An integral terminal sliding mode-based control design is proposed in this paper to enhance the power quality of wind turbines under unbalanced voltage conditions. The design combines the robustness, fast response, an...An integral terminal sliding mode-based control design is proposed in this paper to enhance the power quality of wind turbines under unbalanced voltage conditions. The design combines the robustness, fast response, and high quality transient characteristics of the integral terminal sliding mode control with the estimation properties of disturbance observers. The controller gains were auto-tuned using a fuzzy logic approach.The effectiveness of the proposed design was assessed under deep voltage sag conditions and parameter variations. Its dynamic response was also compared to that of a standard SMC approach.The performance analysis and simulation results confirmed the ability of the proposed approach to maintain the active power,currents, DC-link voltage and electromagnetic torque within their acceptable ranges even under the most severe unbalanced voltage conditions. It was also shown to be robust to uncertainties and parameter variations, while effectively mitigating chattering in comparison with the standard SMC.展开更多
This paper investigates the effects of various parameters on the terminal voltage and frequency of self excited induction generator using genetic algorithm. The parameters considered are speed, capacitance, leakage re...This paper investigates the effects of various parameters on the terminal voltage and frequency of self excited induction generator using genetic algorithm. The parameters considered are speed, capacitance, leakage reactance, stator and rotor resistances. Simulated results obtained using genetic algorithm facilitates in exploring the performance of self-excited induction generator. The paper henceforth establishes the application of user friendly genetic algorithm for studying the behaviour of self-excited induction.展开更多
Virtual synchronous control has been widely studied for the advantages of emulating inertia for voltage source converters (VSCs). A constant dc-link voltage is usually assumed in existing literature to estimate transi...Virtual synchronous control has been widely studied for the advantages of emulating inertia for voltage source converters (VSCs). A constant dc-link voltage is usually assumed in existing literature to estimate transient stability of virtual synchronous generators (VSGs). However, actual power supply in the dc-side of VSGs is limited and different dc-link voltage controllers are needed to achieve power balance between DC side and AC side. Addition of dc-link voltage controller has great influence on transient behavior of VSGs, which has not been investigated by previous research. To fill this gap, this paper gives insights into the effect of dc-link voltage dynamics on transient stability of VSGs. First, two typical kinds of VSGs with dc-link voltage controllers are introduced. Then, mathematical models considering dc-link dynamics are established and the effect of dc-link voltage controllers on transient synchronization stability of VSGs is revealed through equal area criterion (EAC). It is found that dc-link voltage controller would reduce stability margin of VSGs and design-oriented transient stability analysis is carried out quantitively using critical clearing time (CCT). Finally, simulation results are given to validate correctness of theoretical analysis.展开更多
光伏电池作为一种清洁高效的新能源受到广泛关注,但其子模块在串联使用过程中因不均匀老化、局部遮光等原因易发生功率失配,从而产生“热斑效应”,降低光伏电池的利用率和使用寿命。为了使学生深入了解光伏电池模型及其串联不匹配带来...光伏电池作为一种清洁高效的新能源受到广泛关注,但其子模块在串联使用过程中因不均匀老化、局部遮光等原因易发生功率失配,从而产生“热斑效应”,降低光伏电池的利用率和使用寿命。为了使学生深入了解光伏电池模型及其串联不匹配带来的特性表征以及如何解决这一问题,该文研制了一个基于多端口直流变换器的光伏电池DMPPT(distributed maximum power point tracking,最大功率点跟踪)实验平台。首先,对光伏电池进行建模并分析了光伏电池的串联失配特性;然后,分析研究了多端口直流变换器在光伏模块串联应用中的电压均衡策略;最后,研制了36 V/200 W基于多端口Buck-Boost直流变换器的DMPPT实验平台,得到了系统稳态波形,并与采用二极管旁路的方式进行了对比。学生可通过该实验平台和该实验案例更加深入地了解光伏电池模型及其失配特性,以及如何采用多端口变换器实现光伏电池的DMPPT,掌握光伏电池的建模方法,培养发现问题、解决问题、仿真验证的实践能力。展开更多
随着风电场规模越来越大,传统的集中式控制、无功比例分配方式难以保证风电场运行的经济性和安全性,为此提出一种风电场内部分散式无功电压优化控制策略,风电场以分散式方式运行,以减小集电线路损耗和均衡机组机端电压为目标协调机组无...随着风电场规模越来越大,传统的集中式控制、无功比例分配方式难以保证风电场运行的经济性和安全性,为此提出一种风电场内部分散式无功电压优化控制策略,风电场以分散式方式运行,以减小集电线路损耗和均衡机组机端电压为目标协调机组无功出力。首先,基于Distflow潮流模型将优化控制目标建立成一个最优问题。然后,利用基于交替方向乘子法(alternating direction multiplier method,ADMM)的分散式优化算法,将原优化问题分解为若干子问题,通过相邻风机控制器间的信息交互,以分散式方式迭代求解。最后,在MATLAB和PSCAD中验证了所提出分散式优化控制策略的控制效果。结果表明:风电场内部分散式无功电压优化控制能够减轻风电场总站控制器通信负担,使风电场在满足上级无功需求指令的同时能够减小内部损耗,改善馈线电压分布,助力风电场经济、安全稳定运行。展开更多
文摘An integral terminal sliding mode-based control design is proposed in this paper to enhance the power quality of wind turbines under unbalanced voltage conditions. The design combines the robustness, fast response, and high quality transient characteristics of the integral terminal sliding mode control with the estimation properties of disturbance observers. The controller gains were auto-tuned using a fuzzy logic approach.The effectiveness of the proposed design was assessed under deep voltage sag conditions and parameter variations. Its dynamic response was also compared to that of a standard SMC approach.The performance analysis and simulation results confirmed the ability of the proposed approach to maintain the active power,currents, DC-link voltage and electromagnetic torque within their acceptable ranges even under the most severe unbalanced voltage conditions. It was also shown to be robust to uncertainties and parameter variations, while effectively mitigating chattering in comparison with the standard SMC.
