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Improved Model Predictive Direct Power Control of Grid Side Converter in Weak Grid Using Kalman Filter and DSOGI

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Chinese Journal of Electrical Engineering 2019年第4期5卷 22-32页

作者： Liang Chen heng nian Yunyang Xu College of Electrical Engineering Zhejiang UniversityHangzhou 310027China

When grid side converter(GSC)is connected to weak grid,the small signal instability can happen due to terminal characteristics of the GSC that are incompatible with the grid *** issue is not of wide concern in previous studies of direct power control(DPC)of *** small signal analysis,it is shown that the impedance characteristic of the conventional direct power control GSC is not compatible with the inductive grid impedance in weak grid due to its constant power load *** solve the problem,instead of feeding the DPC controller with direct measured voltage and current,a Kalman filter(KF)is used to obtain filtered output current and a double second-order generalized integrator(DSOGI)is used to obtain filtered voltage at the point of common coupling(PCC).These strategies change the impedance characteristic of the GSC dramatically and make it suitable to operate in weak grid where SCR is 2,while the rapid power response is *** proposed strategy is verified through simulation and controller hardware in loop(CHIL)tests.

关键词： Direct power control weak grid grid side converter stability

Improved three-vector based dead-beat model predictive direct power control strategy for grid-connected inverters

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Frontiers of Information Technology & Electronic Engineering 2018年第11期19卷 1420-1431页

作者： Chen-wen Cheng heng nian Long-qi LI College of Electrical Engineering Zhejiang University

Since only one inverter voltage vector is applied during each duty cycle, traditional model predictive direct power control(MPDPC) for grid-connected inverters(GCIs) results in serious harmonics in current and power. Moreover, a high sampling frequency is needed to ensure satisfactory steady-state performance, which is contradictory to its long execution time due to the iterative prediction calculations. To solve these problems, a novel dead-beat MPDPC strategy is proposed, using two active inverter voltage vectors and one zero inverter voltage vector during each duty cycle. Adoption of three inverter vectors ensures a constant switching frequency. Thus, smooth steady-state performance of both current and power can be obtained. Unlike the traditional three-vector based MPDPC strategy, the proposed three vectors are selected based on the power errors rather than the sector where the grid voltage vector is located, which ensures that the duration times of the selected vectors are positive all the time. Iterative calculations of the cost function in traditional predictive control are also removed, which makes the proposed strategy easy to implement on digital signal processors(DSPs) for industrial applications. Results of experiments based on a 1 kW inverter setup validate the feasibility of the proposed three-vector based dead-beat MPDPC strategy.

关键词： Grid-connected inverter Model predictive control Direct power control Three vectors Constant switching frequency Power errors

Enhanced control of DFIG-used back-to-back PWM VSC under unbalanced grid voltage conditions

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第8期8卷 1330-1339页

作者： HU Jia-bing HE Yi-kang nian heng School of Electrical Engineering Zhejiang University Hangzhou 310027 China

This paper presents a unified positive-and negative-sequence dual-dq dynamic model of wind-turbine driven doubly-fed induction generator(DFIG) under unbalanced grid voltage conditions. Strategies for enhanced control and operation of a DFIG-used back-to-back(BTB) PWM voltage source converter(VSC) are proposed. The modified control design for the grid-side converter in the stationary αβ frames diminishes the amplitude of DC-link voltage ripples of twice the grid frequency,and the two proposed control targets for the rotor-side converter are alternatively achieved,which,as a result,improve the fault-ride through(FRT) capability of the DFIG based wind power generation systems during unbalanced network supply. A complete unbalanced control scheme with both grid-and rotor-side converters included is designed. Finally,simulation was carried out on a 1.5 MW wind-turbine driven DFIG system and the validity of the developed unified model and the feasibility of the proposed control strategies are all confirmed by the simulated results.

