为了解决输送皮带长久使用后带来的纵向撕裂问题,文中综合考虑因生产作业现场环境复杂导致检测不准确从而引起的检测误差,提出一种通过DSP快速处理后,基于RGB颜色矩和BRISK特征提取的红外激光条件下的图像特征提取处理方法.通过与传统的Sobel算子和Canny算子所得到的提取效果进行对比分析得出,文中新的运算和特征提取技术较传统方法辨识度和检测精度更高,实时性较快,能够满足复杂环境下皮带撕裂图像特征提取的要求.然后从图像处理效果的角度出发,通过Matlab编程对文中所提方法的有效性进行验证.结果表明,文中的处理技术能够快速识别并提取出皮带撕裂的特征,判断出输送皮带是否发生撕裂.

气体流量测量是气体流体供需双方进行贸易结算的重要依据,也是企业生产经营中的关键技术和产能指标.准确的气体计量结果可以保证贸易结算的公平性.由于超声波流量计具有测量精度高、抗干扰能力强、对外界要求相对较低、流量计本身压力损失相对较小、测量范围宽等优点,超声波测量在气体贸易结算计量中的应用也变得越来越广泛.

对PLC控制系统和传统的继电器控制系统的差异和特征进行了分析,并指出,取代传统继电器控制系统的现代工业控制系统PLC可以加快产品的升级,提高自动化流水线的生产效率,并提出一些改造和替代方法.

细粒、微细粒的分级一直是选矿工作的核心问题,现有的水析装置存在各种不足,因此设计出多产品水析仪以满足实验室对细粒及微细粒级分级效率高,准确性强的要求,并且结构简单,操作方便,耗水量少.系统采用PLC为核心控制平台,控制下位机执行动作指令与数据反馈,达到可无人值守、精确控制水析仪动作、数据采集与传输以及提高系统可靠性、安全性的目的.

In this paper, we investigate a cooperative model predictive control for distributed photovoltaic (PV) power generation systems. A two-level control strategy is proposed. The upper level is cooperative control and the lower level is model predictive control based on dynamic matrix control. The proposed control strategy not only makes all the distributed PV generators converge and operate at the same ratio of the available power, but also regulates the total power output of all the PV generators to ensure the stability of the distributed power generation systems. Simulation results on the 4-machine 14-bus distributed power generation test system are provided to verify the validness and effectiveness of the proposed control strategy.

In recent years, there have been an increasing number of photovoltaic (PV) generators integrated into the modern distribution power network. However, the introduction of a large number of PV units could have a negative impact on the distributed PV grid-connected power generation systems, such as polluting the grid, and causing grid instability, even resulting in the voltage collapse if the relevant stability and control issues are not properly considered. This paper proposes a two-level control strategy, that is, the upper level is cooperative control and the lower level is dynamic matrix control (DMC). The proposed control strategy not only makes all the distributed PV units converge and operate at the same ratio of the available power, but also regulates the total power output of all the PV units to ensure the stability of the distributed power generation systems. Simulation results on the 4-machine 14-bus distributed power generation test system are provided to verify the validness and effectiveness of the proposed control strategy.

This paper proposes a novel active islanding fault detection method based on even harmonics injection and set-membership filtering for the distributed generation systems. Traditional active islanding detections are mainly adding disturbances to frequency or phase of the voltage reference signal. The proposed active method detects islanding fault by injecting even-order harmonics into the current reference signal and monitoring the changes of corresponding voltage harmonics using set-membership filtering. This paper gives the principle of this proposed detection method and analyzes the range of injected even harmonics. We compare the differences of the even-order harmonic voltage between grid-connected and grid-off conditions. The proposed method has a number of advantages such as fast detection speed, almost no non-detection zone, and little impact on power quality. The effectiveness of the proposed method is demonstrated by MATLAB/Simulink simulations. Kalman filtering contrast experiments are presented to confirm that the set-membership filtering is more effective in islanding detection.

SUMMARYThis paper proposes a novel islanding fault detection method for distributed generation systems. Islanding fault detection of distributed generation systems in microgrids and smart grids is an essential security technology. The existing methods for islanding fault detection can be classified as passive methods (such as under/over voltage detection, under/over frequency detection, and voltage phase jump detection, based on natural effects of islanding) and active methods (impedance measurement, slip mode frequency shift, Sandia frequency shift and so on). Once the power consumed by a local load matches the power generated by a local inverter, the islanding phenomenon will be not obvious, and traditional passive methods may fail. In contrast, the active methods can overcome this disadvantage. However, active methods create extra disturbances that may degrade the quality of power generated by the inverter. By reducing the harmonics of the inverter output, coupled with the use of a novel filtering method, the proposed approach can be achieved without additional disturbance and does no nondetection zone islanding detection. In this paper, current harmonic compensation is applied to inverter control to minimize the inverter output harmonics, highlighting on the grid harmonics. Set‐membership filter is developed to estimate the voltage harmonics. Islanding condition is detected by the changes of the specific order harmonics. The effectiveness of the proposed method is demonstrated by simulations. A Kalman filter contrast experiment is presented to confirm that the set‐membership filter can more effectively detect islanding. Copyright © 2013 John Wiley & Sons, Ltd.

This paper proposes a novel distributed H∞, equalization control for distributed generation systems with multiple power generation nodes. Distributed generation becomes a new trend in modern power systems for the future smart grid and receives more and more attention. The proposed control method makes the distributed generation nodes working at the same output ratio by developing the distributed H∞ equalization control which is based on the output feedback from the nearby neighbors and local observers. The sufficient conditions for H∞ equalization control design based on estimation are established in terms of a linear matrix inequality. Simulation results are provided to verify the effectiveness of the proposed method.

In distributed generation systems, islanding detection is one of the necessary safety designs, which requires both quickly and accurately to determine the occurrence of islanding, but cannot reduce the inverter output power quality. The principles of islanding effect occurring and the reasons of blind testing were discussed. The islanding detection method was realized through proposed active phase shift of frequency, and in the worst conditions, SIMULINK simulation experiment was carried out to test the feasibility of this detection method and the presence of small non-detection blind.

As an enormous reserve and widespread emerging green energy, solar energy has been widely appreciated in recent years. Solar PV was one of the most scientific and rational using methods of solar energy. The photovoltaic system components was described, on this basis, several key technologies of the photovoltaic power generation were discussed, including MPPT (Maximum Power Point Tracking) technology, grid technology, energy conversion technology and anti-islanding technology.

The model structure and feature curves of photovoltaic cell were firstly described,then two maximum power point tracking algorithms works of photovoltaic power generation system were given,whose flow charts were given respectively.Finally the performances of the two algorithms were compared through MATALB / SIMULINK simulation experiments.