文摘This paper investigates the effects of various parameters on the terminal voltage and frequency of self excited induction generator using genetic algorithm. The parameters considered are speed, capacitance, leakage reactance, stator and rotor resistances. Simulated results obtained using genetic algorithm facilitates in exploring the performance of self-excited induction generator. The paper henceforth establishes the application of user friendly genetic algorithm for studying the behaviour of self-excited induction.
基金supported in part by National Natural Science Foundation of China(grant No.52207190)Funds for International Cooperation and Exchange of the National Natural Science Foundation of China(No.52061635104)。
文摘Virtual synchronous control has been widely studied for the advantages of emulating inertia for voltage source converters (VSCs). A constant dc-link voltage is usually assumed in existing literature to estimate transient stability of virtual synchronous generators (VSGs). However, actual power supply in the dc-side of VSGs is limited and different dc-link voltage controllers are needed to achieve power balance between DC side and AC side. Addition of dc-link voltage controller has great influence on transient behavior of VSGs, which has not been investigated by previous research. To fill this gap, this paper gives insights into the effect of dc-link voltage dynamics on transient stability of VSGs. First, two typical kinds of VSGs with dc-link voltage controllers are introduced. Then, mathematical models considering dc-link dynamics are established and the effect of dc-link voltage controllers on transient synchronization stability of VSGs is revealed through equal area criterion (EAC). It is found that dc-link voltage controller would reduce stability margin of VSGs and design-oriented transient stability analysis is carried out quantitively using critical clearing time (CCT). Finally, simulation results are given to validate correctness of theoretical analysis.
文摘光伏电池作为一种清洁高效的新能源受到广泛关注,但其子模块在串联使用过程中因不均匀老化、局部遮光等原因易发生功率失配,从而产生“热斑效应”,降低光伏电池的利用率和使用寿命。为了使学生深入了解光伏电池模型及其串联不匹配带来的特性表征以及如何解决这一问题,该文研制了一个基于多端口直流变换器的光伏电池DMPPT(distributed maximum power point tracking,最大功率点跟踪)实验平台。首先,对光伏电池进行建模并分析了光伏电池的串联失配特性;然后,分析研究了多端口直流变换器在光伏模块串联应用中的电压均衡策略;最后,研制了36 V/200 W基于多端口Buck-Boost直流变换器的DMPPT实验平台,得到了系统稳态波形,并与采用二极管旁路的方式进行了对比。学生可通过该实验平台和该实验案例更加深入地了解光伏电池模型及其失配特性,以及如何采用多端口变换器实现光伏电池的DMPPT,掌握光伏电池的建模方法,培养发现问题、解决问题、仿真验证的实践能力。
文摘随着风电场规模越来越大,传统的集中式控制、无功比例分配方式难以保证风电场运行的经济性和安全性,为此提出一种风电场内部分散式无功电压优化控制策略,风电场以分散式方式运行,以减小集电线路损耗和均衡机组机端电压为目标协调机组无功出力。首先,基于Distflow潮流模型将优化控制目标建立成一个最优问题。然后,利用基于交替方向乘子法(alternating direction multiplier method,ADMM)的分散式优化算法,将原优化问题分解为若干子问题,通过相邻风机控制器间的信息交互,以分散式方式迭代求解。最后,在MATLAB和PSCAD中验证了所提出分散式优化控制策略的控制效果。结果表明:风电场内部分散式无功电压优化控制能够减轻风电场总站控制器通信负担,使风电场在满足上级无功需求指令的同时能够减小内部损耗,改善馈线电压分布,助力风电场经济、安全稳定运行。
