Dynamic modelling and performance prediction of brushless permanent magnet drive systems

Three-phase, trapezoidal-EMF, permanent magnet motors have been developed for many applications. However the design of a drive system often necessitates analysis of its dynamic behaviour, to establish that its performance, in terms of its torque-speed characteristic, torque and speed ripple, current spikes etc. will be acceptable. The simulation model described has the flexibility for modelling quite diverse supply conditions, including PWM or current mode, and back-EMF waveforms, as well as alternative control strategies. When coupled with the finite-element analysis of a motor therefore, from which parameters such as the EMF constant and waveform, winding inductances and a cogging torque function can be generated, the model allows the precise steady-state and transient performance to be predicted