Report on Toyota/Prius Motor Torque Capability, Torque Property, No-Load Back EMF, and Mechanical Losses, Revised May 2007

Electromagnetic Analysis and Design Methodology for Permanent Magnet Motors Using MotorAnalysis-PM Software

“…Initial design assumptions include the choice of outer or inner rotor topology, rated current or current density, rated voltage, power and torque, corner speed, materials, size and weight requirements. Table 2 shows the basic specifications of the Toyota Prius 2004 motor used for this analysis [19][20][21].…”

Simplified Thermal Model of PM Motors in Hybrid Vehicle Applications Taking into Account Eddy Current Loss in Magnets

“…In order to analyze oil cooled motors, the thermal conductivity of the air gap assumed as a constant value, one equivalent air gap resistance can be calculated considering the air gap equal to a cylinder. Reference [Hsu et al, 2005] shows that the thermal conductivity of Toyota Prius traction motor is 10 W/m-°C based on the oil and air convective mixture. In this case, the simpler expression for deriving the air gap thermal resistance is given as follows: where r magnet the outer magnet radius; r is the inner stator radius; k ag thermal conductivity of the air gap.…”

Evaluation of 2004 Toyota Prius Hybrid Electric Drive System

“…Additional information about the capabilities and properties of the 2004 Prius are presented in a separate ORNL report [2].…”

“…Additional details about the design and manufacture of the motor are contained in a report that was recently published by ORNL [6]. Supplementary information about locked rotor torque and current performance, which is addressed in Section 3.2.1, is contained in another ORNL report [2].…”

“…A series of locked rotor tests [2] were performed in 2004 and 2005 to determine the general operating capabilities of the traction motor. The 2005 test used a new mechanical-gear mechanism capable of precisely positioning and locking the rotor based on readings from the absolute position sensor in the Prius.…”