A Genetic Algorithm for Optimizing Yaw Operation Control in Wind Power Plants

A genetic algorithm is proposed to optimize the yaw control system used for the stable and efficient operation of turbines in wind power plants.In particular,the factors that produce yaw static deviation are analyzed.Then,the sought optimization method for the yaw static deviation of the wind turbine is implemented by using a lidar wind meter in the engine room in order to solve the low accuracy problem caused by yaw static deviation.It is shown that fuzzy control can overcome problematic factors such as the randomness of wind direction and track the change of wind direction accurately.Power control implementation is simple,as only the voltage and current of the generator need to be measured.

Road Friction Estimation under Complicated Maneuver Conditions for Active Yaw Control

Road friction coefficient is a key factor for the stability control of the vehicle dynamics in the critical conditions. Obviously the vehicle dynamics stability control systems, including the anti-lock brake system（ABS）, the traction control system（TCS）, and the active yaw control（AYC） system, need the accurate tire and road friction information. However, the simplified method based on the linear tire and vehicle model could not obtain the accurate road friction coefficient for the complicated maneuver of the vehicle. Because the active braking control mode of AYC is different from that of ABS, the road friction coefficient cannot be estimated only with the dynamics states of the tire. With the related dynamics states measured by the sensors of AYC, a comprehensive strategy of the road friction estimation for the active yaw control is brought forward with the sensor fusion technique. Firstly, the variations of the dynamics characteristics of vehicle and tire, and the stability control mode in the steering process are considered, and then the proper road friction estimation methods are brought forward according to the vehicle maneuver process. In the steering maneuver without braking, the comprehensive road friction from the four wheels may be estimated based on the multi-sensor signal fusion method. The estimated values of the road friction reflect the road friction characteristic. When the active brake involved, the road friction coefficient of the braked wheel may be estimated based on the brake pressure and tire forces, the estimated values reflect the road friction between the braked wheel and the road. So the optimal control of the wheel slip rate may be obtained according to the road friction coefficient. The methods proposed in the paper are integrated into the real time controller of AYC, which is matched onto the test vehicle. The ground tests validate the accuracy of the proposed method under the complicated maneuver conditions.

An Adaptive Nonsingular Fast Terminal Sliding Mode Control for Yaw Stability Control of Bus Based on STI Tire Model

Due to the bus characteristics of large quality,high center of gravity and narrow wheelbase,the research of its yaw stability control(YSC)system has become the focus in the field of vehicle system dynamics.However,the tire nonlinear mechanical properties and the effectiveness of the YSC control system are not considered carefully in the current research.In this paper,a novel adaptive nonsingular fast terminal sliding mode(ANFTSM)control scheme for YSC is proposed to improve the bus curve driving stability and safety on slippery roads.Firstly,the STI(Systems Technologies Inc.)tire model,which can effectively reflect the nonlinear coupling relationship between the tire longitudinal force and lateral force,is established based on experimental data and firstly adopted in the bus YSC system design.On this basis,a more accurate bus lateral dynamics model is built and a novel YSC strategy based on ANFTSM,which has the merits of fast transient response,finite time convergence and high robustness against uncertainties and external disturbances,is designed.Thirdly,to solve the optimal allocation problem of the tire forces,whose objective is to achieve the desired direct yaw moment through the effective distribution of the brake force of each tire,the robust least-squares allocation method is adopted.To verify the feasibility,effectiveness and practicality of the proposed bus YSC approach,the TruckSim-Simulink co-simulation results are finally provided.The co-simulation results show that the lateral stability of bus under special driving conditions has been significantly improved.This research proposes a more effective design method for bus YSC system based on a more accurate tire model.

