Investigation on a fully digital control system for synchronous reluctance machines

The authors deal with the fully digital control of synchronous reluctance motors. A control algorithm based on the strategy consisting of keeping constant the d axis component of the stator currents, and controlling the torque by the q axis component of these currents is investigated. The effects of the sampling period, the delay due to computation time and the parameter uncertainties, on the stability and the robustness of the current control, are analysed. It is found that, with the proposed control algorithm, values of the sampling period which are compatible with the use of low cost microcontrollers may be chosen. Digital simulations confirm the theoretical study.