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
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
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
An input-output signal selection based on Phillips-Heffron model of a parallel high voltage alternative current/high voltage direct current(HVAC/HVDC) power system is presented to study power system stability. It is w...An input-output signal selection based on Phillips-Heffron model of a parallel high voltage alternative current/high voltage direct current(HVAC/HVDC) power system is presented to study power system stability. It is well known that appropriate coupling of inputs-outputs signals in the multivariable HVDC-HVAC system can improve the performance of designed supplemetary controller. In this work, different analysis techniques are used to measure controllability and observability of electromechanical oscillation mode. Also inputs–outputs interactions are considered and suggestions are drawn to select the best signal pair through the system inputs-outputs. In addition, a supplementary online adaptive controller for nonlinear HVDC to damp low frequency oscillations in a weakly connected system is proposed. The results obtained using MATLAB software show that the best output-input for damping controller design is rotor speed deviation as out put and phase angle of rectifier as in put. Also response of system equipped with adaptive damping controller based on HVDC system has appropriate performance when it is faced with faults and disturbance.展开更多
In this paper, we give a controlled two-degree-of-freedom （TDOF） vibro-impact system based on the damping control law, and then investigate the dynamical behaviour of this system. According to numerical simulation, ...In this paper, we give a controlled two-degree-of-freedom （TDOF） vibro-impact system based on the damping control law, and then investigate the dynamical behaviour of this system. According to numerical simulation, we find that this control scheme can suppress chaos to periodic orbit successfully. Furthermore, the feasibility and the robustness of the controller are confirmed, separately. We also find that this scheme cannot only suppress chaos, but also generate chaos in this system.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
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
The DC distribution network system equipped with a large number of power electronic equipment exhibits weak damping characteristics and is prone to low-frequency and high-frequency unstable oscillations.The current in...The DC distribution network system equipped with a large number of power electronic equipment exhibits weak damping characteristics and is prone to low-frequency and high-frequency unstable oscillations.The current interpretation of the oscillation mechanism has not been unified.Firstly,this paper established the complete statespace model of the distribution system consisting of a large number of electric vehicles,characteristic equation of the distribution network system is derived by establishing a state-space model,and simplified reduced-order equations describing the low-frequency oscillation and the high-frequency oscillation are obtained.Secondly,based on eigenvalue analysis,the oscillation modes and the influence of the key system parameters on the oscillation mode are studied.Besides,impacts of key factors,such as distribution network connection topology and number of dynamic loads,have been discussed to suppress oscillatory instability caused by inappropriate design or dynamic interactions.Finally,using the DC distribution example system,through model calculation and time-domain simulation analysis,the correctness of the aforementioned analysis is verified.展开更多
In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of...In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of transmission lines, increase wear and tear on network components, increase line losses etc. This paper is to maintain the stability of system by damping inter-area oscillations. Implementation of new equipment consists of high power electronics based technologies such as FACTs and proper controller design has become an essential to provide better damping performance than Power System Stabilizer (PSS). With development of Wide Area Measurement System (WAMS), remote signals have become as feedback signals to design Wide Area Damping Controller (WADC) for FACTs devices. In this work, POD is applied to both SVC and SSSC. Simulation studies are carried out in Power System Analysis Toolbox (PSAT) environment to evaluate the effectiveness of the FACTs controller in a large area power system. Results show that extensive analysis of FACTs controller for improving stability of system.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
Active vibration control is an effective way of increasing robustness of the design to meet the stringent accuracy requirements for space structures. This paper presents the results of active damping realized by a pie...Active vibration control is an effective way of increasing robustness of the design to meet the stringent accuracy requirements for space structures. This paper presents the results of active damping realized by a piezoelectric active member to control the vibration of a four-bay four-longern aluminum truss structure with cantilever boundary. The active member, which utilizes a piezoelectric actuating unit and an integrated load cell, is designed for vibration control of the space truss structures. Active damping control is realized using direct velocity feedback around the active member. The placement of the active member as one of the most important factor of affecting the control system performance, is also investigated by modal dissipation energy ratio as indicator. The active damping effectiveness is evaluated by comparing the closed-loop response with the open loop response.展开更多
