Contents I. Introduction
A non-cascading structure of converters is attaining wide popularity as an alternative to the cascaded ones. This is because of the fact that the non-cascading structure based converters offer higher efficiency. Numerous configurations of non-cascading structures have been reported by the researchers. The combinations of forward and flyback converters were initially, employed, to achieve the objective of improved efficiency. A forward converter is employed for power transfer while a flyback sub-converter serves the purpose of improving the input power factor. A circuit employing a forward and a flyback sub-converter is reported in [1]. It was reported to be suitable to improve the input power factor. In [2], a series capacitor on the ac supply side of the converter was employed. The used series capacitor generated a voltage stress on the main power switch. Several potential non-cascading structures are suggested in [3]. New converters can be derived with proper combination of converters, using these structures. A new topology was derived by combining a flyback converter with any of the converter in non-cascading mode [4]. It improved the efficiency as well as the input power factor of the converter. In [5], non-cascading structures given in [3] are divided into three main categories. In [6]–[8], many possible combinations of different topologies were suggested in line with [3]. It was recommended that these combinations could be used for different converters based upon the requirements. Some converters based on non-cascading structures are developed in [9]–[10].
