In order to improve the force tracking performance of hydraulic quadruped robots in uncertain and unstructured environments,an impedance-based adaptive reference trajectory generation scheme is used.Secondly,in order ...In order to improve the force tracking performance of hydraulic quadruped robots in uncertain and unstructured environments,an impedance-based adaptive reference trajectory generation scheme is used.Secondly,in order to improve the robustness to environmental changes and reduce the contact force errors caused by trajectory tracking errors,the backstepping sliding mode controller is combined with the adaptive reference trajectory generator.Finally,a virtual damping control based on velocity and pressure feedback is proposed to solve the problem of contact force disappearance and stall caused by sudden environmental change.The simulation results show that the proposed scheme has higher contact force tracking accuracy when the environment is unchanged;the contact force error can always be guaranteed within an acceptable range when the environment is reasonably changed;when the environment suddenly changes,the drive unit can move slowly until the robot re-contacts the environment.展开更多
Wide area damping controller(WADC) is usually utilized to damp interarea low frequency oscillation in power system. However, conventional WADC design method neglects the influence of signal transmission delay and damp...Wide area damping controller(WADC) is usually utilized to damp interarea low frequency oscillation in power system. However, conventional WADC design method neglects the influence of signal transmission delay and damping performance of WADC designed by the conventional method may deteriorate or even has no effect when signal transmission delay is beyond delay margin, an index that denotes delay endurance degree of power system. Therefore, a new design method for WADC under the condition of expected damping factor and required signal transmission delay is presented in this work. An improved delay margin with less conservatism is derived by adopting a new Lyapunov-Krasovskii function and more compact bounding technique on the derivative of Lyapunov-Krasovskii functional. The improved delay margin, which constructs the correlation of damping factor and signal transmission delay, can be used to design WADC. WADC designed by the proposed method can ensure that power system satisfies expected damping factor when WADC input signal is delayed within delay margin. Satisfactory test results demonstrate the effectiveness of the proposed method.展开更多
Wind energy sources have different structures and functions from conventional power plants in the power system.These resources can affect the exchange of active and reactive power of the network.Therefore,power system...Wind energy sources have different structures and functions from conventional power plants in the power system.These resources can affect the exchange of active and reactive power of the network.Therefore,power system stability will be affected by the performance of wind power plants,especially in the event of a fault.In this paper,the improvement of the dynamic stability in power system equipped by wind farm is examined through the supplementary controller design in the high voltage direct current(HVDC)based on voltage source converter(VSC)transmission system.In this regard,impacts of the VSC HVDC system and wind farm on the improvement of system stability are considered.Also,an algorithm based on controllability(observability)concept is proposed to select most appropriate and effective coupling between inputs-outputs(IO)signals of system in different work conditions.The selected coupling is used to apply damping controller signal.Finally,a fractional order PID controller(FO-PID)based on exchange market algorithm(EMA)is designed as damping controller.The analysis of the results shows that the wind farm does not directly contribute to the improvement of the dynamic stability of power system.However,it can increase the controllability of the oscillatory mode and improve the performance of the supplementary controller.展开更多
A model predictive control（ MPC） based active damping controller for automotive driveline oscillations with time-delay consideration is proposed. A simplified driveline model considering time delay is modeled and co...A model predictive control（ MPC） based active damping controller for automotive driveline oscillations with time-delay consideration is proposed. A simplified driveline model considering time delay is modeled and converted to a linear parameter varying state space equation. Based on the model and model predictive control theory,an active damping controller is designed for drivability and comfortability improvement. In order to verify the designed controller,a driveline with engine is modeled to simulate the tip-in/out driving operation. An MPC active damping controller without considering time delay is simulated together with the proposed controller. The simulation results show that,by adopting the new MPC active damping controller,the vibration of the vehicle is reduced and the drivability and comfortability are improved.展开更多
This paper addresses the enhancement of power system stability by simultaneous tuning of synergetic excitation damping controller and SVC （static var compensator）-based damping controllers. Each machine or generator...This paper addresses the enhancement of power system stability by simultaneous tuning of synergetic excitation damping controller and SVC （static var compensator）-based damping controllers. Each machine or generator is considered as a subsystem and its interaction with the remaining part of the system, the SVC inclusive, is modeled as a quadratic function of the active power delivered by the generator. Stable manifold is constructed for each excitation controller and based on that, an effective damping controller is derived. A lead-lag compensator is employed as a supplementary controller for the SVC. PSO （particle swarm optimization） algorithm is effectively utilized to simultaneously tune the parameters for the excitation damping controller（s） and the SVC supplementary controller. The coordination of the controllers effectively dampens the power angle oscillation and regulates the generator terminal voltage when a fault occurs. Simulation results are obtained by using the PAT （power analysis toolbox） for a SMIB （single machine infinite bus） system and a two area power system.展开更多
