A Method of Reconfiguring Flying Capacitor Multilevel Input Stage for Wide Input Voltage Range Converter Design

Abstract

Wide input or output voltage range converters are required in various applications, including railway, industrial, military, aerospace, and many more. However, it has been challenging to achieve and maintain high efficiency under a wide range of input or output voltages of operation because of shifting operating conditions and compromised component selections required to cover a wide voltage range of operation. In this article, a method of reconfiguring the flying capacitor multilevel power conversion input stage is revealed for a wide voltage range of operation. A pulse voltage is produced by the input stage. With proper configuration under different input voltage levels, the voltage across key components, namely power switches, inductors, and capacitors, can be maintained relatively constant. In this way, components can be selected and optimized for very confined operating conditions. Also, the amplitude and frequency of the pulse voltage produced by the input stage are also maintained relatively constant. Therefore, a followed filter stage, a resonant tank, or an isolation + rectifier stage can be designed and operated with optimization. High and maintained overall efficiency are achieved over a wide change of the input voltage.