Due to inherent advantages of DC system over AC system such as compatibility with renewable energy sources, storage devices and modern loads, Direct Current Microgrid (DCMG) has been one of the key research areas from last few years. The power and energy management in the DCMG system has been a challenge for the researchers. MG structure and control strategies are the integrated part of the power and energy management system. This paper covers all the aspects of the control of DCMG, whether it is DC bus voltage, power or energy related. Different MG Structures with their comparative analysis has been given in this paper. Various control schemes: Basic control schemes like centralized, decentralized and distributed control and multilevel control scheme such as hierarchal control has been discussed. The Power management in grid-connected, Islanded mode and transition mode has been presented. Different energy management strategies have been presented as energy management plays very important role in optimizing the size and rating of energy storage system and their maximum utilization. The energy management of a battery and super capacitor based HESS in all configurations has also been discussed and finally, future trends in further research are presented.

A review on overall control of DC microgrids

Typical active safety systems that control the dynamics of passenger cars rely on the real-time monitoring of the vehicle sideslip angle (VSA), together with other signals such as the wheel angular velocities, steering angle, lateral acceleration, and the rate of rotation about the vertical axis, which is known as the yaw rate. The VSA (also known as the attitude or “drifting” angle) is defined as the angle between the vehicle’s longitudinal axis and the direction of travel, taking the centre of gravity as a reference. It is basically a measure of the misalignment between vehicle orientation and trajectory; therefore, it is a vital piece of information enabling directional stability assessment, such as in transience following emergency manoeuvres, for instance. As explained in the introduction, the VSA is not measured directly for impracticality, and it is estimated on the basis of available measurements such as wheel velocities, linear and angular accelerations, etc. This work is intended to provide a comprehensive literature review on the VSA estimation problem. Two main estimation methods have been categorised, i.e., observer-based and neural network-based, focussing on the most effective and innovative approaches. As the first method normally relies on a vehicle model, a review of the vehicle models has been included. The advantages and limitations of each technique have been highlighted and discussed.

https://www.mdpi.com/2076-3417/8/3/355/pdf

On the vehicle sideslip angle estimation: a literature review of methods, models and innovations

https://onlinelibrary.wiley.com/doi/pdf/10.1002/2050-7038.12885

A brief review on microgrids: Operation, applications, modeling, and control

A comprehensive survey on control strategies of distributed generation power systems under normal and abnormal conditions

Hybrid AC/DC microgrid test system simulation: grid-connected mode.

Microgrid control: A comprehensive survey

Microgrid modelling: A comprehensive survey

In microgrid (MG) modeling, the renewable energy sources (RESs) are mostly represented by the detailed small-signal modeling (SSM) of its interfacing inverter. In these models, the input dc-bus link voltage is assumed to be constant. However, due to generation intermittency of RESs, viz., solar photovoltaics (PV) or wind turbines, this assumption is not appropriate. Also, the effects of storage devices are ignored. Now, this detailed SSM of inverters alongside loads and network gives a system of systems architecture to the MGs, modeling of which leads to a higher-order system with a large number of states. In this work, the SSM of a standard MG system is developed using simplified lower-order models of solar PVs and batteries that incorporate generation uncertainties by considering the dynamics of both input dc and output ac terminals of the inverter. The obtained reduced order model is computationally more efficient. The MG test system includes two PV sources having dedicated parallel RLC loads and low voltage feeder. The proposed model is validated by performing comprehensive time and frequency domain analysis for transient and steady-state operations by MATLAB based simulations and hardware-in-loop tests using the real-time digital simulator (RTDS) and dSPACE processor board.

Simplified Modeling and HIL Validation of Solar PVs and Storage-Based Islanded Microgrid With Generation Uncertainties

Maintaining nominal voltage and frequency ( V-f ) for an isolated microgrid (MG) with photovoltaic (PV)-battery system needs stringent control arrangement due to generation arbitraries of renewable energy sources. In present article, a robust V-f controller based on decentralized output-feedback optimal linear quadratic regulator principle is proposed. As state-feedback is not involved, it avoids the usage of any estimator or observer, which makes it computationally more efficient. Moreover, its decentralized structure works on local parameter measurements that eliminate expensive communication infrastructure, making it economical. All possible uncertainties from both source and load sides, neighboring bus parameters are considered for V-f regulation using the resistive-droop mechanism that is more accurate for low voltage resistive network. For this purpose, a novel lower-order simplified small-signal MG model including two PV-battery with exclusive parallel RLC loads and LV network is used, which accounts for intermittency as variable dc-bus link dynamics. The whole MG model is segregated into two subsystems with inclusion of interconnection dynamics. The viability of proposed controller is verified by comprehensive tests, viz., variable solar irradiance, voltage set-point tracking under continuous-bounded and large-scale load perturbations, nearby bus parameter disturbances using hardware-in-the-loop simulations with real-time digital simulator and MATLAB via dSPACE controller.

Decentralized Output-Feedback-Based Robust LQR V-f Controller for PV-Battery Microgrid Including Generation Uncertainties

Microgrids (MGs) concepts are a systematic way to integrate the supply and demand side along with the storage devices. These mostly use renewable energy resources (RESs) viz. solar PV and wind turbines, interfaced to the low voltage distribution network via an inverter. As several components are involved, MGs has a system of systems (SoSs) architecture and its modeling leads to form a high order system. Hence, for the controllers' design purposes, these models had to be brought down to a reduced lower order system. This paper performs a comparative study of various model order reduction (MOR) techniques viz. aggregation, balanced truncation (BT), singular perturbation (SP) and Hankel norm approximation (HNA) on a two-source autonomous MG system. The standard performance evaluation methods used for a multi-input multi-output (MIMO) system i.e. the step and impulse responses, eigenvalue analysis and Bode plots were considered to determine the effectiveness of these MOR method.

Sachidananda Sen

Papers

Microgrid control: A comprehensive survey

Microgrid modelling: A comprehensive survey

Simplified Modeling and HIL Validation of Solar PVs and Storage-Based Islanded Microgrid With Generation Uncertainties

Decentralized Output-Feedback-Based Robust LQR V-f Controller for PV-Battery Microgrid Including Generation Uncertainties

Assessment of Various MOR Techniques on an Inverter-Based Microgrid Model