An Adaptive Control Strategy for Energy Storage Interface Converter Based on Analogous Virtual Synchronous Generator

In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To address this issue,the application of a virtual synchronous generator(VSG)in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator(AVSG)control strategy for the interface DC/DC converter of the battery in the microgrid.Besides,a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control.Firstly,a theoretical analysis is conducted on the various components of the DC microgrid,the structure of analogous virtual synchronous generator,and the control structure’s main parameters related to the DC microgrid’s inertial behavior.Secondly,the voltage change rate tracking coefficient is introduced to adjust the change of the virtual capacitance and damping coefficient flexibility,which further strengthens the inertia trend of the DC microgrid.Additionally,a small-signal modeling approach is used to analyze the approximate range of the AVSG’s main parameters ensuring system stability.Finally,conduct a simulation analysis by building the model of the DC microgrid system with photovoltaic(PV)and battery energy storage(BES)in MATLAB/Simulink.Simulation results from different scenarios have verified that the AVSG control introduces fixed inertia and damping into the droop control of the battery,resulting in a certain level of inertia enhancement.Furthermore,the additional adaptive control strategy built upon the AVSG control provides better and flexible inertial support for the DC microgrid,further enhances the stability of the DC bus voltage,and has a more positive impact on the battery performance.

基于MCS-51的高精度信号发生器设计与仿真验证

本文设计的信号发生器以MCS-51单片机为核心,辅助以按键电路、显示电路、数模转换电路,能够发出三角波、正弦波、方波、锯齿波四种波形。通过引入DAC0823芯片,将数字量和模拟量进行转换,使得信号发生器发出的波形的误差和噪声干扰更小,并简化了滤波过程。仿真过程中通过软件程序控制硬件电路,利用Keil仿真平台的元器件仿真功能和程序编辑功能将程序搭建好,然后一同放入Proteus仿真平台中,通过后者的元器件选择和参数调节功能将信号发生器的主控电路搭建完成。最后,利用模拟示波器得到了满足设计要求的波形,验证了信号发生器的性能。

Automobile light control system based on CAN bus and contactless switch

In order to solve the complex wiring and low reliability of conventional light control system,an automobile contactless switch light system is designed combined with Hall element and controller area network （CAN） bus technology.The processing system of electromagnetic compatibility controlled by CAN bus is improved to reduce the electromagnetic interference from the controller and other sources of interference.With Freescale＇s high-performance single-chip MC9S08DZ60 and CAN transceiver TJA1050,the overall circuit design and software design are presented.The test results show that the designed light control system is feasible.

MODELING MULTI-TRAFFIC ADMISSION CONTROL IN OFDMA SYSTEM USING COLORED PETRI NET

Call Admission Control (CAC) is one of the key traffic management mechanisms that must be deployed in order to meet the strict requirements for dependability imposed on the services provided by modern wireless networks. In this paper, we develop an executable top-down hierarchical Colored Petri Net (CPN) model for multi-traffic CAC in Orthogonal Frequency Division Multiple Access (OFDMA) system. By theoretic analysis and CPN simulation, it is demonstrated that the CPN model is isomorphic to Markov Chain (MC) assuming that each data stream follows Poisson distribution and the corresponding arrival time interval is an exponential random variable, and it breaks through MC's explicit limitation, which includes MC's memoryless property and proneness to state space explosion in evaluating CAC process. Moreover, we present four CAC schemes based on CPN model taking into account call-level and packet-level Quality of Service (QoS). The simulation results show that CPN offers significant advantages over MC in modeling CAC strategies and evaluating their performance with less computational complexity in addition to its flexibility and adaptability to different scenarios.

Model predictive torque control of permanent magnet synchronous motor system driven by matrix converter

Employing matrix converter （MC） as driving mode, the strategy of model predictive torque control （MPTC） is proposed for three phase permanent magnet synchronous motor （PMSM） system. MC is applied instead of conventional AC DC AC converter to increase the power factor （PF） of the system input side. MPTC is used to select optimal voltage space vector to enable the system to have satisfactory torque and flux control effect. The resultant MPTC strategy not only makes the MC fed PMSM system operate reliably and have perfect control performance, but also makes the PF of the system input side be 1. Compared with direct torque control （DTC）, the proposed MPTC strategy guarantees that MC fed PMSM has better command following characteristics in the presence of variation of load torque and tracking reference speed. Simulation results verify the feasibility and effectiveness of the proposed strategy.

