In this paper, a ZVS interleaved flyback converter with two transformers is presented, which consists of two active clamp flyback converters and the main switch of one converter acts as an auxiliary switch of another converter. This converter has less auxiliary elements and less voltage and current stress compared to similar soft switching interleaved flyback converters. The introduction of a new auxiliary circuit for soft switching, in addition to increasing efficiency, minimizes the number of added semiconductors. Also, another advantage of this structure is the applicability of the provided auxiliary circuit to other isolated converters. The soft switching conditions in this converter are created by the auxiliary circuit in such a way that the converter switches turn on and off under ZVS conditions and the converter diodes turn on and off under ZCS conditions. The efficiency of the proposed ZVS interleaved flyback converter at full load is increased by 5%. Another advantage of the proposed converter is that the Q2 switch, in addition to providing zero voltage switching conditions for the Q1 switch, it also transmits energy and increases the density of the converter power and reduces the current stress. The converter is thoroughly analyzed and a 300W laboratory prototype is made to confirm its correct operation and practical results are presented.

Background and Objectives: Many applications use boost converters as front-end circuits, including power factor correction (PFC), solar power generation, fuel cell power conversion, battery chargers, and uninterruptible power supply. In addition, boost converters have a simple structure with low component counts, which makes them a convenient choice.Methods: This article proposes a coupled-inductor active auxiliary circuit to create a new low-stress boost converter with soft-switching. The proposed auxiliary circuit supplies the main switch and diode with soft-switching ZVC turn-on and ZCS turn-off states. The main switch and diode are not deal with any extra stress of voltage or current. Furthermore, the soft switching condition is also provided for auxiliary circuit components.Results: The proposed auxiliary circuit also has a simple structure, low circulating current losses, low cost, and simplicity in control. The operation state and performance of the proposed soft-switching boost converter are examined, and the design procedure is presented. Finally, a 200W prototype is implemented and tested to validate the theoretical results. The offered experimental data verified the theoretical analysis.Conclusion: This paper provides a new low-stress soft-switching boost converter using a simple coupled-inductor in the auxiliary circuit. Moreover, the auxiliary part consists of two diodes, one switch, one resonance capacitor, and a coupled inductor. The suggested auxiliary circuit provides soft switching condition for the main switch, which provides ZVS in the turn-on transient and ZCS in the turn-off transient, while in this situation, the soft-switching condition is provided for the auxiliary switch, which turns on under ZCS and also turns off with practically ZVS conditions. The auxiliary circuit does not impose additional voltage or current stress on the main switch. A 200 W prototype is implemented to validate the performance of this snubber cell. The experimental data reported here support the theoretical analysis. The best point of efficiency is 95.9% which is occurred at maximum load, and is 6.3% greater than the traditional counterparts.

Background. Peri-implant soft tissue health and esthetic is one of the main factors influencing the longterm survival and success of implants. While platform-switched (PS) implants have been widely studied in terms of marginal bone preservation, the purpose of this study is to review the soft tissue conditions around these implants. Methods. Using pertinent keywords, PubMed and Embase databases were searched for relevant clinical studies which compared the peri-implant soft tissue outcomes of PS implants to the implants with matching diameter abutments. The quality of articles was evaluated using Cochrane Collaboration’ s tool for randomized controlled trials and Methodological Index for Non-Randomized Studies. Results. Eight clinical studies were selected to be reviewed. The articles varied in numerous features such as the implants’ brands, the duration of follow-up and the study quality. The evaluated peri-implant soft tissue parameters included the height or recession in buccal mucosa, height of the mesial and distal papilla, the mucosal thickness, and pink esthetic score. In all studies, PS implants showed better or at least similar results relative to the implants with flat-to-flat or conical connections. The difference between the test and control groups reached statistical significance in three of the reviewed articles. Conclusions. PS implants can provide peri-implant soft tissue health and stability and consequently acceptable clinical results.

switching supervisory is the most important section of a feedback control process in MIMO hybrid systems. By choosing a non-compatible controller, system may go to unstable mode or high overshoot response. In this paper, a new method of switching for selecting MBC controllers is discussed. Results of the simulation show the MIMO (2-in 2-out) linear hybrid system can be switched stable and low overshooting in switching time. This method can be expanded to nonlinear MIMO systems.