Fractional-order control(FOC)has gained significant attention in power system applications due to their ability to enhance performance and increase stability margins.In grid-connected converter(GCC)systems,the synchro...Fractional-order control(FOC)has gained significant attention in power system applications due to their ability to enhance performance and increase stability margins.In grid-connected converter(GCC)systems,the synchronous reference frame phase-locked loop(SRF-PLL)plays a critical role in grid synchronization for renewable power generation.However,there is a notable research gap regarding the application of FOC to the SRF-PLL.This paper proposes a fractional-order SRF-PLL(FO-SRF-PLL)that incorporates FOC to accurately track the phase angle of the terminal voltage,thereby improving the efficiency of grid-connected control.The dynamic performance of the proposed FO-SRF-PLL is evaluated under varying grid conditions.A comprehensive analysis of the small-signal stability of the GCC system employing the FO-SRF-PLL is also presented,including derived small-signal stability conditions.The results demonstrate that the FO-SRF-PLL significantly enhances robustness against disturbances compared with the conventional SRF-PLL.Furthermore,the GCC system with the FO-SRF-PLL maintains stability even under weak grid conditions,showing superior stability performance over the SRF-PLL.Finally,both simulation and experimental results are provided to validate the analysis and conclusions presented in this paper.展开更多
The development of non-linear loads at consumers has significantly impacted power supply systems.Since,the poor power quality has been found in the three-phase distribution system due to unbalanced loads,harmonic curre...The development of non-linear loads at consumers has significantly impacted power supply systems.Since,the poor power quality has been found in the three-phase distribution system due to unbalanced loads,harmonic current,undesired voltage regulation,and extreme reactive power demand.To overcome this issue,Distributed STATicCOMpensator(DSTATCOM)is implemented.DSTATCOM is a shunt-connected Voltage Source Converter(VSC)that has been utilized in distribution networks to balance the bus voltage in terms of enhancing reactive power control and power factor.DSTATCOM can provide both rapid and continuous capacitive and inductive mode compensation.A rectified resistive and inductive load eliminates current harmonics in a three-phase power supply.The synchronous fundamental DQ frame is a time-domain approach developed from three-phase system space vector transformations has been designed using MATLAB/Simulink.The DQ theory is used to produce the reference signal for the Pulse Width Modulation(PWM)generator.In addition,a traditional Propor-tional Integral Derivative(PID)controller is designed and compared with pro-posed soft computing approaches such as Fuzzy–PID and Artificial Neural Network(ANN-PID)and compared accurate reference current determination for Direct Current(DC)bus through DC link.An Analytical explores the pro-posed control strategies given to establish superior outcomes.Finally,total harmo-nic distortion analysis should be taken for performance analysis of the proposed system with IEEE standards.展开更多
State this study looks at how well a three-phase bidirectional converter works for Vehicle-to-Grid(V2G)services by using both Adaptive Neuro-Fuzzy Inference System(ANFIS)and Proportional-Integral(PI)controllers.When c...State this study looks at how well a three-phase bidirectional converter works for Vehicle-to-Grid(V2G)services by using both Adaptive Neuro-Fuzzy Inference System(ANFIS)and Proportional-Integral(PI)controllers.When compared with ANFIS controllers,traditional controllers such as PI and PID show challenges.They may not sufficiently react to changing conditions or non-linearity’s and use fixed gain values requiring hand tuning.By means of learning,ANFIS controllers can thus dynamically change their parameters,so providing enhanced accuracy and flexibility in real-time control.The main objectives are to control the DC link voltage,lower total harmonic distortion(THD),and lower the errors.The Synchronous Reference Frame(SRF)transformation changes three-phase AC into a two-axis(d-q)system,making it easier to control active and reactive power separately.We developed a thorough Simulink model in MATLAB 2023a to model the bidirectional off-board fast charger at a power level of 60 kW.After validation,a 5-kW hardware prototype was built in the lab.The main platform is an AC-DC converter,followed by a DC-DC converter.A programmable DC power supply,Chroma 62050H-600S,connected to the DC-DC converter,mimics the dynamic characteristics of a battery.The control algorithm,deployed on a Spartan-6 LX9 FPGA,manages both voltage and current,maintaining a stable DC link voltage of 800 V.The results obtained indicate that the ANFIS controller outperforms a conventional PI controller when handling dynamic load variations.展开更多
