电池储能系统换流桥IGBT开路故障诊断方法

针对电池储能系统换流桥器件IGBT发生故障时,会导致电压电流的畸变,影响电能质量,严重时会对储能系统的安全运行造成威胁这一问题,分析了换流桥IGBT开路故障时的特性,并在PSCAD/EMTDC环境下搭建电池储能系统模型对IGBT的开路故障进行了仿真研究。在分析和仿真研究的基础上,提出了一种适用于电池储能系统的换流桥IGBT阀开路故障诊断方法。     

VSC-MTDC系统中IGBT开路检测方法研究

文章分析了柔性直流输电系统换流站IGBT开路故障的电流响应与故障特征,并采用直接平均电流法、平均电流Park矢量法和归一化直流分量法对其进行检测。在PSCAD/EMTDC中搭建了三端柔性直流输电系统仿真模型,对3种开路检测方法在不同运行模式和运行工况下的检测性能进行了对比。仿真结果表明,利用换流站交流侧电流中的直流分量作为故障特征,能够在1～2个周波内检测到换流站IGBT开路故障位置;归一化直流分量法在低功率条件下更灵敏,在功率调整、直流电压调整和潮流反转时具有更好的动态检测性能。     

永磁直驱风力发电并网逆变器电流滞环控制

永磁直驱风力发电系统网侧逆变器采用单电流环控制时,其稳定性不足,输出电流谐波含量大、电能质量下降。文章分析了含有LCL滤波并网逆变器的数学模型,提出了瞬时功率外环、电流滞环内环的控制策略。通过仿真结果表明,在该控制策略下,并网系统输出的电流波形较好,谐波含量低,具有良好的动态跟踪响应特点,并满足了风力发电并网的控制要求,有效验证了该控制方法的可靠性和正确性     

永磁直驱式同步风力发电系统滑模自寻最优控制

针对永磁直驱式同步风力发电机系统部分负荷阶段的最大功率捕捉问题,提出了一种滑模自寻最优控制策略。在风力机和永磁同步风力发电机非线性数学模型基础上,利用滑模变结构自寻最优控制算法实现风力发电系统最大功率捕捉,同时用自适应参数改善滑模变结构控制带来的输出颤振。该方法具有无须测量环境风速和精确风力发电系统数学模型的优点。仿真证明该方法具有良好的控制效果。     

永磁同步风力发电系统最大功率跟踪控制策略及仿真分析

以永磁同步风力发电系统为研究对象,分析了永磁同步风力发电系统的风速、风力机、Boost电路和逆变器模型,研究了风力发电系统的最大功率跟踪控制和并网逆变器控制,在Boost升压电路中利用转速、整流直流电压和导通比三者之间的传递关系制定了最大功率跟踪控制策略,通过简易的PQ解耦幅相控制实现系统并网,提高了系统输出功率因数,恒定了直流母线电压,并基于Matlab/Simulink搭建仿真模型验证了该系统控制策略的有效性。     

双馈风力发电系统在电网故障下的动态响应分析

该文在建立电网故障时双馈发电机定子电压空间矢量模型的基础上,对双馈感应发电机以及变换器在电网不对称故障及对称故障时的动态响应特性进行了详细的定量和定性分析,揭示了双馈发电系统暂态故障响应的本质及各电磁量的变化规律.推导出了双馈发电机电网故障电流的最大值及其发生时刻.并在此基础上,提出了实现风电机组故障穿越技术的基本准则.     

风力发电中PWM逆变器交流侧电感的设计

从稳态和动态电流跟踪两方面出发,提出了风力发电系统中PWM逆变器交流侧电感设计的新方法.为了验证所设计的电感,在MATLAB下建立了风力发电系统中的PWM逆变器数学模型,采用空间矢量脉宽调制(SVPWM)方式和电网电压定向矢量控制策略.仿真结果表明:用该方法设计的电感能满足系统的要求.从而验证该方法的可行性和正确性.     

