Development of Commutation Technology for In-vehicle DC Motor Directly Driven by 42V Vehicle Battery

For DC brush motors directly driven by 42V vehicle battery, carbon brush deterioration due to high voltage arc is a major factor to determine motor life [1]. The brush deterioration is significant especially in multipolar motors with lap-wound armature because they allow a large circulating current to flow into their brushes and it decreases commutation performance [2], [3], [4]. In this report, we propose 1) a new brush material capable of preventing brush deterioration even under high-voltage conditions and 2) a new winding method to minimize circulating current under electromagnetic polarization and to suppress high-voltage arc. With each of these new technologies, DC brush motor driven by 42V battery can operate longer than that driven by 14V battery.