Search

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]

• Impacts of non-periodic are similar to harmonic current but more difficult to mitigate. • Time-frequency distortion index is most suitable for non-periodic loads. • Hybrid time-frequency method provides temporally distributed current reference. • Temporal distribution of compensation increases efficiency and reduces overall cost. • Fuzzy algorithm based on non-periodic characteristics decreases bandwidth requirements. This paper presents a new technique for the compensation of non-periodic load current. The method provides control references for three co-located devices, each corresponding to one moving calculation window and one decomposed part of the compensated current. They are slow compensator with high power rating, large calculation window, and low switching frequency; fast compensator with lower power rating, shorter calculation window, and higher switching frequency; and the reactive compensator which is an ordinary static VAR compensator (SVC). A fuzzy based adaptive window is proposed for the slow compensator to find the optimum window for different load characteristics. The technique is evaluated using real-world data and controller hardware-in-the-loop (HIL) implementation. [ABSTRACT FROM AUTHOR]

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]

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]

Electric Power Research Institute's Control Center Application Programming Interface proposed the Common Information Model (CIM) as the common information exchange model, which provides an excellent platform for representing the components of a power system. This paper discusses using CIM for data modeling for ship power system analysis. Features include using the CIM to accommodate shipboard power systems. Detailed data models for a pulsed load and an active filter are presented and validated through simulation in Matlab. The general process to extend CIM for shipboard power system is briefly outlined. Further efforts are underway to develop a CIM-based shipboard baseline test case to standardize modeling terminology. [ABSTRACT FROM AUTHOR]

In this paper we present an approach for real-time simulation and Hardware-in-the-Loop (HIL) testing of Modular Multilevel Converters (MMCs) that rely on switching models while supporting system level analysis. Using the Latency Based Linear Multistep Compound (LB-LMC) approach, we achieved a 50 ns simulation time step for systems composed of several MMC converters and for converters of various complexity. To facilitate system level testing, we introduce the use of a serial communication-based (Aurora) interface for HIL testing of MMC converters and we analyzed the effect that communication latency has on the accuracy of the HIL test. The simulation and HIL results are validated against an MMC laboratory prototype. [ABSTRACT FROM AUTHOR]