This paper tackles two pivotal challenges within Lyapunov-functional-based approaches to analyze and design power system damping control amidst communication time delays.The first challenge addresses the inadequacy of...This paper tackles two pivotal challenges within Lyapunov-functional-based approaches to analyze and design power system damping control amidst communication time delays.The first challenge addresses the inadequacy of the reduced-order system model commonly employed in time-domain methods to accurately capture the stability of the original full-order system.By harnessing dissipativity theory,we introduce a model reduction technique coupled with a condition guaranteeing e-exponential stability solely through the employment of the reduced closed-loop system model.This not only validates the use of model reduction strategies but also furnishes a theoretical underpinning for their application.The second challenge pertains to the computational complexity of nonlinear semidefinite programming problems encountered during the coordinated design of controllers.Rather than pursuing the global optimum,we advocate for a path-following methodology to systematically explore local solutions.This iterative algorithm enhances system damping and H 2 performance by orchestrating automatic and co-ordinated adjustments to control parameters.Numerical experiments conducted on various benchmark systems underscore the efficacy of the proposed approach.展开更多
Wide-area damping controllers(WADCs)help in damping poorly damped inter-area oscillations(IAOs)using wide-area measurements.However,the vulnerability of the communication network makes the WADC susceptible to maliciou...Wide-area damping controllers(WADCs)help in damping poorly damped inter-area oscillations(IAOs)using wide-area measurements.However,the vulnerability of the communication network makes the WADC susceptible to malicious dynamic attacks.Existing cyber-resilient WADC solutions rely on accurate power system models or extensive simulation data for training the machine learning(ML)model,which are difficult to obtain for large-scale power system.This paper proposes a novel non-intrusive hybrid two-stage detection framework that mitigates these limitations by eliminating the need for realtime access to large system data or attack samples for training the ML model.In the first stage,an autoencoder is deployed at the actuator location to detect dynamic attacks with sharp gradient variations,e.g.,triangular,saw-tooth,pulse,ramp,and random attack signals.In the second stage,an unscented Kalman filter with unknown input estimation at the control center identifies smoothly varying dynamic attacks by estimating the control signal received by the actuator using synchrophasor measurements.A modified cosine similarity(MCS)metric is proposed to compare and quantify the similarity between the estimated control signal and the control signal sent by the WADC placed at the control center to detect any dynamic attacks.The MCS is designed to differentiate between events and dynamic attacks.The performance of the proposed framework has been validated on a hardware-in-the-loop(HIL)cyber-physical testbed built by using the OPAL-RT simulator and industry-grade hardware.展开更多
Traditional virtual synchronous generator(VSG)suffers from frequency steady-state deviation in islanded microgrids,which negatively affects the frequency-sensitive loads.Moreover,similar to the synchronous generator,V...Traditional virtual synchronous generator(VSG)suffers from frequency steady-state deviation in islanded microgrids,which negatively affects the frequency-sensitive loads.Moreover,similar to the synchronous generator,VSG introduces active power oscillation,especially under the condition of multiple parallel VSGs,which may cause overload or damage to the VSG because of its low overcurrent capability as a power electronic inverter.To address these issues,a decentralized frequency restoration and power oscillation damping control method is proposed in this paper,in which the global variable characteristic of the microgrid frequency is considered to restore it to the rated value while ensuring precise active power sharing.Moreover,the proposed control method can dampen the power oscillation during load disturbance without affecting the steady-state characteristics.In addition,the fully decentralized manner obviates the requirement for communication networks,thereby considerably reducing the communication burden and improving system reliability.Finally,simulations and experiments are conducted to validate the effectiveness of the proposed control method.展开更多
The self-synchronizing voltage source inverter(SS VSI)is widely studied because of its grid-forming capability.However,the slow response of the active power control loop(APCL)under the weak grid makes it difficult for...The self-synchronizing voltage source inverter(SS VSI)is widely studied because of its grid-forming capability.However,the slow response of the active power control loop(APCL)under the weak grid makes it difficult for the SSVSI to quickly support the frequency of a low-inertia grid.In this pa per,a grid framework is established to analyze the frequency support service process of the SSVSI,and the shortcomings of the regulation of the damping coefficient and virtual inertia co efficient for frequency support are analyzed.Then,an adaptive additional damping control method is proposed to optimize the ability of SSVSI to support the grid frequency.The proposed control method adjusts the damping of the APCL without affect ing the system steady-state characteristics,which improves the active power response speed of the SSVSI.Besides,the pro posed control method adaptively adjusts the additional damp ing coefficient based on the active power response without mea suring the grid parameters.Compared with other forms of con trol,the proposed control method excels in minimizing the rate of change of frequency(RoCoF)and the frequency deviation(FD)within the grid,without succumbing to the constraints posed by unknown grid parameters.Furthermore,the analysis of the system stability is also presented.Finally,the experimen tal hardware results obtained from a miniaturized grid proto type are presented,corroborating the effectiveness of the pro posed control method.展开更多
The mutual impedance between doubly-fed induction generator(DFIG)system and weak grid may cause a resonance,which yields to undesirable distortions and harmonics.The equivalent impedance of DFIG systems is high,which ...The mutual impedance between doubly-fed induction generator(DFIG)system and weak grid may cause a resonance,which yields to undesirable distortions and harmonics.The equivalent impedance of DFIG systems is high,which creates high-frequency resonance(HFR)in interaction with weak grids.Although several studies are conducted to mitigate HFRs,more improvements are needed in terms of damping and phasemargin.Accordingly,an active damping control strategy based on virtual admittance is proposed,which properly mitigates the disturbances.The proposed strategy is accurate as it considers the dynamic high-frequency model of DFIG system to effectively reduce the HFR.The performance of the proposed strategy is verified by using different case studies on a 2 MW DFIG system with time-domain simulations in MATLAB/Simulink environment.展开更多
