μ-Analysis Evaluation of A Novel Combined Current-and-Speed Control for Induction Motors via ILQ Design Method

We proposed combined electric and dynamic system based on the ILQ optimal control, which has high robust performance for induction motor drive. This method realizes an excellent speed control, even if the response of current-control loop is more than three times of the response of speed-control loop. When the motor parameters are varied, the ILQ optimal controller can hold more robust condition than previous method. This paper presents quantitative evaluations for robust stability and robust performance via μ-analysis. Generalized state equations for μ-analysis are derived and compare the ILQ control method with proposed PI method.