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This paper proposes a novel 12-pulse hybrid-mode thyristor rectifier (HMTR) that can operate in either parallel mode or series mode with the help of a switch. No matter in which mode it operates, the proposed 12-pulse HMTR keeps the same pulses in the load current. It is designed to operate in parallel mode when low output voltage is required and in series mode when high output voltage is required. This way, the firing angle of the thyristor is reduced and thereby the total harmonic distortion (THD) in the input current is improved. The predictive current control strategy is also proposed to achieve the hybrid-mode operation. Fast current response is achieved both in parallel and series modes as well as in transitions between parallel and series modes. The concept of the proposed predictive current control scheme is quite simple and understandable, and easy to be implemented by a microprocessor. This paper includes analysis, simulation, experiment, and a comparison of the proposed control method with the conventional PI controller. Results from both simulation and experiment demonstrate the validity of the proposed 12-pulse HMTR and the effectiveness of the predictive current control algorithm.

A novel topology for ripple-free input current circuit is put forward in the paper. Compared to traditional EMI (electromagnetic interference) filter consisting of choke and capacitor, the ripple-free topology can reduce the converter's ripple current with the use of smaller component. The new ripple-free topology proposed in this paper does not need elaborate adjustment of the coupling coefficient as required by conventional ripple-free techniques, and is ripple voltage cancellation or isolation mode, which can attenuate the ripple further if the line impedance is considered. The theoretical prediction is confirmed by experimental results.

This paper proposes a new structure of serial hybrid active power filter which can reduce the power rating of the active power filter dramatically, and has good performance for harmonic suppression. The principle and designing rules are analyzed. The proposed structure is rational and feasible for high kVA applications. Simulation results are presented too.

As the harmonic distortion has become a main concern due to the various nonlinear loads such as uncontrolled/controlled rectifiers being used in industry. The existing multi-pulse thyristor AC/DC converter usually has to operate in a narrow voltage range so as to obtain high power factor and low harmonic injection. This paper proposes a novel multi-pulse flexible-topology thyristor AC/DC converter (MPFTTC) that keeps low total harmonic distortion (THD) and high power factor at the point of common coupling (PCC) over a wide voltage range. Detailed analyses are carried out, including the illustration of the topology-switching mechanism which drives the MPFTTC from one operating mode to the other. In order to achieve fast current control, the predictive current control strategy is presented. A promising application of the proposed MPFTTC in the wind energy conversion system (WECS) is presented, and the control strategy of the WECS is also discussed. At the end of this paper, simulation and experiment of the laboratory prototype verify the feasibility of the MPFTTC as well as the control algorithm.

This paper introduces the construction of highway management standardization and the necessity, also introduced the research status and research contents of highway construction, researched standardized data processing methods of analysis and research. The standardized effect evaluation method there are Min - Max standardization method, More direct comparison analysis, Comprehensive point rating method, Analytic hierarchy process (AHP), this paper also emphase researched Factor analysis, through the analysis that can be effectively factor analysis to evaluate effect. Finally, the article also introduced standardization management in guangdong bosheng expressway. Through the implementation of standardization in design, design units using standard atlas, reduce a lot of computing and graphics, Building materials according to the standard production building material manufacturer, guarantee the quality of the materials.

To measure the surface texture study on the aggregate, this paper based on the principle of laser light scattering method, using the PSD texture analysis, and adopt the existing laser equipment cross-section for the texture sensor, which issued by the laser through a laser beam collimating lens alignment group, setting to form a uniform surface scattering spot. The acquisition process with a laser signal demarcation and the horizontal displacement demarcation of the DC pulse. Also Matlab-based package of fractal analysis procedure Fractalyse can be used in different ways (Box, a small island law, the relevant law, etc.) to measure the fractal dimension of the image, and the process of analysis comes into two parts: the counting method and forecast model. By using the above ways to analyze and calculate the texture data, the fractal dimension have a certain degree of comparability.