Permanent Magnet Synchronous Motors(PMSMs)are widely employed in high-performance drive applications due to their superior efficiency and dynamic capabilities.However,their control remains challenging owing to nonline...Permanent Magnet Synchronous Motors(PMSMs)are widely employed in high-performance drive applications due to their superior efficiency and dynamic capabilities.However,their control remains challenging owing to nonlinear dynamics,parameter variations,and unmeasurable external disturbances,particularly load torquefluctuations.This study proposes an enhanced Interconnection and Damp-ing Assignment Passivity-Based Control(IDA-PBC)scheme,formulated within the port-controlled Hamiltonian(PCH)framework,to address these limitations.A nonlinear disturbance observer is embedded to estimate and compensate,in real time,for lumped mis-matched disturbances arising from parameter uncertainties and external loads.Additionally,aflatness-based control strategy is employed to generate the desired current references within the nonlinear drive system,ensuring accurate tracking of time-varying speed commands.This integrated approach preserves the system’s energy-based structure,enabling systematic stability analysis while enhancing robustness.The proposed control architecture also maintains low complexity with a limited number of tunable parameters,facilitating practical implementation.Simulation and experimental results under various operating conditions demonstrate the effectiveness and robustness of the proposed method.Comparative analysis with conventional proportional-integral(PI)control and standard IDA-PBC strategies confirms its capability to handle disturbances and maintain dynamic performance.展开更多
This paper presents the issue of the Sub-synchronous resonance(SSR)phenomenon in a series compensated DFIG-based wind power plant and its alleviation using a Battery Energy Storage-based Damping Controller(BESSDCL).A ...This paper presents the issue of the Sub-synchronous resonance(SSR)phenomenon in a series compensated DFIG-based wind power plant and its alleviation using a Battery Energy Storage-based Damping Controller(BESSDCL).A supplementary damping signal is developed considering the angular speed deviation and is incorporated into the BESS control system.Wide-area Measurement System data is used to determine the angular speed deviation.A lin-earized system model is developed to perform eigenvalue analysis,and to detect and examine unstable SSR modes.The variation of wind speed and three-phase fault are also taken into consideration to validate the robustness of the controller.To further verify the efficacy of the proposed damping controller,time-domain simulations are performed using MATLAB/Simulink.The application of the proposed BESSDCL stabilizes all the unstable system modes effectively at wind speeds of 7 m/s,9 m/s,and 11 m/s,and at 40%,50%,and 60%series compensation levels,as well three-phase fault conditions.展开更多
This paper proposes a multi-layer multi-agent model for the performance evaluation of powersystems,which is different from the existing multi-agent ones.To describe the impact of the structureof the networked power sy...This paper proposes a multi-layer multi-agent model for the performance evaluation of powersystems,which is different from the existing multi-agent ones.To describe the impact of the structureof the networked power system,the proposed model consists of three kinds of agents that form threelayers:control agents such as the generators and associated controllers,information agents to exchangethe information based on the wide area measurement system (WAMS) or transmit control signals tothe power system stabilizers (PSSs),and network-node agents such as the generation nodes and loadnodes connected with transmission lines.An optimal index is presented to evaluate the performance ofdamping controllers to the system's inter-area oscillation with respect to the information-layer topology.Then,the authors show that the inter-area information exchange is more powerful than the exchangewithin a given area to control the inter-area low frequency oscillation based on simulation analysis.展开更多
High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping str...High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping strategies.This paper analyzes the influences of a feed-forward voltage filter and feedback current filter for the inner controller for the high-frequency impedance characteristics of the MMC based on a model.Moreover,the mechanism,influencing factors,and limitations of the existing strategy including an additional lowpass filter in the voltage feed-forward stage are investigated.Secondly,a resonance suppression strategy for the inclusion of additional cascaded notch filters in the voltage feed-forward stage is proposed,and its parameter design method and applicable scenarios are analyzed.In addition,this paper analyzes the effects of the inclusion of an additional control in other stages for the inner controller of the MMC.Finally,the correctness of the theoretical analysis and the proposed strategy is verified based on the simulation of an actual project on PSCAD/EMTDC.展开更多
A wide-area damping controller(WADC)is effective in damping inter-area low-frequency oscillation(LFO),if the time delay in a wide-area control loop can be properly handled.In order to simplify the WADC design and enla...A wide-area damping controller(WADC)is effective in damping inter-area low-frequency oscillation(LFO),if the time delay in a wide-area control loop can be properly handled.In order to simplify the WADC design and enlarge the delay adaptation range,the classic power system stabilizer(PSS)is adopted,and a new unified residue(UR)method is proposed for compact WADC design.The strategy of control loop selection is also improved by modifying the relative residue index based on a few dominant oscillation modes.The designed PSSbased compact WADC is as simple as classic PSS with no more than two lead-lag phase compensation units.Case studies are carried out on an IEEE 16-machine 68-bus power system.Simulation results demonstrate that the control loop selection before the WADC design is necessary and that the proposed selection strategy can easily pick out the suitable candidate control loops.In addition,it is feasible for the UR method to design WADCs with different time delays in the selected control loops.All the designed WADCs are effective in damping inter-area LFO and robust to time delay variations under operation conditions.Comparisons among five design methods for PSS-based WADC show that the proposed UR method is superior in delay adaptation,the conciseness of WADC structure and computation speed of parameters.展开更多
