Fault Tolerant Control of an Induction Motor Fed by aZ-source Three-Level Neutral Point Clamping Inverter

In this study, a Direct Torque Control is proposed as a Fault tolerant control for an induction motor fed by the Z-source Eight-Switches Three-Phase Inverter (Z-source ESTPI). This structure is the post-fault reconfiguration of the Z-source three-level Neutral Point Clamped (NPC) inverter in the case of IGBTs open circuit. This technique ensures the voltage buck-boost function, reduces torque ripple and ensures the balancing of the middle point of the DC bus voltage. A hysteresis comparator is added to regulate the voltages of the two capacitors. Therefore, an improved switching table is proposed. A simulation is carried-out to demonstrate the feasibility and effectiveness of the Fault tolerant direct torque control solution.