Fault Tolerant Operation of Three-Phase 3 Level T-Type qZS Inverters using Sliding Mode Current Controllers

Due to the boost characteristic and the several possible outputs of quasi-Z-source inverters (qZSI), these topologies can be valuable options to operate under fault conditions, provided the controller is able to take advantage of the available output states. Thus, the development of control systems to take advantage of the available outputs is needed. Hence, this paper focuses on the development of a control system to operate a three-phase three-level T-Type qZSI under fault tolerant conditions. The controller is based on a sliding mode current controller associated to a vectorial modulator selecting the available outputs. The proposed strategy for the controller and modulator is presented taking into consideration the normal and fault-tolerant requirements. The strategy also considers the balance of the capacitors under fault tolerant condition. The converter operating in both modes is tested through several simulation studies.