A Multi-MHz Wireless Power Transfer System With Mains Power Factor Correction Circuitry on the Receiver

Abstract

This paper proposes the implementation of a new system topology for multi-MHz inductive power transfer (IPT) systems, which achieves unity power factor when fed from a mains power supply without traditional active circuitry in the front-end as a mains interface. Experiments were performed using an IPT-link which consists of two 20 cm two-turn aircore printed-circuit-board (pcb) coils separated by an air-gap of 13 cm. At the transmit side, a push-pull load-independent Class EF inverter fed from a rectified 60 Hz power supply with no bulk capacitor was designed to drive the transmit coil at 13.56 MHz. This inverter, which has two choke inductors between the voltage source and the two switches, similar to that of an interleaved boost converter, is suitable to be fed directly from a rectified mains source because it tolerates large changes on the input voltage. The IPT rectifier in the experiments was built using a dual current-driven Class D-based topology which allows for higher output voltage when the induced electromotive force (emf) on the receive coil is low. The final power conversion stage on the receive side is a power factor correction (PFC) boost converter that regulates the output voltage and shapes the current waveform at the input of the system. This stage is the only part of the system with closed-loop control. The end-to-end efficiency was measured at 73.3% with 99.2% power factor, when powering a load of 150 W.

Development of a Fast-Charging Platform for Buried Sensors Using High Frequency IPT for Agricultural Applications

“…First, to employ an off-the-shelf battery charger as the next power conversion stage which requires an input voltage from 95 V to 240 V; and second, to increase the sensitivity of an IPT-based sensor localisation mechanism, which can be then included in the navigation system of the drone [16]. The topology of the rectifier, which has been employed in this type of system [17], can be found in Fig. 6 and the component values are presented in Table II.…”

A 13.56 MHz Inductive Power Transfer System Operating with Corroded Coils

“…The IPT-rectifier was designed and built using a dual Class D topology [18], thereby generating a DC output voltage which ensures simple and reliable output power calculations. This DC-to-DC HF-IPT system quantifies the losses across the entire system accurately, thereby providing a basis to report total losses in the system when alternating between the untreated and the treated coil at the transmit side.…”

Load‐independent inverse class‐E ZVS inverter and its application to wireless power transfer systems

“…The load-independent mode has been applied to class-E [14], inverse class-E [16,17], and class-EF [19] inverters until now. In recent years, the load-independent operation has been attracting attention because this characteristic is suitable for the WPT systems [19][20][21][22][23][24][25][26][27][28][29].…”