Use of unterminated two-port modeling technique in analysis of input filter interactions in telecom DPS systems

A methodology to model and analyze input filter-interactions in telecom distributed power systems is presented based on the use of two-port unterminated modeling technique. Switched-mode converters and input filters are modeled using G-parameter representation where the input port is represented using Norton´s equivalent circuit, and the output port using Thevenin´s equivalent circuit. The used approach results in a unified model applicable to any converter regardless of topology, and the mode of operation or control. The two-port models are first defined as unterminated models where the effect of load is excluded but may be easily included using the developed reflection rules.