This paper proposes two nonlinear blind equalizers: the nonlinear constant modulus algorithm (NCMA) and the nonlinear modified constant modulus algorithm (NCMA) by applying a nonlinear transfer function (NTF) into con...This paper proposes two nonlinear blind equalizers: the nonlinear constant modulus algorithm (NCMA) and the nonlinear modified constant modulus algorithm (NCMA) by applying a nonlinear transfer function (NTF) into constant modulus algorithm (CMA) and modified constant modulus algorithm (MCMA), respectively. The effect of the NTF on CMA and MCMA is theoretically analyzed, which implies that the NTF can make their decision regions much sharper so that the proposed two nonlinear blind equalizers are more robust against the convergency error compared to their linear counterparts. The embedded single layer in NCMA and NMCMA simultaneously guarantees a comparably speedy convergency. On 16-quadrature amplitude modulation (QAM) symbols, computer simulations show that NCMA achieves an 8dB lower convergency mean square error (MSE) than CMA, and NMCMA achieves a 15dB lower convergency MSE than MCMA.展开更多
基于输电线路等传变理论分析可知,电容式电压互感器(capacitive voltage transformer,CVT)的暂态特性会造成参与距离保护计算的电压和电流经过的传变环节不一致,是引起距离保护暂态超越的重要因素。因此提出一种等传变快速距离保护方案...基于输电线路等传变理论分析可知,电容式电压互感器(capacitive voltage transformer,CVT)的暂态特性会造成参与距离保护计算的电压和电流经过的传变环节不一致,是引起距离保护暂态超越的重要因素。因此提出一种等传变快速距离保护方案,使保护安装处的三相电压和电流与故障点电压经过相同的传变环节,新方法主要包括3个步骤,即故障点电压的重新构造、虚拟数字传变以及求解R-L模型微分方程。ATP仿真结果表明,所提方法能有效地减小了CVT引起的暂态误差,故障后15 ms左右测距误差不超过5%,明显优于基于CVT暂态误差估计或系统线路阻抗比的各种自适应保护算法(测距误差不超过5%一般需要30 ms以上)。展开更多
提出了一种基于Buck-Boost电路的新型均衡电路,实现了锂离子串联电池组充放电均衡。根据均衡能量流向,采取两种不同的均衡策略:电池组放电时,均衡能量由电池组向组内荷电状态(state of charge,SOC)较低的单体电池转移;电池组充电时,均...提出了一种基于Buck-Boost电路的新型均衡电路,实现了锂离子串联电池组充放电均衡。根据均衡能量流向,采取两种不同的均衡策略:电池组放电时,均衡能量由电池组向组内荷电状态(state of charge,SOC)较低的单体电池转移;电池组充电时,均衡能量由电池组中SOC较高的单体电池向电池组转移。以单体电池开路电压在线估计为基础,运用开路电压法估算SOC,选取SOC值在一定阈值范围之外的单体电池作为均衡对象,对6节串联的磷酸铁锂电池进行了充放电均衡实验。实验结果表明,该方案可以有效减小单体电池间的不一致性,提升电池组的整体性,同时提高了电池组充放电容量。展开更多
文摘This paper proposes two nonlinear blind equalizers: the nonlinear constant modulus algorithm (NCMA) and the nonlinear modified constant modulus algorithm (NCMA) by applying a nonlinear transfer function (NTF) into constant modulus algorithm (CMA) and modified constant modulus algorithm (MCMA), respectively. The effect of the NTF on CMA and MCMA is theoretically analyzed, which implies that the NTF can make their decision regions much sharper so that the proposed two nonlinear blind equalizers are more robust against the convergency error compared to their linear counterparts. The embedded single layer in NCMA and NMCMA simultaneously guarantees a comparably speedy convergency. On 16-quadrature amplitude modulation (QAM) symbols, computer simulations show that NCMA achieves an 8dB lower convergency mean square error (MSE) than CMA, and NMCMA achieves a 15dB lower convergency MSE than MCMA.
文摘基于输电线路等传变理论分析可知,电容式电压互感器(capacitive voltage transformer,CVT)的暂态特性会造成参与距离保护计算的电压和电流经过的传变环节不一致,是引起距离保护暂态超越的重要因素。因此提出一种等传变快速距离保护方案,使保护安装处的三相电压和电流与故障点电压经过相同的传变环节,新方法主要包括3个步骤,即故障点电压的重新构造、虚拟数字传变以及求解R-L模型微分方程。ATP仿真结果表明,所提方法能有效地减小了CVT引起的暂态误差,故障后15 ms左右测距误差不超过5%,明显优于基于CVT暂态误差估计或系统线路阻抗比的各种自适应保护算法(测距误差不超过5%一般需要30 ms以上)。
文摘提出了一种基于Buck-Boost电路的新型均衡电路,实现了锂离子串联电池组充放电均衡。根据均衡能量流向,采取两种不同的均衡策略:电池组放电时,均衡能量由电池组向组内荷电状态(state of charge,SOC)较低的单体电池转移;电池组充电时,均衡能量由电池组中SOC较高的单体电池向电池组转移。以单体电池开路电压在线估计为基础,运用开路电压法估算SOC,选取SOC值在一定阈值范围之外的单体电池作为均衡对象,对6节串联的磷酸铁锂电池进行了充放电均衡实验。实验结果表明,该方案可以有效减小单体电池间的不一致性,提升电池组的整体性,同时提高了电池组充放电容量。