Design of a Modularized Automatic Measurement and Control System for LaserInduced Breakdown Spectrometer

In order to improve the compatibility of laser-induced breakdown spectroscopy( LIBS) instrument for different types of parts and optimize the analysis and testing processes,a modularized automatic measurement and control system was developed. Based on the characteristics of each LIBS component, the following development steps have been performed:( 1) a summary of characteristic parameters of the component are established;( 2) the integration mechanism of multiple electrical interfaces is designed;( 3) the component control instruction library is developed. The experimental results indicate that the measurement and control system is compatible with most LIBS parts in the market.Spectrometer and laser can be compatible with at least three different types of parts. In addition,a multilayer iterative testing process is designed to improve the efficiency of optimization process of LIBS parameters. The experimental results have shown that the automatic optimization of the delay time compared to the manual testing provides significant gain in testing efficiency. The range of delay time in the experiments is 1. 28 to 10. 28 μs and the step value is 1,0. 5,0. 2 and 0. 1 μs. The gain in testing efficiency has been found to be increased by 73. 76%,75. 93%,78. 81% and 80. 42%,respectively.

Manipulation for degenerative lumbar spondylolisthesis:A systematic review of randomized controlled trials

Objective: To assess the effectiveness and safety of manipulation intervention for degenerative lumbar spondylolisthesis(DLS).Methods: This is a systematic review and meta-analysis. A full-scale retrieval method was performed until February 1, 2021, including nine databases. The homogeneity of different studies was summarized using the Review Manager. The quality of studies was determined with the Cochrane risk-of-bias tool.The evidence quality was graded with the Grading of Recommendations, Assessment, Development, and Evaluations approach.Results: A total of 6 studies involving 524 participants were included. The review demonstrated that manipulation has statistically significant improvements for treating DLS according to Japanese Orthopedic Association scores(mean difference, 3.76;95% confidence interval, 2.63 to 4.90;P <.001) and visual analog scale scores(mean difference,-1.50;95% confidence interval,-1.66 to-1.33;P <.001)compared to the control group. One study reported that the difference in the Oswestry Disability Index between the traction group and the combination of manipulation and traction group was statistically significant(P <.05), while another reported that manipulation treatment can significantly improve the lumbar spine rotation angle on X-ray images compared with the baseline data(P <.05). Moreover, the manipulation group(experimental group) had fewer adverse events than the lumbar traction group(control group).Conclusion: Manipulation intervention is more effective and safer for DLS. Nevertheless, large-scale randomized controlled trials are required to confirm the current conclusions.

Integrated Control System of Vehicle ABS/ASR/ACC Based onMC9S12DP256

The integrated control system of vehicle ABS/ASR/ACC has been developed using the MC9S12DP256 single chip, which is the new Motorola 16-bit product in HSC12 family. The system including the main control module, the data collection module and the drive and fault diagnosis module is demonstrated and its data collection function is presented in detail. The system designed by the modularization can supervise the data, drive the valves and pump. The program can be debugged on line, which is steady and reliable validated by the large numbers of vehicle road tests.

Ultra-Modified Control Algorithms for Matrix Converter in Wind Energy System

This paper proposes an ultra-modified SSA(symmetric sequence algorithm)of space vector modulation of MC(matrix converter).The ultra-modified technique improves the drawbacks of the modified one where it provides a reduction of the total harmonic distortion for both output voltage and current.Also this paper proposes a modified feed forward controller of the MC with indirect space vector modulation.The modified feed forward provides a solution for the change in the output voltage due to change in wind speed,where it provides a constant output voltage with constant frequency even if the wind speed changed.Some of the advantages of MC are introduced in this paper.These advantages represented in the output frequency of MC which may be greater than the input frequency,controlling rms value of the output voltage and the ability to control the IDF(input displacement factor).At the end of this paper simulation and experimental results are introduced which give a precise proof to the proposed algorithms.

Canonic Realizations of Voltage-Controlled Floating Inductors Using CFOAs and Analog Multipliers

New voltage-controlled floating inductors employing CFOAs and an analog multiplier have been presented which have the attractive features of using a canonic number of passive components (only two resistors and a capacitor) and not requiring any component-matching conditions and design constraints for the intended type of inductance realization. The workability and applications of the new circuits have been demonstrated by SPICE simulation and hardware experimental results based upon AD844-type CFOAs and AD633-type/MPY534 type analog multipliers.

Hardware Implementation and System Control Strategy of Videoconference System Based on Rec. H. 261

The design and realization of a videoconference system based on international recommendation are introduced in this paper, and the hardware implementation of video codec based on ITU-T H. 261 is briefly discussed. Furthermore, the buffer control method and the adaptive control strategy for quantization are proposed, which are adaptive and robust. This system can be operated under the transmission rate ranging from 128kb/s to 2Mb/s. With these strategies for the videoconference system, the high quality image is obtained. The time delay of the system is about half a second.

