Design‐oriented model and critical inductance method for long life isolated power converters

Abstract

For moderate-to-high power converters, electrolytic capacitor is an indispensable component. Life of electrolytic capacitor is critical compared with its semiconductor counterparts. This study proposes a new model to analyse the converter life and to design the circuit to lower the current ripple in the electrolytic capacitor in order to reach for longer converter life. Two-stage power converter (a power factor correction converter followed by a DC-DC converter) is the typical practice for AC-DC converter. Forward converter and Flyback converters are the common choices for the downstream converter for this power range. Comparison between two modes of operation, discontinuous conduction mode and continuous conduction mode (CCM), for the two converter topologies shows a typical CCM Forward converter to have almost 300 times longer life than a CCM Flyback converter. Another focus of the work is to analyse the effect of circuit parameters on the converter life. A critical inductance is established to guide the design for long life converters.

Fractional order equivalent series resistance modelling of electrolytic capacitor and fractional order failure prediction with application to predictive maintenance

“…However, electrolytic capacitors have the highest rate of failure among electronic components. As aluminium electrolytic capacitor is known to be the weakest link in power electronics circuits and to have the highest probability of failure compared with other components, the life-time of this component has critical impact on the performance and life-time of the converters [1][2][3][4][5].…”

Lyapunov Based Adaptive-Robust Control of the Non-Minimum phase DC-DC Converters Using Input-Output Linearization

“…Modeling of the DC-DC converters in continuous mode is completely simple and for this reason, most of closed-loop controllers are designed in this operating mode [1]- [4]. Moreover, in high power applications, DC-DC converters have longer life time in continuous conduction [5]. In a discontinuous operation, a small inductor can be used and hence, dynamic response of the system will be absolutely fast.…”

Low‐power single‐stage power factor rectifier based on discontinuous capacitor voltage mode double‐ended forward converter

“…In an effort to comply with the standards, considerable efforts have been made on the development of the power factor correction (PFC) converter topologies. The most commonly used topology in ac/dc conversion is the 'two-stage' topology [3][4][5][6][7][8][9][10][11]. In this topology, a boost converter is controlled to obtain a sinusoidal input current.…”

“…In this topology, a boost converter is controlled to obtain a sinusoidal input current. This PFC stage is then followed by a dc/dc converter which normally provides galvanic isolation and output voltage regulation [3][4][5][6][7]. Although relatively mature, the two-stage PFC converters have two power processing stages with respective control circuits.…”