Interior permanent magnet synchronous motors: Impact of the variability of the parameters on their efficiency

In the scientific literature, various authors presented different control strategies aimed to increase the efficiency of the interior permanent magnet synchronous motors. These strategies, starting from a well-known mathematical model of the dynamic behaviour of the motor, are able to reduce the power losses acting on the magnetizing component of the stator current. However, none of the proposed approaches takes into account that, varying the working conditions of the motor, also the values of the parameters, which have an impact on the power losses, can vary. In this paper, therefore, starting from an accurate measurement of the motor characteristics for various values of speed and load, we present a new control strategy, which, by taking into account the variability of the motor parameters, allows a more efficient reduction of the motor power losses. In order to validate the model, the values of the power losses obtained by using the model are compared with the values obtained by experimentally measuring the power losses.