永磁直驱风力发电系统MPPT控制的研究

文章首先介绍了风力机模型。然后介绍了一种改进型的变步长爬山算法,通过该算法改变直驱风力发电系统三重交错并联Boost变换电路的占空比,从而实现最大功率跟踪,获取最大风能。最后,利用MATLAB/SIMULINK建立直驱永磁风力发电系统仿真模型并进行研究。试验结果表明,改进型变步长爬山算法比传统爬山算法能更快跟踪最大功率点,控制系统具有较好的控制精度和稳定性。     

Intelligent approach to maximum power point tracking control strategy for variable-speed wind turbine generation system

To achieve maximum power point tracking (MPPT) for wind power generation systems, the rotational speed of wind turbines should be adjusted in real time according to wind speed. In this paper, a Wilcoxon radial basis function network (WRBFN) with hill-climb searching (HCS) MPPT strategy is proposed for a permanent magnet synchronous generator (PMSG) with a variable-speed wind turbine. A high-performance online training WRBFN using a back-propagation learning algorithm with modified particle swarm optimization (MPSO) regulating controller is designed for a PMSG. The MPSO is adopted in this study to adapt to the learning rates in the back-propagation process of the WRBFN to improve the learning capability. The MPPT strategy locates the system operation points along the maximum power curves based on the dc-link voltage of the inverter, thus avoiding the generator speed detection.     

Wind velocity and rotor position sensorless maximum power point tracking control for wind generation system

In order to perform maximum power point tracking control of wind generation system, it is necessary to drive windmill at an optimal rotor speed. For that purpose, a rotor position and a wind velocity sensors become indispensable. However, from the aspect of reliability and increase in cost, rotor position sensor and wind velocity sensor are not usually preferred. Hence, wind velocity and position sensorless operating method for wind generation system using observer is proposed in this paper. Moreover, improving the efficiency of the permanent magnet synchronous generator is also performed by optimizing d-axis current using the Powell method.     

Simulation of grid connection and maximum power point tracking control of brushless doubly-fed generator in wind power system

In this paper, based on the analysis of the mathematical model in a common synchronous reference frame of the brushless doubly-fed generator (BDFG), the grid connection strategy and maximum energy extraction control were both analyzed. Besides, the transient simulation of no-load model and generation model of the BDFG have been developed on the MATLAB/Simulink platform. The test results during cutting-in grid confirmed the good dynamic performance of grid synchronization and effective power control approach for the BDFG-based variable speed wind turbines.     

变速恒频风力发电机最大功率跟踪控制策略的研究

分析了风能的特性，对双馈电机数学模型进行了分析与研究，在试验的基础上，基于最佳叶尖速比控制(即风能最大利用率)和机械功率最大转化效率控制，提出了兆瓦级变速恒频双馈风力发电机组双闭环的一种控制策略方案，并用MATLAB软件进行系统仿真，证明该方案是可行的。     

限定寻优区间的风力机最大功率点跟踪控制

自适应转矩控制是为改善风力机跟踪性能而提出的一种最大功率点跟踪控制方法,但是由于受到风速变化的干扰,导致该方法难以搜索至最佳增益系数。文章针对该问题提出一种改进自适应转矩控制方法。该方法通过分析自适应转矩控制的最佳增益系数与风速条件的关系,并据此设置增益系数的寻优区间,以剔除偏离最佳值较大的异常值。研究结果表明,与自适应转矩控制、传统功率曲线法和减小转矩增益控制相比,新方法能有效改善上述问题,并显著提高风能捕获效率。     

笼型异步发电机和SVG用于独立运行风电系统

提出了笼型异步发电机和静态无功发生器(SVG)构成独立运行的风力发电系统,由SVG代替电容器提供发电机励磁,避免了依靠并联电容器提供无功功率的缺点.通过实验装置验证,当输入转速发生变化时,通过SVG的调节.异步发电机输出电压基本保持在一个比较理想的范围.     

Terminal sliding mode control for maximum power point tracking of photovoltaic power generation systems

This paper presents a novel terminal sliding mode control (TSMC) method for maximum power tracking of photovoltaic (PV) power systems. First, an incremental conductance method is used for maximum power point (MPP) searching. It provides good efficiency under rapidly changing atmospheric conditions, but the accuracy for finding the MPP is highly related to the MPP tracking control. Therefore, a TSMC-based controller is developed to regulate the system to the searched reference MPP. Different from traditional sliding mode control, the developed TSMC assures finite convergence time for the MPP tracking. Furthermore, a common singularity problem that exists in traditional TSMC is removed in this paper. Even if considering uncertainty in the PV power system, the TSMC guarantees high robustness. Finally, several simulations and experiments show the expected control performance.     

