大功率P沟道VDMOS器件设计与工艺仿真

作为现代电力电子核心器件之一的P沟道VDMOS （vertical double-diffuse,MOS）器件,一直以来由于应用领域狭窄而并未得到足够的研究。以P沟道VDMOS器件为研究对象,为一款击穿电压超过-200 V的P沟道VDMOS设计了有源区的元胞结构及复合耐压终端结构,并开发了一套完整的P沟道VDMOS专用非自对准工艺流程。最后通过仿真得到器件的击穿电压超过-200 V,阈值电压为-2.78 V,完全满足了设计要求,也为下一步流片提供了有益的参考。     

Parameter design and simulation for animproved direct current side active power filter

Considering the characteristics of the dc side series active power filter (APF) that the output voltage cannot be adjusted and the control circuit is complex , an improved single phase dc series APF topology is proposed. The improvement of the new circuit topology and fundamental working principle are analyzed. Following the circuit power factor pre regulator principle, the designing method for the main circuit parameters is given. The voltage ring and the current ring are designed by using the zero pole method. The main circuit power switch is controlled with the same frequencies, while the control circuit was simplified further. Compared with the paralleled APF, the main circuit of topology structure is simplified and the number of the active switches is reduced, which show low input current harmonics, high power factor, large voltage output adjustment range and low cost. The simulation results prove that the proposed topology is correct and reliable.     

Full bridge LLC series resonant converter for X-Ray high voltage DC power supply

To prevent the duty cycle loss of full-bridge converter controlled by the phase-shifting method, a high frequency high voltage X-ray power supply is proposed. It combines full bridge LLC(FB-LLC) series resonant converter with bipolar single-phase symmetrical voltage multiplier. FB-LLC series resonant, high voltage transformer and bipolar single-phase symmetrical voltage multiplier are used in the main circuit. The LLC series resonant circuit and working conditions of soft switch are analyzed. The fundamental harmonic approximation model is established. The parameters of the main circuit are designed. The simulation results show that the output voltage adjusted continuously within 40~120 kV and without duty cycle loss. The X-ray power supply is proposed to achieve a quick rise and low ripple of output voltage. According to the simulation results, the proposed topology is correct and reliable.     

External characteristics simulation andexperiment of variable damping shock absorbers

The working principle and the valve train characteristics of the developed variable damping shock absorber are analyzed.According to the hydromechanics theory,a mathematical model of the variable damping shock absorber is established through MATLAB and the calculation formula is deduced.The F S curve and F V curve are obtained through computer simulation.According to QC/T545 national standard,external characteristic curve is obtained by bench test.The simulation result is compared with the experimental data and the correctness of the mathematical model is proved.The model accurately describes the variation of damping force with the displacement and can be used for shock absorber design and performance prediction.     

Simulation analysis of control strategy for electric power steering system

The mathematical model of the electric power steering (EPS) system is developed,and control strategy is designed by the way of frequency analysis using Bode diagram,on a basis of steering feel expression．A complete model used for analysis of automotive steering characteristic,with four tire and three freedom vehicle models is built．In order to meet optimal goals,including steering agility,return ability and steering effort requirements of drivers, the rule of controller parameter values under the condition of different speeds and steering torques is concluded through numerous simulation tests．     

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%.     

Research on reliability evaluation model for frequency collapse of power grid

In order to comprehensively consider the possibility and the severity of frequency instability risk, this paper proposes the risk evaluation model and algorithm for frequency collapse of power grid. The uncertainties in generating dispatch, network topology and component outage are considered. The calculation method for system frequency variation is depicted while considering the active power deficiency arising from random failure of generating units, and then various probabilistic risk indices for frequency collapse are defined. The presented method can provide important reference information for evaluating the frequency collapse risk of power grid. The non-sequential Monte Carlo simulation-based results of IEEE-RTS79 show the correctness of the method.     

Simulation for the Power System of Fuel Cell/battery Electric Vehicle

The developmemt and research of taking fuel cell /battery as electric vehicle power is a new direction in abroad. A real-time simulation model for power driving system of a fuel cellbattery powered electric virtual vehicle is established. This electric vehicle powered primarily by 30 kw proton exchange membrane (PEM)fuel cells, with Lead-acid battery as assistant power, and with focus classis as virtual vehicle classis.The electric vehicle is simulated on the advisor platform, and the NEDC driving pattern simulation results show that the electric vehicle can satisfy the need of performance.     

Design and Optimization of VVT System Parameters for Motorcycle Engine

An original variable valve timing mechanism with two-mode intake timing was developed according to the structural characteristics of small medium displacement motorcycle engine. Based on cycle simulation, the effects of the VVT mechanism structural parameters, control parameters and operational parameters on the engine performance were analyzed by embedding the VVT mechanism operational mode and control strategies in the engine cycle simulation. Optimum design for the late intake valve closing, the valve lift, as well as the switching speed of the VVT system was carried out. It has been proved that power and torque of the JH125 motorcycle engine can be effectively improved by loading the new type VVT system.     

