Influence of Nonlinear Factors on Thermal Behavior of Self-Ventilated Wound Rotor Synchronous Generator Under Variable-Speed Variable-Frequency Operations

Accurate analysis of the temperature distribution under variable-speed variable-frequency (VSVF) operations is one of the key issues in preventing thermal faults in the self-ventilated wound rotor synchronous generator (WRSG) and ensuring a stable power supply. To address this issue, the thermal behavior of the VSVF WRSG under the influence of nonlinear factors, such as electromagnetic loss, friction loss, air volume, and flow velocity is predicted and analyzed. Finite element electromagnetic models and the 3-D global fluid–thermal coupling model are developed. The influence of VSVF operations on electromagnetic loss, friction loss, air volume, and flow velocity is explored. Further research is conducted on the temperature distribution patterns of WRSG under the combined effect of the above four nonlinear variables, and the generation mechanism and influencing factors of temperature gradient are discussed from multiple perspectives. Finally, the temperature rise experiment is carried out for verification. The research reveals the influencing mechanism of multiple nonlinear factors on the temperature distribution of WRSG under VSVF operations and offers valuable guidance for the global thermal management of the variable-speed electric machine.