Simulation Research of Control Parameters in Induction Motor Vector Control System

In order to obtain the effect rules of control parameters of speed regulator on performance indexes of induction vector-controlled system and the setting rules of control parameters of speed regulator,according to rotor flux oriented control principle,a vector control model of induction motor is established and simulated with the software of Matlab/Simulink.This vector control system is proved that it possesses good static and dynamic performance.This paper analyzes the effect of control parameters' variations of speed regulator on performance indexes and gives simulation results.     

Speed Estimation Methods Based on Neural Network

In order to solve the speed estimation problems of speed sensorless vector-controlled induction motor drives, the paper presents two speed estimation schemes based on neural network mode identification theory. The advantages of each scheme are discussed and the simulation results show that the estimated speed can trace the actual speed better (even under the circumstances of load variation or speed step variation). Also, these schemes are not sensitive to the variations of motor parameters and the effect of iron loss. Therefore, the proposed neural network based on speed sensorless vector-controlled induction motor drives have good performance in stady-state and transient-state operation.     

Application of state feedback and observer inmulti-axle vehicle steering system

A 3-degrees of freedom multi-axle vehicle dynamic model is established.Taking account of the practical difficulties for measuring the sideslip,rolling angles and rolling angle speed,a Luenberger observer is designed,and the simulation and analysis of the Luenberger observer are performed.The results show that the Luenberger observer has excellent characteristics in the considered speed range in tracking path.Then,a state feedback controller is designed on the basis of the Luenberger observer,and simulation of a multi-axle vehicle is also carried out.The results show that the performances of a multi-axle vehicle with the proposed control strategy is better than a multi-axle vehicle with front wheel steering strategy,and its control system has fine dynamic characteristic and strong robustness,so multi-axle vehicle with the proposed control strategy can improve vehicle handling stability and security.     

Electric Vehicle of Direct Torque Control System Based on TMS320LF2407 Controller

A fully digitized electric vehicle direct torque control system with DSPTMS320LF2407 controller is described. The system hardware and software structures are presented. The performance of the direct torque control system is studied by simulation with MATLAB. Based on the simulation of the induction motor, waveform of current, speed, torque and flux are obtained. The testing results are also presented. Experimental results show that the design is feasible.     

The Adaptive Robust Control Based On Synthetical Algorithm

An adaptive robust control based on synthetical algorithm was presented in this paper. The main character is to put the expert knowledge into parameter identification to realize the robust estimation, and combine the generalised minimum variance control with the pole assignment control for improving the robustness of the controller. Numerical simulation has proved that the control scheme suggested by authors quite prevailed over the general adaptive controller in control effects.     

Disign and Implementation of Speaker Recognition System Based on FPGA

Aiming at the shortcoming of low recognition and training speed in embedded speaker - recognition system based on DS Phard-core processor, a new scheme of system based on FPGA and vector quantization principle is presented. In the speaker-recognition system based on the vector quantization and generation algorithm, a fitness parallel process hardware structure is presented by the scheme which consumes much less time than software processing while getting the fitness. The test shows that the system uses this method obtains both high recognition rate and higher speed in training and recognition.     

A new control design for grid integration ofDFIG wind farm with VSC-HVDC

This paper proposes a control scheme for a doubly-fed induction generator (DFIG) wind farm with VSC-HVDC grid integration to ensure secure and reliable operation of power system with fluctuated wind power penetration. The whole system dynamic models are respectively described. Based on vector control system with a virtual voltage orientation, a steady-state voltage control block and a dynamic voltage control block with a cross-product term of d-q currents are separately designed for WFVSC to control the corresponding parts of the wind farm voltage. Meanwhile, with the consideration of AC and DC side parameter variation and external disturbance, an improved backstepping control scheme with Lyapunov stability provement is also proposed for the GSVSC. The combination of the two schemes makes up the new control design of this study. Besides, to verify the performance of the proposed new control design, three different cases are suggested which contain the AC and DC side parameter variation and external disturbance such as local load cut off-in, grid voltage harmonics. Finally, numerical simulations using MATLAB/Simulink are presented for a 200MW DFIG wind farm with VSC-HVDC grid integration to validate the proposed control scheme and demonstrate the improved system operation performance. Moreover, the corresponding discussions are also presented for further illustrations.     

