Phase-variable model of PM synchronous machines for integrated motor drives

In a phase-variable model of PM synchronous motors and its implementation in integrated motor drive simulations the stator winding inductances and the three-phase flux linkages contributed by permanent magnets are considered as rotor-position dependent. The first-mentioned is calculated by an energy perturbation method using FE solutions, the second is obtained through FE analysis without applying excitation currents. The cogging torque due to slotting is taken into account and is evaluated through FE analysis as well. The proposed phase-variable model is implemented in Simulink in two ways. One is component based, another is equation based. The rotor-position dependence of inductance, the flux linkage due to permanent magnets, and the cogging torque are utilised using a look-up table function. A 2-HP PM synchronous motor is used as an example to examine the model as well as the developed Simulink block. For comparison and verification, the d-q model and the full FE model of the same machine were built to verify the proposed model. The behaviour of these three models is investigated with a vector-control speed regulation system. Simulation results show that the phase-variable model provides the same performance as the full utilisation of FE models but with much faster simulation speed.