Robust Position Observer for Sensorless Direct Voltage Control of Stand-Alone Ship Shaft Brushless Doubly-Fed Induction Generators

The aim of this paper is to investigate an adaptive sensorless direct voltage control(DVC)strategy for the stand-alone ship shaft brushless doubly-fed induction generators(BDFIGs).The proposed new rotor position observer using the space vector flux relations of BDFIG may achieve the desired voltage control of the power winding(PW)in terms of magnitude and frequency,without any speed/position sensors.The proposed algorithm does not require any additional observers for obtaining the generator speed.The proposed technique can directly achieve the desired DVC based on the estimated rotor position,which may reduce the overall system cost.The stability analysis of the proposed observer is investigated and confirmed with the concept of quadratic Lyapunov function and using the multi-model representation.In addition,the sensitivity analysis of the presented method is confirmed under different issues of parameter uncertainties.Comprehensive results from both simulation and experiments are realized with a prototype wound-rotor BDFIG,which demonstrate the capability and efficacy of the proposed sensorless DVC strategy with good transient behavior under different operating conditions.Furthermore,the analysis confirms the robustness of the proposed observer via the machine parameter changes.

Stability Analysis and Enhanced Virtual Synchronous Control for Brushless Doubly-fed Induction Generator Based Wind Turbines

The brushless doubly-fed induction generator(BDFIG)presents significant potential for application in wind power systems,primarily due to the elimination of slip rings and brushes.The application of virtual synchronous control(VSynC)has been demonstrated to effectively augment the inertia of BDFIG systems.However,the dynamic characteristics and stability of BDFIG under weak grid conditions remain largely unexplored.The critical stabilizing factors for BDFIG-based wind turbines(WTs)are methodically investigated,and an enhanced VSynC method based on linear active disturbance rejection control(LADRC)is proposed.The stability analysis reveals that the proposed method can virtually enhance the stability of the grid-connected system under weak grid conditions.The accuracy of the theoretical analysis and the effectiveness of the proposed method are affirmed through extensive simulations and detailed experiments.

Robust direct power control based on the Lyapunov theory of a grid-connected brushless doubly fed induction generator

This paper deals with robust direct power control of a grid-connected bmshless doubly-fed induction generator（BDFIG）. Using a nonlinear feedback lineariza- tion strategy, an attempt is made to improve the desired performances by controlling the generated stator active and reactive power in a linear and decoupled manner. There- fore, to achieve this objective, the Lyapunov approach is used associated with a sliding mode control to guarantee the global asymptotical stability. Thus, an optimal operation of the BDFIG in sub-synchronous operation is obtained as well as the stator power flows with the possibility of keeping stator power factor at a unity. The proposed method is tested with the Matlab/Simulink software. Simulation results illustrate the performances and the feasibility of the designed control.

无刷双馈独立发电系统的改进无参数预测电流控制

无刷双馈感应发电机是一种新型交流感应电机,可用于并网发电和独立发电。模型预测电流控制以其概念直观和动态响应快的特点而备受关注。然而,由于其对模型参数的严重依赖,模型预测电流控制在无刷双馈感应发电机中的实际应用并不理想。为了克服这一问题,该文提出一种应用于独立无刷双馈发电系统的改进无参数预测电流控制方法,该方法用检测的电机状态信息替代系统参数来预测电流变化。仿真和实验表明该方法不仅保持了传统模型预测电流控制的快动态响应性能,同时又不受电机参数变化的影响,具有较强的鲁棒性。

无刷双馈式感应发电机低电压穿越能力分析

通过分析电网电压跌落时无刷双馈式感应发电机的动态模型以及磁通量、反电动势和电流的变化;提出采用crowbar电路和串联动态电阻的组合电路提高发电机低电压穿越能力的方法,并计算其中的电阻值;利用Matlab/Simulink仿真软件建立基于无刷双馈式感应发电机的风力发电系统仿真模型,对比加了保护和不加任何保护装置的风电系统仿真结果的各参数。仿真结果表明,提出的方法能有效保护风力发电机组,提高风力发电机组低电压穿越能力。

无刷双馈风力发电机最大风能捕获仿真

为了最大限度地利用风能,提高风力发电系统的效率,实现无刷双馈风力发电机(BDFIG)的最大风能捕获,提出了一种针对无刷双馈风力发电机的直接功率控制策略。与矢量控制相比,直接功率控制(DPC)省去了复杂的坐标变换,计算量较小,结构简单,提高了系统的动态性能。通过设计滞环控制器与电压矢量表选择合适的电压矢量,能够实现无刷双馈发电机的有功功率与无功功率的解耦控制,并可以保证在风力机转速变化时,功率绕组的输出电流频率保持不变。利用MATLAB/Smulink搭建了无刷双馈风力发电机的直接功率控制模型,对不同风速时的无刷双馈风力发电机运行模式进行了仿真。仿真结果表明,所提方法能够实现对最大风能的快速捕获,并可以实现有功功率与无功功率的解耦控制,提高了无刷双馈风力发电系统的发电效率。

弱电网下无刷双馈风机稳定性分析及虚拟电感控制策略

无刷双馈电机(brushless doubly-fed induction generator,BDFIG)由于省去了电刷和滑环等结构,降低了故障率和维护成本,在海上风力发电领域有巨大的应用潜力。然而,无刷双馈风机系统与弱电网的交互作用和失稳机理尚未探明,给其实际应用和商业推广带来困难。为解决该问题,基于小信号建模方法,建立了计及电流环和锁相环影响的BDFIG系统输入导纳模型,探明了电网电压扰动在控制系统中的传递规律。特别是,分析了弱电网条件下,运行点(有功和无功电流)对系统稳定性的影响机理,并据此得出BDFIG系统电流指令的给定依据。同时,探明了虚拟电感参数对系统稳定性的影响机理,提出了一种虚拟电感控制的参数整定方法,以增强弱电网下系统的稳定性。最后,仿真算例验证了理论分析的正确性和虚拟电感控制策略的有效性。

控制绕组磁链控制的无刷双馈发电机空载并网

和双馈感应发电机相比,无刷双馈感应发电机具有更高的可靠性和更低的维修成本,其在变速恒频风力发电系统中的商业应用已指日可待。提出一种在控制绕组静止坐标系实现的无刷双馈感应发电机的空载并网方法。该方法通过对控制绕组磁链矢量的相位增量与幅值增量的控制,实现功率绕组电压和频率的动态调节以满足并网的条件。在解析分析的基础上,构建了空载并网时控制系统的结构框图。实验结果表明,该方法可以满足无刷双馈电机在风力发电系统中实际应用的需求。

无刷双馈感应发电机空载并网电压相位控制策略

提出了基于控制绕组磁链的无刷双馈感应发电机空载并网电压相位控制方法,根据无刷双馈感应发电机的数学模型及控制策略构建了控制系统结构框图。设计了空载并网实验的硬件电路,实现了无刷双馈感应发电机电压相位的实时控制。在此基础上完成了无刷双馈感应发电机在空载并网时对电压幅值、频率、相位的自动调节,能够在满足并网条件时自动并网,提高了系统并网时的快速性和稳定性。不同转速下的空载并网实验结果验证了所提方法的有效性。