Direct Yaw Moment Control for Distributed Drive Electric Vehicle Handling Performance Improvement

For a distributed drive electric vehicle（DDEV） driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. And direct yaw-moment control（DYC） has been widely studied and applied to vehicle stability control. Good vehicle handling performance： quick yaw rate transient response, small overshoot, high steady yaw rate gain, etc, is required by drivers under normal conditions, which is less concerned, however. Based on the hierarchical control methodology, a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed. The upper-loop control system consists of two parts： a state feedback controller, which aims to realize the ideal transient response of yaw rate, with a vehicle sideslip angle observer; and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain. Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors, the integrated time and absolute error（ITAE） function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix. Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method： yaw rate rising time is reduced, steady yaw rate gain is increased, vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced. The control system improves vehicle handling performance under normal conditions in both transient and steady response. State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.

Research on Direct Yaw Moment Control Strategy of Distributed-Drive Electric Vehicle Based on Joint Observer

Combined with the characteristics of the distributed-drive electric vehicle and direct yaw moment control,a double-layer structure direct yaw moment controller is designed.The upper additional yaw moment controller is constructed based on model predictive control.Aiming at minimizing the utilization rate of tire adhesion and constrained by the working characteristics of motor system and brake system,a quadratic programming active set was designed to optimize the distribution of additional yaw moments.The road surface adhesion coefficient has a great impact on the reliability of direct yaw moment control,for which joint observer of vehicle state parameters and road surface parameters is designed by using unscented Kalman filter algorithm,which correlates vehicle state observer and road surface parameter observer to form closed-loop feedback correction.The results show that compared to the“feedforward+feedback”control,the vehicle’s error of yaw rate and sideslip angle by the model predictive control is smaller,which can improve the vehicle stability effectively.In addition,according to the results of the docking road simulation test,the joint observer of vehicle state and road surface parameters can improve the adaptability of the vehicle stability controller to the road conditions with variable adhesion coefficients.

Model Predictive Yaw Control Using Fuzzy-Deduced Weighting Factor for Large-Scale Wind Turbines

Yaw control system plays an important role in helping large-scale horizontal wind turbines capture the wind energy.To track the stochastic and fast-changing wind direction,the nacelle is rotated by the yaw control system.Therein,a difficulty consists in the variation speed of the wind direction much faster than the rotation speed of the nacelle.To deal with this difficulty,model predictive control has been recently proposed in the literature,in which the previewed wind direction is employed into the predictive model,and the estimated captured energy and yaw actuator usage are two contradictive objectives.Since the performance of the model predictive control strat-egy relies largely on the weighting factor that is designed to balance the two objectives,the weighting factor should be carefully selected.In this study,a fuzzy-deduced scheme is proposed to derive the weighting factor of the mod-el predictive yaw control.For the proposed fuzzy-deduced strategy,the variation degree and the increment of the wind direction during the predictive horizon are used as the inputs,and the weighting factor is the output,which is dynamically adjusted.The proposed model predictive yaw control is demonstrated by some simulations using real wind data and its performance is compared with the conventional model predictive control with thefixed weighting factor.Comparison results confirm the outweighing performance of the proposed control strategy over the conventional one.

基于风力发电机组偏航控制策略关键参数的测试与分析

风电机组偏航控制策略中,各偏航动作之间状态的切换需依靠液压夹钳、电磁刹车与偏航驱动电机共同控制实现,所需4个关键时间点需通过样机测试得出。针对此,以某机型液压系统厂内测试为例,获取液压系统泄压-建压测试曲线;并增设多组对比测试,深入分析影响系统性能的因素;通过多领域融合的系统仿真软件进行仿真分析,为系统快速优化提供更多途径。结果表明:3台液压站所测泄压-建压曲线一致性较高,可准确得到4个时间点;单、双蓄能器对系统泄压-建压速度影响不大;不同回路背压值对系统建压时长影响较大,对泄压时长影响较小;串联制动器总出口压力响应滞后于总入口响应。可利用仿真手段设置更多系统变量组合,进一步快速优化系统策略,降低机组运行故障率。