关键词： Unbalanced grid voltage Doubly-fed induction generator (DFIG) Back-to-back (BTB) Fault-ride through (FRT) Voltage source converter (VSC)

First-round design of the flight scenario for Chang’e-2’s extended mission:take off from lunar orbit

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Acta Mechanica Sinica 2012年第5期28卷 1466-1478页

作者： Yang Gao heng-nian Li Sheng-Mao He State Key Laboratory of Astronautic Dynamics General Establishment of Space Science and Application Chinese Academy of Sciences

Chang＇e-2, Chinese second lunar probe, was inserted into a 100 km altitude low lunar orbit on October 9th, 2010, its purpose is to continuously photograph the lunar surface and possibly chosen landing sites for future lunar missions. The probe will still carry considerable amount of propellant after completing all prescribed tasks in about six months. After the successful launch of Chang＇e-2, we began designing the probe＇s subsequent flight scenario, considering a total impulse of 1 100 m/s for takeoff from low lunar orbit and a maximum 3× 10^6 km distance for Earth-probe telecom- munication. Our first-round effort proposed a preliminary flight scenario that involves consecutive arrivals at the halo orbits around the Earth-Moon L1/L2 and Sun-Earth L1/L2 points, near-Earth asteroid flyby, Earth return, and lunar impact. The designed solution of Chang＇e-2＇s subsequent flight scenario is a multi-segment flight trajectory that serves as a reference for making the final decision on Chang＇e-2＇s extended mission, which is a flight to the Sun-Earth L2 point, and a possible scheme of lunar impact via Earth flyby after remaining at the Sun-Earth L2 point was also presented. The proposed flight trajectory, which possesses acceptable solution accuracy for mission analysis, is a novel design that effectively exploits the invariant manifolds in the circular restricted three-body problem and the patched-manifold-conic method.

关键词： Chang'e-2 Lunar mission Lagrange point Invariant manifold Patched-manifold-conic method

High Frequency Resonance in DFIG-Based Wind Farm with Variable Power Capacity

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Chinese Journal of Electrical Engineering 2017年第3期3卷 52-58页

作者： Yipeng Song heng nian Frede Blaabjerg Department of Energy Technology Aalborg UniversityAalborg East 9220Denmark College of Electrical Engineering Zhejiang UniversityHangzhou310027China

As wind power penetration has been gaining in the power grid for decades,a large number of the doubly fed induction generator(DFIG)based wind farms are being established around the *** power capacities of these wind farms may vary around hundreds of MW,and most of the wind farms are connected to long transmission cables whose impedances can not be ignored and require careful *** works have investigated the impedance interaction between the DFIG based wind farm and long transmission cables which may unfortunately cause high frequency resonance(HFR).The main contribution of this paper is to investigate the influence of the variable wind farm capacity on the behavior of the HFR when certain transmission cables are *** is found out that the potential HFR may happen in certain wind farms,and the larger wind farm capacity causes more severe HFR due to the relatively weaker grid transmission *** results based on Matlab/Simulink are given to validate the analysis of HFR.

关键词： DFIG based wind farm variable power capacity long transmission cable high frequency resonance

Resonance Active Damping and PCC Voltage Quality Improvement of DFIG System Connected to Parallel Compensated Grid

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Chinese Journal of Electrical Engineering 2018年第4期4卷 33-40页

作者： Yipeng Song nian heng Frede Blaabjerg Department of Energy Technology Aalborg UniversityAalborg East 9220Denmark College of Electrical Engineering Zhejiang UniversityHangzhou 310027China

Under the connection to a weak grid,the Doubly Fed Induction Generator(DFIG)based wind power system has potential risk from two operational *** first issue is the High Frequency Resonance(HFR)mode due to the impedance interaction between the DFIG system and the weak *** order to ensure safe and reliable operation of the DFIG system,it is necessary to implement effective active damping strategies to mitigate the *** second issue is low order voltage harmonic distortion at the Point of Common Coupling(PCC),where consequently the performance of other grid-connected devices may *** could be advantageous that the DFIG system is able to improve the voltage quality at PCC by eliminating the low order harmonic *** this paper,both of the above mentioned DFIG operational characters,i.e.,active damping of HFR and the improvement of voltage quality at PCC,will be achieved by implementing advanced control strategies in the Rotor Side Converter(RSC)and the Grid Side Converter(GSC)*** are provided to verify the proposed control strategies for DFIG system connected to a weak grid.

