Coupled Airflow-Thermal Network Model for Large-Scale Offshore Wind Generators With Modular Fractional-Slot Concentrated Winding

The high cost and capacity of offshore wind generators require optimized generator structure and performance. This paper develops a generator with modular fractional-slot concentrated winding and uses a coupled airflow-thermal network model for design optimization. This is a direct-driven permanent magnet generator, and the airflow-thermal network model using lumped parameter method is described in detail. Sensitivity analysis is performed to show the effects of key parameters on the generator flow and thermal performance. Finally, a 3.3 MW prototype is developed for experimental tests. Comparative studies are performed for the computational fluid dynamics simulation method, the airflow-thermal network model, and the prototype experiments. It is shown that the coupled airflow-thermal network model is applicable to large scale wind generators with modular fractional-slot concentrated winding, and is preferable to future offshore wind power engineering.