Wei Liu

Pipeline safety is closely related to people’s lives, environment and economic development. The traditional methods for pipeline inspection are laborious and very expensive, such as non-destructive examination (NDE) and Fitness for service (FFS). In recent years, machine learning (ML) methods have been proven useful to solve pipeline assessment problems. These methods have mainly

A resonant inductor and two clamping diodes are introduced into the secondary phase shift full‐bridge converter (SPS‐FBC), which can well suppress voltage spike across the rectifiers. However, the resonant inductor and two clamping diodes will bring some other problems. In this study, an auxiliary winding in series with the resonant inductor is added to the SPS‐FBC to reset the clamp diode current rapidly. The auxiliary winding not only reduces the circulation losses of the switches and the clamping diodes, but also makes the clamping diodes naturally turn‐off and avoids the reverse recovery even when the output filter inductance and magnetising inductance are relatively large. The principle of operation and performance are illustrated and verified on a 1.5 kW experimental circuit. In addition, the efficiency and losses of the converters with/without reset winding are compared and analysed. The efficiency of the converter with reset winding is significantly improved over the entire operating range and the peak efficiency is 96.60% at full load.

A hybrid full‐bridge converter that consists of a secondary‐side phase‐shift full‐bridge converter (SPS‐FBC) and a full‐bridge LLC converter is proposed in this study. The wide zero‐voltage switching (ZVS) range of the primary switches can be achieved and the series inductor of the SPS‐FBC converter does not need to be specially designed to help achieving the soft switching operation with a set of shared high frequency inverter circuits. The dual outputs of the proposed hybrid converter are connected in series, reducing the voltage stress of the power device in the secondary side. The whole dc‐output voltage can be regulated by primary‐side phase‐shift and secondary‐side phase‐shift dual‐mode control scheme within the desired voltage range, by which the two output voltages are regulated independently and free from cross‐regulation. Therefore, the proposed converter is suitable for high voltage, high power and wide output voltage range applications. The working principle and steady‐state characteristics of the proposed converter are presented and verified in experiment of a 3 kW prototype. The experimental results show that the proposed converter maintains high efficiency throughout the voltage range, and the peak efficiency is 97.43%.