A computationally efficient loss prediction method for PWM VSI driven PM machine over full working conditions

摘要

This paper presents a computationally efficient method to calculate the electrical machine electromagnetic (EM) losses under any working point, where the current harmonics introduced by the PWM voltage source inverter (VSI) are also taken into consideration. The working point of PWM VSI is derived from the given machine working point. After that, based on machine equivalent circuit model, the analytical expression for all winding current harmonics is derived through the Fourier transform. Finally, the machine AC copper loss, core loss, and PM loss are evaluated through proposed simplified loss models. To verify the proposed method, the calculated winding current and voltage are compared with the experimental results and the EM losses are analyzed based on the results obtained through the finite element analysis. The proposed method eliminates the need for loss table and establishes an analytical relationship between working point and various EM losses which enables fast online loss prediction.