Chapter 4
Modelling of Permanent
Magnet Synchronous Generator
4.1 Overview
The permanent magnet synchronous generator is used in this thesis as wind turbine generator because of their high efficiency, low losses, smaller size, less maintenance, high reliability and the ability to operate without gearbox [33], [34]. The main aspect which distinguishes the Permanent Magnet Synchronous machine from other types of electrical machines is that the rotor magnetic flux is generated by permanent magnets, instead of being supplied by other external power sources as in DC machines and synchronous machines. Therefore, there are no rotor copper losses associated with this type of generator. Another main feature of this type of generator is that it can …show more content…
The generators used for wind turbine applications can be divided into two main groups:
•Synchronous generators (SGs) and
•Asynchronous or Induction generators (IGs)
Synchronous generators can be wound rotor synchronous generator (WRSG) or permanent magnet synchronous generator (PMSG). The PMSG can be designed to have higher number of poles and suitable for direct drive gearless wind turbine applications. Presently, many wind-turbine manufacturers use direct-drive PMSG. A direct drive wind turbine system eliminates gear box, reduces size and costs. However, a direct-drive wind turbine operates at very low speeds 50 to 150 rpm [23].
Asynchronous or induction generators can be squirrel cage type or wound rotor induction generator (WRIG) types. WRIG also known as doubly fed induction generator (DFIG) as it can supply power from stator or rotor in to grid.
4.3 Permanent Magnet Synchronous Generator for Variable Speed Wind …show more content…
This is pronounced in the case of a salient pole PMSG in which the permeances in the two axes (d-axis and q-axis) are significantly different. Even in a non-salient (round rotor) PMSG there are negligible differences in the permeances in the two axes due to the large number of slots associated with the windings. The flux produced by a stator winding follows a path through the stator iron, across the air gap, through the rotor iron, and back across the air-gap. For a sinusoidal distributed winding the stator self-inductances of a PMSG can be expressed as
Modelling of Permanent
Magnet Synchronous Generator
4.1 Overview
The permanent magnet synchronous generator is used in this thesis as wind turbine generator because of their high efficiency, low losses, smaller size, less maintenance, high reliability and the ability to operate without gearbox [33], [34]. The main aspect which distinguishes the Permanent Magnet Synchronous machine from other types of electrical machines is that the rotor magnetic flux is generated by permanent magnets, instead of being supplied by other external power sources as in DC machines and synchronous machines. Therefore, there are no rotor copper losses associated with this type of generator. Another main feature of this type of generator is that it can …show more content…
The generators used for wind turbine applications can be divided into two main groups:
•Synchronous generators (SGs) and
•Asynchronous or Induction generators (IGs)
Synchronous generators can be wound rotor synchronous generator (WRSG) or permanent magnet synchronous generator (PMSG). The PMSG can be designed to have higher number of poles and suitable for direct drive gearless wind turbine applications. Presently, many wind-turbine manufacturers use direct-drive PMSG. A direct drive wind turbine system eliminates gear box, reduces size and costs. However, a direct-drive wind turbine operates at very low speeds 50 to 150 rpm [23].
Asynchronous or induction generators can be squirrel cage type or wound rotor induction generator (WRIG) types. WRIG also known as doubly fed induction generator (DFIG) as it can supply power from stator or rotor in to grid.
4.3 Permanent Magnet Synchronous Generator for Variable Speed Wind …show more content…
This is pronounced in the case of a salient pole PMSG in which the permeances in the two axes (d-axis and q-axis) are significantly different. Even in a non-salient (round rotor) PMSG there are negligible differences in the permeances in the two axes due to the large number of slots associated with the windings. The flux produced by a stator winding follows a path through the stator iron, across the air gap, through the rotor iron, and back across the air-gap. For a sinusoidal distributed winding the stator self-inductances of a PMSG can be expressed as