Research on a Novel Inverter of VSC

In order to improve waveform performance of light HVDC system, a lot of switches which operate in high frequency are used, which causes large switching losses and results high cost. A new Buck type voltage source converter(BVSC) is proposed. The new BVSC comprises a dual-buck converter and a three-phase inverter operating in grid frequency. Only two high frequency switches are used, which results good output waveform performance. In order to reduce the high frequency switching losses, a novel improved double-frequency Buck type voltage source converter(DBVSC) is also proposed. An additional dual-Buck converter is added to the BVSC, the added dual-Buck converter deals with the fundamental power that operates in low frequency, and BVSC only deals with harmonic power that operates in high frequency. The output waveform is enhanced and the switching losses are reduced in DBVSC, and the power rating is also increased. The DBVSC is very suitable for large power rating application. The one cycle control theory is adopted to control the proposed DBVSC with analog circuit, which is very simple. The proposed DBVSC and control method are verified by simulation.     

Comparative study of aircraft three-phase power factor corrections

This paper summarizes the requirements of standards for aircraft power supply firstly,and then points out that the input current harmonic and output DC voltage ripple should be considered seriously when designing three-phase power factor correction (PFC)for aircraft under variable line frequency and unbalanced line supply. Based on reviewing the topologies for aircraft three-phase PFC,three typical topologies,i.e. three-phase pulse width modulation (PWM)rectifier,traditional shunt active power filter (APF)and generalized APF,are picked up. A unified single-phase equivalent model is developed for comparing the harmonic suppression performance of the three active PFC schemes. And the switching stress is also calculated for evaluating their efficiency and power density. Three 5 kW PFC are designed by employing each of the three selected schemes. Simulation is carried out to verify the correctness of the theoretical analysis. The theory and simulation results indicate that the generalized APF topology shows the most technical merit for aircraft three-phase PFC. Future research works on generalized APF are also pointed out,which are solving the uncontrollability of its DC output voltage and optimal designing the filter inductors.     

含旋转电机接口和逆变器接口的微网小信号稳定性分析

提出了一种包含了逆变器接口（voltage source inverter,VSI）、同步电机接口（synchronous generator,SG）的独立微网控制策略,并分析了其小信号稳定性。VSI接口和SG接口的分布式电源均采用下垂控制策略,二者之间无需实时通信,可实现负荷功率共享。建立了系统的小信号状态空间模型,主要包括：同步发电机及其控制器的小信号模型、逆变器及其控制器的小信号模型、电网络及负荷小信号模型。计算了下垂增益变化时的根轨迹,得到了系统主特征值随参数变化的根轨迹,计算了不同状态变量对特征值的参与因子。稳定性分析结果表明：当所有分布式电源采用下垂控制时,引入同步发电机接口的分布式电源,系统频率小信号稳定性大大增强。PSCAD时域仿真验证了特征值计算的正确性。     

The modeling and simulation of a new USBCAN bus converter in Stateflow

The USBCAN bus converter is a connector of USB bus and CAN bus.It is difficult to judge whether the device works well or not and meets design requirement or not by ordinary ways.Regarded the Matlab/Simulink/Stateflow toolbox as the platform,the model of a USBCAN bus converter is established.The model of the bus converter is tested and verified in the Matlab/Simulink simulation environment.The results of the simulation analysis show the model is suitable for simulating the working state of the device.A new simulation and judging method for bus converters is proposed.     

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.     

One-cycle Control Three-phase Four-wire Active Power Filter with Four-arm

This paper presents a three-phase four - wire active power filter based on one-cycle control. This method need not sense the three phase load currents or the three phase voltages, need not use any multipliers. It has simplified circuit , and the controller is composed of four integrators with reset along with several flip-flops, comparators and some analog components. The main circuit switching frequency is constant, which is desirable for industrial applications. Analysis and simulation are carried out with the four-arm inverter, the simulation results verify that the APF with one-cycle control can dynamically and effectually compensate the harmonics, reactive current and zero sequence current.     

