Discrete-time dynamic systems demonstrate quite exciting possibilities from the perspective of control as compared with the continuous-time counterpart. Interesting properties of discrete-time dynamic systems include the possibility to algebraically determine previously unknown system parameters by simply measuring the present inputs and outputs of the system. Additionally, achieving a finite settling time with zero steady-state error is only achievable in discrete-time dynamic systems. Deadbeat current control (DBCC) has been used to achieve a finite settling time, especially in grid-connected inverter applications. However, there is no comprehensive study on reviewing or evaluating existing control approaches, to the authors' best knowledge. This paper systematically examined the existing methods by paying attention to four key research issues: 1) research evidences indicating the adoption of DBCC in grid-connected inverter applications (GCIAs), 2) the types of deadbeat control approaches adopted in GCIAs, 3) the best approach in terms of stability especially regarding grid-impedance variation, and 4) the barriers that might prevent the wide adoption of DBCC in GCIAs. Finally, this paper presents a hypothesis based on the simulated results on which approach is superior at present to give readers a direction for further research classification on deadbeat control.INDEX TERMS Deadbeat control, grid-connected inverter, current control, renewable energy sources.

The control of grid‐connected inverters is recently executed with digital microprocessors due to the advances in digital signal processing technology. However, the digital realisation has a drawback of the phase lag induced by the time‐delay. This phase lag challenges the stability and robustness of the controller of the inverters. In view of the challenge, this paper presents a comprehensive review of time‐delay compensation techniques employed in both model‐free (MF), and model‐based (MB) controls of an inverter in grid connection. MF techniques mainly use proportional‐integral, and proportional resonance controllers with some techniques to reduce time‐delay. Meanwhile, for MB, this paper discusses the commonly used control techniques, which are the Smith predictor, modified Smith predictor, deadbeat controller and model predictive controller. Several related techniques from the literature that have been adopted to mitigate the delays are tabulated comprehensively, and critical issues regarding the MF and MB techniques are also discussed. Finally, this paper presents a hypothesis on which technique is superior at present and suggests a hybrid technique from the MF and MB techniques to give readers a direction for further research.

Can dual‐use research be conducted safely, or are some things simply too dangerous to ever be appropriate research topics? Ronald Jackson and Ian Ramshaw offer their own perspectives in interviews about their groundbreaking work with mousepox virus.

Composite resin continues to displace amalgam as the preferred direct restorative material in developed countries. Even though composite materials have evolved to include nanoparticles with high physical properties and low shrinkage stress, dentists have been challenged to efficiently create quality, long lasting, predictable restorations. Unlike amalgam, composite resin cannot be condensed making the establishment of a predictable, proper contact more difficult. In addition, composite requires an understanding of adhesives and an appreciation for their exacting application. These facts combined with the precise adaptation and light-curing of multiple layers makes placement of quality Class II composite restorations tedious and time-consuming. For private practicing dentists, it can also have an effect on economic productivity. Clinicians have always wanted an easier, efficient placement technique for posterior composite restorations that rivals that for amalgam. It appears that advances in instrumentation, materials and technology have finally delivered it.

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