Dynamic optimization design of marine gear transmission system

A dynamic model of transmission system for a marine gear is established considering time-varying mesh stiffness, mesh damping and tooth composite error. The solution efficiency is improved by taking contact line length change of gear pair instead of instantaneous gear mesh stiffness change and making mesh damping and tooth surface equivalent to viscous damping. Multi-objective dynamic optimization design is put into practice to improve the marine gear transmission system using vibration acceleration and mass as target function. The results show that the optimization method can effectively reduce the vibration level and mass of marine gear.     

Electromagnetic torque ripple control of induction motor fed by dual frequency inverter

Direct torque control(DTC)of space vector modulation fed by dual frequency inverter is studied in order to solve the problems of large torque,big flux ripples and inconstant switching frequency of conventional DTC in large power occasions. On the basis of conventional DTC,factors affecting flux and torque ripples are analyzed and the space voltage vector mathematical model of induction motor is deduced,which is implemented by S-function. Based on dual frequency theory,the system is supplied by cascaded inverters to decrease losses. The high frequency unit is in charge of improving the dynamic performance of the system,whose switching current is relatively low;while the low frequency unit is in charge of energy delivery,whose switching frequency is far lower than that of the high frequency unit. The simulation results illustrate that by using this program,the system has a better performance in both dynamic and static performance,and the electromagnetic torque ripple,flux ripple and switching losses are significantly reduced. Thus the system efficiency is improved and suitable for medium and large power occasions.     

Energy conversion analysis of vehicle electromagnetic suspension using power flow method

The energy regenerative characteristic of vehicle electromagnetic suspension is analyzed based on the power flow. In order to solve the key problem of energy quantification of electromagnetic suspension,a calculation and analysis method of energy conversion efficiency is proposed. A comparative work between the active system,passive system and the maximal output power system is made through computer simulation. It is demonstrated that in the aspect of vehicle dynamics,the active system is superior to the passive system. In the aspect of energy regenerative ability,the passive system is superior to the active system. And the energy regenerated by the active system is more than the consumed energy. So the active system has the ability of powering itself.     

Influence of error’s randomness on transmission accuracy of planetary gear

The coupling transmission error model of multistage planetary gear is developed according to precision transmission’s requirement from a geometrical perspective,comprehensively considering eccentric error of the components in machining and assembling,deviation of pitch and deviation of tooth thickness. The work describes the stochastic process of the random variables in the model by Monte Carlo methods,which corresponds better with the law of error statistics. The coupling transmission error model of a material example is analyzed and simulated by the proposed method. Furthermore,the most influential error factors are figured out by spectral analysis. Thus,the results show that random error value is proportional to transmission error,and that the randomness of error’s initial phase tends to reduce transmission error.     

Efficiency optimization matching strategy of continuously variable transmission system with reflux power

To solve the problem that the transmission efficiency of continuously variable transmission system with reflux power varies in a great range, and the traditional control strategy can’t make sure that the overall system is under ideal conditions, an economy control method based on system efficiency optimization is put forward. The engine/transmission efficiency numerical model and system optimization model are built. Taking Matlab/Simulink as the platform, objective throttle position control table and objective ratio control table are obtained by solving the optimization model. Furthermore, ECE+EUDC drive cycle simulation based on the fuel economy of sample car is carried out, and the simulation results indicate that the method of system efficiency optimization make fuel consumption reduce by more than 1.5%.     

Study on Heat Insulation and Use of Passive Evaporated Roof

According to different construction ways and materials, three kinds of roof, that is ,passive evaporated roof with freedom water surface , water stored roof by means of pore material and hygroscopic roof,are introduced in this paper . Meanwhile the theory of heat insulation and energy efficiency on passive evaporation roofs and suitable weather and places to be used are also discussed .The results show that all kinds of passive evaporated roofs have high efficiency in heat insulation because of water's high specific heat and large quantity of absorbed latent heat,and that they can be adopted according to the practical local weather ,natural resource and economical development.     

Modeling and control system simulation of automobile DCT

In order to reduce development time and cost of dual clutch automated mechanical transmission(DCT) control system,the dynamic model of automobile DCT control system is established by Matlab/SimDriveLine and the engine model is improved by neural network.Based on Matlab/Simulink,the simulation models of DCT control during starting phase,shift phase and shift rule are set up,and then the whole system of DCT is simulated.The simulation result indicates that the DCT system dynamic model and the designed controller are reasonable and feasible,and proofs that the model is suitable for developing DCT control system and improves the design efficiency of DCT system.     

