内燃机驱动的自激异步发电系统建模仿真研究

基于Matlab/Simulink软件建立了异步发电机仿真模型,针对采用的笼型异步电动机数据,确定了M文件中异步发电机模型中的相关参数;详细说明了四冲程内燃机在Matlab软件下的建模实现过程和原理;建立了以内燃机为原动机的自激异步发电系统。仿真结果表明,接入负载时,系统有明显的调整过程,通过对比分析有无原动机时电压的变化情况验证了模型的正确性,为实际内燃机驱动的自激异步发电系统研制提供了强有力的理论依据。     

基于模糊PID复合控制的异步电动机软起动器的设计

针对异步电动机直接起动电流较大的问题及传统比例-积分-微分( PID)控制和模糊控制在异步电动机软起动控制中的比较,提出了1种基于模糊PID复合控制的异步电动机软起动器的设计方法.根据对电动机起动特性的分析,在异步电动机起动的不同阶段分别采用模糊控制和PID控制,以达到最佳的起动效果.仿真结果表明,这种复合控制方法解决...     

一种异步电动机故障诊断新方法

针对基于RBF神经网络的异步电动机故障诊断方法存在参数确定较困难的问题,提出了一种基于差分进化算法优化RBF神经网络的异步电动机故障诊断方法。首先采用小波变换对异步电动机运行状态信号进行消噪处理,然后采用主元分析法与小波包分析法相结合方式提取消噪后的异步电动机运行状态信号特征,最后采用差分进化算法优化后的RBF神经网络对异步电动机运行状态信号特征进行诊断。实验结果表明,与未优化的RBF神经网络相比,采用差分进化算法优化后的RBF神经网络可有效识别出异步电动机故障。     

一种异步电动机故障诊断新方法

针对基于RBF神经网络的异步电动机故障诊断方法存在参数确定较困难的问题,提出了一种基于差分进化算法优化RBF神经网络的异步电动机故障诊断方法。首先采用小波变换对异步电动机运行状态信号进行消噪处理,然后采用主元分析法与小波包分析法相结合方式提取消噪后的异步电动机运行状态信号特征,最后采用差分进化算法优化后的RBF神经网络对异步电动机运行状态信号特征进行诊断。实验结果表明,与未优化的RBF神经网络相比,采用差分进化算法优化后的RBF神经网络可有效识别出异步电动机故障。     

基于信息融合的异步电动机故障迹象智能预测系统的研究

异步电动机故障机理较复杂,利用单个信息只能判断异步电动机系统可能在某些方面有故障征兆,结论具有一定的不确定性,特别是异步电动机在早期有劣化迹象时,各个方面的表现都比较弱,需要全面综合众多信息进行有效融合。针对上述问题,提出了一种基于信息融合的异步电动机故障迹象智能预测系统的设计方案,分析了D-S证据理论的原理,并在其基础上给出了基于单个信息和基于多个信息融合的异步电动机故障诊断结果。实际应用表明,该系统具有一定的有效性。     

斩控式三相异步电机节能控制器的设计

本文针对三相异步电动机在轻载或空载的状态下运行时会出现的电动机功率因数变小、效率降低、电能浪费严重等问题,在分析斩控调压节能原理的基础上,提出了斩控式异步电动机节能控制器的设计方法,并对斩控式异步电动机节能控制器的主电路和PI控制器进行了设计.     

基于组态技术的三相异步电动机变频调速方法

研究组态技术在三相异步电动机变频调速问题中的应用,以合理调节三相异步电动机转速为宗旨,提出基于组态技术的三相异步电动机变频调速方法.建立基于单滤波器多模型算法的转速数据可视化挖掘组态模型,估计三相异步电动机转速后,使用基于P1控制器的异步电动机转速调节方法,在负载恒定已知、负载转矩有扰动的条件下,通过对应调速控制器实现三相异步电动机变频调速.实验结果显示:所提方法的转速估计值与实际转速值高度一致,估计精度较高;对三相异步电动机变频调速后,三相异步电动机转速和期望转速仅存在1r/min之差.上述方法对三相异步电动机的转速估计、调速效果均优于对比方法.     