This paper presents an approach for designing parameters of power system stabilizer(PSS)and FACTS damping controllers in a large scale practical power system.The objective is maximizing damping ratio of the target mod...This paper presents an approach for designing parameters of power system stabilizer(PSS)and FACTS damping controllers in a large scale practical power system.The objective is maximizing damping ratio of the target mode,and tracking technology(MTT)is used to avoid frequent alternations of target mode in optimization procedures.An improved planted growth simulation algorithm(IPGSA),which has high search efficiency and quick convergence speed,is proposed to optimize controller parameters coordinately.Based on case study of a large-scale power grid,and by using local and interregional low-frequency oscillation modes as target modes,simulation results verify proposed method in this paper.Furthermore,coordination optimization strategy adapted to multi-operating conditions demonstrates that the proposed approach is robust.展开更多
Integration of renewable energy sources(RES)with a conventional power system has a detrimental effect on interarea oscillation.Most popular RESs are solar photovoltaic(PV)and wind energy conversion systems(WECS).Both ...Integration of renewable energy sources(RES)with a conventional power system has a detrimental effect on interarea oscillation.Most popular RESs are solar photovoltaic(PV)and wind energy conversion systems(WECS).Both solar PV power generation and WECS are integrated with power systems using a power electronic converter.Increasing the amount of RES generation lead towards reduction of system damping,which leads towards inter-area oscillation.Also,the intermittent behavior of a RES reduces the effectiveness of damping controllers.A dynamic controller based wide area damping controller(WADC)is proposed in this paper to increase small signal stability of a RES integrated power system.The WADC is designed for contemplating delay in a communication channel,communication failure and saturation.An anti-windup compensator is developed to overcome the effect of actuator saturation.However,the gain of the anti-windup compensator is calculated using LyapunovKrasovskii functional(LKF)in terms of linear matrix inequality(LMI).The actuator considered in this paper is a unified power flow controller(UPFC).Efficacy of PV and wind power integration on power system is also observed.The efficacy of the developed dynamic controller is verified using IEEE 39 bus and 68 bus power system.展开更多
This paper examines the harmonic oscillations in a grid-connected PV generation farm(PVGF)caused by the parallel connection of an increased number of PV generation units(PVGUs).An equivalent model of the grid-connecte...This paper examines the harmonic oscillations in a grid-connected PV generation farm(PVGF)caused by the parallel connection of an increased number of PV generation units(PVGUs).An equivalent model of the grid-connected PVGF is derived,which clearly explains why there are internal and external oscillation modes in the grid-connected PVGF.An indicator of impedance multiplication(IIM)is proposed to quantitatively estimate the impact of the increased number of PVGUs in parallel connection.The analysis in this paper reveals the mechanism about why the damping of external oscillation modes may decrease when more PVGUs are in parallel connection under the condition that the IIM is positive.An example grid-connected PVGF is presented in this paper to demonstrate and evaluate the derived analysis and conclusions.A method for designing the damping controllers to ensure a negative IIM is proposed.With the damping controllers being installed,the risk of growing harmonic oscillations caused by the increased number of the PVGUs in parallel connection can be effectively eliminated.展开更多
A kind of novel multi-layer piezoelectric actuator is proposed and integrated with controllable constrained damping treatment to perform hybrid vibration control.The governing equation of the system is derived based o...A kind of novel multi-layer piezoelectric actuator is proposed and integrated with controllable constrained damping treatment to perform hybrid vibration control.The governing equation of the system is derived based on the constitutive equations of elastic,viscoelastic and piezoelectric materials,which shows that the magnitude of control force exerted by multi-layer piezoelectric actuator is the quadratic function of the number of piezoelectric laminates used but in direct proportion to control voltage.This means that the multi-layer actuator can produce greater actuating force than that by piezoelectric laminate actuator with the same area under the identical control voltage.The optimal location placement of the multi-layer piezoelectric actuator is also discussed.As an example,the hybrid vibration control of a cantilever rectangular thin-plate is numerically simulated and carried out experimentally.The simulated and experimental results validate the power of multi-layer piezoelectric actuator and indicate that the present hybrid damping technique can effectively suppress the low frequency modal vibration of the experimental thin-plate structure.展开更多
基金Projects(51975376,51505289)supported by the National Natural Science Foundation of ChinaProject(19ZR1435400)supported by the Natural Science Foundation of Shanghai,China。
文摘In order to improve the force tracking performance of hydraulic quadruped robots in uncertain and unstructured environments,an impedance-based adaptive reference trajectory generation scheme is used.Secondly,in order to improve the robustness to environmental changes and reduce the contact force errors caused by trajectory tracking errors,the backstepping sliding mode controller is combined with the adaptive reference trajectory generator.Finally,a virtual damping control based on velocity and pressure feedback is proposed to solve the problem of contact force disappearance and stall caused by sudden environmental change.The simulation results show that the proposed scheme has higher contact force tracking accuracy when the environment is unchanged;the contact force error can always be guaranteed within an acceptable range when the environment is reasonably changed;when the environment suddenly changes,the drive unit can move slowly until the robot re-contacts the environment.