Remote control system based on low voltage power line communication

In view of the reliability and the efficiency of the remote control systems for Electric Power Equipment, a remote control system is proposed in which the control information interacts by low voltage power network communication. Low voltage power network is used as the channel for control information of Electric Power Equipment. The MSK modulation and demodulation technology that is seasoned with the channel characteristics of low voltage power network were selected, while the theory of MSK is analyzed,and the remote control system model to Electric Power Equipment based on low voltage power network communication with MSK and Programmable Logic Controller is constructed. The remote control system for Electric Power Equipment is manufactured based on the model. Theoretical analysis and experimental results show that MSK can satisfy the channel characteristics of low voltage power network, realize reliable transmission of the remote control signals, and improve the reliability of the remote control system while decrease the cost.     

Parameter uncertainty analysis for probability distribution of bulk power systerm reliability

Component reliability parameters are of uncertainty and are affected by the component type, operation time, and weather conditions. So do the reliability indices of bulk power systems. The calculation of its probability distributions and its alteration law affected by parameters uncertainty are researched to provide practical engineering reference with exploring the impact of the parameter uncertainty on reliability assessment. The point estimate method is firstly proposed based on the two-loop Monte-Carlo simulation, and then the improved Monte-Carlo simulation is presented to enhance the calculation efficiency further. Moreover, their theories, merits and faults are explained in detail. It can be seen from the evaluation results for the RBTS power systems that the accuracy of the three methods are similar but the improved Monte-Carlo simulation has the highest efficiency, followed by the point estimate method. The IEEE-RTS 79 power system is evaluated by using the improved Monte-Carlo simulation, and the results verify its validity.     

Modeling and control of An LCL bi-directional inductive power transfer system

Since there exist high-frequency switching networks and complicated operating modes in bi-directional inductive power transfer (IPT) system, it is easy to result in high harmonics and EMI interference. An LCL filter network is introduced to effectively filter out the unwanted harmonics in track current and reduce EMI interference. Based on a mathematical model of the power transmission established by complex analysis of the AC variables, under the condition of maximum transmission efficiency, the phase angle differences between the primary input voltage and secondary output voltage U·so are ±90° and the energy is respectively transferred in forward or backward direction. Moreover, the power magnitude can be controlled by adjusting the modulus of U·pi and U·so. In addition, to keep the track current constant, different phase-shifting control strategies are designed in the primary and secondary parts. Simulation and experimental results show that these strategies can not only adjust track current to keep constant but also dynamically change the direction and magnitude of power transmission according to the working conditions and actual needs of the system load to improve the system operating efficiency.     

RELAP5 Analysis of Passive Emergency Core Cooling System Tests

One of the apparent characteristic of advanced PWR is the high reliability of passive safety system .It is important to assess the operation behavior of such system and the ability of system analysis code as RELAP5.One principal test facility, passive emergency core cooling system experiments is carried out. The RELAP5/Mod3.2 is used to simulated the experiments in this paper. The simulation capability of RELAP5/Mod3.2 in passive emergency core cooling system is assessed through the comparison between the experimental results and calculation results.     

Experimental Analysis of Solar Energy Combined with Phase change Energy Storage Ventilation System

Solar Ventilation System is unstable and uncontrollable, so a new technology is proposed to get a system that takes solar energy as heat source and applies phase change material in daytime to store energy which is used to keep ventilation in nighttime by thermal pressure. This new system is helpful to get the ideal ventilation effect for buildings. Through the experiments on ventilation with PCM of 63℃ and 44℃, ventilation rate change curve is obtained to analyse ventilation system efficiency. The results indicate that using the PCM of 63℃ and 44℃, the total ventilation of the solar ventilation system in 10 hours are respectively 8066 m3 and 6154 m3 at night, and the average ventilation per hour and area are 538 m3/h and 41 m3/h. Based on the experiment, when PCM is palmitic acid, the ventilation effect is superior than that of lauric acid. To sum up, the system of conventional solar rooftop ventilation system combined with phase change materials can intensify the nature ventilation effectively in nighttime for buildings, improve indoor thermal environment and reduce the energy consumption in air conditioning building.     

Energy Efficiency of Water Transportation System for Surface Water Source Heat Pump

The forms of water transportation, arrangement and operation of pumps contribute to the water transportation energy consumption, which influences the energy-saving effect of surface water source heat pump. The relation between the pumping height and energy consumption of pumps is found by analyzing the model of pump energy consumption. The concept and calculation of critical pumping height is presented considering the limited rate of system energy efficiency. Based on the principle that the pump power changes with water flow rate, the determination of pumps arrangement of one or two stage pumps is described with a concrete example. The influence of water flow rate on heat pumps and water pumps is analyzed, and the energy efficiency of constant and variable water volume are compared. The operation way of this example is concluded for the optimal system energy efficiency. It is found that there is a critical pumping height for the energy-saving effect of surface water source heat pump compared with the traditional system. Moreover, the operation strategies should be determined by the system optimal model since the energy consumptions proportions of heat pumps and water pumps are variable.     