客车横摆稳定性预设性能PID控制

针对客车转向横摆稳定性控制问题,提出了一种预定性能PID控制方法。首先,构建了车辆二自由度模型和电液复合转向系统(EHCSS)模型的集成模型。然后,设计了用于客车主动转向控制的预设性能PID控制器,该控制器能够预先设定误差收敛时间和收敛精度。最后,利用硬件在环设备,对所提控制方法进行验证。实验结果表明:预设性能PID可以精准地跟踪期望值,并且误差都收敛于预设性能范围内,有效地提高了客车在转向时的横摆稳定性。

A Novel Pre-control Method of Vehicle Dynamics Stability Based on Critical Stable Velocity during Transient Steering Maneuvering

The current research of direct yaw moment control（DYC） system focus on the design of target yaw moment and the distribution of wheel brake force. The differential braking intervention can effectively improve the lateral stability of the vehicle, however, the effect of DYC can be improved a step further by applying the control of vehicle longitudinal velocity. In this paper, the relationship between the vehicle longitudinal velocity and lateral stability is studied, and the simulation results show that a decrease of 5 km/h of longitudinal velocity at a particular situation can bring 100° increasing of stable steering upper limit. A critical stable velocity considering the effect of steering and yaw rate measurement is defined to evaluate the risk of losing steer-ability or stability. A novel velocity pre-control method is proposed by using a hierarchical pre-control logic and is integrated with the traditional DYC system. The control algorithm is verified through a hardware in-the-loop simulation system. Double lane change（DLC） test results on both high friction coefficient（μ） and low μ roads show that by using the pre-control method, the steering effort in DLC test can be reduced by 38% and 51% and the peak value of brake pressure control can be reduced by 20% and 12% respectively on high μ and low μ roads, the lateral stability is also improved. This research proposes a novel DYC system with lighter control effort and better control effect.

基于T-S模糊理论的车辆主动转向系统多目标控制

主动转向系统能通过主动转角补偿的方式实现横摆力矩控制,以改善车辆转向稳定性。针对横摆力矩控制,提出了基于T-S模糊理论的LQR多目标控制器的主动转向系统。该系统综合考虑主动转向系统的有效工作区间和车辆操纵模型中轮胎的非线性问题,采用T-S模糊理论建立了主动转向系统模型,并基于横摆角速度和车辆侧偏角这两个控制变量,设计了LQR多目标控制器。仿真分析结果表明,所提出的基于T-S模糊理论的LQR多目标控制器的主动转向系统整体上能降低横摆角速度、车辆侧偏角和侧向加速度,并快速达到稳定状态。该系统能有效改善车辆的转向稳定性,从而为主动转向系统的设计和应用提供理论参考与方法依据。

风力发电机组偏航控制系统的优化及仿真

针对风精度在(±150)内时出现了风向标传感器不能正常工作,进而不能实现对风能的最大捕获,降低风力发电机组的发电效率的问题。提出了基于大范围风向变化的偏航控制系统的优化策略:在风向变化绝对值(偏航角度)>150时,改善传感器自身性能;在风向变化绝对值<150时,采用陀螺仪和爬山算法相结合的方法来控制偏航机构。快速调节机舱的偏转角度,实现对捕获最大风能的偏航控制系统的优化。

一种风力发电机组偏航系统的优化设计

作为风力发电机组的关键部件,偏航系统的设计精确性直接决定着机组的使用寿命。文章提出了一种偏航系统的优化控制设计方案,采用的方法是基于功率控制的爬山算法,这种方法可以改善风向变化的绝对值小于15°时偏航控制系统的精度。为验证其准确性,采用Matlab仿真软件建立的偏航控制系统仿真模型进行了仿真实验。仿真结果表明,采用爬山算法可以在保证风能最大捕获的基础上,提高偏航控制系统的精度,优化风力发电机组的偏航控制系统。

风电机组偏航静态偏差对发电性能的影响及优化方法

风电机组的偏航误差主要由偏航控制性能误差和偏航静态偏差决定。文章分析了风电机组偏航静态偏差产生因素及对发电性能的影响,提出了应用机舱式激光雷达测风仪开展实测的偏航静态偏差优化方法,建立了基于偏航扇区划分和风速区段划分的优化模型。通过实例分析可知,偏航静态偏差在低风速段和高风速段对风电机组发电性能影响的敏感度较低,中风速段敏感度最高。文章所提方法可明显减小偏航静态偏差,提高发电机组的发电性能。