Parameter Modifiability Based Transformer Substation State Estimation

The accuracy of transformer substation state estimation is widely low,and one reason of that is inaccurate(parameter) of model.Recently,most of papers about state estimation(SE) focus on improving algorithm.Based on classic SE and parameter estimation(PE),this paper takes advantage of the methods that putting parameters into state vector and putting parameters both into state vector and measurement vector in discussing the influence of parameter on transformer substation SE via simulation.The result of simulation shows: First,the error of parameters will be too high if only putting them into state vector,although the result of SE will be much better.Second,putting parameters both into state vector and measurement vector and giving them appropriate coefficient will lead a better result that can be used by engineering.     

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.     

石羊河流域下游不同年代退耕地风沙流特征研究

不同年代退耕地受水分与植被的影响,地表风沙流输沙量呈规律性变化。以石羊河流域下游民勤治沙站不同年代退耕地为研究对象,用0～100cm的风沙流观测仪测定了不同年代退耕地上的风沙流输沙量,分析了不同退耕年代风沙流年输沙率等特征。研究结果表明：(1)输沙量总体上表现为随退耕时间的增加而呈增加趋势,退耕时间越长,年输沙量越大,同时输沙率受样地周边地貌环境的影响较大;(2)不同年代退耕地输沙量随季节呈规律性变化,而且与风速关系密切,输沙量大小与当地风季发生规律相一致;(3)退耕地风沙流输沙量与退耕年代总体上呈二元线性相关关系,相关系数为0.88;(4)通过聚类分析将10个样地风沙流输沙量分为3类,17年为一类,13年为一类,其余退耕年代的为一类。不同退耕地因退耕时间的不同,受周边地貌,植被的影响,其风沙流输沙量有很大差异,研究结果为退耕地利用与治理提供了科学依据。     

A frequency-domain image registration algorithm using the improved polar transform

The influence of applying different heat transfer models coupled different data processing methods on determining the ground thermal properties and borehole resistance is analyzed and studied in allusion to constant heating flux method of thermal response test. Results indicate that the calculated thermal properties and borehole resistance are different when applying line heat source model and cylindrical heat source model respectively; volume specific heat barely affects the unknown thermal conductivity, but affects the borehole resistance. Three-parameter estimation has good credibility in determination of thermal properties and borehole resistance. However, the stability of three-parameter estimation on the determination of thermal diffusivity is not good. Finally, the approach of three parameters estimation coupled the line heat source model and cylindrical heat source model is proposed to determine the thermal properties and borehole resistance based on the analysis of the minimum average error on the two heat transfer models.     

大豆幼胚子叶体细胞胚诱导主要影响因素的研究

本研究选用东北地区4个主栽大豆品种的幼胚子叶, 探讨了培养基中氮源、生长素和蔗糖, pH值和低温预处理对体细胞胚诱导的影响; 并首次将低温预处理和pH=7.0的培养基应用到体细胞胚诱导中. 结果表明, MSB培养基附加40 mg/L 2,4-D和6%蔗糖, 其体细胞胚诱导率和诱导效率最高, 分别为49%和2.94%. 于4℃低温预处理的材料, 在pH=7.0     

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 the Intelligent Alarm System in Controlling the Automobile Speed

The alarm system in controlling the automobile speed is presented, without change of the original structure, and the design scheme of the system implements sampling, measurement, computing, real-time alarm and delay-time control for the automobile speed according to the safety of the automobile driving. Then, the speed is randomly stored so as to insure the correct data and to effectively analyze the data. Especially, the key techniques of the speed measurement and the refresh storage are pesented in datail in the system.     