The wide-area damping controllers(WADCs),which are essential for mitigating regional low-frequency oscillations,face cyber-physical security threats due to the vulnerability of wide-area measurement system to cyber at...The wide-area damping controllers(WADCs),which are essential for mitigating regional low-frequency oscillations,face cyber-physical security threats due to the vulnerability of wide-area measurement system to cyber attacks and wind power uncertainties.This paper introduces reachability analysis method to quantify the impact of varying-amplitude attacks and uncertain wind fluctuations on the performance of WADC.Firstly,considering wind farm integration and attack injection,a nonlinear power system model with multiple buses is constructed based on Kron reduction method to improve computational efficiency and mitigate the constraints imposed by algebraic constraints.Then,a zonotope-based polytope construction method is employed to effectively model the range of attack amplitudes and wind uncertainties.By conducting reachability analysis,the reachable set preserving the nonlinear characteristics of studied system is computed,which enables the quantification of the maximum fluctuation range of regional oscillations under the dual disturbances.Case studies are undertaken on two multi-machine power systems with wind farm integration.The obtained results emphasize the efficacy of designed method,providing valuable insights into the magnitude of the impact that attacks exert on the operational characteristics of power system under various uncertain factors.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
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
A magneto-rheological（MR） semi-active suspension system with the controllable damping forces has received more attention in reducing the vibration of a vehicle. However, many control strategies only discussed one or...A magneto-rheological（MR） semi-active suspension system with the controllable damping forces has received more attention in reducing the vibration of a vehicle. However, many control strategies only discussed one or two vibration states of the vehicle based on a quarter-car model or a half vehicle model via MR suspensions. They cannot provide a satisfying whole-vehicle performance on a road test. Hence, a full car vibration model via an MR suspension system is proposed. To reduce the heave, pitch and roll motion of the vehicle body and the vertical vibration of four wheels, a fuzzy hybrid controller for vibration attitude of full car via MR suspensions is proposed. First, a skyhook-fuzzy control scheme is designed to reduce the heave, roll and pitch motion of the vehicle body. Second, a revised ground hook control strategy is adopted to decrease the vertical vibration of the wheels. Finally, a hybrid control scheme based on a fuzzy reasoning method is proposed to tune the hybrid damping parameter, which is suitable for coordination the attitude of the vehicle body and the wheels. A test and control system for the vibration attitude of full car is set up. It is implemented on a car equipped with four MR suspensions. The results on random highway and rough road indicate that the fuzzy hybrid controller can decrease the vibration accelerations of the vehicle body and the wheels to 65%-80% and 80%-90%, respectively. It reduces the automotive vibrations of heave, roll and pitch more effectively than a passive suspension and an MR suspension with a traditional hybrid control scheme so that it achieves better ride comfort and road holding concurrently. This paper proposes a new fuzzy hybrid control（FHC） method for reducing vibration attitude of full car via MR suspensions and develops a road test to evaluate the FHC.展开更多
A passive heave compensator is designed to enhance the operation safety of a 4.5 km remotely operated vehicle (ROV).This paper proposes a novel idea of designing a compensator with relatively low natural period to opt...A passive heave compensator is designed to enhance the operation safety of a 4.5 km remotely operated vehicle (ROV).This paper proposes a novel idea of designing a compensator with relatively low natural period to optimize gas volume and while adding a special device to remove the problem of ineffectiveness and resonance in long seas.Numerical simulations are done based on serious dynamic model of the whole system,including the compensator,the umbilical tether and the vehicle,solved by the fourth-order Runge-Kutta scheme.The compensator provides great attenuation of motion and tension in most sea states.As the working depth increases,the system natural period decreases,resulting in the occurrence of risk of resonance.By regulating the system damping,the compensator can be effective in these situations.展开更多
In this paper, a new hybrid control technique, based on a combination of base-isolation and semi-active variable stiffness/damping in a superstructure, is presented. To illustrate the efficiency of the proposed contro...In this paper, a new hybrid control technique, based on a combination of base-isolation and semi-active variable stiffness/damping in a superstructure, is presented. To illustrate the efficiency of the proposed control system, model tests on a mini-electromagnetic shaking table and a numerical simulation were performed. The test and numerical calculation results indicate that this new hybrid control mode with additional damping and smaller additional stiffness can achieve a better control efficiency.展开更多
The paper presents a successful design and good result of grid voltage feed-forward control strategy with no damping regulator of LCL filter applied in Three-phase Pulse Width Modulation( PWM) rectifier under unbalanc...The paper presents a successful design and good result of grid voltage feed-forward control strategy with no damping regulator of LCL filter applied in Three-phase Pulse Width Modulation( PWM) rectifier under unbalance grid condition for renewable energy processing. It is demonstrated that the closed-loop current control is decoupled with the grid voltage feed-forward control,and good waveform of grid current with low order harmonics is obtained under unbalance grid condition. This novel strategy is simple and reliable,applied with PI regulator but no resonant controller in α,β two-phase stationary frame. Moreover,the results of experiment and simulation are also illustrated to validate the novel strategy well applied in the closed-loop current control system under unbalanced grid condition.展开更多
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 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.
