Circuit design and implementation of fault-tolerant step-up converter with variable voltage gain.

In this paper, a fault-tolerant (FT) DC-DC converter that is capable of safe operation under open-circuit and short-circuit switch failures is presented. This study is based on reconfiguration strategy after a switch failure without employing any additional hardware. To maintain normal operation, the designed topology is reconfigured under various switch-fault conditions. Using the simple proposed control unit, it is possible to fast detect and regulate the desired output voltage in both healthy and faulty conditions. The reconfigurable capability allows the converter to operate uninterrupted after a switch fault, and the power flow will be continuous. FT operation and reconfiguration capability of a step-up DC-DC converter under switch failures are investigated in continuous current mode (CCM). A fuse-MOSFET pair is analyzed and designed for FT operation in details. The proposed FT converter has been placed in an integrated transformerless grid-connected PV system, and simulation tests have been performed to confirm the performance of the converter in the application of a grid-connected PV system. Also, experimental results carried out on a prototype demonstrate the effectiveness of the proposed converter in reducing losses associated with power converter in low-power applications.