Stator Flux Linkage Control System for Synchronous Reluctance Motors

The article addresses the problem of synthesizing control systems for synchronous reluctance motors (SynRM) and SynRM with excitation from permanent magnets (PMaSynRM), providing specified mechanical characteristics with a minimum stator winding current. A mathematical model of the SynRM and PMaSynRM has been developed in a coordinate system rotating synchronously with the stator flux linkage vector. For electric drives with SynRM and PMaSynRM for a capacity of 78.5 kW, the dependences of the stator winding current on its flux linkage in various operating modes are obtained. It has been found that the greatest effect of reducing the stator winding current is achieved in the area of constant torque at low loads. An increase in temperature does not affect the stator flux linkage that ensures a minimum of the stator winding current in the SynRM, and in the PMaSynRM it results in a slight deviation in the flux linkage, depending on the ratio of the torque active and reactive components. A vector control system with a stator flux linkage control loop has been synthesized. Dependences ensuring the implementation of the specified mechanical characteristics with the lowest possible stator winding current have been obtained. The results of computer simulation of transients in electric drives with the developed control system are presented, which confirm the operability of the proposed solutions. Recommendations on selecting an approach to minimizing the stator winding current depending on the synchronous motor magnetic system type and operating modes are given.