Dual mode AC DC AC converter for contactless power transfer system

A new type AC DC AC converter which can work in Buck or Boost mode is proposed in order to overcome the deficiencies of the primary circuit of the traditional contactless power transfer system. Through switching this two modes and turning the duty cycles of the switches, not only the resonant current amplitude of the primary resonant current can be controlled to be constant against a wide range variation of input voltage, but also the problems, such as surge current, high cost, complex control etc., caused by the DC filter and DC/DC converter in a traditional CPT system are effectively eliminated. The topology and operation principle of the proposed converter have been analyzed. The corresponding control strategy has been presented and verified by simulation results.     

A Integrate-Reset-Controlled Single Phase Power Factor Correction with High Efficiency

A novel single phase boost type power factor correction circuit is introduced .The converter's efficiency is greatly improved by improving on the traditional boost type power factor correction circuit. Integrate Reset Control circuit is adopted to realize unity power factor. The Integrate Reset Control high efficiency single phase boost type power factor corrector has these characteristics as follows: It's constant frequency operation, which is of advantage of the design of filter. The control circuit is very simple and no need for multiplier. The result is quiet perfect, the input current follows the input voltage very well. The efficiency is very high. The result of simulation and experiment proves the correction of theory analysis.     

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.     

Passive Lossless Forward Converter with Current Double Rectifier

To reset transformer excitation flux reliably,reduce the switching losses and improve influence of EMI noises in high frequency forward converters,several kinds of methods have been proposed,including RCD snubbers,active snubbersand resonant converters,and so on.These methods have many shortages.In consideration of these shortages,this paper puts forward a passive lossless forward converter with current double rectifier(CDR).The circuit does not require an extra switch or additional control circuit,and can resets the transformer excitation flux reliably,and does not include lossy components.So the circuit has higher reliability and higher performance/price ratios than above several kinds of methods. The paper analyzes the frame and operating principle of main circuit in detail.The key parameters design principles of the circuit are given.The simulation results confirm validity of the theoretical analysis results.     

Design of converter of DC-AC type contactless power transfer system

A new type of circuit topology for DC-AC type contactless power transfer(CPT) system is proposed, and the asymmetric DC-AC convert is used to imply the new topology. The topology simplifies the circuit and control of DC-AC type CPT system, reduces the power loss of power conversion of secondary circuit, and improves the overall efficiency and power density of the system. This paper presents the topology of the converter and investigated its control strategy. A model of the system has been derived, with which the system is simulated and studied. The measured experimental results have verified the theoretical and simulation results.     

改进二次型Boost变换器的研究与分析

传统二次型Boost变换器具有较高的升压能力,但其开关器件的电压、电流应力较大,增加了电路的体积与成本。笔者在传统二次型Boost变换器的基础上,结合高增益Boost三端网络,提出改进二次型Boost变换器,并对其连续工作模式下的工作原理及各开关器件的电压、电流应力进行了分析。分析结果表明,改进二次型Boost变换器不仅升压能力有所提升,而且在输出电压相同的情况下,开关器件的电压、电流应力有所降低。最后,通过仿真分析验证了该变换器的正确性和可行性。     

Transverse Effect of Bottom Continuity Tendons in Continuous PC Box Girder

Bottom continuity tendons induce transverse additive effect while providing longitudinal compression during the construction of PC box girder. Taking a cross-sea bridge for example, the mechanism of bottom continuity tendon is investigated. The transverse effect and parameters study are conducted through a refined model. It is illustrated that the state of bottom flange is in a dynamic changeable process during the tensioning of bottom continuity tendons, and the transverse effect caused by the tendons is much more than that by dead loading and other prestressing tendons. The transverse effect is more sensitive to alignment and thickness of the bottom flange, as well as concrete cover of the ducts. Finally, based on the simplified frame analysis, the design method is proposed by introducing prestressing effect simplified factor and duct modified factor.     

