Design of gain-scheduling PID controllers for Z-source inverter using iterative reduction-based heuristic algorithms

Abstract

This paper presents gain-scheduling control strategy for Z-source inverter used in traction motors. An iterative reduction-based heuristic algorithms (IRHA) is introduced for optimization of controller parameters. Since it is difficult to implement a stabilizable optimization with the conventional heuristic algorithm, optimum design can be achieved via creating stable sets by employing IRHA. In this optimization method, a new reduced subset is created at the end of each iteration, thereby reducing computation complexity. The proposed scheme adjusts proportional, integral, differential and derivative kick coefficients (Kp, Ki, Kd and Td). In this study, various PID controllers are designed using IRHA and H∞ norm-based optimization methods. Furthermore, in order to overcome non-linearity which exists in the nature of ZSI, gain scheduling is resorted to. The effectiveness of the proposed gain-scheduled controller structure is demonstrated over different input values and voltage fluctuations.