基金Project(51007042) supported by the National Natural Science Foundation of China
文摘Wide area damping controller(WADC) is usually utilized to damp interarea low frequency oscillation in power system. However, conventional WADC design method neglects the influence of signal transmission delay and damping performance of WADC designed by the conventional method may deteriorate or even has no effect when signal transmission delay is beyond delay margin, an index that denotes delay endurance degree of power system. Therefore, a new design method for WADC under the condition of expected damping factor and required signal transmission delay is presented in this work. An improved delay margin with less conservatism is derived by adopting a new Lyapunov-Krasovskii function and more compact bounding technique on the derivative of Lyapunov-Krasovskii functional. The improved delay margin, which constructs the correlation of damping factor and signal transmission delay, can be used to design WADC. WADC designed by the proposed method can ensure that power system satisfies expected damping factor when WADC input signal is delayed within delay margin. Satisfactory test results demonstrate the effectiveness of the proposed method.
文摘Wind energy sources have different structures and functions from conventional power plants in the power system.These resources can affect the exchange of active and reactive power of the network.Therefore,power system stability will be affected by the performance of wind power plants,especially in the event of a fault.In this paper,the improvement of the dynamic stability in power system equipped by wind farm is examined through the supplementary controller design in the high voltage direct current(HVDC)based on voltage source converter(VSC)transmission system.In this regard,impacts of the VSC HVDC system and wind farm on the improvement of system stability are considered.Also,an algorithm based on controllability(observability)concept is proposed to select most appropriate and effective coupling between inputs-outputs(IO)signals of system in different work conditions.The selected coupling is used to apply damping controller signal.Finally,a fractional order PID controller(FO-PID)based on exchange market algorithm(EMA)is designed as damping controller.The analysis of the results shows that the wind farm does not directly contribute to the improvement of the dynamic stability of power system.However,it can increase the controllability of the oscillatory mode and improve the performance of the supplementary controller.
基金Supported by the National Natural Science Foundation of China(51475043)
文摘A model predictive control（ MPC） based active damping controller for automotive driveline oscillations with time-delay consideration is proposed. A simplified driveline model considering time delay is modeled and converted to a linear parameter varying state space equation. Based on the model and model predictive control theory,an active damping controller is designed for drivability and comfortability improvement. In order to verify the designed controller,a driveline with engine is modeled to simulate the tip-in/out driving operation. An MPC active damping controller without considering time delay is simulated together with the proposed controller. The simulation results show that,by adopting the new MPC active damping controller,the vibration of the vehicle is reduced and the drivability and comfortability are improved.
文摘This paper addresses the enhancement of power system stability by simultaneous tuning of synergetic excitation damping controller and SVC （static var compensator）-based damping controllers. Each machine or generator is considered as a subsystem and its interaction with the remaining part of the system, the SVC inclusive, is modeled as a quadratic function of the active power delivered by the generator. Stable manifold is constructed for each excitation controller and based on that, an effective damping controller is derived. A lead-lag compensator is employed as a supplementary controller for the SVC. PSO （particle swarm optimization） algorithm is effectively utilized to simultaneously tune the parameters for the excitation damping controller（s） and the SVC supplementary controller. The coordination of the controllers effectively dampens the power angle oscillation and regulates the generator terminal voltage when a fault occurs. Simulation results are obtained by using the PAT （power analysis toolbox） for a SMIB （single machine infinite bus） system and a two area power system.
基金supported by the National Key Research and Development Program of China under grant 2022YFA1004600.
