SERVO DRIVE SYSTEM AND CONTROL CHARACTERISTICS OF SALIENT POLE PERMANENT-MAGNET SYNCHRONOUS MOTOR

Permanent magnet (PM) synchronous motors fed by PWM inverters are wide ly used for industrial applications. The PM motors sometimes have a sa liency, in which the q-axis inductance is larger than the d-axis induc tance. This paper describes a high-performance servo drive system of a salient-pole PM motor, in which an armature current vector is activel y controlled according to load conditions in order to use a reluctance torque effectively, and as a result, a large torque can be produced. The control algorithm of the armature current vector is described, tak ing the demagnetization of PM and the magnetic saturation into account . The several characteristics such as torque, power factor, efficiency , power capability, transient responses, and so on are examined in det ail by the computer simulations and experimental results.