Influence of Hotspot Temperature in End Region on Power Regulation Capability of AC-Excited Generation-Motor

An AC-Excited Generator-Motor (ACEGM) is widely used in the variable speed pumped storage power station due to its flexible and powerful power regulation capability. However, the power regulation range can be restricted by the hotspot temperature in the end region of the ACEGM. In order to study the temperature distribution laws of the stator and rotor end structural components, a three-dimensional electromagnetic- fluid-thermal coupling model in the end region of the ACEGM is established. The flux densities, losses and temperatures in the end core, tooth plate, stator clamping plate and rotor retaining ring are studied under the different operating conditions. Through thermal analysis, the hotspot location in the stator and rotor end regions has been pinpointed. The hotspot temperature variations in the stator and rotor end regions along with the changes of the active and reactive powers are studied. The power regulation range of the ACEGM is determined by the thermal limits of the stator and rotor end components. The study can provide a theoretical foundation for optimizing the stator and rotor end-region structures and enhancing the power regulation capability of ACEGMs.