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High performance decoupled active and reactive power control for three-phase grid-tied inverters using model predictive control

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Protection and Control of Modern power Systems 2021年第1期6卷 311-329页

作者： Mohamed Azab EEET Department Yanbu Industrial CollegeYanbu AL SinaiyahSaudi Arabia EEET Department Faculty of EngineeringBenha UniversityBanhaEgypt

Finite control set-model predictive control (FCS-MPC) is employed in this paper to control the operation of a three-phase grid-connected string inverter based on a direct PQ control scheme. The main objective is to achieve high-performance decoupled control of the active and reactive powers injected to the grid from distributed energy resources (DER).The FCS-MPC scheme instantaneously searches for and applies the optimum inverter switching state that can achieve certain goals, such as minimum deviation between reference and actual power;so that both power components (P and Q) are well controlled to their reference values.In addition, an effective method to attenuate undesired cross coupling between the P and Q control loops, which occurs only during transient operation, is investigated. The proposed method is based on the variation of the weight factors of the terms of the FCS-MPC cost function, so a higher weight factor is assigned to the cost function term that is exposed to greater disturbance. Empirical formulae of optimum weight factors as functions of the reference active and reactive power signals are proposed and mathematically derived. The investigated FCS-MPC control scheme is incorporated with the LVRT function to support the grid voltage in fulfilling and accomplishing the up-to-date grid codes. The LVRT algorithm is based on a modification of the references of active and reactive powers as functions of the instantaneous grid voltage such that suitable values of P and Q are injected to the grid during voltage sag.The performance of the elaborated FCS-MPC PQ scheme is studied under various operating scenarios, including steady-state and transient conditions. Results demonstrate the validity and effectiveness of the proposed scheme with regard to the achievement of high-performance operation and quick response of grid-tied inverters during normal and fault modes.

关键词： Model predictive control Finite control set Grid-connected inverter active power Reactive power Distributed generation Low voltage ride through PQ theory FCS-MPC LVRT

Performance of PI controller for control of active and reactive power in DFIG operating in a grid-connected variable speed wind energy conversion system

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Frontiers in Energy 2014年第3期8卷 371-378页

作者： Azzouz TAMAARAT Abdelhamid BENAKCHA Laboratoire LGEB Biskra University Biskra City 07000 Algeria

Due to several factors, wind energy becomes an essential type of electricity generation. The share of this type of energy in the network is becoming increasingly important. The objective of this work is to present the modeling and control strategy of a grid connected wind power generation scheme using a doubly fed induction generator （DFIG） driven by the rotor. This paper is to present the complete modeling and simulation of a wind turbine driven DFIG in the second mode of operating （the wind turbine pitch control is deactivated）. It will introduce the vector control, which makes it possible to control independently the active and reactive power exchanged between the stator of the generator and the grid, based on vector control concept （with stator flux or voltage orientation） with classical PI controllers. Various simula- tion tests are conducted to observe the system behavior and evaluate the performance of the control for some optimization criteria （energy efficiency and the robustness of the control）. It is also interesting to play on the quality of electric power by controlling the reactive power exchanged with the grid, which will facilitate making a local correction of power factor.

关键词： wind power doubly fed induction generator（DFIG） vector control active power reactive power,maximum power point tracking （MPPT）

SMOGN,MFO,and XGBoost Based Excitation Current Prediction Model for Synchronous Machine

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Computer Systems Science & Engineering 2023年第9期46卷 2687-2709页

作者： Ping-Huan Kuo Yu-Tsun Chen Her-Terng Yau Department of Mechanical Engineering National Chung Cheng UniversityChiayi62102TaiwanChina Advanced Institute of Manufacturing with High-Tech Innovations(AIM-HI) National Chung Cheng UniversityChiayi62102TaiwanChina

