Thermal Calculation of a New Synchronous Generator Design with Transverse Flux

Electric machines with transverse flux are mainly used in low-speed electric drive applications, in particular, for wind turbines and vehicle propulsion systems. Owing to its possibility to produce higher torque densities, the design of transverse flux electric machines is seen as a promising option for decentralized wind energy. The article presents a calculated assessment of the thermal state of the 5 kW transverse flux synchronous generator with excitation from permanent magnets of a new patent-protected design with a double stator located on one side of the rotor. The values of the machine housing heat transfer coefficients are specified according to the product of the Grashof and Prandtl criteria for both a single-phase module and a three-phase machine. The average values by which the temperatures of the cooling surfaces, stator winding and rotor disk exceed their standardized levels were calculated using the dependence between similarity criteria. Full 3D models of the single-phase module and three-phase generator with transverse magnetic flux are developed. The 3D simulation results have confirmed the correctness of the thermal state assessment of the new design, obtained using the dependence between the similarity criteria.