Comparison and Analysis of Reliability Between 3/2 Connection and 4/3 Connection of Station

The main electrical scheme of a station is principal part of power system electrical connection,and its structure not only determines whether customers can acquire enough electric energy,but also influence economical efficiency of construction and reconstruction of a station.3/2 Connection and 4/3 Connection have been widely used in large scaled station.Three groups of alternative designs are chose in the article,of which the first group is single unit connection,and the other two are combined unit connection,and in each group there are one 3/2 Connection and 4/3 Connection plan.A reliability analysis system of main electrical scheme has been applied,to compare and analyze the reliability and economical efficiency of these two kinds of connection comprehensively.The result involves adequacy,security,economical efficiency indices and sensitivity analysis of component dependability parameter of each design.The result shows both 3/2 Connection and 4/3 Connection has its own relative merits,but 3/2 Connection has well applicability: Failure rate of generation has most obvious influence on reliability of the main electrical scheme.And quantified calculation of reliability is necessary in planning and choice of main electrical scheme of station.     

Improvement and simulation on direct torque control system of permanent magnet synchronous motor

To solve the problems of large flux, torque ripple and inconstant inverter switching frequency in conventional direct torque control (DTC), a space vector modulation (SVM) technique is introduced to the conventional PMSM-DTC system and analyzed thoroughly based on the mathematical model. This novel control method which enjoys the advantages of VC and DTC has only one easy adjustable PI regulator and is easy to realize. The simulation verifies that this control system is capable of effectively improving the steady state performance and keeping the excellent dynamic performance of the PMSM-DTC system simultaneously and remain the switching frequency constant.     

Application of Fuzzy Control in Direct Torque Control of an Induction Motor

The key of motor control is to control motor's torque essentially.Direct torque control,which emerged after the field-oriented control,directly stresses the instantaneous torque control of induction machine,which avoids some problems existing in field-oriented control,thus,it gets more attention.In conventional direct torque control system,switch vector is selected directly by the errors of stator flux-linkage and torque,after introducing fuzzy logic,optimal selecting switch state is realized by various strategies by distinguishing the grade of the errors of stator flux-linkage and torque,the dynamic and steady state performances of induction motors are improved.This paper presents a design method of the fuzzy controller.Simulation results demonstrate that it is effective,the stator currents pulsation at start-up and the torque pulsation are decreased.     

Automobile anti lock braking system control based on a least squares support vector machine

Using the referenced slip rate and angle acceleration of the wheel as input vectors and the braking pressure as an output vector, an automobile anti lock braking system (ABS) controller based on a least squares support vector machine (LS SVM) was designed. Training the LS SVM controller using the supporting vector, the parameter of the controller was calculated. An anti lock braking system was designed that includes an input layer, a control layer, and an output layer. Using wheel speed as an input, the braking pressure of each wheel was calculated. The pulse width modulation (PWM) method was used to control the braking pressure, and thereby to bring ABS control. An automotive ABS test and control system was constructed. Road tests under different conditions were completed according to international standards. Test results show that an anti lock braking control method based on LS SVM has good braking stability and adaptability. It is an effective new ABS control method.     

Intelligent Control to the Automatic Cruise System of AMT Vehicle

A dual closed-loop automatic cruise control system is proposed according to the properties of the AMT system with cruise control function inside, which is developod by the authors. The human simulated intelligent fuzzy control is applied to the inner loop of throttle position control while the conventional fuzzy control is applied to the outer loop of vehicle speed control. The scheme of the whole control system and the design process of the controller are presented. The experimental results show that with the proposed dual closed-loop control system, the unstable phenomena of engine speed can be eliminated and the throttle control responses fast without buffeting. Moreover, the system has the advantages of easy manipulation and reliable operation. The controller has the advantages of free of accurate mathematical model and easy to carry out and high robust and so on.     

The design of torque dynamic sliding mode controller in permanent magnet synchronous generator for wind turbine

Permanent magnet synchronous generator for wind turbine is a multivariable nonlinear system with strong coupling. Considering the influence of the volatile parameters of the generator on the performance of vector control, the torque dynamic sliding-mode control strategy is further studied. The proposed first order dynamic sliding-mode control strategy reduces the chattering by using a new switch function constituted with derivative element. With the dynamic sliding-mode controller in the power outer loop, the PMSG vector control system shows excellent robustness and insensitivity to the parameters and disturbance, which is confirmed by simulation.