A fuzzy control and neural network based rotor speed controller for maximum power point tracking in permanent magnet synchronous wind power generation system

When the wind speed changes significantly in a permanent magnet synchronous wind power generation system,the maximum power point cannot be easily determined in a timely manner. This study proposes a maximum power reference signal search method based on fuzzy control, which is an improvement to the climbing search method. A neural network-based parameter regulator is proposed to address external wind speed fluctuations, where the parameters of a proportional-integral controller is adjusted to acc...     

基于最大电功率跟踪的风力发电系统幂指数趋近滑模控制

文章考虑机组转轴摩擦损耗和发电机本体的电损耗,从减小发电功率损耗、提高整机风电转换效率出发,设计了一种基于MPPT原理下的最大电功率点跟踪(MEPT)控制策略,该策略在考虑转轴摩擦损耗和发电机绕组损耗基础上,推导出发电机最大电功率跟踪输出控制模型方程。采用转矩跟踪型MPPT控制策略,利用动态滑模控制原理,设计了基于幂指数趋近律的风电系统MEPT滑模功率控制器。控制律引入输入变量的积分,在时间上形成滑模控制的动态连续性,抑制了MEPT功率跟踪的抖振,增强了控制精度、平滑性与鲁棒性。通过静、动态多种风况的Matlab仿真实验,验证了MEPT控制的正确性。     

分布式光伏发电系统最大功率点跟踪技术比较研究

基于当前光伏阵列最大功率点跟踪技术的研究现状,介绍了适用于分布式光伏发电系统最大功率点跟踪的各种常用控制方法,阐述了每一种控制方法的技术原理,分析和比较了这些常用控制方法的特点,总结了各自的优点和缺点,最后对分布式光伏发电系统最大功率点跟踪方法的选择问题进行了探讨,并指出了具体选择方法时应综合考虑的各种因素。     

A photovoltaic powered electrolysis converter system with maximum power point tracking control

One of the main problems for renewable and other innovative energy sources is the storage of energy for sustainability. This study focuses on two different scenarios to benefit from solar energy more efficiently. Photovoltaic (PV) energy is converted to the desired voltage level using a buck converter for generating hydrogen with electrolysis process. A maximum power point tracking (MPPT) algorithm is used to benefit from the photovoltaic sources more efficiently. The basic electrolysis load for hydrogen production needs low voltage and high current and controlled sensitively to supply these conditions. The photovoltaic powered buck converter for electrolysis load was simulated in MATLAB/Simulink software using a perturb and observe (P and O) MPPT algorithm and PI controller. The simulation results show that in normal, short circuit and open circuit working conditions the PV and load voltages are stabilized. The efficiency of the proposed system is reached more than 90% for high irradiance levels.     

基于新型扰动观察算法MPPT控制

文章结合光伏阵列的数学模型及其输出特性,提出一种固定电流法结合扰动法的控制方法。对该方法进行了理论分析,并在Matlab/Simulink环境下建立了光伏发电系统的仿真模型。仿真结果表明,光伏系统在正常情况下以及光照强度发生突变的时,都能够快速得追踪到最大功率点,该方法具有良好的控制性能。     

Fuzzy logic control based maximum power tracking of a wind energy system

In this paper a utility interactive wind energy conversion system (WECS) with an asynchronous (AC–DC–AC) link is described. The control system has the objective of identifying and extracting the maximum power from the wind energy system and transferring this power to utility. A fuzzy logic control (FLC) technique has been implemented to design the tracking controller of the WECS. A wind speed step model was used in the design phase. The performance of the WECS with the proposed fuzzy logic controller is tested using real meteorological data. Its robustness and effectiveness are demonstrated by the simulation results of the controlled system.     

A review of maximum power point tracking algorithms for wind energy systems

This paper reviews state of the art maximum power point tracking (MPPT) algorithms for wind energy systems. Due to the instantaneous changing nature of the wind, it is desirable to determine the one optimal generator speed that ensures maximum energy yield. Therefore, it is essential to include a controller that can track the maximum peak regardless of wind speed. The available MPPT algorithms can be classified as either with or without sensors, as well as according to the techniques used to locate the maximum peak. A comparison has been made between the performance of different MPPT algorithms on the basis of various speed responses and ability to achieve the maximum energy yield. Based on simulation results available in the literature, the optimal torque control (OTC) has been found to be the best MPPT method for wind energy systems due to its simplicity. On the other hand, the perturbation and observation (P&O) method is flexible and simple in implementation, but is less efficient and has difficulties determining the optimum step-size.     

