A novel approach of power converter topology based on the immittance conversion theory

Abstract

In recent years, immittance conversion theory has attracted interest as a novel power conversion approach. Immittance conversion is defined by the fact that the impedance at the sending end of the conversion circuitry is proportional to the admittance at the receiving end. In other words, it is possible to convert voltage source into current source, or vice-versa. Two types of immittance conversion elements, such as distributed constant line and lumped L-C circuit, have been proposed. However, the application of these immittance conversion elements to power converters have some restrictions because of their inherent defects. A novel immittance conversion element, which the authors call "/spl pi/-LC circuit", is proposed in order to overcome these defects. This proposed circuit converts the fundamental and the third harmonic components in conformity with the immittance conversion theory. The /spl pi/-LC circuit is expected to apply to various power converters. The practical applications of the immittance conversion element, such as DC power supply and utility interactive inverter, are presented. The effectiveness of these converters is confirmed by simulation and experiment.