基于AQUATOX模拟的小球藻处理水产养殖废水试验

目的 为实现低碳快捷处理水产养殖废水,探究利用小球藻处理废水的最优方案。方法 以某鲅鱼养殖基地水体为对象,利用AQUATOX软件建立水生态环境模型,根据不同的水产养殖废水浓度、水力停留时间和流量建立5个试验组,稀释后投加5 mg/L的小球藻藻种,模拟分析小球藻的处理效果,并将结果与实测数据进行对比。结果 投加小球藻的最适比例为:ρ(小球藻)∶ρ(TN)∶ρ(NH_(3)-N)∶ρ(TP)∶ρ(CODcr)=1∶16.8∶3.2∶0.8∶40;最适投加比例的小球藻对废水中的TN、TP、NH_(3)-N、CODCr的处理效率分别达到了73%、72.5%、94%、75%;藻生物量也达到了初始值的26倍。结论 应用AQUATOX模型可以快速实现小球藻处理水产养殖废水方案优化,TN、TP、NH_(3)-N和CODcr质量浓度模拟结果的平均相对误差分别为0.32%、2.52%、4.83%和0.10%。

基于系统结构图的模拟电子技术课程教学探索

掌握知识是教学目标的核心要素,对基本元件和基本电路的深入探索是领悟模拟电子技术课程知识的关键。为此,该文提出以系统结构图为工具开展课程教学,首先分析教学内容与系统结构图的关联关系,然后通过两个知识点的分析过程,阐述系统结构图在课程教授中的具体应用,最后运用案例分析、仿真实践、翻转教学等教学方法,实现启发学生融会贯通、注重创新培养、强化学生自主探究的目标。

模拟电子技术与自动控制原理课程融合促进教学探索

多课程交叉融合的教学模式能够提高人才培养质量。首先,通过梳理和整合模拟电子技术和自动控制原理两门课程的教学内容,构建深度融合关联思维导图,明晰知识点对应关系。其次,针对具体知识点,采用多角度理论推演、交叉案例分析、综合性项目设计、虚拟仿真平台共享和课程思政融合等方式,设计具体实施内容。最后,探索了多种教学方法在融合促进教学中的应用,增强了学生对理论知识的理解和运用,提高了教学效果。

MCS-51单片机温度控制系统

通过硬件和软件两方面介绍了MCS-51单片机温度控制系统,用该系统对电阻炉进行控制效果较好。

基于Visual Basic6.0下PC机与MCS-51单片机的串行通信

由PC机控制单片机组成的分级式测控系统有着广泛的应用。以往的PC机通信程序多数是通过汇编语言或BIOS功能调用的MS -DOS下的串行通信程序。这类程序编写较为困难且不易向Windows环境移植。在VisualBasic6 0编程环境下 ,利用Win32应用程序接口 (Win32API)中的通信API开发了PC机串行通信程序 ,以MCS - 5 1单片机控制板为实例给出了PC机与单片机通信的具体程序实例。

MCS-51单片机在电子皮带秤自动化中的应用

电子皮带秤被广泛地应用于矿山、煤炭、化学工业和码头等行业,他是一种非常重要的动态测量系统。利用MCS51单片机特点,在电子皮带秤原有机械结构的基础上加入了由单片机称重的自动控制系统,实现了电子皮带秤调节的自动化。同时,对电子皮带秤自动控制系统中的软件组成以及调节过程进行了详细的阐述,为该系统的广泛应用提供了思路。

MCS-51单片机和PC机间的串口通信

概述了PC机与单片机间进行串行口通信的基本原理,介绍了PC机与下位机之间的通信协议,并详述了在Visual C++环境下上位机利用MSComm通信控件与单片机之间进行RS232异步串行口通信的实现,给出了实现通信的硬件设计、串行口属性的初始化、与下位机进行通信的控制代码以及下位机的程序流程图。

基于MCS-51单片机的智能化多功能电动康复床控制系统设计

设计了基于MCS-51单片机C8051F040的智能化多功能电动康复床控制系统。通过对控制部分的硬件电路、软件程序及系统抗干扰的设计,使病人实现了对康复床进行定时体位调整和自动避障的智能控制,也实现了医疗康复的自动化、智能化。该系统具有操作简单、实用性强、可靠性高、成本低的特点。

基于DAC阵列的光交叉芯片控制驱动系统

为标定光交叉芯片驱动电压,控制光交叉芯片实现光路由功能,提出并搭建了基于多通道DAC(Digital to Analog Converter)阵列的控制驱动电路系统。系统主要由控制系统模块、多路驱动电路模块及上位机控制模块构成。控制电路和驱动电路具有调校简单、可双极性输出、输出路数多、加电精确度较高的特点,解决了当前驱动电路工作繁琐、加电极性单一、加电路数少、精度差的问题。上位机控制模块除了可控制驱动电路施加控制电压外,还可接收来自数据采集装置采集到的光功率信号作为控制驱动系统的反馈信号。通过分析控制电压与光功率之间的关系,可得到最佳的光交叉芯片控制驱动电压。系统测试实验结果表明,该系统能提供高精确度的双极性驱动电压,有效地对光交叉芯片进行驱动。可在较短的时间内标定出光开关的控制电压,完全可以满足有源光交叉芯片控制中对驱动电压的需求。该系统在光交叉芯片控制方面具有一定的应用价值。