一种新型H桥五电平有源中点钳位逆变器控制策略

保持母线中点电位和悬浮电容电压的稳定是H桥型五电平有源中点钳位型逆变器稳定工作的前提。针对上述问题,本文在载波层叠调制策略的基础上,分析不同开关状态对悬浮电容电压的影响,通过选择合适的冗余开关状态实现悬浮电容电压的稳定;对于母线中点电位平衡控制问题,提出了修正H桥左右桥臂参考波电压比例分配实现平衡控制,最后通过Matlab/Simulink仿真结果验证所提控制策略的有效性。     

10kV中压直流电力推进变频器拓扑与控制策略

为了满足10 kV舰船中压直流综合电力推进系统对于高效率、高功率密度中压推进变频器的需求,本文分析了现有多电平拓扑的特性与适应性,提出了两种适用于开绕组多相电机的10kV推进变频器拓扑结构:五电平有源中点箝位(ANPC)/H桥拓扑以及对称混合九电平拓扑。两种拓扑结构使用的悬浮电容和开关器件数量完全相等。本文分析了这两种拓扑的工作原理和调制策略,分别建立了开关函数模型,并得出了母线中点电压和悬浮电容电压在理想情况下均可保持自平衡的结论。分别搭建了这两种拓扑的小功率样机并进行了实验验证。     

A tube-based robust nonlinear predictive control approach to semiautonomous ground vehicles

This paper proposes a robust control framework for lane-keeping and obstacle avoidance of semiautonomous ground vehicles. It presents a systematic way of enforcing robustness during the MPC design stage. A robust nonlinear model predictive controller (RNMPC) is used to help the driver navigating the vehicle in order to avoid obstacles and track the road centre line. A force-input nonlinear bicycle vehicle model is developed and used in the RNMPC control design. A robust invariant set is used in the RNMPC design to guarantee that state and input constraints are satisfied in the presence of disturbances and model error. Simulations and experiments on a vehicle show the effectiveness of the proposed framework.     

Development of an errorable car-following driver model

An errorable car-following driver model is presented in this paper. An errorable driver model is one that emulates human driver’s functions and can generate both nominal (error-free), as well as devious (with error) behaviours. This model was developed for evaluation and design of active safety systems. The car-following data used for developing and validating the model were obtained from a large-scale naturalistic driving database. The stochastic car-following behaviour was first analysed and modelled as a random process. Three error-inducing behaviours were then introduced. First, human perceptual limitation was studied and implemented. Distraction due to non-driving tasks was then identified based on the statistical analysis of the driving data. Finally, time delay of human drivers was estimated through a recursive least-square identification process. By including these three error-inducing behaviours, rear-end collisions with the lead vehicle could occur. The simulated crash rate was found to be similar but somewhat higher than that reported in traffic statistics.     

DSP-based self-organising fuzzy controller for active suspension systems

This study proposed a self-organising fuzzy controller (SOFC) for controlling an active suspension system to evaluate its control performance. During the control process, the SOFC continually updated the learning strategy in the form of fuzzy rules. The fuzzy rule table of this SOFC could be initially set to zero. This not only overcame the difficulty in finding appropriate membership functions and control rules for designing a fuzzy controller, but also solved the database problem where the fuzzy rules of a fuzzy controller, once determined, remained fixed and could not suitably regulate them in real time to optimise the dynamic response of the system required to gain the desired control performance. To demonstrate the applicability of the proposed SOFC for active suspension systems, a quarter-car hydraulic-servo suspension system was designed and constructed to evaluate the feasibility of active suspension control. Additionally, to conform to real-time application requirements in the vehicular industry, the SOFC was implemented with a digital signal processor to control the hydraulic-servo suspension system so that the control performance could be determined. The SOFC has shown a better control performance in suppressing the vibration amplitude of the vehicle body for enhancing the structural safety of the vehicle and increasing the life of the suspension system. It also effectively suppressed the amplitude of the vehicle body acceleration and reduced the tire deflection for improving the ride and the handling quality of a vehicle better than a passive control, as verified in experimental results.     

基于层次分析法的客车安全性评价体系研究

通过评价指标选取原则,将客车安全分为主动安全、被动安全、车辆技术管理三大指标体系,利用层次分析法,把定性指标定量化,确定各指标权重,并综合分析得出客车的安全性评价值。     

基于MATLAB的主动悬架的最优控制分析

本文通过建立二自由度车辆悬架模型,应用了最优控制理论设计了主动悬架控制器,并在MATLAB/SIMULINK中建立了系统模型并进行了仿真。研究结果表明主动悬架比被动悬架的控制效果要好。     

刚性索悬索桥主缆张拉施工控制方法

为掌握刚性索悬索桥施工过程中桥梁真实的应力和线形状态,针对刚性索悬索桥的主缆在塔上张拉,其索力形成机理为主动受力的特点,研究计入主缆外包钢套筒、吊杆外包钢套筒作用的主缆张拉有限元法,并采用该方法对无应力索长控制法、张拉力控制法、塔顶有效索力控制法和跨中有效索力控制法4种主缆张拉控制应力方法确定的成桥状态进行比较。结果表明:无应力索长法与张拉力控制法的索力差距十分微小、主缆的存余有效索力与常规悬索桥模型的较为接近、成桥状态的变形最小,较利于结合构件安装线形的调整控制成桥线形。经有限元模拟和张拉控制应力修正,对某刚性索悬索桥进行了施工控制,结果表明实桥测试数据与理论计算符合良好。     

一种三相有源电力滤波器控制新方法

定时控制瞬时值比较法用于三相有源电力滤波器时存在局部稳定性问题,为此本文运用双向互补对其进行改进,并进行了稳定性分析.结果表明,与传统定时控制瞬时值比较法相比,它扩展了稳定区域,改善了补偿性能,仿真结果也验证了理论分析的正确性.