Vector control of synchronous permanent magnet motors including stator iron loss

To achieve high-performance speed control of synchronous permanent magnet motors (PM motors), the influence of iron loss cannot be neglected as it depends on the driving frequency in high-speed operation. This paper presents a voltage equation and the vector control of PM motors including stator iron loss. The stator iron loss is introduced as an equivalent iron loss resistance in voltage equations on the assumption that the iron loss is produced in equivalent eddy current windings on the d-q axis. The effect of the stator iron loss can be represented as equivalent iron loss resistance, which is inserted in series with the exciting inductance. As the d-q axis flux interferes through the equivalent iron loss resistance, the electromagnetic torque is affected by the equivalent iron loss resistance. To achieve vector control, the d-q axis is decoupled by nonlinear control voltages. As a result, the instantaneous torque control scheme is equal to that of DC machines and the torque control is simplified. The useful features and validity of the proposed control method are confirmed by computer simulations.