Combined Thermofluid and Electromagnetic Optimisation of Stator Vent Cooling

Abstract

A combined electromagnetic and thermal modelling approach has been developed to optimise the design of multiple radial stator vents in an air-cooled, synchronous generator with a power rating of several hundred kVA. An experimentally validated 3-D Conjugate Heat Transfer Computational Fluid Dynamics model has been created and coupled with 2-D Electromagnetic Finite Element Analysis. Correlations between the combined vent width and rotor copper, rotor iron and stator iron losses were derived from the electromagnetic analysis. These correlations were implemented into the optimisation procedure of the parametric thermofluid model. Five parameters: vent locations, widths and the height of a baffle, were optimised simultaneously with the aim of minimising the peak stator winding temperature. The peak stator winding temperature was reduced by 11.1 %. The average stator winding temperature decreased by 6.3 %. To maintain the machine's power output, the removal of active stator material was compensated by increasing the rotor current.

Thermal and Electromagnetic Stator Vent Design Optimisation for Synchronous Generators

“…The optimisation procedure was executed using the ANSYS DesignXplorer feature within Workbench, which can be used to make changes to all aspects of the CFD modelling, including the geometry, mesh and solver settings. Combining all steps of the solution and optimisation process in one software package facilitates the creation of a model robust enough to handle the automatic updates during the optimisation process [24], [25].…”

“…Whilst five geometrical parameters were optimised, numerous variable input parameters were defined to robustly result in high quality meshing and to update the variable copper and stator iron losses according to the electromagnetic modelling results generated in section II. The optimisation methodology is based on the findings in [24] and [25]. The Adaptive Single-Objective optimisation algorithm was chosen for this investigation.…”

Reduced Order Lumped Parameter Thermal Network for Dual Three-Phase Permanent Magnet Machines

“…III. COMPLETE HIGH-ORDER LPTN In general, LPTNs provide a precise temperature estimation with low computational time compared to computational fluid dynamics (CFDs) [11] or finite element (FE) methods [16]. Nevertheless, some LPTN parameters, also known as critical parameters [21], are not easy to be analytically calculated, due to the uncertainty of material properties, and they strongly influence the LPTN accuracy.…”

“…When designing an EM, a complete and multi-physics approach should be considered by including electromagnetic, thermal, and mechanical aspects [9][10][11]. In fact, in modern applications, where high-performance needs to be reached in limited dimensional constraints, there is a drive towards boosted power density, i.e.…”

Challenges and Future opportunities of Hairpin Technologies

“…The electric loading deals with the conductors' current density and thus relies on the cooling system. Hence, today, there is an ever-increasing need of powerful computational tools to analyse complex thermofluid phenomena, innovative cooling systems to increase the current density and new insulation materials to withstand very high temperatures [7]- [8]. On the other hand, there is also interest in exploiting new materials [9] featuring excellent magnetic characteristics to increase the magnetic loading.…”