Dynamic reactive power compensation equipment typically requires a fast response to output the necessary reactive power.The term"dynamic response time of reactive power"is often used but has never been clear...Dynamic reactive power compensation equipment typically requires a fast response to output the necessary reactive power.The term"dynamic response time of reactive power"is often used but has never been clearly defined.This paper summarizes the reactive power calculations under different definitions and algorithms and considers these calculations in terms of signal processing to simulate and analyze the step response.This paper subsequently focuses on the widely used instantaneous reactive power algorithm and finally concludes that the dynamic reactive power response time closely depends on the reactive power calculation method itself.The single-phase instantaneous reactive power algorithm has the fastest response time.The reactive power response time of dynamic reactive devices in power systems is a minimum of a quarter of one cycle time for the well-known and widely used single-phase reactive power algorithms.展开更多
A new type of traction drive system consisting of solid-state traction transformer(SSTT),inverter unit,auxiliary inverter,traction motor and other key components is built in order to suit the demand of developing the ...A new type of traction drive system consisting of solid-state traction transformer(SSTT),inverter unit,auxiliary inverter,traction motor and other key components is built in order to suit the demand of developing the next-generation electric traction system which will be efficient and lightweight,with high power density.For the purpose of reducing system volume and weight and improving efficiency and grid-side power quality,an efficient SSTT optimized topology combining highvoltage cascaded rectifiers with high-power high-frequency LLC resonant converter is proposed.On this basis,an integrated control strategy built upon synchronous rotating reference frame is presented to achieve unified control over fundamental active,reactive and harmonic components.The cartier-interleaving phase shift modulation strategy is proposed to improve the harmonic performance of cascaded rectifiers.In view of the secondary pulsating existing in a single-phase system,the mathematical model of secondary power transfer is built,and the mechanism of pulsating voltage resulting in beat frequency of LLC resonant converter is revealed,so as to design optimum matching of system parameters.Simulation and experimental results have verified that the traction system and control scheme mentioned in this paper are reasonable and superior and that they meet the future application requirements for rail transit.展开更多
基金supported in part by the Natural Science Foundation of China(No.52077144)the Youth Innovative Research Team of Science and Technology Scheme,Sichuan Province,China(No.22CXTD0066).
文摘Fractional-order control(FOC)has gained significant attention in power system applications due to their ability to enhance performance and increase stability margins.In grid-connected converter(GCC)systems,the synchronous reference frame phase-locked loop(SRF-PLL)plays a critical role in grid synchronization for renewable power generation.However,there is a notable research gap regarding the application of FOC to the SRF-PLL.This paper proposes a fractional-order SRF-PLL(FO-SRF-PLL)that incorporates FOC to accurately track the phase angle of the terminal voltage,thereby improving the efficiency of grid-connected control.The dynamic performance of the proposed FO-SRF-PLL is evaluated under varying grid conditions.A comprehensive analysis of the small-signal stability of the GCC system employing the FO-SRF-PLL is also presented,including derived small-signal stability conditions.The results demonstrate that the FO-SRF-PLL significantly enhances robustness against disturbances compared with the conventional SRF-PLL.Furthermore,the GCC system with the FO-SRF-PLL maintains stability even under weak grid conditions,showing superior stability performance over the SRF-PLL.Finally,both simulation and experimental results are provided to validate the analysis and conclusions presented in this paper.