基于自抗扰控制器的直驱式永磁同步风电系统双PWM控制

针对直驱式永磁同步风力发电机组,分别设计了电机侧和电网侧的变换器自抗扰控制器,从而实现在额定风速以下对电机侧的最大风能跟踪控制、电网侧直流电容电压恒定控制。与常规PI控制器相比,采用自抗扰控制器的直驱动式永磁同步发电系统,能够实现对指令转速快速及无超调跟踪、有效抑制风速变化及电网电压扰动对电容电压的影响,具有较为优秀的控制性能。     

直驱式永磁同步风力发电系统的整合模型与仿真

直驱式永磁同步发电机组具有控制回路少、控制简单的优点,在风力发电系统中得到越来越广泛的应用。文章针对直驱式永磁同步风力发电系统的结构、运行特性及功率传输特点,列写出各个模块的电压方程及状态方程,进而建立其整合模型;使用MATLAB进行仿真,验证了该模型的正确性及可靠性,对风电系统的控制策略研究提供了有效帮助。     

基于无直流储能元件小型直驱风力发电系统的一种新型PWM算法

为简化系统结构及减小变流器体积,采用一种新型小型直驱风力发电系统结构,系统发电机侧以电流源形式提供能量,且变流器直流环节无储能电感及电容。由于中间无直流储能环节,直流侧电流波动较大,如何在直流电流波动大的情况下保证并网电流波形正弦及对幅值的控制,是系统控制的关键及难点。通过分析该系统的运行特性,提出一种新型PWM算法,并基于此提出一种动态控制策略,搭建了系统仿真模型。仿真结果表明,应用所提出的PWM算法及控制策略,系统能够很好地实现对并网电流波形及幅值的控制。     

永磁同步电机变频调速节能系统设计与效益分析

通过对某车辆厂电机耗能情况调研发现该厂大多数正在使用的电机设备使用年限较长、设备陈旧,并且长期处于低效益运行,浪费大量的电能。针对该厂动力车间Y系列三相异步电机进行改造,设计永磁同步电机变频调速控制系统替代Y系列三相异步电机。从节能的角度分析永磁同步电机变频调速控制系统带来的经济效益,最终得出替换Y系列三相异步电机的必要性及合理性。     

Low power wind energy conversion system based on variable speed permanent magnet synchronous generators

This paper presents a low power wind energy conversion system (WECS) based on a permanent magnet synchronous generator and a high power factor (PF) rectifier. To achieve a high PF at the generator side, a power processing scheme based on a diode rectifier and a boost DC–DC converter working in discontinuous conduction mode is proposed. The proposed generator control structure is based on three cascaded control loops that regulate the generator current, the turbine speed and the amount of power that is extracted from the wind, respectively, following the turbine aerodynamics and the actual wind speed. The analysis and design of both the current and the speed loops have been carried out taking into consideration the electrical and mechanical characteristics of the WECS, as well as the turbine aerodynamics. The power loop is not a linear one, but a maximum power point tracking algorithm, based on the Perturb and Observe technique, from which is obtained the reference signal for the speed loop. Finally, to avoid the need of mechanical sensors, a linear Kalman Filter has been chosen to estimate the generator speed. Simulation and experimental results on a 2‐kW prototype are shown to validate the concept. Copyright © 2013 John Wiley & Sons, Ltd.     

PWM整流器在变速恒频风力发电系统中的应用

变速恒频风力发电系统要求励磁电源有良好的输入、输出特性和能量双向流动的能力.交-直-交双PWM变频器是理想的励磁电源,而PWM整流器是其中一项关键技术.文章从三相电压型PWM整流器主电路拓扑结构出发,建立了基于三相静止坐标系和两相同步旋转坐标系的数学模型.阐述了电压、电流双闭环控制的基本原理和空间矢量脉宽调制技术在三相PWM整流器中的应用.在Matlab/Simulink环境下,对其进行了单位功率因数整流和逆变的仿真研究.结果证明,该整流器是满足交流励磁需要的理想整流电源.     

