OPTIMAL TORQUE OPERATION OF DIGITALLY CONTROLLED PERMANENT-MAGNET SYNCHRONOUS MOTOR-DRIVES

The electromagnetic torque developed in permanent magnetic synchronous motor drives is analysed and discussed accounting for different motor structures. An electromagnetic model has been developed and used in digital control to obtain an optimal torque: maximal mean torque free of pulsation for a given current. This is obtained by imposing a minimised instantaneous current in the motor accounting for actual motor flux distribution which is the cause of torque pulsations. The model uses the finite elements technique to determine the motor parameters and an iterative procedure to predetermine the adequate current reference. Different motor structures have been studied and an experimental verification for one of them is given.