文摘This paper tackles two pivotal challenges within Lyapunov-functional-based approaches to analyze and design power system damping control amidst communication time delays.The first challenge addresses the inadequacy of the reduced-order system model commonly employed in time-domain methods to accurately capture the stability of the original full-order system.By harnessing dissipativity theory,we introduce a model reduction technique coupled with a condition guaranteeing e-exponential stability solely through the employment of the reduced closed-loop system model.This not only validates the use of model reduction strategies but also furnishes a theoretical underpinning for their application.The second challenge pertains to the computational complexity of nonlinear semidefinite programming problems encountered during the coordinated design of controllers.Rather than pursuing the global optimum,we advocate for a path-following methodology to systematically explore local solutions.This iterative algorithm enhances system damping and H 2 performance by orchestrating automatic and co-ordinated adjustments to control parameters.Numerical experiments conducted on various benchmark systems underscore the efficacy of the proposed approach.
基金supported in part by ANRF(No.CRG/2021/003827/EEC)SERB(No.SIRE/SIR/2022/000984)。
文摘Wide-area damping controllers(WADCs)help in damping poorly damped inter-area oscillations(IAOs)using wide-area measurements.However,the vulnerability of the communication network makes the WADC susceptible to malicious dynamic attacks.Existing cyber-resilient WADC solutions rely on accurate power system models or extensive simulation data for training the machine learning(ML)model,which are difficult to obtain for large-scale power system.This paper proposes a novel non-intrusive hybrid two-stage detection framework that mitigates these limitations by eliminating the need for realtime access to large system data or attack samples for training the ML model.In the first stage,an autoencoder is deployed at the actuator location to detect dynamic attacks with sharp gradient variations,e.g.,triangular,saw-tooth,pulse,ramp,and random attack signals.In the second stage,an unscented Kalman filter with unknown input estimation at the control center identifies smoothly varying dynamic attacks by estimating the control signal received by the actuator using synchrophasor measurements.A modified cosine similarity(MCS)metric is proposed to compare and quantify the similarity between the estimated control signal and the control signal sent by the WADC placed at the control center to detect any dynamic attacks.The MCS is designed to differentiate between events and dynamic attacks.The performance of the proposed framework has been validated on a hardware-in-the-loop(HIL)cyber-physical testbed built by using the OPAL-RT simulator and industry-grade hardware.
基金supported by the National Key Research and Development Program of China(No.2022YFF0608700)。
文摘Traditional virtual synchronous generator(VSG)suffers from frequency steady-state deviation in islanded microgrids,which negatively affects the frequency-sensitive loads.Moreover,similar to the synchronous generator,VSG introduces active power oscillation,especially under the condition of multiple parallel VSGs,which may cause overload or damage to the VSG because of its low overcurrent capability as a power electronic inverter.To address these issues,a decentralized frequency restoration and power oscillation damping control method is proposed in this paper,in which the global variable characteristic of the microgrid frequency is considered to restore it to the rated value while ensuring precise active power sharing.Moreover,the proposed control method can dampen the power oscillation during load disturbance without affecting the steady-state characteristics.In addition,the fully decentralized manner obviates the requirement for communication networks,thereby considerably reducing the communication burden and improving system reliability.Finally,simulations and experiments are conducted to validate the effectiveness of the proposed control method.
基金supported by the Natural Science Foundation of China(No.52077070)Young Scientists Fund of National Natural Science Foundation of China(No.52207201)+1 种基金Hunan Provincial Natural Science Foundation of China(No.2024JJ3012)Young Scientists Fund of Hunan Provincial Natural Science Foundation of China(No.2024JJ6172).
文摘The self-synchronizing voltage source inverter(SS VSI)is widely studied because of its grid-forming capability.However,the slow response of the active power control loop(APCL)under the weak grid makes it difficult for the SSVSI to quickly support the frequency of a low-inertia grid.In this pa per,a grid framework is established to analyze the frequency support service process of the SSVSI,and the shortcomings of the regulation of the damping coefficient and virtual inertia co efficient for frequency support are analyzed.Then,an adaptive additional damping control method is proposed to optimize the ability of SSVSI to support the grid frequency.The proposed control method adjusts the damping of the APCL without affect ing the system steady-state characteristics,which improves the active power response speed of the SSVSI.Besides,the pro posed control method adaptively adjusts the additional damp ing coefficient based on the active power response without mea suring the grid parameters.Compared with other forms of con trol,the proposed control method excels in minimizing the rate of change of frequency(RoCoF)and the frequency deviation(FD)within the grid,without succumbing to the constraints posed by unknown grid parameters.Furthermore,the analysis of the system stability is also presented.Finally,the experimen tal hardware results obtained from a miniaturized grid proto type are presented,corroborating the effectiveness of the pro posed control method.
文摘The mutual impedance between doubly-fed induction generator(DFIG)system and weak grid may cause a resonance,which yields to undesirable distortions and harmonics.The equivalent impedance of DFIG systems is high,which creates high-frequency resonance(HFR)in interaction with weak grids.Although several studies are conducted to mitigate HFRs,more improvements are needed in terms of damping and phasemargin.Accordingly,an active damping control strategy based on virtual admittance is proposed,which properly mitigates the disturbances.The proposed strategy is accurate as it considers the dynamic high-frequency model of DFIG system to effectively reduce the HFR.The performance of the proposed strategy is verified by using different case studies on a 2 MW DFIG system with time-domain simulations in MATLAB/Simulink environment.
