Application of Optimal Control for Synchronous Reluctance Machines in Feed Drives of Machine Tools

The demand for cost-effective and ecologically sustainable components of machine tools is increasing continuously. Synchronous reluctance machines (SynRM) have become more and more attractive for variable speed drive applications in recent years due to the absence of permanent magnets. Advanced control approaches such as Linear Quadratic Integral (LQI) controllers or model predictive controllers (MPC) are well explored for permanent magnet synchronous machines (PMSM). This paper simulatively investigates these controllers for a SynRMdriven feed drive axis in machine tools. To evaluate this new drive concept, a simple model for SynRM considering the non-linear motor parameters is introduced. Advanced control approaches, i.e. a combination of Dead-Beat predictive controller and (LQI) controller is proposed for the position control task for SynRM in feed drives. The dynamic behavior of the feed drive system is modelled as a mass-spring-damper, which is taken into account when designing the optimal controllers. The aim is to achieve an optimal position/speed control with high bandwidth and low sensitivity to disturbances, such as torque ripples and sudden load changes. The control performance is compared with classic Proportional Integral (PI) controllers in both time domain and frequency domain through simulation.