Resonant Hybrid Flyback, a New Topology for High Density Power Adaptors

Abstract

In this article, an innovative power adaptor based on the asymmetrical pulse width modulation (PWM) flyback topology will be presented. Its benefits compared to other state-of-the-art topologies, such as the active clamp flyback, are analyzed in detail. It will also describe the control methods to achieve high efficiency and power density using zero-voltage switching (ZVS) and zero-current switching (ZCS) techniques over the full range of the input voltage and the output load, providing comprehensive guidelines for the practical design. Finally, we demonstrate the convenience of the proposed design methods with a 65 W adaptor prototype achieving a peak efficiency of close to 95% and a minimum efficiency of 93.4% at full load over the range of the input voltage, as well as a world-class power density of 22 W/inch3 cased.

Dual-Input Isolated DC-DC Converter with Ultra-High Step-Up Ability Based on Sheppard Taylor Circuit

“…Figure 14 is the measurement of the voltages of boosting capacitors. This figure reveals that voltages of C 1 and C 2 are in turn 34 V and 45 V, both voltage magnitudes of which meet the theoretical results of Equations (4) and (8). While step change takes place from half load to full load and then drops back, Figure 15 shows the related output voltage and current.…”

“…Figure 1 illustrates a hybrid generation system that includes two sources, a high step-up converter, and an inverter for AC application, which reveals that a dual-input converter with high step-up voltage gain is urgent in such system. Theoretically, conventional step-up converters, like Boost and Flyback [3][4][5][6], can achieve a high voltage gain under the operating with extremely high duty ratio or the design of a much higher turns ratio. However, extreme high duty cycle or turns ratio will dramatically degrade the conversion efficiency due to large conduction loss and copper loss of windings.…”

Non-Linear Capacitance of Si SJ MOSFETs in Resonant Zero Voltage Switching Applications

“…The clear consequence of this analysis is that in single device resonant topologies the most relevant parameter is the total stored charge in the output capacitance of the device. Moreover, the bigger the divergence between the equivalent charge related capacitance C oss(tr) and energy related capacitances C oss(er) the higher the required initial energy in the inductor (11). Si SJ MOSFETs have the biggest divergence between the values among the three compared devices.…”

“…Commonly used resonant converter topologies may comprise one single switching device or several of them, stacked in pairs and conforming one or several building blocks, so-called half bridges. Examples of single switch resonant or quasi-resonant topologies are the fly-back and its variants [11], and the Critical Conduction Mode (CrCM) [12] boost converter. For high-power applications are common two switch topologies, like the Transition Conduction Mode (TCM) [13] boost converter and the half-bridge LLC [14], and four switch topologies, like the Phase Shift Full Bridge (PSFB) [15], [16], the Dual Active Bridge (DAB) [17] and the full-bridge LLC.…”

Resonant Asymmetrical Half-Bridge Flyback Converter

“…In [28], the AHB flyback converter is unstable with the PWM control method. The article [20,30] proposes a resonant AHB flyback, which provides a ZVS function on its switches. However, the efficiency at light load and dynamic response are not mentioned.…”