Characterization of the Thermal Performances of Low-Cost Sub-Fractional Horsepower BLDC Claw-Pole Motor Designs

Automotive auxiliary drives often have to operate over a large temperature range, e.g., between -40 and 135 degrees Celcius. Especially for operation at high ambient temperatures, the understanding of their thermal characteristics is highly important as, e.g., the electromagnetic characteristics of permanent-magnets are strongly temperature-dependent. To this aim, this paper investigates the steady-state and transient thermal performances of different low-cost sub-fractional horsepower single-phase BLDC claw-pole motor designs suitable, e.g., for fan applications. Both numerical and experimental analyses are carried out to determine the parameters of a simple thermal equivalent circuit. The studied claw-pole motor designs show similar thermal performances, which allows all of them to be used in an automotive auxiliary drive system.