Abstract
This paper analyses and compares candidate zero dv / dt half-wave Class-E rectifier topologies for integration into multi-MHz inductive power transfer (IPT) systems. Furthermore, a hybrid Class-E topology comprising advantageous properties from all existing Class-E half-wave zero dv / dt rectifiers is analyzed for the first time. From the analysis, it is shown that the hybrid Class-E rectifier provides an extra degree of design freedom that enables optimal IPT operation over a wider range of operating conditions. Furthermore, it is shown that by designing both the hybrid and the current-driven rectifiers to operate below resonance provides a low deviation input reactance and inherent output voltage regulation with duty cycle allowing efficient IPT operation over wider dc load range than would otherwise be achieved. A set of case studies demonstrated the following performances: First, for a constant dc load resistance, a receiving end efficiency of 95% was achieved when utilizing the hybrid rectifier, with a tolerance in required input resistance of 2.4% over the tested output power range (50–200 W). Second, for a variable dc load in the range of 100–10%, the hybrid and current-driven rectifiers presented an input reactance deviation less than 2% of the impedance of the magnetizing inductance of the inductive link respectively and receiving end efficiencies greater than 90%. Third, for a constant current in the receiving coil, both the hybrid and the current-driven rectifier achieve inherent output voltage regulation in the order of 3% and 8% of the nominal value, respectively, for a variable dc load range from 100% to 10%.
Highlights
W EAKLY coupled inductive links, Fig. 1, tend to operate in the low MHz region in order to increase their link efficiency [1]–[3]
This paper provides a design framework for Class-E half-wave zero dv/dt rectifier topologies which allows the designer to select the optimal topology based on power levels, frequency of operation, and inductive link properties
Based on the analytical results the following conclusions can be made about half-wave Class-E rectifiers operating with a duty cycle equal or lower than 50% when designed for inductive power transfer (IPT)
Summary
W EAKLY coupled inductive links, Fig. 1, tend to operate in the low MHz region in order to increase their link efficiency (ηlink ) [1]–[3]. The optimal link efficiency (ηlink,opt) of a particular inductive link geometry occurs when the receiving coil (Lrx ) is tuned at the frequency of the generated magnetic field and the ratio of the ac load resistance (Rac) to the reactance of the tuning capacitor (Crx ) satisfies a specific value (αopt) [1]. Manuscript received September 5, 2016; revised November 4, 2016; accepted December 2, 2016. Date of publication February 6, 2017; date of current version June 23, 2017. Recommended for publication by Associate Editor J.
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