电网故障下直驱永磁风力发电机组机侧变流器改进控制策略

文章对电网电压跌落时的直驱永磁同步风力发电机组的低电压穿越过程进行深入研究,在电网电压跌落时,通过分析发电机机侧变流器最大风能跟踪控制策略,提出一种补偿q轴电流参考值抑制直流母线电压的新方法,并加入弱磁控制,使发电机输出功率迅速有效降低,进而维持机侧与网侧变流器的功率平衡及母线电压稳定。电网持续故障且超出规定时间时,为风电机组增加了卸荷电路,保证机组安全退出运行。分析结果验证了所提方案的正确性和有效性。     

Aggregated models of permanent magnet synchronous generators wind farms

This paper evaluates the responses of three aggregated models of a wind farm consisting of variable speed permanent magnet synchronous generator wind turbines when wind fluctuations or grid disturbances occur. These responses are compared with those of the detailed wind farm model, in order to verify the effectiveness of the studied aggregation methods for this type of wind farms. The equivalent wind farm models have been developed by adapting different aggregation criteria that already exist in technical literature and had been applied to other technologies. In this work, these methods have been modified to suit them to the permanent magnet synchronous generator technology. The results show that the three aggregated models provide very similar results to the detailed model, both in the evolution of active power when fluctuations in wind speed occur, and in the active power and DC-link voltage during the two simulated voltage dips. Notably, the aggregated model with an approximate mechanical torque offers excellent results.     

Adaptive back-stepping control for a permanent magnet synchronous generator wind energy conversion system

The maximize energy captured from the wind of a grid-connected variable speed Wind Energy Conversion System (WECS) based on a Permanent Magnet Synchronous Generator (PMSG) is investigated in this paper. An adaptive back-stepping control scheme is applied to achieve maximum power point tracking in the coefficient of maximum power. The features of the proposed control scheme are that it deals with the random nature of wind speed, the uncertainties and external perturbations the acting on WECS effectively, where the bounds of the perturbations are not known in advance. At the same time, a proof of the convergence of the closed-loop system under the proposed controller is derived using the Lyapunov stability theory. Finally, simulations are conducted to illustrate the effectiveness of the proposed approach.     

Loss evaluation and design optimisation for direct driven permanent magnet synchronous generators for wind power

When designing a generator for a wind turbine it is important to adapt the generator to the source, i.e. the wind conditions at the specific site. Furthermore, the variable speed operation of the generator needs to be considered. In this paper, electromagnetic losses in direct driven permanent magnet synchronous generators are evaluated through simulations. Six different generators are compared to each other. The simulations are performed by using an electromagnetic model, solved in a finite element environment and a control model developed in MATLAB. It is shown that when designing a generator it is important to consider the statistical wind distribution, control system, and aerodynamic efficiency in order to evaluate the performance properly. In this paper, generators with high overload capability are studied since they are of interest for this specific application. It is shown that a generator optimised for a minimum of losses will have a high overload capability.     

脉动风速和电网故障作用下双馈风电机组传动系统动态响应特性

为研究大容量双馈风电机组在脉动风速、齿轮时变啮合特性和电网扰动等多因素耦合作用下传动系统的动态响应特性,在Matlab/Simulink平台上,采用集中质量法建立了机组传动系统弯扭耦合动力学模型,并结合双馈风电机组运行及控制模型,形成机组传动系统的机电耦合模型,分析了机组在多种脉动风速及其与电网对地短路故障同时作用条件下传动系统的动态响应特性。计算结果表明：机组传动系统对低频振动频率具有欠阻尼特性,当脉动风速的脉动频率接近传动系统的一阶固有频率时会与传动系统产生共振;通过对比有无齿轮时变啮合激励,可以甄别传动系统与齿轮啮合激励的共振点;电网三相对地短路故障引起的传动系统振动最为剧烈,其最大振动峰峰值随风速的增加非线性增大,随风速湍流强度的增加线性增大。