Battery management systems (BMS) are widely used in energy storage systems and electric vehicles. The precise estimation of state-of-charge is a key factor affecting the performance of BMS. For the difficulty of calculating the charge status of storage lithium battery (e.g. poor estimation and reliability), this study presents the way of unscented Kalman particle filter (UPF) based on the online recursive least square method matched by dual polarisation battery model. The results show that, compared to the extended Kalman filter (EKF), extended Kalman particle filter (EKPF) and the unscented Kalman filter, the estimate accuracy was improved by 50.9, 33.4 and 19.6%, respectively. The online parameter identification assisted by UPF shows stronger inhibitory effect and the convergence stability. Besides, in comparison to the offline parameter identification with UPF, the estimated accuracy of 27.59% was improved by using the online parameter identification.
An intelligent releaser with embedded network control function is introduced. And the field bus technology, embedded technology, Ethernet technology and intelligent protection control technology are integrated and applied to the actual products. Based on the front edge of the world's intelligent electric appliance, the mining vacuum circuit breaker (VCB) of low voltage and large current, which has protective and communication function, has been developed. Moreover, the intelligent protection and control function, network communication and monitor function are implemented by adding the intelligent control module and adopting embedded system and TCP/IP protocol. The system covers the main functions, such as, the protection of short circuit, over-voltage, under voltage, overload and earthing, the real-time communication between Ethernet and terminal computer, the display about the current and voltage of circuit and faults information, the historical data review and print. In order to increase the efficiency, realize the monitoring on-line for remote distance, the intelligent VCB based on the network, communication, openness and compatibility has been developed
A flat-plate and pin-plate electrode gas discharge model based on fractal theory has been established in this paper. And to show the influence of the variation of electric field on the discharge routine development, the whole gas discharge process has been simulated and quantificationally analyzed. Moreover, the combination effect of the electric field and the random consideration on the discharge has been investigated. And the whole spatio-temporal evolvement behavior of the gas discharge path is computed using finite element method (FEM) and figured out. From the simulation results, it can be found that, the micro-discharge-channels have the tendency of being in the whole discharge space. And the discharge development routine is mainly determined by the electric field and the material diversity of the dielectric medium.
Considering the traffic organization project and traffic signal control project of the small and medium-sized cities in China, based on the dynamic optimization theory of operations research, this paper puts forwards the method of optimization design between the traffic organization and the traffic signal control of urban traffic, sets up the frame of the dynamic optimization. The whole design of the dynamic optimization is divided into three stages, the first stage, based on the original traffic organization project, the traffic signal control project is optimized, the second stage, based on the optimized traffic signal control project after the first stage, the traffic organization project is optimized, the third stage, based on the optimized traffic organization project after the second stage, the traffic signal control project is optimized again, finally the best project is got. This paper takes the conference intersection of HuaiRou district for example, gets the dynamic optimization project between the traffic organization and the traffic signal control, and it is found that this method is better than the past methods after the analysis by computer simulation.
The paper presents a method of the series arc fault for DC systems. The aim of the study is to find some current characteristics, which can be significant for the purpose of arc detection. The validity of the proposed method is testified by analyzing the arc fault current signal. The low voltage series DC arc study is carried out on the currents waveforms acquired during some tests on electric appliances. A Fast Fourier Transformation(FFT) is applied to decompose the monitored current signals into a series of detailed arcing features. Dynamic time warping (DTW) is used to measure the input and the known arc model. The pattern matching algorithm is then used to detect and classify the arc fault. As a result, the method is effective in detecting and classifying the arc fault, and easy to be realized in the practical cases.
By calculating the flow field of 2D high voltage SF 6 circuit breaker (HV SF 6 CB) under the small capacitive current interruption, a 252kV HV SF 6 CB is taken as the investigation example. By modeling and calculating, the flow parameters have been simulated under the small capacitive current interruption condition and the variation of the internal flow parameters, such as the velocity, pressure, density, temperature and Mach number have been numerically simulated and analyzed. There exist strong nonlinear variation of the flow parameters during the breaking process, therefore the chaos theory is applied to determine the internal chaotic characteristic. By using the CC method and the Wolf algorithm, the maximum Lyapunov exponent (LEmax) of the above main flow parameters has been obtained, and the internal factors affecting the chaos phenomenon of the SF 6 CB have been further analyzed.
High precision domain discretization and field solution efficiency is the barrier of electric field numerical simulation for multi-dielectrics and complex structure by finite element method (FEM). In this paper, by applying the adaptive control strategy in the transformation between coarse grid and fine grid, an adaptive multigrid-finite element method (AMG-FEM) based on non-structure grid is presented. For simulating the multi-dielectrics and complex electric filed, domain decomposition method (DDM) is employed. And the feasibility and validity of the proposed AMG-FEM/DDM with higher precision and efficiency is verified by calculating the electric field of a vacuum interrupter (VI). And the electric field distributions of the VI with different opening strokes have been figured out dynamically.
In this paper, the author analyzes the operation characteristics of urban expressway, presents the method of expressway and frontage coordinated control by the idea of freeway corridor control. According to traffic behaviors, the expressway dynamic traffic flow model and frontage traffic model, entry queue model and intersection queue model are used to describe traffic dynamics. By several different optimal per-formances criterion, corresponding optimization strategies and solution algorithm are determined to be the foundation of the further work to develop real time control algorithms.
Teaching status of electrical engineering courses is analyzed.According to the basic request to the plan for educating and training outstanding engineers for the applied bachelors,the reformation of electrical engineering curriculum systems is studied.The new curriculum systems orienting to cultivation of outstanding engineers are presented.By pointing out teaching goal,and reforming teaching method,measure and experiment contents,practice and application ability for students is cultivated.As a results,ideation and innovation ability are trained,improving education purpose of effectively.
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