Flux Weakening Control of Permanent Magnet Synchronous Motor with Losses Reduction

Permanent magnet synchronous motors (PMSM) are used in electric locomotives, electric buses, electric cars, etc. Torque vector control strategy by flux weakening is widely used for PMSM. A flux weakening effect of PMSM is described in this paper that is implemented by increasing negative value of flux producing current component at speed value lower than nominal. The main goal of experiment was to find optimal values of that current component in order to ensure the highest efficiency and the smallest losses of motor. By setting the negative value of flux producing current component the losses are reduced. The experiments were carried out using different values of motor speed and torque producing current component. Experiment results showed that with increasing negative value of flux producing current component input power is reduced and efficiency increased consequently.