Optimization of Stator Winding Turn Numbers for EV Tap-Change PMSM According to Driving Cycles

Driving cycles are used to test the fuel economy and driving range of the electric vehicle propulsion motor and inverter on dynamometer. For a longer driving range, the propulsion motor and inverter need high efficiency at the driving cycle’s frequent speed and torque points. In this paper, tap-change PMSM (Permanent Magent Synchronous Motor) is studied as an electric vehicle propulsion motor for a better efficiency with two driving cycles: UDDS and HWFET. They have different high energy demand drive speeds which are 3krpm and 7krpm. With energized stator winding selection, tap-change motor high efficient regions can be adjusted to the each high energy demand drive points of UDDS and HWFET. Thus the designed tap-changes PMSM winding turn numbers are selected to minimize the motor copper loss and inverter loss at both driving cycles high energy demand drive speeds. The designed tap-change motor is implemented by rewinding a mass produced PMSM for a electric vehicle. By comparison experimental results of the motor and inverter loss with the mass produced PMSM, the designed tap-change one has a 1.63% energy efficiency improvement according to combined driving cycles.