Temperature evaluation of traveling-wave ultrasonic motor considering interaction between temperature rise and motor parameters

• The proposed model differs from the previous models with constant parameters.
• The interaction between the temperature variation and motor parameters is considered.
• This model was verified by comparing the predicted temperatures with the measured one.
• This model has more accurate predicted temperature.
• This model is important to reduce the heat loss, improve the design, control and reliability life of TWUSM.

In this paper, a novel model for evaluating the temperature of traveling-wave ultrasonic motor (TWUSM) is developed. The proposed model, where the interaction between the temperature rise and motor parameters is considered, differs from the previous reported models with constant parameters. In this model, losses and temperature rises of the motor were evaluated based on the temperature-related varying parameters: the feedback voltage Vaux of the stator, dielectric permittivity ɛ and dielectric loss factor tan δ. At each new temperature, Vaux, ɛ and tan δ were updated. The feasibility and effectiveness of this proposed model was verified by comparing the predicted temperatures with the measured one. The effects of driving voltage, driving frequency and ambient temperature on the predicted temperature were also analyzed. The results show that the proposed model has more accurate predicted temperature than that with constant parameters. This will be very useful for the optimal design, reducing the heat loss, improvement of control and reliability life of TWUSM.