Current Situation and Trend of the Traction CVT

In a toroidal CVT, power transmission is accomplished by means of a special traction oil that displays high shear resistance under a state of high pressure . A toroidal CVT can be used even with engines that generate large torque and provide excellent ratio change response and high efficiency . The history of research of the toroidal CVT are summarized and the toroidal CVT up to date is reported. The varieius aspects on the toroidal CVT are summarized ,including EHL theory , toroidal double cavity system,traction fluid ,ratio control system, traction drive system , efficiency analysis ,and so on. Finally ,The development of the toroidal CVT in the future is indicated.     

Improvement of vehicle air-conditioning duct and analysis of its impact on occupant thermal comfort

A numerical simulation on the air flow in vehicle air-conditioning duct is conducted by applying computational fluid dynamics（CFD）code Fluent and its result is compared to test result within a very small difference. Besides, the result shows that the distribution of air flow is so uneven that the thermal comfort of driver is rather poor. To improve it, the air-conditioning duct system is optimized by response surface methodology which took three structural dimensions of the deflector attached to it as design variables and considered the airflow ratio of the driver side and the overall airflow as optimized purposes, and then the thermal comfort analysis of the driver was performed to the improved air-conditioning system. As a result, the airflow ratio of the driver side is improved to 51.3% from 44.9% due to the optimized air-conditioning duct, as well as that the thermal comfort of the driver is obviously improved.     

Optimum Planting System for Energy Saving and Healthy Demanded

It is proved that planting is effective to improve environment both indoor and outdoor resulted from the functions of plants to clean air and save energy. So the contradiction between saving energy and comfort,healthy demanded by people can be solved by planting. The planting have being emphasized and expanded during recent years,but in the planting plan,just the function of beautifying the environment is concerned and the function of ecological and saving energy are neglected. The analysis on the ooptimum system of planting is to make the planting system as an organic composition in the effectiveness structure and space layout of the city. Based on the study on equivalent relation of different effects on environment, the optimum system of planting structure will be determined in order to achieve the integrated effects of planting on environment.     

Discussion about Saving Energy in Refrigeratory

Food refrigeration is regarded as a high energy consuming trade. Under the long period system of state operated enterprise,there are many phenomenons of ignoring energy management and wasting energy. Energy consuming is not very clear for production.Consuming in our country is far more than the international standard and there is a distance between the middle_westland and the eastland. As a enterprise that faces the international market,it is important for it to strength the management so that the cost can be reduced. Considering those phenomenons of ignoring energy management and wasting energy in refrigeratory at present, some measures such as improved the unreasonable operation process, strengthening the energy management and automation to realize automatizing operation are improved to reduce the cost for refrigeratory trades.     

Building Energy Conservation with MARKAL Model

MARKAL is a generic model tailored by the input data to represent the evolution over a period of usually 40 to 50 years of a specific energy system at the national, regional, state or province, or community level. The database specifies the energy demands -industrial, commercial, residential, and transportation that need to be satisfied over the next several decades. It describes the available sources of supply of energy, either domestic resources or imports of oil, coal, natural gas, nuclear fuel, and renewable. A menu of technologies is provided for extracting, transporting, converting, and using energy, both existing technologies and those expected to be available within the time horizon of the model. The essential characteristics of the technologies are specified, such as their investment cost, operating and maintenance costs, service life, fuel use, efficiency, availability, output, and maximum expected market penetration. As a linear program, the model then chooses the best combination of these technologies to satisfy the projected energy demands. The basic components in a MARKAL model are specific types of energy or emission control technology. Both the supply and demand sides are integrated, so that one side responds automatically to changes in the other. The model selects that combination of technologies that minimizes total energy system cost. In the end, the article describes energy conservation for building in Chongqing.     

Simulation of The Torque Control System of Motor for Hybrid Vehicle

A strategy for induction motor control based on the grade of errors is developed to improve the performance of hybrid vehicle drive system. The stator flux error, electric magnetic torque error and flux position angle are used as control variables, and rules for the switching states are chosen according to the errors and the principle of the Direct Torquc Control. This strategy improves efficiently the electric magnetic torque response of the system. The result of simulation shows that this strategy is an ideal control strategy of hybrid vehicle, which can make the motor generate the electric magnetic torque efficiently, steadily and quickly.     

Multi-object Optimization Design of Engine Mounting System Parameters

A multi-object optimization model is proposed with respect to the completed vehicle in ergonomics,which takes the root-mean-square value of body in multiple work condition and the decoupled energy of engine mounting system as a general object. The optimization values is given. An example shows that the vibration of an automobile can be reduced effectively by choosing proper parameters of mounting system.Moreover, comfort of automobile can be improved.