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.
文摘An input-output signal selection based on Phillips-Heffron model of a parallel high voltage alternative current/high voltage direct current(HVAC/HVDC) power system is presented to study power system stability. It is well known that appropriate coupling of inputs-outputs signals in the multivariable HVDC-HVAC system can improve the performance of designed supplemetary controller. In this work, different analysis techniques are used to measure controllability and observability of electromechanical oscillation mode. Also inputs–outputs interactions are considered and suggestions are drawn to select the best signal pair through the system inputs-outputs. In addition, a supplementary online adaptive controller for nonlinear HVDC to damp low frequency oscillations in a weakly connected system is proposed. The results obtained using MATLAB software show that the best output-input for damping controller design is rotor speed deviation as out put and phase angle of rectifier as in put. Also response of system equipped with adaptive damping controller based on HVDC system has appropriate performance when it is faced with faults and disturbance.
基金supported by the National Natural Science Foundation of China (Grant No 10472091)
文摘In this paper, we give a controlled two-degree-of-freedom （TDOF） vibro-impact system based on the damping control law, and then investigate the dynamical behaviour of this system. According to numerical simulation, we find that this control scheme can suppress chaos to periodic orbit successfully. Furthermore, the feasibility and the robustness of the controller are confirmed, separately. We also find that this scheme cannot only suppress chaos, but also generate chaos in this system.
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.
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.
基金supported by the State Grid Shandong Electric Power Company Economic and Technical Research Institute Project(Grant No.SGSDJY00GPJS2100135).
文摘The DC distribution network system equipped with a large number of power electronic equipment exhibits weak damping characteristics and is prone to low-frequency and high-frequency unstable oscillations.The current interpretation of the oscillation mechanism has not been unified.Firstly,this paper established the complete statespace model of the distribution system consisting of a large number of electric vehicles,characteristic equation of the distribution network system is derived by establishing a state-space model,and simplified reduced-order equations describing the low-frequency oscillation and the high-frequency oscillation are obtained.Secondly,based on eigenvalue analysis,the oscillation modes and the influence of the key system parameters on the oscillation mode are studied.Besides,impacts of key factors,such as distribution network connection topology and number of dynamic loads,have been discussed to suppress oscillatory instability caused by inappropriate design or dynamic interactions.Finally,using the DC distribution example system,through model calculation and time-domain simulation analysis,the correctness of the aforementioned analysis is verified.
文摘In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of transmission lines, increase wear and tear on network components, increase line losses etc. This paper is to maintain the stability of system by damping inter-area oscillations. Implementation of new equipment consists of high power electronics based technologies such as FACTs and proper controller design has become an essential to provide better damping performance than Power System Stabilizer (PSS). With development of Wide Area Measurement System (WAMS), remote signals have become as feedback signals to design Wide Area Damping Controller (WADC) for FACTs devices. In this work, POD is applied to both SVC and SSSC. Simulation studies are carried out in Power System Analysis Toolbox (PSAT) environment to evaluate the effectiveness of the FACTs controller in a large area power system. Results show that extensive analysis of FACTs controller for improving stability of system.
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.
文摘Active vibration control is an effective way of increasing robustness of the design to meet the stringent accuracy requirements for space structures. This paper presents the results of active damping realized by a piezoelectric active member to control the vibration of a four-bay four-longern aluminum truss structure with cantilever boundary. The active member, which utilizes a piezoelectric actuating unit and an integrated load cell, is designed for vibration control of the space truss structures. Active damping control is realized using direct velocity feedback around the active member. The placement of the active member as one of the most important factor of affecting the control system performance, is also investigated by modal dissipation energy ratio as indicator. The active damping effectiveness is evaluated by comparing the closed-loop response with the open loop response.
基金supported in part by the Young Elite Scientists Sponsorship Program by the Chinese Society for Electrical Engineering under Grant CSEE-YESS-2022019in part by the Guangzhou Basic and Applied Basic Research Foundation under Grand 2024A04J3672in part by the National Natural Science Foundation of China under Grant 52207106.
