Showing papers by "Jihong Wang published in 2015"
TL;DR: A comprehensive and clear picture of the state-of-the-art technologies available, and where they would be suited for integration into a power generation and distribution system is provided in this article.
2,790 citations
TL;DR: In this article, a wind turbine with compressed air energy storage and a mechanical transmission mechanism is designed and implemented for power integration within the hybrid system, which can transmit additional driving power generalized from the stored compressed air to the turbine shaft for smoothing the wind power fluctuation.
84 citations
TL;DR: Generation-integrated energy storage (GIES) systems store energy at some point along the transformation between the primary energy form and electricity as discussed by the authors, and they have been proposed for wind, nuclear power and they arise naturally in photocatalysis systems that are in development.
43 citations
TL;DR: In this article, a Generalized Predictive Control (GPC) strategy for the superheated steam temperature regulation in a supercritical coal-fired power plant is presented, where a Controlled Auto-Regressive Moving Average (CARMA) model is derived from using the experimental data to approximately predict the plant's future behavior.
Abstract: The design and implementation of a Generalized Predictive Control (GPC) strategy for the superheated steam temperature regulation in a supercritical (SC) coal-fired power plant is presented. A Controlled Auto-Regressive MovingAverage (CARMA) model of the plant is derived from using the experimental data to approximately predict the plant's future behavior. This model is required by the GPC algorithm to calculate the future control inputs. A new GPC controller is designed and its performance is tested through extensive simulation studies. Compared with the performance of the plant using a conventional PID controller, the steam temperature controlled by the GPC controller is found to be more stable. The stable steam temperature leads to more efficient plant operation and energy saving, as demonstrated by the simulation results. Plant performance improvement is also tested while the plant experiences the load demand changes and disturbances resulting from the malfunctioning of coal mills.
32 citations
02 Nov 2015
TL;DR: The derived proportion integration (PI) controller proves to be optimum where it is a compromise between compensating the random time delay effects and degrading the system dynamic performance.
Abstract: The deregulation of the electricity market made, the open communication infrastructure an exigent need for, future power system. In this scenario dedicated, communication links are replaced by shared networks., These shared networks are characterized by random time, delay and data loss. The random time delay and data loss, may lead to system instability if they are not considered, during the controller design stage. Load frequency control, systems used to rely on dedicated communication links. To, meet future power system challenges these dedicated, networks will be replaced by open communication links, which make the system stochastic. In this paper the, stochastic stabilization of load frequency control system, under networked environment is investigated. The shared, network is represented by three states which are governed, by Markov chains. A controller synthesis method based on, the stochastic stability criteria is presented in the paper. A. one-area load frequency control system is chosen as case, study. The effectiveness of the proposed method for the, controller synthesis is tested through simulation. The, derived PI controller proves to be optimum where it is a, compromise between compensating the random time delay, effects and degrading the dynamic performance.
23 citations
TL;DR: The cosimulation study and experimental validation results show that the MOEA engine optimizer can find the optimal HCCI engine actuators' settings with satisfactory accuracy and a much lower time consumption than usual.
Abstract: Modern engines feature a considerable number of adjustable control parameters With this increasing number of degrees of freedom (DoFs) for engines and the consequent considerable calibration effort required to optimize engine performance, traditional manual engine calibration or optimization methods are reaching their limits An automated and efficient engine optimization approach is desired In this paper, interdisciplinary research on a multiobjective evolutionary algorithm (MOEA)-based global optimization approach is developed for a homogeneous charge compression ignition (HCCI) engine The performance of the HCCI engine optimizer is demonstrated by the cosimulation between an HCCI engine Simulink model and a Strength Pareto Evolutionary Algorithm 2 (SPEA2)-based multiobjective optimizer Java code The HCCI engine model is developed by Simulink and validated with different engine speeds (1500–2250 r/min) and indicated mean effective pressures (IMEPs) (3–45 bar) The model can simulate the HCCI engine's indicated specific fuel consumption (ISFC) and indicated specific hydrocarbon (ISHC) emissions with good accuracy The introduced MOEA optimization is an approach to efficiently optimize the engine ISFC and ISHC simultaneously by adjusting the settings of the engine's actuators automatically through the SPEA2 In this paper, the settings of the HCCI engine's actuators are intake valve opening (IVO) timing, exhaust valve closing (EVC) timing, and relative air-to-fuel ratio $\lambda$ The cosimulation study and experimental validation results show that the MOEA engine optimizer can find the optimal HCCI engine actuators' settings with satisfactory accuracy and a much lower time consumption than usual
20 citations
TL;DR: A method based on the finite difference approximation is proposed in this paper for estimating the maximum time delay tolerance, which has a simple structure and is easy to apply.
