Eureka! Institutional Repository

The present thesis, studies the Maximum Torque Per Ampere (MTPA) control technique, for driving a Permanent Magnet Synchronous Machine. System’s implementation developed in simulation environment and the type of motor used, is Interior Permanent Magnet (IPM). The IPM machines are used in a wide range, due to their efficient performance in terms of power density, power losses and power factor. By applying the MTPA technique, motor’s performance improves, as power losses are reduced. The MTPA algorithm adjusts the engine speed in a way, that time responses are immediate and also calculates the minimum current needed to achieve the requested speed, considering the load that is applied to the shaft. Although the motor uses less current in its windings, which is the reason that it reduces copper losses, it maintains its performance. Another feature of IPM motors, is the saliency effect that happens in the air gap. The MTPA technique takes advantage of this feature, in order to succeed the requested torque values, with the lowest possible current consumption. The greater the saliency effect, the more obvious the benefits of the MTPA technique. Due to the MTPA’s algorithm complexity, the speed controller wasn’t developed by the standard method of transferring equations, because it demands a lot of computational resources. The situation above, is optimized by using Look Up Tables into the controller’s circuits, in order to release some of the computational resources. The MTPA technique is applied to systems where the low power consumption is on high priority, or autonomous systems where batteries are required. All of the above statements are confirmed by the analysis in the theoretical part and the results of the experiments carried out.