Quantitative assessment on synchronisation capability of a line-start permanent magnet synchronous motor with hybrid rotor

The authors devote a quantitative assessment on the synchronisation capability of a line-start permanent magnet synchronous motor (LSPMSM) equipped with a hybrid rotor. The quantitative assessment is realised by determining a load criterion consisting of load torques and inertias under which the motor will just synchronise. During the process of load-criterion determination, close attention is paid to parameters governing the motor synchronisation behaviour. Following the principle of stator-current error minimisation, the time-variant magnetising inductances and permanent magnet (PM) flux linkages of the analysed LSPMSM are simplified into slip-dependent constants via the simple and robust genetic algorithm (GA). The load criterion is then obtained after the establishment of a dynamic motor model involving the simplified parameters. Prototyping tests focused on motor speed-time responses under different mechanical loads are carried out to validate the obtained load criterion and the paper analyses.