关键词： DFIG system weak grid High Frequency Resonance(HFR) harmonic distortion active damping

Fast optimization of impulsive perturbed orbit rendezvous using simplified parametric model

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Astrodynamics 2021年第4期5卷 391-402页

作者： An-Yi Huang Ya-Zhong Luo heng-nian Li State Key Laboratory of Astronautic Dynamics Xi’an 710043China National University of Defense Technology Changsha 410073China Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions Changsha 410073China

A novel simplified parametric model for long-duration impulsive orbit rendezvous is *** on an existing fast estimation method,the optimal impulses and trajectory can be expressed by only ten parameters whose initial values can be easily ***,these parameters are used to predict orbital deviations with a target orbit.A simple correction process is designed to sequentially update the parameters based on the J_(2) perturbed analytical dynamic equations of circular ***,an iteration loop is formed to obtain the precise parameters and optimal *** simulation results confirm that the simplified parametric optimization method can be applied to elliptical orbits of small eccentricity and adapts well to both analytical and high-precision *** deviations could always converge within five iterations and the calculation was more efficient than the existing methods.

关键词： impulsive trajectory optimization long-duration perturbed rendezvous parametric model

Using Inverter-Based Renewable Generators to Improve the Grid Power Quality-A Review

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Chinese Journal of Electrical Engineering 2018年第4期4卷 16-25页

作者： Tao Wang heng nian Z.Q.Zhu Department of Electronic and Electrical Engineering University of SheffieldSheffieldS13JDU.K. College of Electrical Engineering Zhejiang UniversityHangzhou 310027China

With the increasing penetration of renewable power in the grid,renewable generators are expected to play more important roles rather than merely working as active power *** the high controllability and considerable idle capacity of the inverter-based renewable generators,various auxiliary functions for them have been studied to benefit the *** these auxiliary functions,the grid power quality improvement is very *** paper presents a review of the emerging control strategies for inverter-based renewable generators to improve grid power *** related papers are classified with different power quality issues and technical routes,and a comprehensive comparison is *** future trends of this research area are also discussed.

关键词： Renewable generator auxiliary function power quality improvement grid voltage harmonic and unbalance

Optimized Auxiliary Frequency Control of Wind Farm Based on Piecewise Reduced-order Frequency Response Model

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 791-802页

作者： Xu Zhang Chen Zhao Junchao Ma Long Zhang Dan Sun Chenxu Wang Yan Peng heng nian the School of Electrical Engineering Zhejiang UniversityHangzhou 310058China Electric Power Research Institute of State Grid Zhejiang Electric Power Corporation Hangzhou 310014China

With the increasing wind power penetration in the power system,the auxiliary frequency control(AFC)of wind farm(WF)has been widely *** traditional system frequency response(SFR)model is not suitable for the wind power generation system due to its poor accuracy and *** this paper,a piecewise reduced-order frequency response(PROFR)model is proposed,and an optimized auxiliary frequency control(O-AFC)scheme of WF based on the P-ROFR model is ***,a full-order frequency response model considering the change in operating point of wind turbine is established to improve the *** order to simplify the fullorder model,a P-ROFR model with second-order structure and high accuracy at each frequency response stage is *** on the proposed P-ROFR model,the relationship between the frequency response indexes and the auxiliary frequency controller coefficients is expressed ***,an OAFC scheme with the derived explicit expression as the optimization objective is proposed in order to improve the frequency support capability on the premise of ensuring the full release of the rotor kinetic energy and the full use of the effect of time delay on frequency ***,the effectiveness of the proposed P-ROFR model and the performance of the proposed OAFC scheme are verified by simulation studies.

关键词： Frequency response piecewise reduced-order wind farm auxiliary frequency control