A Seven Level Fault Tolerant Switched Capacitor Boost Inverter With a Single DC Source
Anil Kumar Yarlagadda, Vimlesh Verma, Mohd Tariq, Shabana Urooj
Abstract
A Fault-Tolerant Multi-Level Inverter (FT-MLI) is essential to ensure power supply continuity for crucial applications. At the same time, the cost and efficiency of MLI is also important for its successful use in the commercial market. The existing seven level FT-MLI topologies demand more than one input DC source, which increases the cost function. This article proposes a single DC source seven level FT-MLI topology with minimum number of switches (IGBT) to reduce the cost function. The proposed FT-MLI topology generates seven level output voltage with 1.5 times voltage boosting. In case of open or short circuit fault on any single or multi switch, the topology continues to operate with five level output voltage using reserved switches. It consists of eight active switches, two diodes, two capacitors, six thermal fuses, and three reserved switches. In comparison to the existing seven level fault tolerant (open circuit and short circuit fault) topologies, the suggested structure requires minimum number of component count. The efficiency and power losses of the proposed structure are analyzed theoretically. The proposed topology has an efficiency of 96 % at an output power of 600 W under healthy condition and 97% at an output power of 272 W under post fault condition. The level shift pulse width modulation approach is used to generate required triggering pulse for the switch during pre-fault and post-fault. The proposed topology is simulated in the MATLAB/Simulink platform and experimentally verified using dSPACE 1104. The response of the output voltage and current during the transition from pre-fault to post-post fault for each switch fault are presented.