wind turbine projects whose power is greater than MW, it is variable speed wind turbines that will develop in the future for this range of power generated.
Indeed the latter has several advantages, in particular, better exploitation of the wind energy, the reduction of the oscillations of the couple and the mechanical efforts, and great flexibility as for the connection to the network thanks to the use of total power converters controllable.