Point Tracking Mode Research Articles

Power coordination control strategy of microgrid based on photovoltaic generation

In order to solve the large-scale grid-connected photovoltaic cells caused by power fluctuations, power quality decline and other issues. This paper proposes and researches a power coordination control strategy for microgrid based on photovoltaic power generation. The principle of photovoltaic cells and the switching of maximum power point tracking and limited power mode are studied. The stability control methods of DC bus voltage, AC bus wire and frequency are studied. The model of microgrid is established and moreover, based on the power of microgrid and the charging state of storage battery, the operation of microgrid is divided into different working modes. The stable operation of microgrid is realized by adjusting the output power of each unit in different working modes. The calculation shows that the control strategy can effectively reduce the power fluctuation in the microgrid and improve the output power of renewable energy. Finally, the feasibility and effectiveness of the proposed methods are verified by experiments.

Harnessing Maximum Power from PV Module using DC-DC Converter

Solar energy is one of the most potent sources of energy. In the wake of depleting fossil fuel energy sources and growing environmental concerns, world is in a relentless drive towards utilizing natural resources like sun efficiently. The aim of the project is to make the solar module work in MPPT mode (Maximum Power Point Tracking) Mode. At this condition, the system is able to extract maximum power from the module without affecting the PV module. MPPT control here is obtained using boost converter. Applying PWM with proper controlling algorithm will vary the duty ratio of the converter such that system will run in MPP mode.

Control Strategies for Enhancing Frequency Stability by DFIGs in a Power System with High Percentage of Wind Power Penetration

Nowadays, regarding high percentage of wind power penetration in power systems, operating conditions of power system necessitates wind turbine generators (WTGs) to contribute in frequency regulation of the system, similar to the conventional units. To reach this goal, active power output of WTGs must be controlled, but this issue distances the operating conditions of WTGs from maximum power point tracking (MPPT) mode. This paper initially presents a completed model of doubly fed induction generator (DFIG) for dynamic studies in frequency stability analysis. Next, a coordinated control strategy to regulate active power command set point (Pcmd) for individual WTGs in a wind farm (WF) and a control strategy to regulate wind power output of DFIG upon operator’s request is presented. Stability is assured under different wind conditions in the proposed control strategy. Individual WTGs set point allocation is performed applying fuzzy logic controller (FLC), while emotional learning based intelligent controller is used in regulation of the coefficient in the DFIG to reach the best stability conditions. Simulation results, performed on a test system consisting of both conventional units and WTGs, validate the effectiveness of the proposed control strategy in comparison with other mentioned solutions.

A nonlinear control algorithm for a wind turbine

Purpose – The purpose of this paper is to propose a new nonlinear control algorithm to control a wind turbine based on permanent magnet synchronous generator (PMSG) connected to the grid via a back-to-back converter. The control algorithm is composed of a flatness-based method for the machine side convertor (MSC) and a voltage-oriented method for the grid side converter (GSC). Design/methodology/approach – For the MSC control, the output variable is chosen properly to prove that the system is flat at first. Then, the appropriate reference trajectories are planned on its components. The reference trajectories are such designed that the system operates in maximum power point tracking (MPPT) mode. Finally, state feedback regulators are used to force the system output to follow its reference. To control the GSC, a classical voltage-oriented control method is used. Findings – The simulation results obtained with a random wind speed are presented in order to prove the validity of the proposed control algorithm. These results show that the system is controlled successfully while it operates in the MPPT mode or in its maximum power limitation mode. Originality/value – In this paper, a new algorithm based on flatness property is presented to control a variable speed wind turbine based on a PMSG. The proposed control method allows the system to operate in optimal operating modes.

Spacecraft Attitude Determination System Using Nano-Optical Devices and Linux Software Libraries

This paper presents a new spacecraft attitude determination system based on small optical devices and Linux-based software. This technology intends to support nanosatellite operations by providing low-cost, low-mass, low-volume, low-power, and redundant attitude determination capabilities with quick and straightforward onboard programmability for real-time spacecraft operations. The chosen commercial-off-the-shelf optical devices perform sensing and image processing on the same circuit board, and they are biologically inspired by insects’ vision systems, which measure optical flow and/or track objects while navigating the environment. The firmware on the devices is modified here to enable communication with PC/104 form-factor embedded computers running RealTime Application Interface for Linux. Algorithms are developed for operations using optical flow mode and point-tracking mode, and an application programming interface, along with Simulink® S-functions, is created. The performances of the proposed system, used in optical flow mode, point-tracking mode, and a combination of the two, are assessed using a spacecraft simulator at Rensselaer Polytechnic Institute, and they are compared with measurements from the PhaseSpace® motion-tracking system.

Synthetically Control of a Hybrid PV/FC/SC Power System for Stand-Alone Applications

In this study, a simple and practical control scheme for power assignment and load-following of a Hybrid Power System (HPS) is proposed. The system consists of Photovoltaic (PV), Fuel Cell (FC), Super-Capacitor (SC), dc load, ac load and different kinds of converters. PV is chosen as a prior source, which normally operates in Maximum Power Point Tracking (MPPT) mode. In order to achieve 24 h power supply under various natural conditions, FC is used as a backup source to provide the power deficit between solar generation and load demand. Taking the slow FC system dynamics into account, FC power slope has been limited to protect FC from fuel starvation, whereas SC is chosen to satisfy the requirement of the sudden load and solar radiation changes. Besides, a V/f controller is designed to meet ac load demand, while keeping the voltage and frequency within an acceptable range. All the details of this study, including system structure, control diagrams and MATLAB simulation results, are presented.