Usually, the deadbeat control strategy is applied to three-phase voltage source PWM rectifiers. Often, deadbeat control uses a forward predictive algorithm of the reference current to compensate the control delay. Because of the uncertainty of reference variations, single predictive algorithm may cause large current overshoot or phase delay in different reference changes. The paper obtained the relationship among the prediction parameter, the current overshoot, and the phase delay after comparing and analyzing three commonly used predictive algorithms. Based on it, a new predictive algorithm was introduced using fuzzy control method. This algorithm chose appropriate prediction parameter according to different reference current changes, which was a tradeoff between current overshoot and phase delay. As a result, the maximum value of current overshoot was limited and the phase delay was optimized. Finally, an experimental prototype of a three-phase voltage source PWM rectifier controlled by a TMS320F2812 DSP was built and tested. The experimental results verified the validity of the proposed control approach.

First of all, the principle of the high-frequency AC current bus distributed power system, which has the characteristic of good load expansibility and isolation of high voltage is introduced. Then, based on the principle, a novel topology of DC power supply with multiple and isolated output is presented and working stage is analyzed in detail. A prototype has been used in solid state fault current limiter with 10 kV voltage successfully.

Using adjustable speed scheme in high power motor drive can not only save energy greatly but also improve the dynamic performance of the motor. Recently, medium-voltage inverter becomes the most popular scheme for high-power motor drive, but in some especial fields multi-phase motor drives have more advantages. In this paper a vector control method of six-phase synchronous motor (SM) based on three-level inverter is studied and some key techniques are analyzed in detail such as air gap flux-oriented vector control of six-phase SM, space vector pulse-width modulation (SVPWM) of six-phase three-level inverter and its neutral-point control. Then a 690 V/200 kW three-level inverter of six-phase SM is developed, and experimental results verify the techniques presented in the paper

This paper deals with a 3KW power factor correction (PFC) circuit based on the isolated full-bridge (FB) converter. The operation principle of the very converter is simply analyzed. Digital design consideration based on the small-signal dynamic modeling of the isolated PFC converter is specified in this paper. Implementation strategy and cost effectiveness of digital control for the single-stage PFC converter are studied. A transformer is used to provide galvanic isolation enables a wide range of output voltages, either lower or higher than the input voltage, allowing multi-output solutions. The adopted digital control strategy features fast dynamic response and excellent steady regulation characteristic without multiplying the input feedforward. High power factor and high efficiency are both achieved by combining FB main circuit and digital control. That flexibility is greatly increased can further contribute to system integration research on distributed power system[1]. Without multiplying the input feedforward, fast dynamic can be achieved due to the flexibility of digital control strategy. The above excellent performances are verified by an experimental prototype, whose output power is 3KW and PFC operating frequency is 110K.

This paper focuses on the relationship of three-level and two-level pulse width modulation (PWM) methods. A scheme of three-level space-vector PWM (SVPWM) based on one chip DSP is proposed depends on two groups of three-phase traditional PWM cell integrated in DSP. Neutral-point balance is achieved by adjusting the output voltage vectors based on the neutral-point current judging. This method simplified the digital control of three-level inverters, and improved the reliability of system. 660 V three-level converter with full digital control is proposed to verify the scheme.

This paper proposes a new structure of serial hybrid active power filter which can reduce the power rating of the active power filter dramatically, and has good performance for harmonic suppression. The principle and designing rules are analyzed. The proposed structure is rational and feasible for high kVA applications. Simulation results are presented too.

Some important factors of a series hybrid active power filter are presented in this paper for the case when the load is varied in a wide range and/or the source voltage is seriously distorted. Special designs of passive filters, adaptive control of parameter and multi variant control are discussed in detail. The filter is stable, has good performance, and causes small, capacitive reactive current. The simulation and experimental results accorded with the theoretical analysis results.

Recent development and research trends related to the EMC/EMI issues in power electronics system are reviewed. Research activities on EMI characterization of power converters, the EMI power filter design, EMI suppression techniques for drive system and switching power supply, PCB layout, EMI modeling and simulation for power electronics systems are discussed separately in different sections.