Applied Mechanics and Materials Vols. 719-720

Abstract: This paper proposes a stator flux estimation method for induction motor based on Prescribed Convergence Law algorithm. A stator flux observer is designed and applied for direct torque control (DTC) of induction motor. The observer tracks stator current and its differential with Prescribed Convergence Law algorithm of second order sliding mode in order to estimate rotor flux, and then estimate stator flux using the relationship between stator flux and rotor flux. This paper takes the differential of estimated flux error as disturbance and divides the MIMO (Multiple Input Multiple Output) observer model into two separate SISO (single input single output) systems, which simplifies the stability analysis. The observer is applied to DTC of induction motor and achieves a good control effect. Simulation experiment results validate the proposed method.

Abstract: This paper presents a training system based on low-voltage cascaded PWM STATCOM.It is intended to train the employee in power grid companies.The system is characterized by load disturbance in 380-V power grid and imaginary power compensation of transformerless cascade PWM STATCOM with star-configuration. A two-hierarchy DC voltage balance strategy is adopted to stabilize the H-bridge capacitors in the compensation procedure. Simulation and experimental waveform indicate that a 380V-20kvar cascade STATCOM with star-configuration compensate the the imaginary power shortage within 20ms.

Abstract: System identification is the basis for control system design. For linear time-invariant systems have a variety of identification methods, identification methods for nonlinear dynamic system is still in the exploratory stage. Nonlinear identification method based on neural network is a simple and effective general method that does not require too much priori experience about the system to be identified. Through training and learning, the network weights are corrected to achieve the purpose of system identification. The paper is about the identification of multivariable nonlinear dynamic system based on PID neural network. The structure and algorithm of PID neural network are introduced and the properties and characteristics are analyzed. The system identification is completed and the results are fast convergence.

Abstract: As aviation technology continues to evolve, the function and safety of a large maneuvering have been required highly. As a large maneuvering system is becoming more and more complex , the trajectory design and simulation of a large maneuvering have become an important mean to ensure the mobile flight safety and design. The main focus of this research is to analyze the accuracy of the strapdown navigation algorithm and its impact in large motorized sport state by the large maneuvering trajectory design and its inertial system simulation. The authors build the model of the maneuvering trajectory by the Matlab program which is based on the design principle of the maneuvering flight path. Then, by using some coordinate system and the classical strapdown algorithm, specially attitude updating algorithm, the location update algorithm and the velocity update algorithm, the designed maneuvering trajectory model has been simulated and the simulation results are analyzed.

Abstract: This paper analyses and researches the performance and principle of DSTATCOM in distribution network .Detecting means and control method of DSTATCOM are key point of this paper. The paper determines the detecting means of improved d-q transformation theory of vector control based on instantaneous reactive power and adopts a novel strategy based on the prediction table of double variable. Moreover, the simulation of DSTATCOM is presented with MATLAB. The simulating results prove the DSTATCOM put forward in the paper can realize dynamic reactive power compensation efficiently.

Abstract: The property of temperature-frequency drift has an effect on the passband ripples, center frequency and insertion loss of FBAR filters, reducing the reliability of its electrical application. A temperature-frequency drift simulation of a typical Mo/AlN/Mo FBAR is achieved by means of finite element analysis software ANSYS, the simulated temperature coefficient of frequency is about-35ppm/°C within the temperature range of-50°C~150°C. By adding a compensated layer with positive temperature coefficient in the FBAR structure, the effects of the compensated layer thickness on temperature-frequency drift, resonant frequency and electromechanical coupling are analyzed. The simulated temperature coefficient of frequency of designed temperature compensated FBAR, which composed of Mo/AlN/SiO₂/Mo, is about 0.8ppm/°C, the property of temperature-frequency drift is effectively improved.

Abstract: Exponential stability for the singular distributed parameter systems is discussed in the light of the theory of GE₀-semigroup in Hilbert space. The necessary and sufficient conditions concerning the exponential stability are given.

Abstract: The handing over of cooperative guidance is a new problem of network anti-aircraft missile weapon system. The goal is to change the un-matching status which damage zone of one missile and guidance zone of one radar. Some articles are about of this issue but the research is not in-depth. This article provided a detailed analysis of the components of anti-aircraft missile system and engagement flow. It gives some definition and concept of cooperative guidance. The AAWS (Anti-aircraft Weapon System) for AAM (Anti-aircraft Missile) cooperative guidance model is established. It contains concept model of system, coordinate transaction model, errors model and radar tracking probability model. Radom errors are simulated. The Monte-Carlo method is used to have the relationship between errors and cooperative guidance ship probability. The reliable of cooperative guidance model is proved by simulation, which established in this paper. The results of error analysis can be used for precision controlling.

Abstract: To overcome the shortcoming that the traditional cymometer has a relatively large delay, small measuring range, low precision, poor reliability and complicated circuit; A design of digital cymometer based on EDA technology is proposed. The design is programmed with the hardware description language of VHDL. And it takes full advantages of Max+PlusII software to compile and simulate. All the functions are downloaded into and debugged on the chip of EP1K100QC in ACEX1K series from Altera Company. The experimental results show that this system has a very high reliability and small measuring error. The function of this system completely satisfies the demand of the design.

Abstract: Currently, the JTAG debugging is the most popular technology in the embedded ARM system. After providing a perfect JTAG debug method based on the GPIO pins of ARM chip, the paper analyzed the inner technology by which JTAG standard was accomplished. At last, the focus has been put on the analyses of the Boundary-Scan Chain working processes.