Efficiency-optimized variable structure direct torque control for synchronous reluctance motor drives

Abstract EN

Direct torque control (DTC) is known to produce fast response and robust control in ac adjustable-speed drives.

However, in the steady-state operation, notable torque, flux and current pulsations occur.

A new direct torque and flux control strategy based on variable-structure control and space vector pulse width modulation is proposed for synchronous reluctance motor drives considering iron losses.

The DTC transient merits and robustness are preserved and the steady-state behavior is improved by reducing the torque and flux pulsations.

In addition, efficiency optimization strategy is executed by adjusting the amplitude of stator reference flux continuously, independent of drive parameters.

Finally, the validity and capability of the method are verified by simulation and experimental result.