Self-oscillating galvanic isolated bidirectional Very High Frequency DC-DC converter

Abstract

This paper describes a galvanic isolated bidirectional Very High Frequency (VHF = 30 MHz -300MHz) Class-E converter. The reason for increasing the switching frequency is to minimize the passive components in the converter. To make the converter topology bidirectional the rectifier has to be synchronous. This increases the complexity of the gate drives, which in this paper is solved by using a self-oscillating gate drive. A bidirectional converter has been implemented and is described in this paper; the converter reaches efficiencies above 80% in forward conduction mode and 73.5% in reverse conduction mode. The designed converter operates at a switching frequency of 35.6 MHz, which is well within the VHF range. The same converter is also implemented with PCB embedded inductors to minimize cost and the physical volume of the total converter. 978-1-4799-6735-3/15/$31.00 ©2015 IEEE

EMC investigation of a Very High Frequency self-oscillating resonant power converter

“…When designing resonant converters the rectifier [11] is designed first. Then the inverter [14] is designed to match the input impedance of the rectifier. The load is a 60 V LED and due to the high output voltage a Class-DE rectifier is chosen since the peak voltage of the diode is equal to the output voltage.…”

“…The design for the Class-E inverter is described in [14] where the circuit components needed to obtain zero voltage switch (ZVS) is found from the load impedance. Ideally the Class-E inverter and Class-DE rectifier have no rapid transients since they are soft switching.…”

Synchronous Rectifier for High-Frequency Switch-Mode Power Supplies Using Phase-Locked Loops

“…Research developed self-oscillating gate drives for both single switch [5] and half-bridge configurations [6]. Additionally, single-switch self-oscillating active rectifiers have been demonstrated in [7], [8]. These gate drives all utilizes passive components and the intrinsic capacitances of the MOSFET to generate multi-MHz gate signals, achieving ZVS.…”

Microfabricated Air-Core Toroidal Inductor in Very High-Frequency Power Converters

“…However, they have a high voltage stress factor across the switch (drain-to-source voltage divided by the input voltage). This voltage stress can be 3.5 to 4 times higher than input supply voltage [33]- [37]. As a result, a high voltage switch with high breakdown voltage is required.…”