Influence of control strategy on neural point voltage behaviour in permanent magnets synchronous machine

Torque-control systems for inverter-fed permanent-magnet synchronous motors commonly include two or three current-control loops. The options are founded on the fact that the phase currents are linked, or that with floating neutral-point voltage the torque control range can be increased. A comparison is made of the performances and drawbacks of the two solutions in the control-variables limitation range, with perfect loops and in the linear range when loop imperfections are considered