Generalized synthesis and applications of zero-impedance converter and its dual

Abstract

We present a synthesis method for converting to zero a nonzero impedance or admittance. The former case is called a zero-impedance converter (ZIC). Its dual is the latter case, called the zero-admittance converter (ZAC). The ZIC comprises a current positive-feedback loop within a voltage negative-feedback loop. The ZAC comprises a voltage positive-feedback loop within a current negative-feedback loop. Exact expressions are derived for the required transfer functions of the feedback circuits in the positive-feedback loops, which perform the functions of the ZIC and the ZAC. In both cases, the negative feedback loop controls the system stability and dynamics. The synthesis method also simplifies the design of standard negative-feedback loops. The ZIC can be used for synthesizing load-independent constant-voltage power converters and voltage-source-fed motor drives. The ZAC can be used for synthesizing load-independent constant-current power converters and current-source-fed motor drives. The converters can be considered to approach the ideal Thevenin voltage source (ZIC) and the Norton current source (ZAG) in their transient responses and ideal sources in steady state.