In this paper, the control of the electric vehicle with in-wheel motor drives is presented. Electric vehicle control is implemented through a drive motor control strategy based on the theory of discrete-time sliding mode. The speed controller is obtained as a combination of discrete-time first order sliding mode control and discrete-time realization of super twisting control algorithm that is commonly used in second-order sliding mode. The design of the proposed speed controller is performed using a discrete-time model of electrical drive. Various tests were performed in Matlab/Simulink software to validate the electronic differential system, vehicle model and engine control algorithm for different types of vehicle movement.
A building-integrated microgrid (BIM) has been a widely utilized concept in low-carbon smart cities. The key advantages of microgrids are using locally available renewable energy sources (RES) and reducing dependency on fossil fuels. Solar photovoltaic (PV) systems and battery storage systems play a crucial role in BIM to achieve desired goals. Due to legal/regulatory and technical restrictions, the distribution system operator (DSO) often imposes zero energy export (ZEE) for these microgrids. Therefore, the sizing of solar-battery systems in BIM, which will be technically feasible and economically optimized, is a challenge for designers, owners and DSO. The objective of this paper is to show the practical approach for design and sizing a microgrid for public buildings using the real data sets of a power consumption and solar energy production. As an example, the BIM for the Faculty of Electrical Engineering, University of Sarajevo is presented.
Direct current (DC) power systems are gaining interest in the last decade due to increased utilization of DC outputted power sources, DC based energy storage (ES) elements and DC inputted loads. Microgrids are also becoming widely researched as the main foundation of smart grid. It is therefore logical to try to utilize DC microgrid (DCMG) concepts in organization of power systems in wide range of applications. DC microgrids have several important advantages compared to alternating current (AC) microgrids. The control system is essential in order to keep DCMG operating properly, reliable and efficient. Their control structures, with special interest in hierarchical control are explored and compared in this paper in terms of architecture and techniques. This paper presents real world applications using DCMG concept. Future research propositions given in the final chapter can be used as a foundation for researchers exploring the area.
Energy consumed by trams is studied in many papers, with a wide diversity of approaches regarding how to model and solve this problem. A novel approach to modeling the power consumption of trams is presented in this paper. To identify the unknown parameters influencing the rolling resistance force acting on the tram, it is necessary to measure the power consumption and speed of a single tram (or multiple trams if there are different car types in operation). The developed model of the tram is calibrated with data from the Sarajevo tram system. Simulation results are compared with measurements and a good correlation was obtained. The power consumption model of the tram with identified parameters can be further used to develop a framework for the power consumption estimation of the traction substation.
Application of a discrete time (DT) sliding mode controller (SMC) in the control structure of the primary controller of a three-phase LCL grid inverter is presented. The design of the inverter side current control loop is performed using a DT linear model of the grid inverter with LCL filter at output terminals. The DT quasi-sliding mode control was used due to its robustness to external and parametric disturbances. Additionally, in order to improve disturbance compensation, a disturbance compensator is also implemented. Also, a specific anti-windup mechanism has been implemented in the structure of the controller to prevent large overshoots in the inverter response in case of random disturbances of grid voltages, or sudden changes in the commanded power. The control of the grid inverter is realized in the reference system synchronized with the voltage of the power grid. The development of the digitally realized control subsystem is presented in detail, starting from theoretical considerations, through computer simulations to experimental tests. The experimental results confirm good static and dynamic performance.
The Advanced Distribution Management System (ADMS) has grown to be a highly complicated system that comprises distribution generation, batteries, power electronics, and, in case of an urban area, an electric transportation system. One of the most essential features of ADMS is maintaining node voltages and branch thermal ratings within defined limits while maintaining minimal system losses and maximizing the use of renewable energy. Voltage VAr control (VVC) is extensively used to address these challenges and is becoming increasingly significant in ADMS. A side from the necessity to manage the system status, VVC must be adaptable to accommodate future Smart City (SC) requirements such as electric-vehicle charging and energy recuperation management. The majority of existing systems control the DC electric transportation system separately from the entire AC system. This paper attempts to tackle the problem using a hybrid single model that incorporates both: AC and DC network components.
This article proposes a new robust dead‐beat controller for multivariable systems using multirate sampled data. Applying a discrete‐time higher order sliding mode control approach, the proposed dead‐beat controller design uses the state‐space nominal model (model without disturbances) of the system and its controllability indices to compute the state feedback matrix. The obtained control annihilates the system state in a minimal number of sampling periods. For example, a heuristic procedure for selecting a sampling time is considered in order to keep maximal amplitudes of control inputs within the allowable limits. Since the dead‐beat control has poor robustness, a new discrete‐time supertwisting disturbance observer is used to suppressed disturbance effects. Stability analysis of the proposed observer has shown that it is suitable for Lipschitz type of disturbances. The sampling period of the disturbance observer is generally smaller than the control sampling period. Properties of the proposed control system are demonstrated in simulation examples.
Modern control techniques of electrical drives (EDs) use robust control algorithms. One of such algorithms is variable structure control (VSC) with sliding mode (SM). SM control needs more information on the controlled plant than the conventional PI(D) control. Valid mathematical model of the controlled plant is necessary for the SM controller design. Generalized mathematical model of two-phase electrical machine and its adaptation to direct current (DC) and induction motor (IM) are given in this paper, employed in the cascade control structure. Also, the basic SM control theory and discrete-time controller design approach, developed by the authors, are given. Finally, experimentally realized examples of speed and position control of DC and IM are given as an illustration of the efficiency of the promoted EDs controller design via discrete-time VSC.
Abstract The paper proposes a discrete-time sliding mode controller for single input linear dynamical systems, under requirements of the fast response without overshoot and strong robustness to matched disturbances. The system input saturation is imposed during the design due to inevitable limitations of most actuators. The system disturbances are compensated by employing nonlinear estimation by integrating the signum of the sliding variable. Hence, the proposed control structure may be regarded as a super-twisting-like algorithm. The designed system stability is analyzed as well as the sliding manifold convergence conditions are derived using a discrete-time model of the system in the δ-domain. The results obtained theoretically have been verified by computer simulations.
Distribution network power flow (DNPF) is a core application of distribution management system (DMS). Two methods to implement fast DNPF are using Newton-Raphson (NR) approach and current iteration (CI) approach. In distribution systems with high penetration of renewable energy sources both methods must be able to model PV nodes correctly and efficiently. This paper explores implementations of NR DNPF and CI DNPF, their execution time and performance in networks with numerous distributed generators.
This paper proposes a control method for multi-input linear systems that provides the closed-loop system dynamics of an arbitrary order having a specified feasible spectrum of poles. By appropriate selection of auxiliary outputs, the system is decoupled into a set of subsystems. The number of these subsystems is equal to the number of control inputs. The desired dynamic of the considered system is achieved using higher order sliding mode, where the sliding mode of appropriate order is realized in each subsystem. The proposed control approach is illustrated by a simulation example.
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