Urban rail trains have undergone rapid development in recent years due to their punctuality,high capacity and energy efficiency.Urban trains require frequent start/stop operations and are,therefore,prone to high energ...Urban rail trains have undergone rapid development in recent years due to their punctuality,high capacity and energy efficiency.Urban trains require frequent start/stop operations and are,therefore,prone to high energy losses.As trains have high inertia,the energy that can be recovered from braking comes in short bursts of high power.To effectively recover such braking energy,an onboard supercapacitor system based on a radial basis function neural networkbased sliding mode control system is proposed,which provides robust adaptive performance.The supercapacitor energy storage system is connected to a bidirectional DC/DC converter to provide traction energy or absorb regenerative braking energy.In the Boost and Buck modes,the state-space averaging method is used to establish a model and perform exact linearization.An adaptive sliding mode controller is designed,and simulation results show that it can effectively solve the problems of low energy utilization and large voltage fluctuations in urban rail electricity grids,and maximise the recovery and utilization of regenerative braking energy.展开更多
列控系统的安全苛求对车载设备的可靠性提出了更高的需求,有效的可靠性模型与合理的维修策略对预防潜在故障、提高设备可靠性具有重要意义。针对现有车载设备可靠性建模和维修策略考虑因素不全面的问题,提出了一种考虑随机冲击与冗余的...列控系统的安全苛求对车载设备的可靠性提出了更高的需求,有效的可靠性模型与合理的维修策略对预防潜在故障、提高设备可靠性具有重要意义。针对现有车载设备可靠性建模和维修策略考虑因素不全面的问题,提出了一种考虑随机冲击与冗余的可靠性模型构建方法与一种不完美维修条件下的预防性维修模型。首先,考虑自然性能退化和外界随机冲击,针对车载设备及其冗余分别建立不同的性能退化模型并计算相应的可靠度函数;其次,利用Copula函数求解联合分布函数作为整体可靠度函数,在可靠度阈值约束下,通过单个预防性维修周期内的可靠度函数求解预防性维修间隔,同时考虑不完美维修对于维修策略的影响,以可靠度阈值和预防性维修次数作为决策准则,构建车载设备全生命周期内的维护费用率模型;最后,以列车自动防护控制单元(Automatic Train Protection Control Unit,ATP-CU)为例进行数值仿真,验证所提模型的有效性。结果表明:提出的基于Copula函数求解车载设备及其冗余的可靠性建模方法相比传统的独立可靠性分析方法能够更好地把握其性能的演化情况;在仿真环境下,当可靠度阈值为0.85、预防性维修次数为7次时,ATP-CU及其冗余全生命周期内的最小维护成本率为21.47元·d-1。展开更多
基金the Science and Technology Project of Henan Province under Grant No.14210221036.
文摘Urban rail trains have undergone rapid development in recent years due to their punctuality,high capacity and energy efficiency.Urban trains require frequent start/stop operations and are,therefore,prone to high energy losses.As trains have high inertia,the energy that can be recovered from braking comes in short bursts of high power.To effectively recover such braking energy,an onboard supercapacitor system based on a radial basis function neural networkbased sliding mode control system is proposed,which provides robust adaptive performance.The supercapacitor energy storage system is connected to a bidirectional DC/DC converter to provide traction energy or absorb regenerative braking energy.In the Boost and Buck modes,the state-space averaging method is used to establish a model and perform exact linearization.An adaptive sliding mode controller is designed,and simulation results show that it can effectively solve the problems of low energy utilization and large voltage fluctuations in urban rail electricity grids,and maximise the recovery and utilization of regenerative braking energy.
文摘列控系统的安全苛求对车载设备的可靠性提出了更高的需求,有效的可靠性模型与合理的维修策略对预防潜在故障、提高设备可靠性具有重要意义。针对现有车载设备可靠性建模和维修策略考虑因素不全面的问题,提出了一种考虑随机冲击与冗余的可靠性模型构建方法与一种不完美维修条件下的预防性维修模型。首先,考虑自然性能退化和外界随机冲击,针对车载设备及其冗余分别建立不同的性能退化模型并计算相应的可靠度函数;其次,利用Copula函数求解联合分布函数作为整体可靠度函数,在可靠度阈值约束下,通过单个预防性维修周期内的可靠度函数求解预防性维修间隔,同时考虑不完美维修对于维修策略的影响,以可靠度阈值和预防性维修次数作为决策准则,构建车载设备全生命周期内的维护费用率模型;最后,以列车自动防护控制单元(Automatic Train Protection Control Unit,ATP-CU)为例进行数值仿真,验证所提模型的有效性。结果表明:提出的基于Copula函数求解车载设备及其冗余的可靠性建模方法相比传统的独立可靠性分析方法能够更好地把握其性能的演化情况;在仿真环境下,当可靠度阈值为0.85、预防性维修次数为7次时,ATP-CU及其冗余全生命周期内的最小维护成本率为21.47元·d-1。