DESIGN AND CONTROL OF FAULT TOLERANT BIDIRECTIONAL INTERLEAVED CONVERTER FOR BATTERY CHARGING APPLICATIONS

Abstract

Most industrialized countries are aiming towards cleaner modes of transportation, and Electric Vehicles (EVs) are top contenders for the same. EVs are largely seen as the future of the transportations business. Although the topic is a great deal of research, this research focuses on improving the reliability of the system by making it fault tolerant. DC-DC converters are one of the most important and challenging subsystems in charging systems. The reliability of the system has always been an issue because of the failures of the semiconductor switches. The study presents the design and control of a 1kW fault-tolerant bidirectional interleaved converter for battery charging applications. It also proposes an algorithm for detection of fault in any of the switches and uses a 3- phase bidirectional interleaved non- isolated converter. The converter’s working is simulated based on two configurations that conducts using all legs at once and redundant leg-based topology so that the converter functions like the prior fault condition. The algorithm makes use of the digitally implemented circuit and hence does-not affect the cost of the system much. A modified PI control integrated with fault detection control scheme is implemented to charge the battery in constant current mode and ensure minimum ripples in output voltage and current. While discharging, voltage mode control is implemented using the PI control. The fault-tolerant capability ensures the continuous operation of the converter even after a fault and made it suitable for EVs battery charging applications.