The Switched Reluctance Generator for Wind Power Conversion

The use of wind energy has become increasingly important as a renewable energy source, so there is an increasing interest in exploiting it using a Switched Reluctance Machine (SRM).

Introduction

In the last decades, the SRM serves as an important alternative in various applications both within the industrial and domestic markets, as a motor showing good mechanical reliability, high torque-volume ratio and high efficiency,and it is of low cost.Eventhough SRM is easy to build,in the past it was a source of complaints concerning to its dynamic performance and the peculiar characteristics of its command and control.The development of power electronics, and the advancements in the field of semiconductors brought improvements in technology of this kind of machine, leading to the creation of a diversified application of SRMs.The machine has a stator of wound-up salient poles which after energising, synchronized with the position of the rotor, develops a torque that tends to align the poles in such a way that it diminishes the reluctance in the magnetic circuit.

SRG operation

The Switched Reluctance Machine (SRM), seems simple from the construction point of view but it is characterized by a peculiar mode of controlling its phase currents.The reason of its reliability during fault conditions is the electrical independence among phases.The control system of this converter should regulate the magnitude and the waveshapes of the phase currents inorder to fulfil the requirements of torque and output power available, and to ensure safe operation of the generator. This reveales that the electronic switches associated with controller are fully controlled devices.These devices work to invert the voltage applied to the phases in certain angular positions.

Concepts on the conversion of wind energy

The efficient captation of the wind energy, requires the existence of a constant wind flow sufficiently strong. Currently, wind turbines are designed inorder to achieve a maximum power at wind speeds above 10 m/s. If needed, they can be adjusted to the local wind profile.The maximum theoretical efficiency for the wind to energy conversion is 59,3% .

Wind System Simulation

This work analyses two kinds of mechanical coupling of the turbine to the generator which are; the direct coupling to the turbine shaft and the SRG coupling to the turbine shaft through a gearbox.

Conclusion

The SRG is a valid alternative in wind energy applications so, it is reasonable to foresee that in the medium power wind systems, the SRGs allow good performance in extracting the energy carried by the wind.But it is a fact that the SRG is noisier than the other conventional systems.

For more details, refer to the following pdf file;
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