基于云模型的PIDNN偏航控制系统研究

风力发电机的偏航系统是典型的非线性系统,难以建立精确的数学模型;常规的PID控制方法很难获得期望的稳定性、鲁棒性等控制性能,采用PID神经网络(PIDNN)和云模型分类方法,建立不同的PIDNN控制模型解决不同风速、风向的偏航控制;仿真实验结果表明,与常规PID控制相比,云模型与PID神经网络的结合能够显著提高偏航控制系统的稳定性和鲁棒性。

大型风力发电机偏航系统控制策略研究现状及展望

偏航系统控制策略直接决定着风力发电系统的经济效益。本文在介绍偏航系统工作原理的基础上,把风力发电机偏航系统控制策略分为重启对风策略和执行对风策略,并分别评述了研究现状。分析结果表明当前业界的研究热点主要集中于偏航系统执行对风策略方面,偏航系统重启对风策略新的研究开展较少。文中在量化分析偏航系统实际运行数据、风电场风速风向实测数据及风电机组功率曲线的基础上,指出传统的偏航系统重启对风策略存在过多将偏航系统寿命消耗在低风速区的不足,影响了偏航系统寿命周期综合经济效益;偏航系统重启对风策略制定需综合考虑风电场实际风能特征、风电机组发电功率特征等因素,研究能实现偏航系统动作寿命的高效利用的新型重启对风策略具有重要的价值,值得关注。

风力发电机组主动偏航系统

整个风电机组高效稳定运行的关键是控制技术,而主动偏航控制系统是水平轴风电机组控制系统的重要组成部分。为了解决风向的不确定性对风机功率的影响,笔者设计模糊控制器,使风机准确跟踪风向,完成最大捕获风能的控制策略。同时为了避免偏航过程中电缆的缠绕、绞死,保护在强风天气下工作的风机,对风机的解缆和90°侧风提出了设计思路,给出了具体控制流程图。结果表明:该套主动偏航系统的存在可以使风力发电机运转平稳可靠,高效利用风能,符合偏航系统的控制要求。

基于机舱式激光雷达测风仪的风电机组偏航控制偏差测试方法

偏航控制系统是水平轴风电机组控制系统的重要组成部分,风电机组安装之后,受到叶轮紊流、偏航控制策略、风向标零位安装方位角等的影响引起机组偏航控制偏差的出现,直接影响了风电机组的经济性和安全性。分析了偏航控制偏差产生的原因,提出了一种基于机舱式激光雷达测风仪的风电机组偏航控制偏差测试方法,并通过对现场测试数据的分析,提出了考虑风速变化的分段优化方法和建立来流风向和机舱位置风向的传递函数方式对偏航控制偏差优化的建议,提升在运风电机组的发电性能。

基于单片机的浓缩风能型风力发电机调向控制系统

风力发电机的调向控制对于保证其正常发电十分重要。根据浓缩风能型风力发电机的形体结构,设计了机械传动机构和基于89C51单片机的调向自动控制系统。实验结果表明整个系统可在风向变化超过±15°时自动迎风,达到了设计要求。该系统可应用于浓缩风能型风力发电机的中大型并网发电机组。

基于模糊控制和功率控制的风电偏航研究

就整个风电系统来说控制技术是机组高效稳定运行的关键,而偏航控制系统是水平轴风电机组控制系统的重要组成部分。风力发电机的偏航系统是一个典型的非线性系统,且难以建立精确的数学模型。针对风向变化的随机性和不确定性等特点,将模糊逻辑控制技术和功率控制相结合设计了控制器,实现了对风过程可控,能够准确跟踪风向,完成了最大捕获风能的控制策略。利用MATLAB进行仿真,证明所确定的方法符合偏航系统的控制要求,由仿真图可以看出,效果良好,具有较高稳定性、可靠性等。