A Novel Fault Tolerant Full Bridge DC/DC Converter for Photovoltaic application

Abstract: Power switches in converters are prone to open and short circuit faults. Faulty power switch in converters worsens the converter performance and it may result in failure of other devices also. Further when main power switch fails, it results in breakdown of entire system. Therefore for reliability improvement of full bridge DC/DC converter in PV system, this research paper presents a novel fault tolerant converter topology  for exact faulty power switch localization and isolation from main path so that redundant faulty power switch can be brought in action and still system will provide desired output power. The converter presented here need two redundant power switches and relays to provide fault tolerant competence. It has four operating states which are normal state, faulty state, fault diagnostic state and fault recovery state. In the technique presented here RMS current at given test points is computed and compared with threshold RMS current for determination of faulty power switch. Graph theory is used to show the topological equivalence of converter in normal and fault recovery states. Simulation and experimental results have shown that converter efficiency remains same in both normal and fault recovery state

Error-voltage-based open-switch fault diagnosis strategy for matrix converters with model predictive control method

This paper proposes an error-voltage based open-switch fault diagnosis strategy for matrix converter (MC). A finite control set model predictive control (FCS-MPC) method is used to operate the MC. The MC system performances under normal operation and under a single open-switch fault operation are analyzed. A fault diagnosis strategy has also been implemented in two steps. First, the faulty phase is detected and identified based on a comparison of the reference and estimated output line-to-line voltages. Then, the faulty switch is located by considering the switching states of the faulty phase. The proposed fault diagnosis method is able to locate the faulty switch accurately and quickly without additional voltage sensors. Simulation and experimental results are presented to demonstrate the feasibility and effectiveness of the proposed strateg

Simultaneous On-State Voltage and Bond-Wire Resistance Monitoring of Silicon Carbide MOSFETs

In fast switching power semiconductors, the use of a fourth terminal to provide the reference potential for the gate signal—known as a kelvin-source terminal—is becoming common. The introduction of this terminal presents opportunities for condition monitoring systems. This article demonstrates how the voltage between the kelvin-source and power-source can be used to specifically monitor bond-wire degradation. Meanwhile, the drain to kelvin-source voltage can be monitored to track defects in the semiconductor die or gate driver. Through an accelerated aging test on 20 A Silicon Carbide Metal-Oxide-Semiconductor-Field-Effect Transistors (MOSFETs), it is shown that there are opposing trends in the evolution of the on-state resistances of both the bond-wires and the MOSFET die. In summary, after 50,000 temperature cycles, the resistance of the bond-wires increased by up to 2 mΩ, while the on-state resistance of the MOSFET dies decreased by approximately 1 mΩ. The conventional failure precursor (monitoring a single forward voltage) cannot distinguish between semiconductor die or bond-wire degradation. Therefore, the ability to monitor both these parameters due to the presence of an auxiliary-source terminal can provide more detailed information regarding the aging process of a device