Designing a Hybrid State Feedback Control Structure for a Drive With a Reluctance Synchronous Motor

Drives with a reluctance synchronous motor (RSM) are currently being intensively developed due to the simple construction and easily available materials used for their construction. These machines are also characterized by high efficiency. Designing a control system is not trivial due to the nonlinearity of the model describing this motor. In order to simplify the mathematical model of RSM, a linearization technique based on the lumped perturbation approach was proposed. A modified mathematical description of flux surface and inductance was proposed and applied. An original hybrid state feedback control (SFC) structure of a drive with a reluctance synchronous motor has been proposed. In the range of admissible changes of state variables, the regulator operates in the linear region and has the structure of an SFC. When the state variable limits (maximum values) are reached, the control structure performs predictive control to maintain the limit values. The synthesis of the control structure is described in detail. The proposed control structure is experimentally compared with a cascade control and model predictive one. The obtained results indicate a similar dynamical behavior and much better load torque compensation obtained for hybrid SFC. The proposed approach assures precise limitation of state variables resulting safe operation of the drive.