Normal and degraded operation of the open-end winding induction machine fed by 2-level inverters in cascading

Introduction. The machine-converter system is a prevalent and essential configuration, widely used not only in variable-speed industrial drive applications, but also in high-tech transportation and power fields. Problem. Conventional drive systems, particularly those supplied by standard 2-level inverters, face major challenges regarding the enhancement of their dynamic performance and drive availability. To overcome these limitations, a solution involves utilizing the open-end stator winding induction machine associated with cascaded 2-level inverter topologies. The goal of this work is to improve the availability of the drive system by increasing its degrees of freedom through the association of an open-end winding induction machine by two cascaded 2-level inverters. Methodology. The mathematical modeling of this machine is presented and validated using MATLAB/Simulink. To evaluate the machine’s performance, it is first powered by two cascaded 2-level inverters and subsequently by three cascaded 2-level inverters. Following this initial evaluation, the machine is then fed by two cascaded 2-level inverters operating in degraded mode. This analysis features different failure configurations, and the specific operational conditions that must be respected. Results. This topology enhances dynamic performances and enables effective power segmentation as well as a degraded mode operation. These benefits are confirmed by the simulation results. The scientific novelty is based on demonstrating the effectiveness of degraded mode control, which gives the machine-cascaded inverters topology a superior advantage in terms of reliability and performances. Practical value. This topology provides a highly reliable and fault-tolerant drive solution, ensuring better performance during normal operation and better availability after an inverter failure. References 15, tables 1, figures 24.