Applied Mechanics and Materials Vols. 651-653

Abstract: Traditional voltage regulating means, for example, change the transformation ratio of on-load tap-changing transformer, switch on/off parallel compensation capacitor etc, could not solve transient voltage drop effectively due to slow response speed and inaccurate control. SVC and SVG adopt power electronic device that may be turned on/off at high speed and instantaneous reactive power theory, could output huge reactive power within very short time smoothly, so they are capable to suppress transient voltage drop.This paper analyzes the principles of SVC and SVG to suppress transient voltage drop theoretically, studies their characteristics in this respect through simulation, puts forward precautions for both devices to further suppress transient voltage drop according to the simulation result.

Abstract: With the development of distributed generation technology rapidly, a large number of wind, solar and other renewable energy access to access system . Since renewable energy is intermittent and stochastic, which posed economic dispatch system a serious challenge. Consider the system operating costs and sewage expenses, the paper constructs multi-objective micro-grid system economic dispatch model composed by the wind turbine, diesel engine, battery and load. And through MATLAB / Simulink simulation, model is established to verify the correctness and effectiveness.

Abstract: The traditional method of power system reserve capacity is not suitable for the power system with large-scale wind power integration. This paper analyzed the prediction error of wind power, the introduction of the system reliability index, established a correlation mode between wind power prediction error and the spare demand change; the introduction of interruptible load to replace part of the reserve capacity, combining probability of the using of spare capacity in historical data, according to the standby capacity demand use of decision theory expected value method is used to solve the optimal reserve. The practical examples prove that the algorithm is feasible.

Abstract: Development of smart grid spawned the big data in electric power industry, the cloud computing platform provided the solution for the big data in electric power industry, it has a significant effect for batch jobs, but its real-time is not guaranteed. For the real-time problem of cloud computing platform, the Storm platform will be introduced to monitor the grid power. This paper studies the fair share scheduling algorithm under the Storm platform. It introduced the concept of Storm framework briefly, then, proposed the fair share scheduling algorithm according to the lack of current Storm scheduling algorithm, finally, the experiment proved that the scheduling algorithm based on fair share improved the resource utilization of Storm cluster and reduced the processing delay of the data.

Abstract: Li-ion battery, as a new type of energy storage equipment, has small size, large power density, high individual voltage, low rate of self-discharging and small self-resistance etc. It substitutes the traditional power battery in AGV.In practical process, due to the difference of battery cells, after a period of charge-discharge time, the upper and lower voltage limits of every unit of batteries become various, seriously affecting the system performance. The idea of upper and lower equalizer is released for this case. Then, a further research is made on the equalizer circuit of li-ion battery. The experiment result proves the correctness of design on several types of lithium battery equalizer circuit.

Abstract: Due to small size, large power density, high individual voltage, low self-discharging, and low internal resistance, li-ion battery substitutes other types of battery used as power supply. In practice, because of difference of every cell, after a period of charge-discharge time, the upper limit voltage of every unit becomes various, seriously affects the system’s performance. The idea of upper equalizer is released, then, a further research is made on the equalizer circuit of li-ion battery. The experiment result proves the correctness of design on li-ion battery equalizer circuits.

Abstract: The key technology of electric vehicle battery management lies in the battery state of charge (SOC) estimation, accurate and efficient estimation of SOC can provide the reference data for the control system of the electric vehicle in time. On the basis of the Ah measurement method, Calman filtering method, open circuit voltage method to estimate method, the estimation procedure to estimate the charged battery optimized Calman filtering method, effectively shorten the calculation process, improve the estimation accuracy, in the normal operation of electric vehicles under the influence of comprehensive consideration about the discharge voltage, battery temperature to estimate the state of charge, the Calman filter optimization algorithm, and its application in the electric vehicle battery management system. The experimental results show that, the algorithm can calculate the real-time high charge state of surplus value, provides a set of effective estimation scheme of calculating the battery charge state.

Abstract: This paper expounds the principle of lead-acid battery intelligent charging system, design the main circuit of the intelligent charging system, the positive and negative pulse charging circuit, control circuit and software design of intelligent charging system. Experimental results show that the system USES intelligent charging method can effectively improve the charging efficiency of battery and prolong the service life of the battery, can be widely used in lead-acid battery charging system, which has a broad prospect of industrialization and social benefits.

Abstract: Because of the problems of fault diagnosis in the power electric circuit and the merit of FCM is efficient in clustering and the merit of hidden Markov model (HMM) that have the ability to deal with continuous dynamic signals and the merit of support vector machine (SVM) with perfect classifying ability, With the features extracted from the circuit, based on the trained FCM algorithm, HMM was used to calculate the matching degree among the unknown signal and the circuit’s states, which formed the features for SVM to diagnosis. Double-bridge 12-pulse rectifier is used as a example to verifiy the effectiveness of the method. The experimental results show that the proposed method has a good correct rate.

Abstract: As a distributed controllable loads, Plug-in electric vehicles (PEVs) connecting to the smart grid and participating in frequency regulation is drawing more and more attention. Depending on Vehicle-to-Grid (V2G) technology to realize the energy interaction between PEVs and the power grid, a dynamic control model of PEVs is proposed by considering the dynamic characteristics of the battery charging/discharging, and the dynamic model consider PEVs participating in frequency regulation is established. Finally, through the SIMULINK simulation based on the model, it demonstrates that the model responds well to the system frequency deviation, and it is important to improve frequency stability and realize the rapid recovery of power system.