Earticle

In order to solve the problems of subsection vacuum switch repair deficiency and blind repair and to improve the accuracy of the subsection vacuum switch condition assessment we put forward a strategy based on the theory of fuzzy evaluation. Firstly, a layered evaluation index system on the base of preventive experiments, including working surroundings, operation history, maintenance records, and accessories section and so on is built. Then, the relative impairment degree is introduced to describe the relative grade of subsection vacuum switch changing from actual conditions to faults. The member functions for qualitative indices and the quantitative indices are respectively determined with helps of a fuzzy statistic method and a fuzzy distribution method. An operation condition evaluation model evaluates the state of every grade and gives a comprehensive assessment of subsection vacuum switch, is established on the base of the fuzzy synthetic judgment. Example analysis shows t the method for the safe operation of the transformer condition assessment of reliability is higher and more accurate.

This essay presents the design method of applying ultrasonic levitation bearing to high-speed motor and using single supporting rotor of ultrasonic levitation high-speed motor. It adopts piezoelectric transducer, the permanent magnet synchronous motor spindle; the radiation surface of transducer and the levitation support cap of the spindle adopt the conical structure with the same taper. It ensures that the spindle is highly automatic centering when it rotates at the high speed. The test results show that the spindle runs smoothly without having contact friction noise and problems of torque fluctuation and radial vibration caused by the electromagnetic coupling, when the output power of the ultrasonic power supply is at 500w, the speed of the spindle is over 20000rpm, and the levitation clearance is more than 100nm, which is more than the sum of roughness Ra for two contact surfaces.

Aimed at that standard interval arithmetic is easy to cause error explosion, as well as traditional affine arithmetic is easy to cause calculation error due to not considering the correlation among the first degree item, quadratic term, even the multiple-item and the nonlinear term expressed by the same noise, this paper proposed an improved algorithm which took affine algorithm operation as the main body. When there are those correlation items, the algorithm calculates the upper and lower bound of their total value by interval arithmetic, then uses the bound information and introduces the new noise affine form to instead of those terms. The method improved the conventional affine operation by combining interval arithmetic. When it applied to calculate the nonprobabilistic reliability index, the calculation results has higher accuracy than the interval arithmetic and the conventional affine algorithm, and it has strong practical significance.

This paper presents a quantum-dot cellular automata (QCA) 3-8 decoder with low hardware complexity. The proposed architecture is based on inverter chains to get inverse value and cross over a wire. We also use 5-input majority voting gates for 3-input AND gates. In this paper, we focus on the hardware complexity to reduce the number of cells and minimize wasting an area. Our architecture has not only an excellent regularity and scalability but a strong signal strength so that it is easy to extend a structure and connect with other circuit.

This essay presents the theory about the levitation support of the ultrasonic vibration for the motor rotor, designs an ultrasonic levitation support structure, and theoretically calculates the levitation force by adopting the conical radiation surface to provide the levitation support for the motor rotor. By using the designed device, this essay analyzes and tests the bearing capacity, obtains the relationship between the levitation force and the levitation clearance, and conducts the experimental studies to the relationship between the highest speed of the rotor and the levitation clearance. The results show that the ultrasonic vibration can enhance the supporting effect and increase the maximum speed of the rotor by reducing the clearance, therefore achieve the levitation of the rotor.

In this paper, a master manipulator control system in a master-slave robot which uses trinocular stereo vision is presented. The system utilizes three real-time cameras to identify and track the movements of the master handle, while also measuring the master handle position. The system follows a basic four step process. First, the master handle in the image is identified using the contrast between the handle and the background. Second, the speed and direction of the next position for the master handle is predicted in real-time by using the Kalman filter. Third, the position of the master handle is measured in real-time using stereo matching, which utilizes the method of combining feature matching and region gray matching to consistently identify the markers on the master handle and eliminate error matching. The experimental results in this study conclude that the master-handle manipulator control system is fast and exact.

This paper presents the comparison between two topologies of hybrid direct current circuit breaker (HDCCB) that are designed by ABB and Alstom Grid. The main difference between two topologies is the use of the semiconductor in each topology. ABB used IGBT cells whereas Alstom Grid used IGBT cells and thyristors. The working principles of each topology are presented and their advantages and disadvantages are shown in this study. Two HDCCB topologies are implemented in MATLAB / Simulink to clarify the comparison. The effect of the time delay in the topology of Alstom Grid is also discussed in this study.

For an interior permanent magnet synchronous motor (IPMSM) control system, the actual maximum torque per ampere (MTPA) trajectory may deviate from the ideal one with parameter variances, and thus the system may not obtain the maximum torque output. In view of this problem, a novel parameter identification method based on the model reference adaptive system (MRAS) is proposed in this paper. In this method, the deviations of MTPA trajectories with parameter variances are analyzed and evaluated firstly, and then the q-axis inductance and the rotor flux linkage are identified on-line in a full rank MRAS model according to Popov Hyper Stability Theorem. Finally, the feasibility and validity of the designed method are proved through simulation results.

In order to solve the problem of low positioning accuracy, poor automation, less efficient that common shears work in the production of boiler air preheater heat transfer components, a new type of Double CNC shearing machine system is designed on the basis of common shears. The PLC, Ball screw and Servo system are used to control the feeding length accurately, a touch screen is applied as a display device and input system at the same time, the utility of system is improved greatly. In this article, the design process, basic structure and operating principle of the system are introduced, the design ideology and PLC program flow are described, there is a brief description about the system program debugging results as well. At the end, the rationality of the design is proved combined by the actual use.