The power factor is the ratio between the active and apparent power,and it is available to determine the operational capability of the intended circuit or the parts.The excitation current of the synchronous motor is an essential parameter required for adjusting the power factor because it determines whether the motor is under the optimal operating status.Although the excitation current should predict with the experimental devices,such a method is unsuitable for online real-time prediction.The artificial intelligence algorithm can compensate for the defect of conventional measurement methods requiring the measuring devices and the model optimization is compared during the research process.In this article,the load current,power factor,and power factor errors available in the existing dataset are used as the input parameters for training the proposed artificial intelligence algorithms to select the optimal algorithm according to the training result,for this algorithm to have higher accuracy.The SMOGN(Synthetic Minority Over-Sampling Technique for Regression with Gaussian Noise)is selected for the research by which the data and the MFO(Moth-flame optimization algorithm)are created for the model to adjust and optimize the parameters automatically.In addition to enhancing the prediction accuracy for the excitation current,the automatic parameter adjusting method also allows the researchers not specializing in the professional algorithm to apply such application method more efficiently.The final result indicated that the prediction accuracy has reached“Mean Absolute Error(MAE)=0.0057,Root Mean Square Error(RMSE)=0.0093 andR2 score=0.9973”.Applying this method to themotor control would be much easier for the power factor adjustment in the future because it allows the motor to operate under the optimal power status to reduce energy consumption while enhancing working efficiency.

关键词： Synchronous machine power factor excitation current active power apparent power

Design of robust intelligent protection technique for large-scale grid-connected wind farm

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Protection and Control of Modern power Systems 2018年第1期3卷 179-191页

作者： Omar Noureldeen I.Hamdan Electrical Engineering Department Faculty of EngineeringSouth Valley UniversityQena 83523Egypt

This paper presents a design of robust intelligent protection technique using adaptive neuro-fuzzy inference system(ANFIS)approach to detect and classify the fault types during various faults occurrence in large-scale grid-connected wind farm.Also,it is designed to determine the fault location and isolate the wind turbine generators located in the faulted zone during fault occurrence and reconnect them after fault clearance.The studied wind farm has a total rating capacity of 120 MW,where it consists of 60 doubly fed induction generator(DFIG)wind turbines each has a capacity of 2 MW.Moreover,the wind farm generators are positioned in 6 rows,where each row consists of 10 generators.The impacts of fault type,fault location,fault duration,cascaded faults,permanent fault and external grid fault on the behaviours of the generated active and reactive power are investigated.Also,the impacts of internal and external faults in cases of different transition resistances are investigated.The simulation results indicate that,the proposed ANFIS protection technique has the ability to detect,classify and determine the fault location,then isolate the faulted zones during fault occurrence and reconnect them after fault clearance.Furthermore,the wind turbines generators which are located in un-faulted zones can stay to deliver their generated active power to the grid during fault period.

关键词： ANFIS Fault location DFIG Wind farm active power Reactive power

Economic Improvement of power Factor Correction: A Case Study

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Journal of power and Energy Engineering 2021年第6期9卷 1-11页

作者： Kassem Wahab Mohamad Rahal Roger Achkar Department of Computer and Communications Engineering Faculty of Engineering American University of Science and Technology Beirut Lebanon

power factor (PF) is simply an expression of energy efficiency, which is always expressed in terms of percentage. Technically, PF is a ratio of real power in Kilowatts to the apparent power, which is always expressed in kilovolts amperes. In AC power analysis, power is always expressed in three ways, the real power (P), reactive power (Q), and the apparent power (S). The real power is the work useful power, while the reactive power is the wasted power in the 3-phase AC system, and the apparent power is the vectorial sum of the two powers. The increase of reactive power will reduce the presence of real power, thus making the power to be more expensive. In this paper, we will analyze the importance of improving the power factor by applying a bank of capacitors to a case study in Lebanon. Analysis of the economic improvement in the application of power factor correction is carried out. The result shows a reduction of 12 percent in the total cost.

关键词： power Factor Reactive power kVAR Inductive Apparent power active power

Low power Wide Dominos Design in sub-65nm CMOS Technologies 8th

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Low Power Wide Dominos Design in sub-65nm CMOS Technologies