In this paper, a PWM plus secondary-side phase-shift (SSPS) controlled full-bridge three-port converter (FB-TPC) is proposed for renewable power system, which is derived by integrating two interleaved Buck/Boost circuits (IBBC) and a SSPS full-bridge converter (FBC), to interface the energy source, energy storage element and output load simultaneously. The two switching legs are shared by the IBBC and FBC, which improves the active devices sharing ratio and power density. With PWM plus SSPS control scheme, decoupled power control can be realized and the converter can achieve wide input voltage range power conversion. And zero-voltage-switching (ZVS) of both the primary and secondary switches are achieved in a wide range. Furthermore, the circulating current can be greatly eliminated, which helps to reduce conduction losses. Moreover, the voltage stresses on the secondary rectifier are effectively suppressed since the power switches and diodes are clamped to output voltage. The operation principles, output characteristics, ZVS performances and control strategy are analyzed in detail. Experimental results of a 600-W prototype are provided to verify the effectiveness and the advantages of the proposed converter.  Index Terms-Power converter, DC-DC converter, three-port converter, zero-voltage switching, spacecraft power system.  Manuscript

A systematic method for deriving soft-switching three-port converters (TPCs), which can interface multiple energy, is proposed in this paper. Novel full-bridge (FB) TPCs featuring single-stage power conversion, reduced conduction loss and low voltage stress are derived. Two non-isolated bidirectional power ports and one isolated unidirectional load port are provided by integrating an interleaved bidirectional Buck/Boost converter and a bridgeless Boost rectifier via a high frequency transformer. The switching bridges on the primary side are shared, hence the number of active switches is reduced. Primary-side pulse width modulation and secondary-side phase shift control strategy are employed to provide two control freedoms. Voltage and power regulations over two of the three power ports are achieved. Furthermore, the current/voltage ripples on the primary-side power ports are reduced due to the interleaving operation. Zero-voltage-switching and zero-current-switching are realized for the active switches and diodes, respectively. A typical FB-TPC with voltage-doubler rectifier developed by the proposed method is analyzed in detail. Operation principles, control strategy and characteristics of the FB-TPC are presented. Experiments have been carried out to demonstrate the feasibility and effectiveness of the proposed topology derivation method.  Index Terms-DC-DC converter, three-port converter, renewable energy, bridgeless boost rectifier, secondary-side regulation. Manuscript

This study focuses on the relationship between learning styles and language learning strategies in the EFL context in China. The study presents two kinds of data: quantitative and qualitative. In the quantitative study, the subjects consisted of 187 second-year undergraduates. Two self-reported inventories, the Chinese version of MBTI-G and a questionnaire on the use of learning strategies adapted from O’Malley and Chamot’s classification system, were used to examine the students’ learning styles and learning strategies respectively. Structured interviews have been performed among the six high and low achievers in the qualitative aspect of the study. The analyses show that learning styles have a significant influence on learners’ learning strategy choices. There is evidence that the Judging scale correlates positively with seven sets of learning strategies. Thus it turns out to be the most influential learning style variable affecting learners’ learning strategy choices. Compared with low achievers, high achievers are more capable of exercising strategies that are associated with their non-preferred styles. Based on the available research results, it is proposed that learning styles may influence learners’ language learning outcomes through their relationship with learning strategies. The pedagogical implications of these findings are discussed, as are suggestions for future research.

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This paper focuses on the effects of vehicle gap changes on fuel and emission performance of the simulated traffic flow in the adaptive cruise control (ACC) strategy. Firstly, the close correlation of vehicle gap changes and the host car's behaviors was explored with the measured car-following data. Secondly, the correlation between the host car's velocity and vehicle gap changes with different memory steps was also explored to develop the nth car’s optimal velocity function. Thirdly, a microscopic traffic simulation program was created for analyzing the traffic flow evolution process and approximately estimating the fuel consumptions and exhaust emissions. As a result, it was seen that vehicle gap changes with memory significantly affect fuel economy and emission performance of the simulated traffic flow in the ACC strategy, which can result in low fuel consumptions and exhaust emissions. This study is an incremental step forward for designing the control strategy of the ACC system.