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In this article, an approach is proposed for the online diagnostic analysis of power electronic converters utilizing real-time, probabilistic digital twinning. Under this approach, a digital twin (DT) of a power converter is defined as a real-time, probabilistic simulation model with stochastic (random) variables, developed using generalized polynomial chaos expansion. The DT models are partitioned in perspective of control layers for power converter subsystems in the approach, with emphasis on the application and converter control layers. Real-time executed solvers of these divided probabilistic DT models are embedded into power converter controllers running on field programmable gate array (FPGA) computing devices. Using a monitoring system, the real-time probabilistic DTs at each control layer and the corresponding physical twins of the power converter are compared by the controllers to determine if the power converter is operating within probable behavior. Knowing the large computational cost of probabilistic modeling, the resource usage and timing of real-time DT solvers on modern FPGAs is reported for common power electronic converter topologies, showing the approach is feasible and able to perform probabilistic real-time simulation of smaller power converters in perspective of application and converter control layers using ≤ 2 μs time steps, with as low as 70 ns steps; while staying embeddable within FPGA-based controllers. To highlight the capabilities of the proposed approach, a case study is presented using a probabilistic DT in the application layer controller of a pair of converters to comparatively monitor their behavior and corresponding controller action under hardware-in-the-loop testing. [ABSTRACT FROM AUTHOR]

The ability to manage energy within an autonomous microgrid, which enables system optimization, requires coordinated control of the connected power sources. This generally involves coordination of active and reactive power generation. To increase energy management capability, coordination of converter connected power sources can be extended to other tasks such as harmonic compensation and load balancing. However, some units in microgrids, such as wind and photovoltaic (PV) power sources, have local criteria such as maximum power point tracking that determines the reference value for active power generation. In this paper, a distributed control structure for independent sharing of tasks among sources is introduced where units with local active current reference can contribute to generation of only non-active current components in coordination with other units while their active current is generated autonomously. For task-sharing among units, an objective function based on current components is presented. In order to verify the proposed method, optimization of a microgrid with a PV unit is simulated. [ABSTRACT FROM AUTHOR]

This paper describes the implementation of a distributed coordinating control system for power electronic converters in a shipboard distribution system that ensures system optimization dynamically. Multiple agents take part in the process to determine optimal power sharing for the converters. A distributable optimization method suitable for real-time coordination of converters is developed for deployment in multi-agent system type frameworks. The presented optimal power-sharing method ensures minimum distribution losses and economic dispatch of sources while enforcing constraints such as source ramp rates and capacity limits. [ABSTRACT FROM PUBLISHER]

When the control functions of various types of power electronics systems are examined, a significant degree of common functionality emerges, irrespective of the target application. It is possible to define hierarchical control architectures for these systems using common interface definitions between control system divisions or layers. Such definitions enable the use of common designs for multiple applications and the use of commercially available electronics and communications modules allowing cost reduction in power electronics applications. This paper presents various partitioning strategies of a hierarchical control architecture for use in high power electronics control systems and defines various parameters/functions that need to be handled within each layer, and those that need to be communicated between the layers. Each layer has characteristic processing and communication speed requirements, irrespective of the final applications. [ABSTRACT FROM PUBLISHER]

A new high-impedance fault (HIF) detection method using time-frequency analysis for feature extraction is proposed. A pattern classifier is trained whose feature set consists of current waveform energy and normalized joint time–frequency moments. The proposed method shows high efficacy in all of the detection criteria defined in this paper. The method is verified using real-world data, acquired from HIF tests on three different materials (concrete, grass, and tree branch) and under two different conditions (wet and dry). Several nonfault events, which often confuse HIF detection systems, were simulated, such as capacitor switching, transformer inrush current, nonlinear loads, and power-electronics sources. A new set of criteria for fault detection is proposed. Using these criteria, the proposed method is evaluated and its performance is compared with the existing methods. These criteria are accuracy, dependability, security, safety, sensibility, cost, objectivity, completeness, and speed. The proposed method is compared with the existing methods, and it is shown to be more reliable and efficient than its existing counterparts. The effect of choice of the pattern classifier on method efficacy is also investigated. [ABSTRACT FROM AUTHOR]