We developed a novel absolute multi-pole encoder structure to improve the resolution of the multi-pole encoder, realize absolute output and reduce the manufacturing cost of the encoder. The structure includes two ring...We developed a novel absolute multi-pole encoder structure to improve the resolution of the multi-pole encoder, realize absolute output and reduce the manufacturing cost of the encoder. The structure includes two ring alnicos defined as index track and sub-division track, respectively. The index track is magnetized based on the improved gray code, with linear halls placed around the track evenly. The outputs of linear halls show the region the rotor belongs to. The sub-division track is magnetized to N-S-N-S (north-south-north-south), and the number of N-S pole pairs is determined by the index track. Three linear hall sensors with an air-gap of 2 mm are used to translate the magnetic filed to voltage signals. The relative offset in a single N-S is obtained through look-up. The magnetic encoder is calibrated using a higher-resolution incremental optical encoder. The pulse output from the optical encoder and hall signals from the magnetic encoder are sampled at the same time and transmitted to a computer, and the relation between them is calculated, and stored in the FLASH of MCU (micro controller unit) for look-up. In the working state, the absolute angle is derived by looking-up with hall signals. The structure is simple and the manufacturing cost is very low and suitable for mass production.展开更多
Unit commitment(UC), as a typical optimization problem in electric power system, faces new challenges as energy saving and emission reduction get more and more important in the way to a more environmentally friendly s...Unit commitment(UC), as a typical optimization problem in electric power system, faces new challenges as energy saving and emission reduction get more and more important in the way to a more environmentally friendly society. To meet these challenges, we propose a UC model considering energy saving and emission reduction. By using real-number coding method, swap-window and hill-climbing operators, we present an improved real-coded genetic algorithm(IRGA) for UC. Compared with other algorithms approach to the proposed UC problem, the IRGA solution shows an improvement in effectiveness and computational time.展开更多
电力系统状态估计(power system state estimation,PSSE)在现代智能电网的稳定运行中起着至关重要的作用,但它也容易遭受网络攻击。虚假数据注入攻击(false data injection attacks,FDIA)是最常见的网络攻击方式之一,它可以篡改量测数...电力系统状态估计(power system state estimation,PSSE)在现代智能电网的稳定运行中起着至关重要的作用,但它也容易遭受网络攻击。虚假数据注入攻击(false data injection attacks,FDIA)是最常见的网络攻击方式之一,它可以篡改量测数据并绕过不良数据检测(bad data detection,BDD)机制,从而导致不正确的状态估计结果。文中提出一种基于数据驱动的针对PSSE的FDIA防御框架,该框架包含异常检测子框架和数据恢复子框架。异常检测部分采用改进的图卷积网络(improved graph convolutional network,IGCN)模型,该模型采用动态的边缘条件滤波器作用于图结构中,有效利用电力系统的拓扑信息、节点特征和边特征,从而检测出异常值。数据恢复部分采用变分自编码器(variational auto-encoder,VAE)模型,该模型将深度学习思想与贝叶斯推理相结合,可以有效地将异常数据恢复到在正常运行情况下的数值。针对不同攻击强度和攻击程度下的IEEE 14系统进行案例研究,以评估防御框架的检测与恢复性能。仿真结果表明,基于IGCN的异常检测子框架性能优于常规的数据驱动模型框架,其总体精确率为99.348%,召回率为99.331%,F1值为99.324%,基于VAE的数据恢复子框架的总体平均绝对误差为0.00534 p.u.,证明了防御框架优异的检测与恢复性能。展开更多
基金Funded partly by Heilongjiang Province Financial Fund for Researchers Returning from Abroad
文摘We developed a novel absolute multi-pole encoder structure to improve the resolution of the multi-pole encoder, realize absolute output and reduce the manufacturing cost of the encoder. The structure includes two ring alnicos defined as index track and sub-division track, respectively. The index track is magnetized based on the improved gray code, with linear halls placed around the track evenly. The outputs of linear halls show the region the rotor belongs to. The sub-division track is magnetized to N-S-N-S (north-south-north-south), and the number of N-S pole pairs is determined by the index track. Three linear hall sensors with an air-gap of 2 mm are used to translate the magnetic filed to voltage signals. The relative offset in a single N-S is obtained through look-up. The magnetic encoder is calibrated using a higher-resolution incremental optical encoder. The pulse output from the optical encoder and hall signals from the magnetic encoder are sampled at the same time and transmitted to a computer, and the relation between them is calculated, and stored in the FLASH of MCU (micro controller unit) for look-up. In the working state, the absolute angle is derived by looking-up with hall signals. The structure is simple and the manufacturing cost is very low and suitable for mass production.
基金the National Natural Science Foundation of China(Nos.61004088 and 61374160)
文摘Unit commitment(UC), as a typical optimization problem in electric power system, faces new challenges as energy saving and emission reduction get more and more important in the way to a more environmentally friendly society. To meet these challenges, we propose a UC model considering energy saving and emission reduction. By using real-number coding method, swap-window and hill-climbing operators, we present an improved real-coded genetic algorithm(IRGA) for UC. Compared with other algorithms approach to the proposed UC problem, the IRGA solution shows an improvement in effectiveness and computational time.
文摘电力系统状态估计(power system state estimation,PSSE)在现代智能电网的稳定运行中起着至关重要的作用,但它也容易遭受网络攻击。虚假数据注入攻击(false data injection attacks,FDIA)是最常见的网络攻击方式之一,它可以篡改量测数据并绕过不良数据检测(bad data detection,BDD)机制,从而导致不正确的状态估计结果。文中提出一种基于数据驱动的针对PSSE的FDIA防御框架,该框架包含异常检测子框架和数据恢复子框架。异常检测部分采用改进的图卷积网络(improved graph convolutional network,IGCN)模型,该模型采用动态的边缘条件滤波器作用于图结构中,有效利用电力系统的拓扑信息、节点特征和边特征,从而检测出异常值。数据恢复部分采用变分自编码器(variational auto-encoder,VAE)模型,该模型将深度学习思想与贝叶斯推理相结合,可以有效地将异常数据恢复到在正常运行情况下的数值。针对不同攻击强度和攻击程度下的IEEE 14系统进行案例研究,以评估防御框架的检测与恢复性能。仿真结果表明,基于IGCN的异常检测子框架性能优于常规的数据驱动模型框架,其总体精确率为99.348%,召回率为99.331%,F1值为99.324%,基于VAE的数据恢复子框架的总体平均绝对误差为0.00534 p.u.,证明了防御框架优异的检测与恢复性能。