A Non-linear Circuit Model of A Self Scanned Photodiode Array Image Sensor

A non-linear circuit model of photodiode built according to the working principle of self-scanned photodiode array image sensor is presented for improving the property of the sensor. Through the analysis of the non_linear circuit model,we get the state equations, and the equations are resolved with Runge_Kutta algorithm. The Runge_Kutta algorithm is realized in C language, and the numeric result of the circuit is obtained. The analysis of the numeric result of the model shows that the non_linear performance of the sensor can be improved by reducing the capcitor of the PN junction and the dynamic performance of the image sensor can be enhanced by paralleling capacitor C M , and all the analysis is consistent with the real measurement results of the sensor. The circuit model of photodiode is improved over previous model.     

BOF-caster matching model in steelmaking plant of all plate and strip using precision design principle

Using precise design principle, a multi-objective programming mathematical model of the BOF-Caster matched is established for single production line in the steelmaking plant of all plate and strip, according to the segmentation of steel grade and product specification of product mix. Objectives of the model have less investment, less difference between production capacity of the converter and continuous caster, higher operating rate of converter and higher level of weighted average casting speed. The model is solved by the improved delaminating sequence method. Then, the overall configuration method of BOF-continuous casting in the steelmaking plant is proposed through integrating single production lines. According to the production outline of a new large steel plant, the result of the model shows that the configuration scheme of the steelmaking workshop of the steel plant is a better design scheme.     

Integrated Control Strategy for Dual State Continuously Variable Transmission System

Continuously variable transmission (CVT) is the ideal transmission for automobile, it is also one of the most important research items of researchers and automobile companies all over the world. In order to research vehicle with torque converter as starter and metal pushing belt as high speed transmission equipment(dual state CVT system), based on the test data of engine and torque converter, the integrated control strategy for vehicle with dual state CVT system is proposed and integrated control simulation for car with dual state CVT system is finished at the condition of multi mode. The research results provide the theory method of analysing and designing for CVT vehicle.     

LCL型CPT系统的参数设计方法及频率特性分析

以金鲳鱼为原料,固定小麦粉与水的质量比为2∶1,食盐添加量2%,微波真空度0.095 MPa,在单因素试验的基础上,通过正交试验对微波真空技术膨化鱼糜饼工艺条件进行优化。结果表明,鱼糜饼制作的最佳工艺条件为:鱼糜含量35%,膨化温度100℃,膨化时间20 min,鱼糜饼厚度2 mm,在该工艺条件下,制得的膨化鱼糜饼色泽金黄、质地酥脆、风味清香,成品膨化率可达到540%。     

An Artificial Neural Network Circuit Model for Routing Communication Traffic

A new fluid artificial neural network circuit model for routing communication traffic is proposed.The features of the model are that it can make use of all topology information of the network,and the optimization calculation is performed with electric circuit,and the most optimum route for communication traffic in the network can be obtained in circuit reaction time.Simulation results indicate that the model is correct and feasible. [WT5HZ]     

Dual channel transmission method based on LSK and PSKfor passive setting system

For separate transmission of received data and current fuze status data in a paasive setting system, a dual channel transmission method based on LSK and PSK is proposed. The corresponding feedback transmission model is set up. The methods for circuit realization and circuit parameters selection are also presented. This method has the advantage of easy circuit realization, low energy consumption, and quick and reliable information feedback. The test shows it can realize the stable dual feedback of 6.25 kbps setting data and 50 kbps status data of fuze in the same wireless channel when the DC voltage is not lower than 3 V. The design and modulation of principal prototype have been completed.     

考虑三维地震动作用下振动台试验隔震层简化

基于等效原则、相似理论,考虑三维地震动作用下振动台试验中原型结构隔震层的简化,并对模型结构隔震层进行系统研究。针对不同高宽比隔震结构,提出完全等效简化方法和部分等效简化方法,包括隔震垫等效、模型支座参数及坐标确定、相似关系确定等。利用不同高宽比隔震结构振动台试验,结合有限元数值模拟,进行方法验证。理论推导与数值模拟证明简化方法具有良好的准确性,且在误差允许范围内,简化后的隔震层所获得的加速度、速度、位移等动力特性与简化前相同,可以用于振动台试验模型设计。