文摘The wide-area damping controllers(WADCs),which are essential for mitigating regional low-frequency oscillations,face cyber-physical security threats due to the vulnerability of wide-area measurement system to cyber attacks and wind power uncertainties.This paper introduces reachability analysis method to quantify the impact of varying-amplitude attacks and uncertain wind fluctuations on the performance of WADC.Firstly,considering wind farm integration and attack injection,a nonlinear power system model with multiple buses is constructed based on Kron reduction method to improve computational efficiency and mitigate the constraints imposed by algebraic constraints.Then,a zonotope-based polytope construction method is employed to effectively model the range of attack amplitudes and wind uncertainties.By conducting reachability analysis,the reachable set preserving the nonlinear characteristics of studied system is computed,which enables the quantification of the maximum fluctuation range of regional oscillations under the dual disturbances.Case studies are undertaken on two multi-machine power systems with wind farm integration.The obtained results emphasize the efficacy of designed method,providing valuable insights into the magnitude of the impact that attacks exert on the operational characteristics of power system under various uncertain factors.
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.
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 by National Natural Science Foundation of China (Grant No. 60674097, Grant No. 60804018)Visiting Scholar Foundation of Key Laboratory of Optoelectronic Technology and Systems of Ministry of Education in Chongqing University of China, and Chongqing Municipal Natural Science Foundation of China (Grant No. 2008BB2407, Grant No. 2009AC3079, Grant No. 2009BB3416)
文摘A magneto-rheological（MR） semi-active suspension system with the controllable damping forces has received more attention in reducing the vibration of a vehicle. However, many control strategies only discussed one or two vibration states of the vehicle based on a quarter-car model or a half vehicle model via MR suspensions. They cannot provide a satisfying whole-vehicle performance on a road test. Hence, a full car vibration model via an MR suspension system is proposed. To reduce the heave, pitch and roll motion of the vehicle body and the vertical vibration of four wheels, a fuzzy hybrid controller for vibration attitude of full car via MR suspensions is proposed. First, a skyhook-fuzzy control scheme is designed to reduce the heave, roll and pitch motion of the vehicle body. Second, a revised ground hook control strategy is adopted to decrease the vertical vibration of the wheels. Finally, a hybrid control scheme based on a fuzzy reasoning method is proposed to tune the hybrid damping parameter, which is suitable for coordination the attitude of the vehicle body and the wheels. A test and control system for the vibration attitude of full car is set up. It is implemented on a car equipped with four MR suspensions. The results on random highway and rough road indicate that the fuzzy hybrid controller can decrease the vibration accelerations of the vehicle body and the wheels to 65%-80% and 80%-90%, respectively. It reduces the automotive vibrations of heave, roll and pitch more effectively than a passive suspension and an MR suspension with a traditional hybrid control scheme so that it achieves better ride comfort and road holding concurrently. This paper proposes a new fuzzy hybrid control（FHC） method for reducing vibration attitude of full car via MR suspensions and develops a road test to evaluate the FHC.
基金the National High Technology Research and Development Program (863) of China(No. 2008AA092301-1)the National Natural Science Foundation of China(No. 50909061)the PH. D. Programs Foundation of Ministry of Education of China(No. 20070248103)
文摘A passive heave compensator is designed to enhance the operation safety of a 4.5 km remotely operated vehicle (ROV).This paper proposes a novel idea of designing a compensator with relatively low natural period to optimize gas volume and while adding a special device to remove the problem of ineffectiveness and resonance in long seas.Numerical simulations are done based on serious dynamic model of the whole system,including the compensator,the umbilical tether and the vehicle,solved by the fourth-order Runge-Kutta scheme.The compensator provides great attenuation of motion and tension in most sea states.As the working depth increases,the system natural period decreases,resulting in the occurrence of risk of resonance.By regulating the system damping,the compensator can be effective in these situations.
基金Societal Commonweal Fund Project (2001DIB20098) Earthquake Science Associate Fund (603011)
文摘In this paper, a new hybrid control technique, based on a combination of base-isolation and semi-active variable stiffness/damping in a superstructure, is presented. To illustrate the efficiency of the proposed control system, model tests on a mini-electromagnetic shaking table and a numerical simulation were performed. The test and numerical calculation results indicate that this new hybrid control mode with additional damping and smaller additional stiffness can achieve a better control efficiency.
文摘The paper presents a successful design and good result of grid voltage feed-forward control strategy with no damping regulator of LCL filter applied in Three-phase Pulse Width Modulation( PWM) rectifier under unbalance grid condition for renewable energy processing. It is demonstrated that the closed-loop current control is decoupled with the grid voltage feed-forward control,and good waveform of grid current with low order harmonics is obtained under unbalance grid condition. This novel strategy is simple and reliable,applied with PI regulator but no resonant controller in α,β two-phase stationary frame. Moreover,the results of experiment and simulation are also illustrated to validate the novel strategy well applied in the closed-loop current control system under unbalanced grid condition.
