Cohesive Motion Control Algorithm for Formation of Multiple Autonomous Agents

This paper presents a motion control strategy for a rigid and constraint consistent formation that can be modeled by a directed graph whose each vertex represents individual agent kinematics and each of directed edges represents distance constraints maintained by an agent, called follower, to its neighbouring agent. A rigid and constraint consistent graph is called persistent graph. A persistent graph is minimally persistent if it is persistent, and no edge can be removed without losing its persistence. An acyclic (free of cycles in its sensing pattern) minimally persistent graph of Leader-Follower structure has been considered here which can be constructed from an initial Leader-Follower seed (initial graph with two vertices, one is Leader and another one is First Follower and one edge in between them is directed towards Leader) by Henneberg sequence (a procedure of growing a graph) containing only vertex additions. A set of nonlinear optimization-based decentralized control laws for mobile autonomous point agents in two dimensional plane have been proposed. An infinitesimal deviation in formation shape created continuous motion of Leader is compensated by corresponding continuous motion of other agents fulfilling the shortest path criteria

An Overview of Fully Integrated Switching Power Converters Based on Switched-Capacitor versus Inductive Approach and Their Advanced Control Aspects

This paper reviews and discusses the state of the art of integrated switched-capacitor and integrated inductive power converters and provides a perspective on progress towards the realization of efficient and fully integrated DC–DC power conversion. A comparative assessment has been presented to review the salient features in the utilization of transistor technology between the switched-capacitor and switched inductor converter-based approaches. First, applications that drive the need for integrated switching power converters are introduced, and further implementation issues to be addressed also are discussed. Second, different control and modulation strategies applied to integrated switched-capacitor (voltage conversion ratio control, duty cycle control, switching frequency modulation, Ron modulation, and series low drop out) and inductive converters (pulse width modulation and pulse frequency modulation) are then discussed. Finally, a complete set of integrated power converters are related in terms of their conditions and operation metrics, thereby allowing a categorization to provide the suitability of converter technologies

Forecasting of Global Solar Insolation Using Ensemble Kalman Filter Based Clearness Index Model

This paper describes a novel approach in developing a model for forecasting of global insolation on a horizontal plane. In the proposed forecasting model, constraints such as latitude and whole precipitable water content in vertical column of that location, have been used. These parameters can be easily measurable with global positioning system (GPS). The aforesaid model has been developed by using the above datasets generated from different locations of India. The model has been verified by calculating theoretical global insolation for different sites covering east, west, north, south and central region with the measured values from the same locations. The model has also been validated on a region, from which data has not been used during the development of the model. In the model clearness index coefficients (KT) are updated using ensemble Kalman filter (EnKF) algorithm. The forecasting efficacies using KT model and EnKF algorithm have also been verified by comparing two popular algorithms namely recursive least square (RLS) and Kalman filter (KF) algorithms. Minimum mean absolute percentage error (MAPE), mean square error (MSE) and correlation coefficient (R) value obtained in global solar insolation estimation using EnKF in one of the location is 2.4, 0.0285 and 0.9866 respectively

Multi-objective Optimized Smart Charge Controller for Electric Vehicle Applications

The continuous deployment of distributed energy sources and increase in the adoption of Electric Vehicles (EVs) require smart charging algorithms. Existing EV chargers offer limited flexibility and controllability, and do not fully consider factors (such as, EV user waiting time and length of next trip) as well as the potential opportunities and financial benefits from using EVs to support the grid, charge from renewable energy and deal with the negative impacts of intermittent renewable generation. The lack of adequate smart EV charging may result in high battery degradation, violation of grid control statutory limits, high greenhouse emissions and charging cost. In this paper, a Neuro-Fuzzy-PSO based novel and advanced smart charge controller is proposed which considers user requirements, energy tariff, grid condition (e.g., voltage or frequency), renewable (PV) output and battery state of health. A rule based Fuzzy controller becomes complex as the number of inputs to the controller increases. Also, it becomes difficult to achieve an optimum operation due to conflicting nature of control requirements. To optimize the controller response, Particle Swarm Optimization (PSO) technique is proposed to provide a global optimum solution based on a pre-defined cost function and to address the implementation complexity PSO is combined with neural network. The proposed Neuro-Fuzzy-PSO control algorithm meets EV user requirements, work within technical constraints and is simple to implement in real-time (and requires less processing time). Simulation using MATLAB and experimental results using dSPACE digital real-time emulator are presented to demonstrate the effectiveness of the proposed controller

Anti-windup compensator design for power system subjected to time-delay and actuator saturation

In this study, a delay-dependent anti-windup compensator (AWC) is designed for supplementary damping control (SDC) of flexible AC transmission system (FACTS) device to enhance the damping of inter-area oscillations of the power system subjected to time-delay and actuator saturation. By employing global signal measurements, an SDC of FACTS device is designed without considering the effect of time-delay and actuator saturation to stabilise the power system using a robust output feedback controller with pole placement approach. Then, based on the generalised sector condition and Lyapunov–Krasovskii functional, an add-on delay-dependent AWC is designed to mitigate the adverse effect of time-delay and actuator saturation non-linearity. For the design of delay-dependent AWC, sufficient conditions guarantee the asymptotic stability of the closed-loop power system are formulated in the form of linear matrix inequalities (LMIs). These conditions are cast into the LMI-based convex optimisation problem to compute the AWC gains. To evaluate the effectiveness of the proposed controller, non-linear simulations were performed first using MATLAB/Simulink. Then, the authors implemented the proposed controller in real-time using the Opal-RT digital simulator. From the obtained results, it is observed that the proposed controller enhances the damping of inter-area oscillations by compensating the effect of time delay and actuator saturation

Adaptive double-integral-sliding-mode-maximum-power-point tracker for a photovoltaic system

This study proposed an adaptive double-integral-sliding-mode-controller-maximum-power-point tracker (DISMC-MPPT) for maximum-power-point (MPP) tracking of a photovoltaic (PV) system. The objective of this study is to design a DISMC-MPPT with a new adaptive double-integral-sliding surface in order that MPP tracking is achieved with reduced chattering and steady-state error in the output voltage or current. The proposed adaptive DISMC-MPPT possesses a very simple and efficient PWM-based control structure that keeps switching frequency constant. The controller is designed considering the reaching and stability conditions to provide robustness and stability. The performance of the proposed adaptive DISMC-MPPT is verified through both MATLAB/Simulink simulation and experiment using a 0.2 kW prototype PV system. From the obtained results, it is found out that this DISMC-MPPT is found to be more efficient compared with that of Tan's and Jiao's DISMC-MPPTs