This paper presents an analog-digital hybrid strategy for implementing Model Predictive Control (MPC) as applied to grid-connected converters. It highlights the challenges associated with finite control set MPC (FCS-MPC) and proposes solutions to mitigate these limitations. A fair comparison between a fully digital microprocessor−based implementation and an analog-assisted digital system is also presented. To validate the proposed architecture and analyze its advantages and limitations, MPC is implemented for a grid-connected Voltage Source Converter (VSC). At each sampling instant, the MPC algorithm solves the system’s mathematical model and an optimization problem over a two-step prediction horizon to determine the optimal switching state for the subsequent time step. This work presents the possible applicability of analog-digital hybrid systems in computationally intensive real-time scenarios. It also brings out the practical challenges in the implementation of such systems.

This paper presents an analog-digital hybrid approach for implementing a digital twin estimator aimed at health monitoring of power electronic converters. The digital twin serves as a real-time virtual counterpart of the physical converter, replicating its key dynamic characteristics to enable predictive diagnostics and performance optimization. The proposed framework leverages analog-digital processing to enable direct integration with sensor outputs and parallel operation alongside the converter on the same embedded control platform. This embedded implementation facilitates adaptive control and supports real-time decision-making. The effectiveness of the proposed method is validated through its application to a DC-DC buck converter implemented on the developed analog-digital hybrid system. This work demonstrates the potential of hybrid computation for real-time health monitoring and highlights key implementation considerations for embedded analog-digital system-based digital twin systems.

This paper is on the possible uses of analog computing in the acceleration of digital implementations of real-time simulation and control in power engineering. We present a brief history of analog and hybrid computing, make the case for a renewed interest in the use of hybrid computing in power engineering, and provide practical results from a small-scale hybrid computer as applied to specific cases. We consider a hybrid computing approach in which the analog computing part consists of analog integrators, scalers and adders, and a digital processor to perform algebraic computations. The digital processor also monitors, controls and reprograms the analog part. We discuss three broad areas that potentially benefit from hybrid computing: real-time simulation, real-time optimization in the control of power electronic converters, and real-time estimators in the closed-loop control of power electronic systems.

Monitoring of remote microgrids helps in providing better service to the consumers. Prior idea of location/nature of fault and/or device malfunction saves a lot of time for the maintenance engineer during outrages. Thus, the off-site monitoring of microgrids ensures the proper operation as well as efficient work execution during clearance of fault as it gives an idea for the visiting engineer about the location of fault and malfunctioning devices. In this paper, a digital twin based scheme is presented for monitoring the power flow of remote microgrid. Digital twin is a real-time, physics based simulation integrated with the real physical system and provides the estimate of different characteristics in real-time. A physics based digital twin of the remote microgrid (wherein DGs are controlled with conventional droop scheme) is modeled using simulation and the power flow of the microgrid is monitored using digital twin model. The scheme is validated on a real-time simulation platform (RTSP) for different type of loads. Different cores of the RTSP are used for implementing the physical microgrid system and digital twin based monitoring scheme.

The capacitor of each module of the Modular Multilevel Converter needs to be pre-charged to a certain voltage level to enable generation of desired voltage at the output. The aim of this paper is to present a review of pre-charging methods used from the time the concept of Modular Multilevel Converter was introduced to the state of the art of the pre-charging process, based on available literature. Simulation of pre-charging when Modular Multilevel Converter is operated in inverter mode is presented, for a laboratory scale set-up. Experimental results of controlled pre-charging in open loop for a three level Modular Multi-level Converter in inverter mode are given.

Sources within an islanded microgrid employ droop control to share power according to their rating. To optimally design microgrids subject to constraints in voltage and frequency, it is imperative to evolve strategies which simplify representation of diverse sources. This paper proposes a concept of representing any source operating with droop control to be represented as voltage source in series with impedance. The value of impedance as derived, depends on power output of the source and droop gains. To verify the proposed method, simulation of microgrid using MATLAB/Simulink is done with actual inverter based sources and their equivalent proposed system. The strategy may be useful for steady state studies, analyzing different operating points and overall system design.

Traditional microgrids have sources whose transient response is limited by process or mechanical time constants depending on the technology used. Inverter based sources provide the flexibility in designing and tuning the controller parameters so as to operate microgrid within specified constraint in voltage and frequency. For this it is imperative to investigate the effect of controller parameters and different operating conditions on inverter response and define the response in terms of standard transient parameters such as damping, natural frequency and inertia. In this work a methodology has been defined to model the inverter based source as voltage magnitude and phase transfer function. Effect of controller and filter parameters as well as different operating conditions on low, medium and high frequency inverter transients is then obtained and analyzed. Simulation of an inverter based source, is done using Simulink/MATLAB software to validate the analysis.

Voltage sags have emerged to be serious power quality issues especially with the ever expanding size and complexity of the grid. While efforts to mitigate this problem are being continuously made, it is difficult to completely eliminate these sags. To quantify the ride through capability, establish sensitivity of the equipment and test the working of installations made, it is essential to have voltage sag generators. The present work involves in development of a voltage sag generator using power electronic converters. It concentrates on the emulation of a voltage sag of the required characteristics (magnitude, duration and phase shift) using a voltage source inverter, in low voltage systems. Study is carried out with simulation and results are validated by hardware experimental setup.