基金supported in part by an International Research Partnership“Electrical Engineering-Thai French Research Center(EE-TFRC)”under the project framework of the Lorraine Universite´d’Excellence(LUE)in cooperation between Universite´de Lorraine(France)and King Mongkut’s University of Technology North Bangkok(year 2021-2024/2025-28)by the National Research Council of Thailand(NRCT)under Research Team Promotion Grant(Senior Research Scholar Program)under Grant No.N42A 680561by the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation under Research project Grant No.B41G680025.
文摘Permanent Magnet Synchronous Motors(PMSMs)are widely employed in high-performance drive applications due to their superior efficiency and dynamic capabilities.However,their control remains challenging owing to nonlinear dynamics,parameter variations,and unmeasurable external disturbances,particularly load torquefluctuations.This study proposes an enhanced Interconnection and Damp-ing Assignment Passivity-Based Control(IDA-PBC)scheme,formulated within the port-controlled Hamiltonian(PCH)framework,to address these limitations.A nonlinear disturbance observer is embedded to estimate and compensate,in real time,for lumped mis-matched disturbances arising from parameter uncertainties and external loads.Additionally,aflatness-based control strategy is employed to generate the desired current references within the nonlinear drive system,ensuring accurate tracking of time-varying speed commands.This integrated approach preserves the system’s energy-based structure,enabling systematic stability analysis while enhancing robustness.The proposed control architecture also maintains low complexity with a limited number of tunable parameters,facilitating practical implementation.Simulation and experimental results under various operating conditions demonstrate the effectiveness and robustness of the proposed method.Comparative analysis with conventional proportional-integral(PI)control and standard IDA-PBC strategies confirms its capability to handle disturbances and maintain dynamic performance.
文摘This paper presents the issue of the Sub-synchronous resonance(SSR)phenomenon in a series compensated DFIG-based wind power plant and its alleviation using a Battery Energy Storage-based Damping Controller(BESSDCL).A supplementary damping signal is developed considering the angular speed deviation and is incorporated into the BESS control system.Wide-area Measurement System data is used to determine the angular speed deviation.A lin-earized system model is developed to perform eigenvalue analysis,and to detect and examine unstable SSR modes.The variation of wind speed and three-phase fault are also taken into consideration to validate the robustness of the controller.To further verify the efficacy of the proposed damping controller,time-domain simulations are performed using MATLAB/Simulink.The application of the proposed BESSDCL stabilizes all the unstable system modes effectively at wind speeds of 7 m/s,9 m/s,and 11 m/s,and at 40%,50%,and 60%series compensation levels,as well three-phase fault conditions.
基金supported in part by the National Natural Science Foundation of China under Grants Nos. 50707035, 50595411, 60425307, 60221301 and 50607005, in part by the 111 project (B08013)Program for Changjiang Scholars and Innovative Research Team in University (IRT0515)in part by the Program for New Century Excellent Talents in University (NCET-05-0216)
文摘This paper proposes a multi-layer multi-agent model for the performance evaluation of powersystems,which is different from the existing multi-agent ones.To describe the impact of the structureof the networked power system,the proposed model consists of three kinds of agents that form threelayers:control agents such as the generators and associated controllers,information agents to exchangethe information based on the wide area measurement system (WAMS) or transmit control signals tothe power system stabilizers (PSSs),and network-node agents such as the generation nodes and loadnodes connected with transmission lines.An optimal index is presented to evaluate the performance ofdamping controllers to the system's inter-area oscillation with respect to the information-layer topology.Then,the authors show that the inter-area information exchange is more powerful than the exchangewithin a given area to control the inter-area low frequency oscillation based on simulation analysis.
基金supported in part by Science and Technology Project of State Grid Corporation of China,“Research on Harmonic Oscillation ProblemsSuppression Strategies of Flexible DC Connected to AC Grid”,(No.SGTYHT/17-JS-199).
文摘High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping strategies.This paper analyzes the influences of a feed-forward voltage filter and feedback current filter for the inner controller for the high-frequency impedance characteristics of the MMC based on a model.Moreover,the mechanism,influencing factors,and limitations of the existing strategy including an additional lowpass filter in the voltage feed-forward stage are investigated.Secondly,a resonance suppression strategy for the inclusion of additional cascaded notch filters in the voltage feed-forward stage is proposed,and its parameter design method and applicable scenarios are analyzed.In addition,this paper analyzes the effects of the inclusion of an additional control in other stages for the inner controller of the MMC.Finally,the correctness of the theoretical analysis and the proposed strategy is verified based on the simulation of an actual project on PSCAD/EMTDC.
