Maximum Power Point Tracking (MPPT) is an important process in Photovoltaic (PV) systems because of the need to extract maximum power from PV panels used in these systems. Without the ability to track and have PV pane...Maximum Power Point Tracking (MPPT) is an important process in Photovoltaic (PV) systems because of the need to extract maximum power from PV panels used in these systems. Without the ability to track and have PV panels operate at its maximum power point (MPP) entails power losses;resulting in high cost since more panels will be required to provide specified energy needs. To achieve high efficiency and low cost, MPPT has therefore become an imperative in PV systems. In this study, an MPP tracker is modeled using the IC algorithm and its behavior under rapidly changing environmental conditions of temperature and irradiation levels is investigated. This algorithm, based on knowledge of the variation of the conductance of PV cells and the operating point with respect to the voltage and current of the panel calculates the slope of the power characteristics to determine the MPP as the peak of the curve. A simple circuit model of the DC-DC boost converter connected to a PV panel is used in the simulation;and the output of the boost converter is fed through a 3-phase inverter to an electricity grid. The model was simulated and tested using MATLAB/Simulink. Simulation results show the effectiveness of the IC algorithm for tracking the MPP in PV systems operating under rapidly changing temperatures and irradiations with a settling time of 2 seconds.展开更多
Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of tw...Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of two-mass drive train, a Squirrel Cage Induction Generator (SCIG), and voltage source converter control by Space Vector Pulse Width Modulation (SPVWM). To achieve Maximum Power Point Tracking (MPPT), the reference speed to the generator is searched via Extremum Seeking Control (ESC). ESC was designed for wind turbine region II operation based on dither-modulation scheme. ESC is a model-free method that has the ability to increase the captured power in real time under turbulent wind without any requirement for wind measurements. The controller is designed in two loops. In the outer loop, ESC is used to set a desired reference speed to PI controller to regulate the speed of the generator and extract the maximum electrical power. The inner control loop is based on Indirect Field Orientation Control (IFOC) to decouple the currents. Finally, Particle Swarm Optimization (PSO) is used to obtain the optimal PI parameters. Simulation and control of the system have been accomplished using MATLAB/Simulink 2014.展开更多
Under the trends to using renewable energy sources as alternatives to the traditional ones,it is important to contribute to the fast growing development of these sources by using powerful soft computing methods.In thi...Under the trends to using renewable energy sources as alternatives to the traditional ones,it is important to contribute to the fast growing development of these sources by using powerful soft computing methods.In this context,this paper introduces a novel structure to optimize and control the energy produced from a variable speed wind turbine which is based on a squirrel cage induction generator(SCIG)and connected to the grid.The optimization strategy of the harvested power from the wind is realized by a maximum power point tracking(MPPT)algorithm based on fuzzy logic,and the control strategy of the generator is implemented by means of an internal model(IM)controller.Three IM controllers are incorporated in the vector control technique,as an alternative to the proportional integral(PI)controller,to implement the proposed optimization strategy.The MPPT in conjunction with the IM controller is proposed as an alternative to the traditional tip speed ratio(TSR)technique,to avoid any disturbance such as wind speed measurement and wind turbine(WT)characteristic uncertainties.Based on the simulation results of a six KW-WECS model in Matlab/Simulink,the presented control system topology is reliable and keeps the system operation around the desired response.展开更多
最优转矩法因其所需测量状态较少、易于实现的特点,被广泛应用于风力机的最大功率点跟踪(Maximum power point tracking,MPPT)控制.传统的最优转矩法只考虑系统的稳态工作点,依靠系统本身的特性进行转速调节,在一定程度上限制了转速调...最优转矩法因其所需测量状态较少、易于实现的特点,被广泛应用于风力机的最大功率点跟踪(Maximum power point tracking,MPPT)控制.传统的最优转矩法只考虑系统的稳态工作点,依靠系统本身的特性进行转速调节,在一定程度上限制了转速调节速度.本文使用滑模变结构控制的思想,在最优转矩法的基础上设计得到一种变结构控制器,增大了转速跟踪过程中的不平衡转矩,缩短了系统的调节时间.仿真结果表明本文提出的改进方法可以获得良好的转速跟踪效果,从而提高风力机的风能捕获效率.展开更多
