Applied Mechanics and Materials Vols. 448-453

Abstract: This paper presents a discharge inspection method based on new active inverter feedback discharge after comparison with the check discharge from pure resistance of power station batteries. A new active inverter system has been developed with SPWM pulse width modulation technology, which is based on DC/DC circuitry, along with a three-phase full bridge inverter and control topology circuits. In addition, the principle for selecting the parameters of RCL elements of the system has been analyzed. This paper also presents a detection method combining active detection with passive detection for the islanding effect which exists in the grid-connected discharge system, according to the islanding effect of grid-connected discharge equipment, so as to stably discharge without interference on the grid.

Abstract: Nowadays the main highway illumination facilities are HPSL (high pressure sodium lamp). With the technology development of LED (light emitting diode), it is used for highway lighting become possible gradually. This paper compared features of HPSL and LED, meanwhile give a deep discussion.

Abstract: New switching power supply gradually replaced the traditional linear power supply, but rarely has the operational status monitoring function. The design includes the main power supply and monitoring circuit design. The main circuit topology of the power supply is flyback DC-DC conversion body. The selection of the control circuit is current-controlled PWM chip. The monitoring circuit includes the design of detection and display circuit. The voltage and the current are detected respectively with the aid of the resistive subdivision in the testing circuit. The display circuit adopts PIC for sampling signal processing, and the dot matrix LCD12864 is used to display this power operating parameters. The power supply control system is simulated in Saber and Proteus software which monitors and observes the various parts of the circuit voltage and the output waveform. Finally, the hardware circuit is built and tested to prove the designed digital intelligent power feasibility.

Abstract: In recent years, with the rapid development of transportation industry, lighting installations were installed in the toll station and some important highway with dense traffic. Illumination plays an important role in the highway. This paper first introduced the illumination, lamps and lanterns, light source selection. Then the lighting power supply system was analyzed.

Abstract: SVG can compensate reactive power deficiency, suppress harmonics, improve three-phase imbalance and power quality more flexibly. There are very few small volume SVG products available for low voltage distribution network in the past. The generic SVG products are very expansive, thus not suitable for low voltage distribution network. Therefore, it is an urgent task to design a new generation distribution network SVG product that offers good value for money. This paper studied a SVG digital controller based on TMS320F28335 DSP chip. The fast and powerful computing and parallel operation capability of TMS320F28335 can satisfy the real-time, multifunction and multiple objective coordination control of SVG. Applied the instantaneous reactive power theory and adopted current direct control mode, an enhanced filtering algorithm to filter instantaneous sampling value is proposed. Automatic bi-directional compensation control strategy effectively reduced voltage variation at the user side. Its effectiveness is verified by an engineering project.

Abstract: In order to realize the integration of electronic circuits and avoid the electromagnetic interference between mutual inductance components and periphery circuit, the paper put forward a new kind of coupling element-mutual capacitance components, which were dual with mutual inductance components, according to the duality principle and the gyrator application theory. First of all, the paper used the basic electrical components-operational amplifier, resistance and capacitor to set up the circuit implementation model of mutual capacitance component, and then selected device parameters to execute theory calculation. On the basis of the previous step, a simulation software-PSpice, was used to simulate the model. Finally, comparison of two different groups of simulation data showed the correctness of the circuit model and the feasibility of the mutual capacitance component.

Abstract: Bearing electrical erosion caused by circulating bearing current exists in the high-power induction motor, which affects the safety of drive system. This paper presents a theoretical analysis of the generation of circulating bearing current based on electromagnetic field theory. 2D finite element analysis is adopted to calculate the parasitic capacitance and loop current method based electrical network theory is used to analysis the distribution of the common mode current. A new and reasonable circulating current equivalent circuit is built up. A 300kW induction motor fed by PWM inverter is simulated with MATLAB /SIMULINK software and the circulating bearing current of the motor is calculated.

Abstract: This paper describes a design optimization to achieve optimal performance of a two novel single-phase short-stroke tubular linear permanent magnet motors (TLPMMs) with rectangular and trapezoidal permanent magnets (PMs) structures. The motors equipped with a quasi-Halbach magnetized moving-magnet armature and slotted stator with a single-slot carrying a single coil. The motors have been developed for reciprocating compressor applications such as household refrigerators. It is observed that the TLPMM efficiency can be optimized with respect to the leading design parameters (dimensional ratios). Furthermore, the influence of mover back iron is investigated and the loss of the motor is computed. Finite element analysis (FEA) is employed for the optimization, and the optimal values of the ratio of the axial length of the radially magnetized magnets to the pole pitch as well as the ratio of the PMs outer radius-to-stator outer radius (split ratio), are identified.

Abstract: The paper gives the definition of the mathematical electrical circuit scheme, the extended element basis, the minimum and full functional element basis. The theorem about functionality of the full minimum element basis for the synthesis of mathematical diagrams of electrical circuits, which consists of: ideal conductor, ideal switch, one independent and one dependent source of electrical energy, capacitance or inductance, was convinced. There are a few variants of functionally complete minimal element bases.

Abstract: Geomagnetic field changes acutely during geomagnetic storms. According to Faraday's law of electromagnetic induction, the change of the geomagnetic field produces geomagnetically induced current (GIC) in power grid, which directly damages the power equipment and threatens safe operation of power grid. The more dramatically geomagnetic field changes, the bigger geomagnetically induced current in power grid becomes, and thus, the greater harm it brings to power grid. In this paper, based on the H and D components of recent geomagnetic storm data measured by several mid-to-low latitude geomagnetic observatories, the variation law of the amplitude of north-south and east-west geomagnetic component change rate (dX/dt and dY/dt) pulse with geomagnetic latitude was analyzed when geomagnetic field changed very severely. Finally, the possibilities of power grid in different direction affected by GIC with the change of latitude were discussed. The analysis results will contribute to the evaluation, measurement and control of GIC in Chinese current and future power grid.