Applied Mechanics and Materials Vols. 313-314

Abstract: Applying EDA technology, the dc speed governing system was designed, which produces digital signal of PWM waveform. These produced signals can be directly added to the dc machines, by changing the duty ratio of impulse wave, to realize speed regulation, not needing D/A transformation. With a high reliability and strong antijamming capability, this design is used widely. The simulation results of MAX + plus II software indicates that the desired effect is achieved for this design.

Abstract: A high step-up DC-DCconverter is proposed in this paper. The proposed converter has two transformers.The primary sides of them are paralleled virtually and the secondary sides haveseries connection to increase the voltage gain. An active clamp circuit isemployed to suppress the switch voltage stresses and obtainzero-voltage-switching (ZVS) operation of the switches. Voltage doubler isselected as an output rectifier to increase the voltage gain and confine thevoltage across the output diodes to the output voltage. Since the output diodecurrents are controlled by the total leakage inductance of the transformers,the reverse-recovery problem of the output diodes is significantly alleviated.Due to the ZVS operation and the alleviated reverse-recovery problem, theswitching losses of the proposed converter are significantly reduced and theefficiency is improved. Steady-state analysis is performed. Experimentalresults based on a prototype are also provided to verify the effectiveness andfeasibility of the proposed converter.

Abstract: Modular multilevel converter (MMC) is one of the most attractive converter topology intended for high power conversion without transformer. In this paper, a new modulation method for MMC is proposed and verified by simulated model. The main advantage of reduced switching frequency is also proved in the simulation results.

Abstract: A new method of traffic control based upon real-time number of the vehicles at the intersection was pulled forward. Serial vehicle detectors were used to detect the number of the vehicle waiting to pass through the intersection. One or more control boxes were used to control the traffic lights according to real traffic condition and transreceived data between itself and the detectors. The information transmission between the detectors and the controllers is based upon 2.4G ISM band. Arithmetic on the system operation, which took the pedestrians and the situation of excessive vehicles into account, is introduced.

Abstract: For a long time, settings complexity makes the settings remote modification technology is difficult to be applied on the relay protective devices effectively. To solve the key technical problems of relay protective devices settings remote modification, this paper makes an in-depth research of setting group remote control model. The setting group remote control model based on protective relaying and fault information system is proposed with the setting group services mapping between IEC61850 and IEC60870-5-103. The setting group remote control models working mechanism is deeply analysed via the setting group views. Base on the analysis, an enhanced control flow and task block method are provided to avoid the edit setting group data being changed abnormally, which improves the reliability of setting group remote control remarkably. The setting group remote control model introduced in this paper is applied successfully and its reliability is approved.

Abstract: Against the characteristics of the temperature in reactor such as time-delay, time-varying and difficulty to build a precise mathematical model in the chemical industry. Through the analysis of dynamic characteristics of the controlled object, the method of fuzzy-PID control was designed based on a predictive model. According to the detected temperature signal, the output deviation of the controller and the on-line identification of prediction model, this algorithm gains the predictive value which uses a generalized predictive model and the fuzzy-PID control. Then compare the predictive value with the reference trajectory to get the deviation. Finally use this deviation and the change of the deviation to optimize the PID control parameters and attain the appropriate amount of system control. The simulation results show that the fuzzy-PID control based on prediction model has strong adaptability, good robustness, control accuracy and higher practical value.

Abstract: A novel fuzzy control soft starting medium voltage induction motor is presented in this paper, Introduced the principle and the design of software and hardware on the medium voltage soft starter for asynchronous motors. According to analysis of the starting characteristic of induction motors, discussed a design method of medium voltage induction motor soft starting based on fuzzy Proportional-Differential (PD) control. Through measuring the input current, fuzzy control and PD control are used in the different phases of starting process to get the best control results.

Abstract: A new three-phase power-factor-correction (PFC) scheme is discussed using two single phase power factor correction circuit parallel connected. Two phase orthonormal voltage is produced by means of a auto transformer from a three phase input,fluctuation of neutral point by three single phase power-factor-correction circuit parallel connected is canceled,coupling interference is reduced among three phases,digitally controlled Power Factor Correction Boost Converters is adapted,input current wave sine with unity power factor suppress the secondary harmonic of input AC side is realized,voltage and low current stresses across each switch are reduced. Simulation and experimental results prove that it can achieve high power factor,low current,good capability of anti-interference and high reliability.

Abstract: A robust tracking control method for 3 DOF helicopter via least squares support vector machine with considering uncertainty and bounded disturbance is proposed in this paper. The inversion errors which is brought due to modeling errors and uncertainty can be compensated by least squares support vector machine, and the optimal regulator guaranteed dynamic characteristics of approximate linearization system and response quality of tracking error dynamic. Finally, the stability and convergence analysis of error dynamic system is proven by Lyapunov stability theory and numerical simulations have demonstrated the effectiveness of the proposed approach.

Abstract: With the increase of mining depth, the condition of underground water gushing becomes more complicated and uncertain; thus, the traditional pump control program cannot meet all the needs of safety production in coal mines. To this condition, the automatic pump control system based on KJD30Z mine intrinsically safe industrial control computer has been put forward, and pump automatic control system is formed. The automatic control of pump turn-on, turn-off and shift are realized according to the change of water bunker level. And so the real-time monitor of underground pump station from ground centralized control, In this way, better communication and alarm function can be formed, which is also quite helpful for the reliability of drainage system and the operation of economy.