Fast multi-pole preconditioned GMRES high order boundary element method for power frequency electric field of multi-medium

In order to improve the computational accuracy and cost for multi-medium power frequency electric field (PFEF) solved by low order boundary element method (BEM) and preconditioned generalized minimal residual (GMRES),a hybrid technique combining the high order BEM and fast multi-pole (FM) method has been introduced to low order BEM. The FM preconditioned GMRES high order BEM is proposed to solve three dimension electric field distribution. The high order BEM model for three dimension electric field distribution is built, and the basic principles and implementation steps of the FM preconditioned GMRES high order BEM are given. The higher accuracy has verified in two medium test models. Part key devices in 500 kV substation is carried out to demonstrate that FM preconditioned GMRES high order BEM is much faster and more efficient than the preconditioned GMRES BEM in the computational cost and the storage of computer. The simulation values of this method are compared with measured values in 500 kV substation. It is found that the max relative error is 8.65%, so this method is suggested for use in large-scale and multi-medium PFEF problems.     

Design of an electric parameter measurement instrument for power generation equipment

Because electric parameters are crucial for indicating the operating condition of power generation equipment, an intelligent instrument for electric parameters measurement of power generation equipment was developed. A Hanning windowing interpolation algorithm based on FFT and a hardware frequency track were adopted to reduce the effect of leakage and fencing. In addition, a high speed AD conversion based on an external bus interface, a multiple feedback filter, an application of μC/GUI, and a multitask scheduler all were designed to improve timing and anti jamming. Test results indicate the system is stable and easily operated. The measured relative error of electric parameter is less than 0.5%.     

Kinematic displacements control simulation and configuration optimizing of six DOFs parallel mechanism for wind tunnel experimental platform

6PUUS parallel mechanism for wind tunnel experimental platform is studied,and its operational principle and movement requirements are analyzed. According to the theory of inverse kinematics and spatial Descartes coordinate transformation of 6PUUS parallel mechanism,kinematic positions of pull rods and kinematic interpolation paths of sliders are derived base on Euler angle of any experimental pose. The detailed algorithm for spatial position interpolation is summarized and its validity is proved by a simulation case in the end. Key factors of nonoccurrence of sliders collision at work are concluded by means of simulation analysis,and combined with the variety of mechanism parameters,optimized size parameters of pull rods and movable platform are also found. It is proved that this method and the simulation algorithm are useful and helpful for the optimizing design and singularity poses analysis of the parallel mechanism.     

Comparative study of low voltage ride-through techniques for doubly-fed induction generator wind turbines under asymmetrical grid faults

Asymmetrical grid faults occur more frequently and have more adverse effects on the doubly fed induction generator (DFIG) than symmetrical grid faults in the transmission system. The transient response of DFIG under asymmetrical grid faults is analyzed firstly. Meanwhile, operation behaviors of several low voltage ride-through (LVRT) techniques under severe asymmetrical grid faults are given by simulation with the Matlab/Simulink software. Then the characteristics of these LVRT techniques are further researched and analyzed based on the simulation results. Finally, the economies of these LVRT techniques are discussed. The conclusion lays a certain foundation for engineering development of these LVRT techniques.     

Design and numerical simulation for flow deflector in the gas flue of selective catalytic reduction denitrification system

Four design schemes of flow deflector in the gas flue of selective catalytic reduction (SCR) denitrification system are simulated based on K ε turbulence model and 2D model by Fluent. By analyzing the speed profile and pressure drop of the import and export, the effects of the flow deflector on the import and export speed profile, pressure drop, and energy dissipation are studied. It can be concluded that flow field distribution could be significantly improved by putting the flow deflector into the gas flue. Reasonable flow deflector design can not only make the flow field distribution uniform but also reduce the pressure drop and the energy dissipation. With the increase of flow deflector dimensions, the flow field distribution will be more uniform. The pressure drop and the energy dissipation will increase because of the increase of resistance caused by flow deflector. The research results are helpful for designing selective catalytic reduction denitrification system.      

Parameter Design for the Power Train and Simulation of the Dynamic Performance of Elctrical Vehicle

The method and principle of the parameter design for the power train of EV is explored and discussed,then the parametersof EV. based on SC7101 are reasonably selected.The method of calculating the SOC of Lead_acid battery is provided and the relation among the electromotive force,the interior resistance, the polarized resistance and the SOC are analyzed. The capacity is compensated according to the relation between the capacity and the temperature, which is the basis on which the energy management system is designed and improved. The dynamic model which reflects the dynamic characteristics of the power train is established,then the dynamic performance of the EV based on SC7101 is simulated, and the factors that affect the continuous mileage of EV are analyzed,the measures to increase the continuous mileage are provided.The result shows that the analysis of the electric characteristics of battery and the dynamic model are correct,and the dynamic performance perfectly meets the need of the design target.