The current phase angle deduction of IPMSM for the maximum efficiency driving

In this paper, the equivalent circuit of an IPMSM in which the d, q-axis inductance and iron loss are considered is developed. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated. By using the Current Vector Control Test(CVCT), widely used among operation-state tests, and Direct Current Test(DCT) method, widely used among stop-state tests, the inductance was calculated. In addition, the iron loss was measured at the motor, which does not magnetize the permanent magnet, and the mechanical loss was measured at the rated speed. At a fixed torque condition, efficiency of 86.23% was generated and the current phase angle was 10°. The error between the theoretical value of the torque calculated in the equivalent circuit at the maximum operating efficiency and the experimental value was only 2.2%.