文摘The development of non-linear loads at consumers has significantly impacted power supply systems.Since,the poor power quality has been found in the three-phase distribution system due to unbalanced loads,harmonic current,undesired voltage regulation,and extreme reactive power demand.To overcome this issue,Distributed STATicCOMpensator(DSTATCOM)is implemented.DSTATCOM is a shunt-connected Voltage Source Converter(VSC)that has been utilized in distribution networks to balance the bus voltage in terms of enhancing reactive power control and power factor.DSTATCOM can provide both rapid and continuous capacitive and inductive mode compensation.A rectified resistive and inductive load eliminates current harmonics in a three-phase power supply.The synchronous fundamental DQ frame is a time-domain approach developed from three-phase system space vector transformations has been designed using MATLAB/Simulink.The DQ theory is used to produce the reference signal for the Pulse Width Modulation(PWM)generator.In addition,a traditional Propor-tional Integral Derivative(PID)controller is designed and compared with pro-posed soft computing approaches such as Fuzzy–PID and Artificial Neural Network(ANN-PID)and compared accurate reference current determination for Direct Current(DC)bus through DC link.An Analytical explores the pro-posed control strategies given to establish superior outcomes.Finally,total harmo-nic distortion analysis should be taken for performance analysis of the proposed system with IEEE standards.
基金the financial support provided by the Royal Academy of Engineering,UK(Project Reference No:TSP-2526-7102),which enabled the successful execution of this research work.
文摘State this study looks at how well a three-phase bidirectional converter works for Vehicle-to-Grid(V2G)services by using both Adaptive Neuro-Fuzzy Inference System(ANFIS)and Proportional-Integral(PI)controllers.When compared with ANFIS controllers,traditional controllers such as PI and PID show challenges.They may not sufficiently react to changing conditions or non-linearity’s and use fixed gain values requiring hand tuning.By means of learning,ANFIS controllers can thus dynamically change their parameters,so providing enhanced accuracy and flexibility in real-time control.The main objectives are to control the DC link voltage,lower total harmonic distortion(THD),and lower the errors.The Synchronous Reference Frame(SRF)transformation changes three-phase AC into a two-axis(d-q)system,making it easier to control active and reactive power separately.We developed a thorough Simulink model in MATLAB 2023a to model the bidirectional off-board fast charger at a power level of 60 kW.After validation,a 5-kW hardware prototype was built in the lab.The main platform is an AC-DC converter,followed by a DC-DC converter.A programmable DC power supply,Chroma 62050H-600S,connected to the DC-DC converter,mimics the dynamic characteristics of a battery.The control algorithm,deployed on a Spartan-6 LX9 FPGA,manages both voltage and current,maintaining a stable DC link voltage of 800 V.The results obtained indicate that the ANFIS controller outperforms a conventional PI controller when handling dynamic load variations.
文摘Dynamic reactive power compensation equipment typically requires a fast response to output the necessary reactive power.The term"dynamic response time of reactive power"is often used but has never been clearly defined.This paper summarizes the reactive power calculations under different definitions and algorithms and considers these calculations in terms of signal processing to simulate and analyze the step response.This paper subsequently focuses on the widely used instantaneous reactive power algorithm and finally concludes that the dynamic reactive power response time closely depends on the reactive power calculation method itself.The single-phase instantaneous reactive power algorithm has the fastest response time.The reactive power response time of dynamic reactive devices in power systems is a minimum of a quarter of one cycle time for the well-known and widely used single-phase reactive power algorithms.
文摘A new type of traction drive system consisting of solid-state traction transformer(SSTT),inverter unit,auxiliary inverter,traction motor and other key components is built in order to suit the demand of developing the next-generation electric traction system which will be efficient and lightweight,with high power density.For the purpose of reducing system volume and weight and improving efficiency and grid-side power quality,an efficient SSTT optimized topology combining highvoltage cascaded rectifiers with high-power high-frequency LLC resonant converter is proposed.On this basis,an integrated control strategy built upon synchronous rotating reference frame is presented to achieve unified control over fundamental active,reactive and harmonic components.The cartier-interleaving phase shift modulation strategy is proposed to improve the harmonic performance of cascaded rectifiers.In view of the secondary pulsating existing in a single-phase system,the mathematical model of secondary power transfer is built,and the mechanism of pulsating voltage resulting in beat frequency of LLC resonant converter is revealed,so as to design optimum matching of system parameters.Simulation and experimental results have verified that the traction system and control scheme mentioned in this paper are reasonable and superior and that they meet the future application requirements for rail transit.
