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In recent years, demand response programs have attracted attentions for reducing network peak. Demand Response (DR) is the variation of energy consumption by customers in response to incentives, aiming to reduce consumption at peak hours. In general, DR methods might be based on price or incentive; this paper studies Interruptible/Curtailable (I/C) Demand Response Program. In this paper, the effect of changes in incentives and penalties on the implementation of I/C service on the microgrid is studied considering different uncertainties. The microgrid studied in this paper can exchange power with the upstream network. Effect of implementing I/C service in different modes on operation cost, customer profit, load factor, and peak reduction is evaluated in this paper. To prove the effectiveness of the presented method, this model is implemented on an 11-bus microgrid in a 24-hour period, and the results are investigated.

– Due to the increasing need of electrical energy and environmental issues corresponding to fossil fuels such as global warming, renewable energy sources attracted a lot of engineers and researchers to themselves. Among renewable energy sources, wind energy as the most accessible energy source, has been among the most popular research topics in recent years. Doubly-Fed Induction Generator (DFIG) is a commonly used configuration for variable speed Wind Energy Conversion Systems (WECSs) because of its independent control of active and reactive powers and extensive range of wind speed variations. In this paper, a Pulse Width Modulation (PWM) rectifier and a Z-Source Inverter (ZSI) are used as Grid Side Converter (GSC) and Rotor Side Converter (RSC), respectively. Z-Source Inverter is a newly proposed power electronic converter which has solved the limitations and disadvantages of conventional voltage source and current source inverters. A modified Space Vector Modulation (SVM) technic based on Sliding Mode generator power control is used to control the switching pattern of the ZSI. To verify the effectiveness of the proposed control system, simulations result in MATLAB/Simulink software are presented. Different wind speeds as well as independent control of active and reactive powers are examined through these simulations.

Today, with the movement of power systems towards competition and breaking the monopoly, the importance of ancillary services like reactive power and voltage control has increased. One of the most important services is power reactive service. Independent System Operator (ISO)has to provide reactive power in deregulated environments which are considered one of the six ancillary services of power system which should be provided by the ISO to improve system security. ISO is responsible to provide reactive power in deregulated environments. Purpose of this paper is to present a method for pricing reactive power. In this method, reactive power pricing is performed based on Financial Transmission Rights (FTRs). The novelty of this study is that it has offered a new method for pricing reactive power based on FTR. Reactive power pricing methods presented so far have not considered congestion costs of the transmission system but this method considers congestions costs also through considering FTR. In this paper, results of this method are evaluated on a standard IEEE-30 bus test system and compared with current pricing method used for pricing reactive power in Iran.

Due to their complicated dynamics coupled with kinematics and non-holonomic underactuated behavior, spherical robots cannot unveil their full maneuverability when linear controllers are applied. Because of that, position and trajectory tracking of spherical robots have been the main challenges recently tackled in the literature. In this paper, two controllers are introduced to provide the effective path following of a 2-DOF spherical robot. A sliding mode controller (SMC) and a fuzzy sliding mode controller (FSMC) are designed and compared. The Lyapunov stability theorem is employed to analyze the stability of the controller and the tracking error. The simulation results indicate that the spherical robot controlled by the proposed methods is capable of moving to a desired point from any given initial point with minimum tracking error.

DC microgrid (MG) is an important structure of future electrical power systems, with many advantages in off grid and application for grid connected operation. It is considered for its stability, safety, reliability, and optimum efficiency. Power produced with renewable energy sources or changes in different stages or for reliability issue is controlled by power electronic advices like converters and inverters. Although some researches could invent new methods for dealing with challenges in microgrid systems, some aspects are still under research. Meanwhile, grounding architectures impact on power electronic converters needed to investigate more. This research presents the grounding method acts as a high impedance grounding in normal condition to avoid DC stray currents flow, and for fault transients acts as solid grounding. Then ground fault current is limited through a limiter resistor, to the permissible value, resulted in protecting power electronic interfaces.

In this paper a controller is designed for voltage source converters (VSC) using Nyquist array. Real systems existing in industry are nonlinear systems with multiple inputs and multiple outputs (MIMO). Such systems are always affected by different undesired factors like noise and distortion. But multivariable control design for linear systems is based on theories which are robust against noise, disturbances and uncertainties. DC and AC part of VSC are affected with disturbances which should be controlled. Thus, a Nyquist array is applied to VSC to study design and analysis of multivariable control based on the presented theories. The proposed controller is illustrated by simulation.

This paper deals with a reliable control technique to control wind generator. The wind generator’s structure is categorized as a complicated nonlinear system. The accurate scheme of this system cannot be obtained, so the model has high uncertainty and nonlinearity. So, controlling of this system becomes more attractive for scholars; however, many of approaches were given for regulating of wind generators explore these kind of systems in a normal weather situations. In practice several generators operate in an unpleasant weather condition. For having a realistic controller, is assumed that there are uncertainties in the model, for this purpose wind generator is recommended in the cold climate, also with the ice on generators blades. A promising controller is modeled, in order to control the pitch angel of wind. Finally, simulation outcomes will be provided to confirm the presented control approach.

This paper presents a Linear-Quadratic-Gaussian with Loop-Transfer-Recovery (LQG/LTR) controller for a three-phase voltage source converter (VSC) system acting as a rectifier. The actual model of VSC has nonlinear dynamics with multiple inputs and multiple outputs (MIMO). Furthermore, the systems dynamics is always affected by noise and disturbance. Moreover, due to the nonlinear behavior of the VSC, any proposed controller must show robustness against modeling uncertainties. The presented approach employs control theories so that the resulted linear controller shows robustness to the nonlinearities and measurement noise. The effectiveness of the proposed work is numerically verified.

In this paper, simultaneous employment of electrical vehicle-to-grid (V2G) and wind power generation in security constrained unit commitment (SCUC) problem are considered. SCUC problem as one of the most highlighted research area in electrical power system provides a commitment scheduling table for the generation units in which generation operator aims to maximize system security as well as to minimize generation costs along with the satisfying system and units constraints. The technology of V2G as a new energy resource absorbed remarkable consideration, recently. V2G reduces the dependence of generation procedure to the small and costly thermal units and subsequently has tremendously impact on diminishing operation costs as well as ameliorate of load vacillations management. Besides the V2G, utilization of renewable energies like wind-based generation gained considerable attention in last decade. In this paper, simultaneous employment of V2G and wind power in scheduling and operation of power systems considering the uncertainty of wind generation is presented. Numerical results of independent use of V2G and simultaneous utilization of V2G and wind-based generation are provided and effects of such the obligations on the reduction of generation costs and enhancement of operation indexes and penetration of wind farms in power systems are investigated.

Due to their complicated dynamics and underactuated nature, spherical robots require advanced control methods to reveal all their manoeuvrability features. This paper considers the path tracking control problem of a spherical robot equipped with a 2-DOF pendulum. The pendulum has two input torques that allow it to take angles about the robot’s transverse and longitudinal axes. Due to mechanical technicalities, it is assumed that these angles are immeasurable. First, a neural network observer is designed to estimate the pendulum angles. Then a modified sliding mode controller is proposed for the robot’s tracking control in the presence of uncertainties. Next, the Lyapunov theorem is utilized to analyse the overall stability of the proposed scheme, including the convergence of the observer estimation and the trajectory tracking errors. Finally, simulation results are provided to indicate the effectiveness of the proposed method in comparison with the other available control approaches.