基于神经网络的异步电动机故障诊断专家系统的研究

针对传统的专家系统在对异步电动机进行故障诊断时知识获取困难且无法解决新故障的问题,提出了一种基于神经网络的异步电动机故障诊断专家系统的设计方案,给出了系统结构及神经网络模型设计。仿真结果表明,该系统能够很好地结合专家系统与神经网络的优势,达到了异步电动机故障诊断的预期目标。     

三相异步电动机发热原因分析与对策

三相异步电动机由于结构简单、价格低廉、维护方便等优点被广泛应用于现代企业中。电动机发热问题与其安全运行息息相关,本文对三相异步电动机发热的主要原因做了比较详细的分析,并为采取合理的对策提供了理论依据。     

异步电动机低速直接转矩控制的建模与仿真

研究电动机低速转矩控制问题,针对电动机直接转矩控制低速性能响应不好的问题,影响了异步电动机在低速范围内的应用,为解决上述问题,增加异步电动机的应用范围,提出一种U-I模型的定子磁链观测和补偿的新方法,以提高低速性能.利用matlab工具箱中的电力系统模块建立了直接转矩控制系统的仿真模型,并进行了仿真.仿真结果表明对直接转矩控制系统的低速性能的改善有明显的效果,为拓展异步电动机在低速范围内的应用,提供了理论基础.     

逆变并网中LCL无源阻尼分裂电容设计

与传统的L型和LC型滤波器相比,LCL型滤波器具有高频衰减效果好、输出电流谐波小的优点,但是易出现电压和电流振荡尖峰,破坏系统的稳定性。本文采取在电容上串联电阻来改善振荡问题,同时针对电容上串联阻尼电阻之后带来的功率损耗问题,引入了无源阻尼分裂电容的方法。该方法首先将LCL滤波器的电容分裂成两部分,其容量和与完全电容相同;然后根据滤波器谐振频率处幅值增益和阻尼电阻的功率损耗来设计电容比例,将阻尼电阻与小电容串联;最后进行储能变流器逆变并网仿真,实验结果证明LCL无源阻尼分裂电容可以抑制并网电压和并网电流的幅值增益,相比完全电容法明显降低了电容支路上阻尼电阻带来的功率损耗。     

基于ARMA模型的工业电容退化状态研究方法

随着中国制造2025计划的推广,工业电源正处于高速发展期,大型铝电解电容的需求越来越大.电容的故障会令工业流水线中断,产生极大的损失,因此工业电容的寿命预测（RUL）具有重要意义.本文通过对铝电解电容充电状态EIS频谱分析,建立电容的状态的量化模型.根据电容状态量化数据,建立ARMA电容退化预测模型.最后通过美国航天航空局的等效串联电阻EIS频谱数据集进行验证.结果表明ARMA电容退化模型对铝电解电容的状态预测有很大的准确性.     

Dynamic power stabilization model for improved conduction and switching loss using boost rectifiers

The power stabilization is the key issue considered in electric circuits in recent days. The growing use of electricity increases the requirement of stabilized power supply to the devices. Towards this, various stabilization models are presented earlier with different converters and rectifiers. However, they suffer to produce high stabilized power supply to the circuits and devices. To improve the performance, an efficient dynamic power stabilization model with reduced conduction/switching loss is presented in this paper. Initially, the converter switches the incoming voltage in the series of conductors and maintains the output voltage. Consider the incoming voltage is IV_i, then it has been regulated through a series of diodes and capacitors. At each parallel circuits, there exists a diode and capacitor which is capable of storing incoming voltage and enables to boost of the incoming voltage to step up to produce a higher voltage. A MOSFET is designed to control the output voltage to produce a steady voltage supply. It maintains the incoming and output voltage from different diodes. Based on the required voltage level, it triggers the conditions and triggers the circuits to maintain the voltage stability. As the MOSFET attached to the circuit maintains the conditions of capacitors and inductors in the previous cycle with the voltage available in each component, it performs power stabilization approximation, and according to that, a set of series circuits are switched to produce steady voltage. The parallel circuits are activated only when the input voltage is up to the required output voltage. Otherwise, the series circuit has been triggered to produce output voltage at the required level. Each series circuit has been embedded with a capacitor which is capable of storing incoming voltage and boost them to the higher voltage. The proposed method has increased the efficiency of boost rectifiers and produced efficient results than previous methods.     

2–6 GHz GaN distributed power amplifier MMIC with tapered gate‐series/drain‐shunt capacitors

In this article, using a 0.25 μm GaN HEMT process, we present a 2–6 GHz GaN two‐stage distributed power amplifier MMIC that utilizes tapered gate series capacitors and nonuniform drain transmission lines with tapered shunt capacitors to simultaneously obtain a linear gain enhancement and optimum load line for each transistor. By using well‐derived equations to provide each transistor with the optimum load impedance and to tune the phase delay between the input and output transmission lines, the nonuniform distributed power amplifier is designed for second‐stage amplification, and satisfactory performance is demonstrated. The phase balance and tapering of the gate series capacitors have a role in improving the linear gain of the two‐stage amplifier. The measured data show a linear gain of 22 ± 1 dB, an input/output return loss of more than 15 dB, saturated output power of 41.2–43.1 dBm under a continuous‐wave mode, and a power‐added efficiency of 18–22% from 2 to 6 GHz which are very competitive values compared with previous works. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:456–465, 2016.     

