Particle swarm optimisation in efficiency improvement of vector controlled surface mounted permanent magnet synchronous motor drive

Application of particle swarm optimisation (PSO) in efficiency optimisation of vector controlled surface mounted permanent magnet synchronous motor (PMSM) drive is presented in this study. Analytical expressions for the controllable electrical loss in PMSM are derived and optimised through control of direct axis (d-axis) stator current, according to the desired speed of operation and load torque. The optimal value of d-axis current has been obtained through analytical method as well as through PSO. The motor efficiency is maximised by using the optimal d-axis current to minimise the air gap flux, resulting in reduction of the core losses, especially at light load conditions. The robustness of the efficiency optimisation algorithms are demonstrated through parametric sensitivity analysis. Implementations of efficiency optimisation algorithms are carried out in Matlab and the performance of PMSM drive is described under steady state as well as transient operating conditions. The effect of efficiency optimisation algorithms in different region of operation of PMSM such as constant speed-variable load torque and constant torque-variable speed modes are described.