2004 Toyota Prius electric motor simulation using
This example presents the analysis of the 2004 Toyota Prius traction electrical motor using
The 2004 Toyota Prius has a 8-pole permanent magnet motor with interior magnets. The single layer windings are made of 3 phases. The stator has 48 slots. The motor can deliver a maximum torque of 400 Nm and a peak-power output of 50 kW over the speed range of 1200–1540 rpm. The detailed design data of the motor can be found in the corresponding simulation file provided together with
Figure 1 shows the RMS line-to-line back-EMF vs. rotor speed obtained using the D-Q Analysis of
click to view larger image
Figure 1. Simulated RMS line-to line back-EMF vs. rotor speed.
Figure 2. Measured back-EMF vs. rotor speed.
The back-EMF waveform at 3000 rpm computed using a series of magnetostatic simulations for different rotor positions is shown in Figure 3. The measured back-EMF waveform at the same rotor speed found in  is presented in Figure 4.
Figure 3. Simulated line-to-line back-EMF waveform at 3000 rpm.
Figure 4. Measured line-to-line back-EMF waveform at 3000 rpm.
To obtain the torque characteristics vs. advance angle the locked rotor test was performed and the measured results are presented in . Since the torque does not depend on speed, the D-Q Analysis of
Figure 5. Simulated torque vs. advance angle curves at various currents.
Figure 6. Measured torque vs. electrical angle curves at various currents.
The further analysis determined that the current value of 216 A is required to generate the Prius motor maximum torque of 400Nm. As it can be seen from Figure 7 the advance angle for the maximum torque is 50 electrical degrees.
Figure 7. Simulated torque curve with magnet and reluctance torque components vs. advance angle at 216 A.
Once the maximum torque current and advance angle are determined the torque-speed characteristic and some other important parameters of the Prius motor can be obtained using the D-Q Analysis of
The efficiency map of the Prius motor computed using the D-Q Analysis of
Figure 8. Simulated torque-speed and other characteristics for the maximum torque operation.
Figure 9. Maximum torque-speed performance specifications for the Prius motor found in .
Figure 10. Simulated efficiency map of the Prius motor.
Figure 11. Measured efficiency map of the Prius motor.
Finally, the dynamic finite element simulation of the motor driven from a three-phase voltage inverter at a fixed rotor speed of 1200 rpm was performed. The current hysteresis control was applied to provide the maximum torque operation at 216 A and advance angle of 50 electrical degrees. The resulting current, phase voltage and torque waveforms are shown in Figure 12, the time-averaged quantities are presented in Figure 13. The instantaneous flux density distribution of the Prius motor is shown in Figure 14.
Figure 12. Simulated current, phase voltage and torque waveforms at 1200 rpm.
Figure 13. Dynamic FE simulation time-averaged quantities.
Figure 14. Instantaneous flux density distribution of the Prius motor.
 J.S. Hsu, C.W. Ayers, C.L. Coomer, R.H. Wiles, T. A. Burress – REPORT ON TOYOTA/PRIUS MOTOR TORQUE CAPABILITY, TORQUE PROPERTY, NO-LOAD BACK EMF, AND MECHANICAL LOSSES, Oak Ridge National Laboratory, ORNL/TM-2004/185
 J.S. Hsu, S.C. Nelson, P.A. Jallouk, C.W. Ayers, R.H. Wiles, S.L. Campbell, C.L. Coomer, K.T. Lowe, T.A. Burress – REPORT ON TOYOTA PRIUS MOTOR THERMAL MANAGEMENT, Oak Ridge National Laboratory, ORNL/TM-2005/33
 R.H. Staunton, C.W. Ayers, L. D. Marlino, J.N. Chiasson, T.A. Burress – EVALUATION OF 2004 TOYOTA PRIUS HYBRID ELECTRIC DRIVE SYSTEM, Oak Ridge National Laboratory, ORNL/TM-2006/423