基于滞环电流控制的模块化多电平脉冲整流器及其仿真

本文介绍了一种全新的模块化三电平整流电路拓扑结构，这种三电平整流电路由两个串联的全桥整流臂组成，可以被高度模块化地做成多电平整流器，作者对其中的三电平整流电路的工作状态进行了详尽的分析。仿真结果验证滞环电流控制法可以减小整流器输入电流的谐波畸变并实现输出端两个串联电容器的电压平衡。     

基于改进串联合闸电阻的变压器励磁涌流抑制研究

在利用合闸电阻抑制变压器轻载或空载合闸时产生励磁涌流的基础上,提出一种在合闸电阻上串联适当电容器的改进方法。该方法在原有的合闸电阻上串联电容,通过适当选取电容的容值,以减少励磁涌流的大小,加快励磁涌流的衰减速度。将该方法与分相合闸技术相结合,可最大程度实现变压器励磁涌流的抑制。仿真实验结果验证了该方法的可行性。     

New EBG of CSRR with lumped capacitors applied to oscillator harmonics suppression

In this article, a compact electromagnetic band‐gap (EBG) structure is presented to reject harmonics of a crystal oscillator in the power distribution network. Compared to traditional EBG structures of complementary split ring resonator (CSRR), the proposed CSRR adding lumped capacitors (LC‐CSRR) provides a higher rejection‐performance at the series self‐resonant frequency of the lumped capacitors. A four‐layer printed circuit board is designed and fabricated to measure the S‐parameters of the proposed EBG structure, and a harmonics power testing board is presented to measure rejection performance of the proposed EBG structure. The measured results show that the proposed EBG obtains an attenuation of 60 dB over the whole range of global navigation satellite system band. By inserting the proposed EBG structure of LC‐CSRR, we measure that the harmonics powers can be decreased by 28.8 dB between the input and output of the EBG.     

A magnetoelectric energy harvester and management circuit for wireless sensor network

This paper presents an electromagnetic energy harvesting scheme by using a composite magnetoelectric (ME) transducer and a power management circuit. In the transducer, the vibrating wave induced from the magnetostrictive Terfenol-D plate in dynamic magnetic field is converged by using an ultrasonic horn. Consequently more vibrating energy can be converted into electricity by the piezoelectric element. A switching capacitor network for storing electricity is developed. The output of the transducer charges the storage capacitors in parallel until the voltage across the capacitors arrives at the threshold, and then the capacitors are automatically switched to being in series. More capacitors can be employed in the capacitor network to further raise the output voltage in discharging. For the weak magnetic field environment, an active magnetic generator and a magnetic coil antenna under ground are used for producing an ac magnetic field of 0.2–1 Oe at a distance of 25–50 m. In combination with the supply management circuit, the electromagnetic energy harvester with a rather weak power output (about 20 μW) under an ac magnetic field of 1 Oe can supply power for wireless sensor nodes with power consumption of 75 mW at a duration of 620 ms.     

基于PLC的自动控制实验平台设计

针对目前过程控制教学中往往采用电子电容模拟控制过程,提出一套基于PLC的面向实际被控对象的实验平台设计方案.介绍了三菱Q系列PLC和GOT组态软件应用于该平台系统的设计和实现方法.实际运行表明,该实验平台效果良好.     

半导体激光器驱动电路的计算机仿真分析

直接调制的大电流窄脉宽驱动电源是半导体激光器获得高峰值功率输出的重要保证.为了研究半导体激光器驱动电路,提高系统的精度和抗干扰能力,采用计算机仿真的方法分析了半导体激光器脉冲电源基本电路和雪崩晶体管脉冲电源电路.通过仿真结果表明,脉冲电源中元件的寄生电感及串联电阻对激光器工作电流脉冲的波形影响很大.当奇生电感小时,放电电流波形的上升时间就短.可为设计半导体激光器驱动电路时,提供选取R、C、L的依据,并保证工作在欠阻尼的情况下,要获得最大的放电电流,储能电容器上的充电电压要高,使电路的串联电阻尽量要小.