基金supported by the National Natural Science Foundation of China(No.51407160,No.51777193)the Key Research and Development Program of Zhejiang Province(No.2019C01149)。
文摘A wide-area damping controller(WADC)is effective in damping inter-area low-frequency oscillation(LFO),if the time delay in a wide-area control loop can be properly handled.In order to simplify the WADC design and enlarge the delay adaptation range,the classic power system stabilizer(PSS)is adopted,and a new unified residue(UR)method is proposed for compact WADC design.The strategy of control loop selection is also improved by modifying the relative residue index based on a few dominant oscillation modes.The designed PSSbased compact WADC is as simple as classic PSS with no more than two lead-lag phase compensation units.Case studies are carried out on an IEEE 16-machine 68-bus power system.Simulation results demonstrate that the control loop selection before the WADC design is necessary and that the proposed selection strategy can easily pick out the suitable candidate control loops.In addition,it is feasible for the UR method to design WADCs with different time delays in the selected control loops.All the designed WADCs are effective in damping inter-area LFO and robust to time delay variations under operation conditions.Comparisons among five design methods for PSS-based WADC show that the proposed UR method is superior in delay adaptation,the conciseness of WADC structure and computation speed of parameters.
基金This work was supported by the Shanghai Science and Technology Commission Innovation Action Plan(Grant No.18DZ1203200).
文摘This paper presents an approach for designing parameters of power system stabilizer(PSS)and FACTS damping controllers in a large scale practical power system.The objective is maximizing damping ratio of the target mode,and tracking technology(MTT)is used to avoid frequent alternations of target mode in optimization procedures.An improved planted growth simulation algorithm(IPGSA),which has high search efficiency and quick convergence speed,is proposed to optimize controller parameters coordinately.Based on case study of a large-scale power grid,and by using local and interregional low-frequency oscillation modes as target modes,simulation results verify proposed method in this paper.Furthermore,coordination optimization strategy adapted to multi-operating conditions demonstrates that the proposed approach is robust.
文摘Integration of renewable energy sources(RES)with a conventional power system has a detrimental effect on interarea oscillation.Most popular RESs are solar photovoltaic(PV)and wind energy conversion systems(WECS).Both solar PV power generation and WECS are integrated with power systems using a power electronic converter.Increasing the amount of RES generation lead towards reduction of system damping,which leads towards inter-area oscillation.Also,the intermittent behavior of a RES reduces the effectiveness of damping controllers.A dynamic controller based wide area damping controller(WADC)is proposed in this paper to increase small signal stability of a RES integrated power system.The WADC is designed for contemplating delay in a communication channel,communication failure and saturation.An anti-windup compensator is developed to overcome the effect of actuator saturation.However,the gain of the anti-windup compensator is calculated using LyapunovKrasovskii functional(LKF)in terms of linear matrix inequality(LMI).The actuator considered in this paper is a unified power flow controller(UPFC).Efficacy of PV and wind power integration on power system is also observed.The efficacy of the developed dynamic controller is verified using IEEE 39 bus and 68 bus power system.
基金supported by the Special Key Project of Science and Technology of Gansu Province entitled key technology and demonstrating applications of market driven consumption and dispatching control of new energy electricity generation based on concentrating solar,photovoltaic and wind power(19ZD2GA003).
文摘This paper examines the harmonic oscillations in a grid-connected PV generation farm(PVGF)caused by the parallel connection of an increased number of PV generation units(PVGUs).An equivalent model of the grid-connected PVGF is derived,which clearly explains why there are internal and external oscillation modes in the grid-connected PVGF.An indicator of impedance multiplication(IIM)is proposed to quantitatively estimate the impact of the increased number of PVGUs in parallel connection.The analysis in this paper reveals the mechanism about why the damping of external oscillation modes may decrease when more PVGUs are in parallel connection under the condition that the IIM is positive.An example grid-connected PVGF is presented in this paper to demonstrate and evaluate the derived analysis and conclusions.A method for designing the damping controllers to ensure a negative IIM is proposed.With the damping controllers being installed,the risk of growing harmonic oscillations caused by the increased number of the PVGUs in parallel connection can be effectively eliminated.
基金This project is supported by National Natural Science Foundation of China(No.50275114,No.10476020).
文摘A kind of novel multi-layer piezoelectric actuator is proposed and integrated with controllable constrained damping treatment to perform hybrid vibration control.The governing equation of the system is derived based on the constitutive equations of elastic,viscoelastic and piezoelectric materials,which shows that the magnitude of control force exerted by multi-layer piezoelectric actuator is the quadratic function of the number of piezoelectric laminates used but in direct proportion to control voltage.This means that the multi-layer actuator can produce greater actuating force than that by piezoelectric laminate actuator with the same area under the identical control voltage.The optimal location placement of the multi-layer piezoelectric actuator is also discussed.As an example,the hybrid vibration control of a cantilever rectangular thin-plate is numerically simulated and carried out experimentally.The simulated and experimental results validate the power of multi-layer piezoelectric actuator and indicate that the present hybrid damping technique can effectively suppress the low frequency modal vibration of the experimental thin-plate structure.
