Failure detection of switching device in a cascaded h-bridge modular multilevel converter
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Date
2019-06
Authors
Nurnazmi Syuhada Binti Nazeri
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Abstract
Switching devices such as MOSFET, IGBT and BJT are widely used in power electronic applications. However, the failures of the switching devices can occur due to the manufacturing defects or the errors in the wiring connection. As the consequences, major problems such as short circuited and damaged equipment will occur. Therefore, it is important to create a system that can detect the failure of the switching devices to prevent further damages. The development of the failure detection system for the switching devices consists of two important components which are H-bridge Inverter model and the MATLAB Function coding. Both components are built by using MATLAB R2017b software for the simulation works. The H-bridge design is made up of four power MOSFETs. The function of H-bridge is to simulate the failure of the switching devices. In addition, MATLAB Function coding is built to detect the failure of the switching devices. From the H-Bridge Inverter simulation, the values of current, temperature, and dv/dt are extracted. The extracted values are assigned as the input for the MATLAB Function coding to detect the failure of the switching devices. The maximum absolute rating of current, temperature and dV/dt are 50A, 150℃, and 50V/ns respectively. In this project, two different input DC voltage, 24V, and 600V are supplied to the H-Bridge Inverter to test the working of the failure detection system. When 24V is supplied to the H- Bridge Inverter the failure detection shows that no failure occurred to the switching devices. Meanwhile, when the 600V is supplied to the H-Bridge Inverter the failure detection able to detect the failure that occurs to the switching devices due to the output rating of the current, temperature and dV/dt from the H-Bridge simulation are higher than its absolute maximum rating of the Power MOSFET. The result shows that the failures in the switching devices can be detected by using the failure detection system that has been created.