Stator Current Vector Determination Under Consideration of Local Iron Loss Distribution for Partial Load Operation of PMSM

Iron losses have a large share in the overall losses of high power density electrical machines operating as variable speed drives. Especially in the partial load area, the ratio of iron losses is dominant with respect to the copper losses. Therefore, commonly used control strategies, such as maximum torque per ampere or maximum torque per voltage, aiming at minimizing the current for given restrictions as the maximum voltage do not select the best direct and quadrature currents to maximize the efficiency or minimize the overall losses at each operating point. This paper elaborates a stator current vector determination strategy considering the iron loss distribution at all operating points, comparing different iron loss models in a machine with distributed windings. Depending on the operating point and the operational conditions of the machine, the overall losses can be reduced up to 7%.