Abstract: Networked control system is a research area where the theory is behind practice. Closing the feedback loop through shared network induces time delay and some of the data could be lost. So the network induced time delay and data loss are inevitable in networked control Systems. The time delay may degrade the performance of control systems or even worse lead to system instability. Once the structure of a networked control system is confirmed, it is essential to identify the maximum time delay allowed for maintaining the system stability which, in turn, is also associated with the process of controller design. Some studies reported methods for estimating the maximum time delay allowed for maintaining system stability; however, most of the reported methods are normally overcomplicated for practical applications. A method based on the finite difference approximation is proposed in this paper for estimating the maximum time delay tolerance, which has a simple structure and is easy to apply.
13 citations
TL;DR: In this article, a control-oriented linearized model that relates small deviations of the capacitance, load admittance, and angular velocity, to corresponding deviations of voltage amplitude is proposed.
Abstract: The complexity and strong nonlinearity of the model of a self-excited induction generator hinder the systematic design of a voltage regulation system. Using a special reference frame aligned with the stator voltage vector, the paper succeeds in developing a control-oriented linearized model that relates small deviations of the capacitance, load admittance, and angular velocity, to corresponding deviations of the voltage amplitude. Transfer functions are also computed based on the linear model. A stability analysis predicts rapidly decaying oscillatory transients combined with a primary component with slower exponential decay. Simulated transient responses of the full and linearized models demonstrate the validity of the approximation and are in good agreement with experiments.
13 citations
TL;DR: In this article, a simplified dynamic model for the integrated gasification combined cycle (IGCC) process is developed, in which Texaco gasifier is chosen to give the basic representation for the IGCC process.
Abstract: Integrated gasification combined cycle (IGCC) is considered as a viable option for low emission power generation and carbon dioxide sequestration. As a part of the process of IGCC plant design and development, modelling and simulation study of the whole IGCC process is important for thermodynamic performance evaluation, study of carbon capture readiness and economic analysis. The work presented in the paper is to develop such a whole system model and simulation platform. A simplified dynamic model for the IGCC process is developed, in which Texaco gasifier is chosen to give the basic representation for the IGCC process. The chemical equilibriums principle is used to predict the syngas contents in the modelling procedure. The influences of key parameters to regulate the input such as oxygen/coal ratio and water/coal ratio to syngas generation are studied. The simulation results are validated by comparing with the industry data provided by the Lu-nan fertilizer factory. Water-shift reactor, gas turbine and ...
12 citations
21 Dec 2015
TL;DR: This paper presents the stabilization of parallel DC/DC converters over stochastic nondeterministic network represented by Markov chains.
Abstract: Microgrids and Hybrid Electric Vehicles rely on parallel DC/DC converters for power generation. DC/DC converters are connected in parallel to share the same load. The control signals are distributed through wires. The wiring increases the complexity and reduces the reliability. The recent advances in shared wireless networks made them viable and cheap alternative to direct wiring. Distributing the control signals over shared networks reduces the complexity in the wiring and enhances the reliability. Transmitting control signals through shared network induces time delay and data loss which may destabilize the system. These imperfections make the system stochastic and in many cases these imperfection can be modeled using Markov chains. This paper presents the stabilization of parallel DC/DC converters over stochastic nondeterministic network represented by Markov chains.