针对小型单相风力发电并网系统(发电机额定功率1 k W),基于滑模控制的强鲁棒性和快速响应特性,设计了一种滑模MPPT控制算法,并做了优化。该并网系统由MPPT控制算法直接给定并网电流有效值,并捕捉电网电压波形来共同确定系统给定的并网...针对小型单相风力发电并网系统(发电机额定功率1 k W),基于滑模控制的强鲁棒性和快速响应特性,设计了一种滑模MPPT控制算法,并做了优化。该并网系统由MPPT控制算法直接给定并网电流有效值,并捕捉电网电压波形来共同确定系统给定的并网电流参考值,以此来实现并网系统的MPPT控制要求。通过MATLAB/Simulink仿真软件对该系统控制方案进行仿真分析,仿真结果说明所设计的滑模MPPT控制算法能够使得整个并网系统快速有效地跟踪最大功率点以及实现并网时功率因数等于1;优化后的方案能够一定程度削弱系统在稳态运行时的抖振以及并网电流波形畸变的问题。展开更多
基金supported by the National Natural Science Foundation of China(61203129,61174038,61473151,51507080)the Fundamental Research Funds for the Central Universities(30915011104,30920130121010,30920140112005)
文摘Maximum Power Point Tracking (MPPT) is an important process in Photovoltaic (PV) systems because of the need to extract maximum power from PV panels used in these systems. Without the ability to track and have PV panels operate at its maximum power point (MPP) entails power losses;resulting in high cost since more panels will be required to provide specified energy needs. To achieve high efficiency and low cost, MPPT has therefore become an imperative in PV systems. In this study, an MPP tracker is modeled using the IC algorithm and its behavior under rapidly changing environmental conditions of temperature and irradiation levels is investigated. This algorithm, based on knowledge of the variation of the conductance of PV cells and the operating point with respect to the voltage and current of the panel calculates the slope of the power characteristics to determine the MPP as the peak of the curve. A simple circuit model of the DC-DC boost converter connected to a PV panel is used in the simulation;and the output of the boost converter is fed through a 3-phase inverter to an electricity grid. The model was simulated and tested using MATLAB/Simulink. Simulation results show the effectiveness of the IC algorithm for tracking the MPP in PV systems operating under rapidly changing temperatures and irradiations with a settling time of 2 seconds.
文摘Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of two-mass drive train, a Squirrel Cage Induction Generator (SCIG), and voltage source converter control by Space Vector Pulse Width Modulation (SPVWM). To achieve Maximum Power Point Tracking (MPPT), the reference speed to the generator is searched via Extremum Seeking Control (ESC). ESC was designed for wind turbine region II operation based on dither-modulation scheme. ESC is a model-free method that has the ability to increase the captured power in real time under turbulent wind without any requirement for wind measurements. The controller is designed in two loops. In the outer loop, ESC is used to set a desired reference speed to PI controller to regulate the speed of the generator and extract the maximum electrical power. The inner control loop is based on Indirect Field Orientation Control (IFOC) to decouple the currents. Finally, Particle Swarm Optimization (PSO) is used to obtain the optimal PI parameters. Simulation and control of the system have been accomplished using MATLAB/Simulink 2014.
文摘Under the trends to using renewable energy sources as alternatives to the traditional ones,it is important to contribute to the fast growing development of these sources by using powerful soft computing methods.In this context,this paper introduces a novel structure to optimize and control the energy produced from a variable speed wind turbine which is based on a squirrel cage induction generator(SCIG)and connected to the grid.The optimization strategy of the harvested power from the wind is realized by a maximum power point tracking(MPPT)algorithm based on fuzzy logic,and the control strategy of the generator is implemented by means of an internal model(IM)controller.Three IM controllers are incorporated in the vector control technique,as an alternative to the proportional integral(PI)controller,to implement the proposed optimization strategy.The MPPT in conjunction with the IM controller is proposed as an alternative to the traditional tip speed ratio(TSR)technique,to avoid any disturbance such as wind speed measurement and wind turbine(WT)characteristic uncertainties.Based on the simulation results of a six KW-WECS model in Matlab/Simulink,the presented control system topology is reliable and keeps the system operation around the desired response.
文摘最优转矩法因其所需测量状态较少、易于实现的特点,被广泛应用于风力机的最大功率点跟踪(Maximum power point tracking,MPPT)控制.传统的最优转矩法只考虑系统的稳态工作点,依靠系统本身的特性进行转速调节,在一定程度上限制了转速调节速度.本文使用滑模变结构控制的思想,在最优转矩法的基础上设计得到一种变结构控制器,增大了转速跟踪过程中的不平衡转矩,缩短了系统的调节时间.仿真结果表明本文提出的改进方法可以获得良好的转速跟踪效果,从而提高风力机的风能捕获效率.
文摘针对小型单相风力发电并网系统(发电机额定功率1 k W),基于滑模控制的强鲁棒性和快速响应特性,设计了一种滑模MPPT控制算法,并做了优化。该并网系统由MPPT控制算法直接给定并网电流有效值,并捕捉电网电压波形来共同确定系统给定的并网电流参考值,以此来实现并网系统的MPPT控制要求。通过MATLAB/Simulink仿真软件对该系统控制方案进行仿真分析,仿真结果说明所设计的滑模MPPT控制算法能够使得整个并网系统快速有效地跟踪最大功率点以及实现并网时功率因数等于1;优化后的方案能够一定程度削弱系统在稳态运行时的抖振以及并网电流波形畸变的问题。