A novel adaptative maximum power point tracking algorithm for small wind turbines

A novel maximum power point tracking algorithm for small wind turbines is proposed. The solution presented here is an adaptive intelligent algorithm that uses a new advanced perturb and observe method to search for the optimum relationship of the system for tracking the maximum power point even under variable wind conditions. The validity of the proposed algorithm is analysed and the design procedure is presented. Its main virtue resides in its capability to adapt to changes in the turbine and in the surrounding environment, even under variable wind conditions, improving the efficiency of the system. The experimental results confirm the validity of the proposed algorithm.     

An analysis of subsynchronous resonance in hybrid marine current and wind farms with squirrel cage induction generator

Subsynchronous resonance (SSR) is a well-known phenomenon in series-compensated systems with synchronous generators. With the rapid growth of renewable energy systems, it is likely that with its integration to series-compensated system for the transmission of bulk power may lead to the problem of SSR. This paper conducts an analysis of SSR phenomena in the squirrel cage induction generator-based hybrid wind farm and marine current farm connected to series-compensated system with power variation due to the addition or removal of small turbine units. A dynamic model has been developed to analyse the induction generator effect and torsional interaction of SSR on the IEEE first bench mark model for SSR studies. The eigenvalue analysis was performed on the developed model with MATLAB and the time domain electro magnetic transient simulation performed on DiGSILENT Power Factory confirms the predicted results by the eigenvalue analysis.     

A maximum power point tracking for photovoltaic-SPE system using a maximum current controller

Processes to produce hydrogen from solar photovoltaic (PV)-powered water electrolysis using solid polymer electrolysis (SPE) are reported. An alternative control of maximum power point tracking (MPPT) in the PV-SPE system based on the maximum current searching methods has been designed and implemented.Based on the characteristics of voltage–current and theoretical analysis of SPE, it can be shown that the tracking of the maximum current output of DC–DC converter in SPE side will track the MPPT of photovoltaic panel simultaneously.This method uses a proportional integrator controller to control the duty factor of DC–DC converter with pulse-width modulator (PWM).The MPPT performance and hydrogen production performance of this method have been evaluated and discussed based on the results of the experiment.     

Adaptive maximum power point tracking control of fuel cell power plants

A fuel cell's output power depends nonlinearly on the applied current or voltage, and there exists a unique maximum power point (MPP). This paper reports a first attempt to trace MPPs by an extremum seeking controller. The locus of MPPs varies nonlinearly with the unpredictable variations in the fuel cell's operation conditions. Thus, a maximum power point tracking (MPPT) controller is needed to continuously deliver the highest possible power to the load when variations in operation conditions occur. A two-loop cascade controller with an intermediate converter is designed to operate fuel cell power plants at their MPPs. The outer loop uses an adaptive extremum seeking algorithm to estimate the real-time MPP, and then gives the estimated value to the inner loop as the set-point, at which the inner loop forces the fuel cell to operate. The proposed MPPT control system provides a simple and robust control law that can keep the fuel cell working at MPPs in real time. Simulation shows that this control approach can yield satisfactory results in terms of robustness toward variations in fuel cell operation conditions.     

Power quality improvement of solar photovoltaic transformer-less grid-connected system with maximum power point tracking control

This paper presents a transformer-less single-stage grid-connected solar photovoltaic (PV) system with active reactive power control. In the absence of active input power, grid-tied voltage source converter (VSC) is operated in the reactive power generation mode, which powers control circuitry and maintains regulated DC voltage. Control scheme has been implemented so that the grid-connected converter continuously serves local load. A data-based maximum power point tracking (MPPT) has been implemented at maximum power which performs power quality control by reducing total harmonic distortion (THD) in grid-injected current under varying environmental conditions. Standards (IEEE-519/1547) stipulates that current with THD greater than 5% cannot be injected into the grid by any distributed generation (DG) source. MPPT tracks actual variable DC link voltage while deriving maximum power from PV array and maintains DC link voltage constant by changing the converter modulation index. Simulation results with the PV model and MPPT technique validations demonstrate effectiveness of the proposed system.