CONTROL SCHEME OF A PERMANENT-MAGNET SYNCHRONOUS MACHINE-DRIVE

Among the different types of variable speed or position drives, the permanent-magnet synchronous motor, fed by a semiconductor inverter is applied increasingly for different applications on aircraft technology, information techniques and industrial automation. This paper examines the operational characteristics of conventional permanent-magnet synchronous motor supplied via a three-phase transistor inverter. The characteristics of the. machine depends largely on its feeding scheme. These may be current or voltage supply. Here a current source with a linear smoothing inductor or a voltage source with a voltage smoothing circuit are used. The control strategy of the studied system is based on the control of the machine phase current in order to have the machine phase angle in a permissible limit and to minimize the torque pulsation. The inverter drive signals are synchronized to the rotor position using a simple position detector so that synchronism between feed currents and the rotor flux is ensured for any speed. The system and its control scheme are simulated in Basic using pc-158 microcomputer of Zenith Data system. The simulation algorithm which is given in the paper is simple and can easy changed for any voltage wave form source or for current source.