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A nonlinear multivariable highly coupled system that is susceptible to both internal and external perturbations is the permanent magnet synchronous motor. A new reaching law‐based control approach that combines a sliding‐mode disturbance observer and an enhanced two‐vector model predictive current control is suggested in order to enhance the dynamic performance of the permanent magnet synchronous motor and its robustness to system disturbances. First, a new reaching law is developed in this paper to resolve the conflict between the traditional reaching law's chattering of the system and the reaching time of the sliding‐mode surface. This new reaching law not only makes the system's response more rapid but also reduces chattering; second, taking into account the possibility of systems with internal parameter uptake and external load disturbance, a sliding‐mode disturbance observer based on t is developed. Finally, the q‐axis current obtained from the speed sliding‐mode control rate is added to the model predictive current control, and an optimal duty cycle model predictive current control based on space vector modulation is designed because the traditional two‐vector model predictive current control is to optimize the duty cycle and voltage vectors separately, and the switching frequency is not fixed. The method suggested in this research may successfully suppress the sliding‐mode control system chattering and increase the resilience and dynamic response performance of the speed control system, according to simulation findings compared to the traditional reaching law and traditional duty cycle. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Grid‐connected voltage source inverters with LCL filters have been widely used for distributed generation systems in renewable energy systems. The presence of LCL resonance influences the overall performance and complicates the system control design, especially when the uncertainties caused by the component parameter variations and disturbances are considered. In order to improve the system performance under uncertain conditions, this paper presented a model‐based discrete sliding mode control (SMC) with disturbance observer (DOB) for three‐phase LCL‐filtered grid‐connected inverters. In this work, the inverter model is modified by using a virtual damping resistor to eliminate the resonance of the LCL filter and improve the stability, even consider the variations of the grid impedance. To save the sensors and predict the forward step of the state variables, a discrete state observer is adopted in the control. To enhance the robustness of the system, a DOB is designed in the SMC controller to estimate the disturbances so that the system uncertainties can be effectively compensated. Finally, comparative simulations and experiments are constructed to demonstrate the effectiveness of the proposed method. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The control system design scheme for improving disturbance response have been proposed in recent years. In general, system identification is required to estimate disturbance, and the control performance depends on an identification accuracy. In contrast, the data‐driven control scheme has been proposed in which the control parameters are directly calculated from operational data without system identification. This paper proposes the data‐driven control scheme that simultaneously designs a controller and a disturbance estimator. In the proposed scheme, the control parameters are calculated by using the least‐squares method. Specifically, the disturbance is suppressed only using the desired reference model, controller and the adjustable parameter γ. Finally, the effectiveness of the proposed scheme is numerically demonstrated. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

We document a novel bidding pattern observed in procurement auctions from Japan: winning bids tend to be isolated, and there is a missing mass of close losing bids. This pattern is suspicious in the following sense: its extreme forms are inconsistent with competitive behavior under arbitrary information structures. Building on this observation, we develop systematic tests of competitive behavior in procurement auctions that allow for general information structures as well as nonstationary unobserved heterogeneity. We provide an empirical exploration of our tests, and show they can help identify other suspicious patterns in the data. [ABSTRACT FROM AUTHOR]

In this article, we investigate the challenges in designing a communication network robust against earthquake-induced disasters. Due to the heterogeneity of local geology conditions, an earthquake may cause different devastating effects on network links at different locations. Therefore, the aim of this research was to develop a network design method that, based on actual seismic hazard information, finds appropriate geographical routes for network links under a cost constraint to maximize the robustness of the network. We carried out experiments on local as well as nationwide networks considering many possible earthquake scenarios in Japan. The results suggest that the shortest route is often the optimal route, and, in some cases, long detour routes can significantly reduce the average endto- end disconnection probability compared to the shortest route solutions. This gives a network operator guidelines to design a network that is resilient against earthquake disasters at the lowest possible cost. [ABSTRACT FROM PUBLISHER]

The United Nations Office for Disaster Risk Reduction reported that the 2011 natural disasters, including the earthquake and tsunami that struck Japan, resulted in $366 billion in direct damages and 29,782 fatalities worldwide. Storms and floods accounted for up to 70% of the 302 natural disasters worldwide in 2011, with earthquakes producing the greatest number of fatalities. Average annual losses in the United States amount to about $55 billion. Enhancing community and system resilience could lead to massive savings through risk reduction and expeditious recovery. The rational management of such reduction and recovery is facilitated by an appropriate definition of resilience and associated metrics. In this article, a resilience definition is provided that meets a set of requirements with clear relationships to the metrics of the relevant abstract notions of reliability and risk. Those metrics also meet logically consistent requirements drawn from measure theory, and provide a sound basis for the development of effective decision-making tools for multihazard environments. Improving the resiliency of a system to meet target levels requires the examination of system enhancement alternatives in economic terms, within a decision-making framework. Relevant decision analysis methods would typically require the examination of resilience based on its valuation by society at large. The article provides methods for valuation and benefit-cost analysis based on concepts from risk analysis and management. [ABSTRACT FROM AUTHOR]

An adaptive lattice filter for filtering impulsive noise is designed using a cyclic enzyme system. The cyclic enzyme system has a memory mechanism and can maintain the previous output for some duration independently of the system input. The partial autocorrelation (PARCOR) coefficient computed through the system is then robust against impulsive noise that appears as large spikes of short duration. Furthermore, a set of PARCOR coefficients estimated by the new filter is always stable. The effectiveness is investigated analytically and through computer simulation. [ABSTRACT FROM AUTHOR]