10 citations
TL;DR: In this paper, a full dynamic mathematical model of an automotive windshield wiper system is developed and validated, and a unique mathematical model is developed to capture the devices two speed operation.
Abstract: In order to remain competitive, automotive companies use advanced simulation methods to assist in product development. Hardware in the loop (HIL) simulation is one such technique. To use HIL in the development of automotive electronic control units (ECU), accurate simulation models of the ECU's sensors and actuators are needed. In this work, a full dynamic mathematical model of an automotive windshield wiper system is developed and validated. In the modelling phase, the wiper motor is analysed and a unique mathematical model is developed to capture the devices two speed operation. A multi-body dynamic model of the linkages is implemented using the MathWorks' SimMechanics software. The model is validated experimentally and its parameters are identified using genetic algorithms. The model is then simplified to allow it to be simulated in real time, making it suitable for HIL simulation. The HIL compatible model is used in the development of Automotive ECUs.
07 Jul 2015
TL;DR: The proposed control strategy can achieve the desired control performance under disturbances and uncertainties caused by unknown external forces, frictions, initial positions and sudden changes in desired position.
Abstract: In this paper a practical method for robust control of an inverted pendulum driven by a linear pneumatic actuator is presented. The whole system mathematical model is derived, verified and utilized in the paper to guide the initial design of the robust control strategy. The control strategy consists of an inner loop controlling the force acting on the piston by means of a PI controller; and the position and angle of the pendulum are controlled via a full state feedback outer loop controller. A friction estimator compensates for the variable nonlinear friction distribution. The merits and strength of the controllers are highlighted by comparison of the control strategy with a more complex model-based nonlinear feedback linearization controller for the inner loop. The proposed control strategy can achieve the desired control performance under disturbances and uncertainties caused by unknown external forces, frictions, initial positions and sudden changes in desired position.
07 Jul 2015
TL;DR: A new hybrid wind turbine concept is presented comprising a small scale wind turbine, a scroll air motor and a planetary gear box, which acts as the key power transmission component, allowing for smooth power generation by adding power through compressed air energy storage in moments of wind troughs and enables maximum power point tracking of the turbine.
Abstract: The share of renewable energy utilization is growing fast in recent years, resulting in an increase in intermittence in power supply systems. Additionally, the demand profile will change drastically in the short and long term through increasing electrification of transport and heating, respectively. It is an important task to address the impact caused by the generation and demand uncertainties. In this paper, a new hybrid wind turbine concept is presented comprising a small scale wind turbine, a scroll air motor and a planetary gear box, which acts as the key power transmission component. It functions as a power split device, allowing for smooth power generation by adding power through compressed air energy storage in moments of wind troughs and, furthermore, enables maximum power point tracking of the turbine. In this paper a dynamic mathematical model is derived and simulation results are analyzed, while highlighting the benefits of the proposed design structure.
21 Dec 2015
TL;DR: In this article, a gas turbine operating currently in North Benghazi Power Plant (NBPP) is the process chosen to be the focus of study in the paper and the CVA is described from mathematics and linear algebra view points.
Abstract: The topic of modeling and identification of gas turbines has become an interesting research area for many years and will become so for many years to come. This paper clarifies what is known as Canonical Variate Algorithm or canonical variate analysis (CVA) method of subspace state space system identification. A gas turbine operating currently in North Benghazi Power Plant (NBPP) is the process chosen to be our focus of study in the paper. The CVA is described from mathematics and linear algebra view points. The process of gas turbine under investigation is illustrated and discussed. Through gathered operating data from the power plant under study and MATLAB System Identification Toolbox, the state space model is developed and tested against different data signals. Simulation results have shown the robustness and the accuracy of the presented method of identification.