Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Thermal analysis of a permanent magnet synchronous generator for a 10 MW wind turbine
Submission Author:
Gabriel Fernandes Bravo , SP , Germany
Co-Authors:
Gabriel Fernandes Bravo, Marcos Vinício Oro, Matheus Protasio de Lima, Edson Bazzo
Presenter: Gabriel Fernandes Bravo
doi://10.26678/ABCM.COBEM2021.COB2021-1337
Abstract
The offshore environment provides not only more consistent, stronger, and less turbulent winds with smaller shear but also logistical advantages. Besides, noise and visual problems are avoided, depending on the distance from the coast. Therefore, the use of offshore wind generators has grown over the last few years, and, in this context, direct-drive permanent magnet synchronous generators (DD-PMSG) are an attractive topology, since less maintenance is required, due to gearbox elimination. To ensure that the generator is working safely – mostly because of winding and permanent magnet temperature limits – thermal control is required. Thus, this work presents the thermal behavior analysis of a 10 MW inner rotor DD-PMSG. The main losses - mostly through copper, iron, and magnets - were estimated and used as input data for the lumped parameter model with forced air cooling on the outer surface of the stator, which led to extreme temperatures. Therefore, the cooling strategy was changed for direct and indirect water cooling and simulated for a range of flow rates. Direct cooling consists of water channels inside the winding, which is the main source of energy losses. On the other hand, indirect cooling consists of water channels in the stator yoke above the slot. Mean copper temperature was found approximately 1.5 times higher for indirect cooling, resulting in about a 1% efficiency difference between direct and indirect cooling, which represents a large amount of power for a 10MW generator. Consequently, direct water cooling was found to be more efficient, with over 93% efficiency. Additionally, magnets and winding temperatures were found below 70 °C and 100 °C, respectively, for direct cooling.
Keywords
PMSG, Heat transfer, Lumped Paramenter, wind energy, Direct Drive
