Improving Thermal Analysis Accuracy of LPTN for Vehicle Claw-Pole Alternator by Calibrating Forced Convection Coefficients Based on Experimental Results

Claw-pole alternators are particularly important for vehicle power generation due to their low cost, simple design, and mechanical robustness. High and low temperatures around vehicle claw-pole alternators (VCPAs) change their internal temperature distributions, thus thermal analysis is required for designing VCPAs. Aiming at improving the accuracy of evaluating the temperature of VCPAs, a novel lumped parameter thermal network (LPTN) is proposed to analyze the steady-state temperature of a double excitation VCPA under various ambient temperatures. The forced convection coefficients are calibrated in order that the LPTN can simulate the real heat transfer of the VCPA. The nonlinear least square method is applied to obtain the calibrated coefficients within a range of the tested ambient temperatures. Moreover, the effectiveness of the proposed method is verified via simulation studies, whereby the results show that the proposed LPTN with calibrated convection coefficients can accurately evaluate the temperature of VCPAs. Finally, these results soundly supply the technical knowledge for the thermal analysis and facilitate selecting the optimal scheme for machine designers.