基于改进BP神经网络非正弦供电下异步电动机转速估计

非正弦供电下异步电动机电压、电流和功率都比较难以确定，电压、电流波形发生严重的畸变，含有大量的谐波，对于非电气量的转速易受到大量谐波的干扰，脉动比较严重，准确地测定比较困难，传统的测速方式成本高，需要维护，不经济，但对于电动机的电压、电流容易通过PT和CT获取，易实现转速的在线估算和测量，本文提出了改进的BP神经网络来训练非正弦供电下异步电动机机端电压、电流、功率因数和转速之间的复杂映射关系，并了改进的BP算法，仿真结果和试验结果证明了利用此神经网络的软测量技术来估计转速达到了较高的精度。     

非正弦条件下无功功率定义分析与展望

非正弦电路中,有功功率定义已被公认,无功功率的定义却一直还没有定论。本文描述了在非正弦波形下有关无功功率的三种定义,其一是时域分析法,其二是频域分析法,其三是三相电路瞬时无功功率;对已提出的一些无功功率定义做了详细的分析和评述;最后总结了新的无功功率理论应该满足的要求。     

结晶器非正弦振动曲线的傅立叶级数解

根据薄板坯连铸机结晶器的振动波形解出了一种非正弦振动曲线的级数表达式 ,并进行了分析     

降低基于PSWF的非正弦调制信号PAR方法

针对基于椭圆球面波的非正弦调制信号峰均功率比大的问题,提出了降低峰均功率比方法。该方法根据基于椭圆球面波的非正弦调制符号时域特性,通过选择峰均功率比小于期望值的调制符号进行传输,从而达到降低调制信号峰均功率比的目的。理论分析和仿真结果表明,该方法不仅有效降低了调制信号的峰均功率比,而且不会降低通信系统的误码性能,也不会导致调制信号功率谱展宽和功率谱集中度变差。     

Optimal C-Type Filter Design to Maximize Transformer's Loading Capability under Non-sinusoidal Conditions

The main purpose of this article is to employ the C-type passive filters for maximization of the loading capability of transformers under non-sinusoidal conditions. For this aim, an optimal passive filter design approach is proposed regarding minimization of the harmonic loss factor (F_HL), which is defined in IEEE standard C57.110 to represent the loading capability of the transformers supplying non-sinusoidal load currents. With respect to IEEE standard 519, displacement power factor and individual harmonics & total harmonic distortions of the voltage and current are considered as constraints of the proposed optimal filter design approach. In addition, numerical results are presented to figure out that the proposed approach provides higher loading capability of the transformers under non-sinusoidal conditions when compared with the other two optimal filter design approaches based on minimization of the current total harmonic distortion and minimization of the voltage total harmonic distortion.     

Single Source Hybrid Drive for Multi-Functional Ultrasonic Motor

We previously reported a multi-functional single-stator piezoelectric motor, which can produce translational or rotary motions in a simple structure. In this paper, we will present the theoretical analysis and experimental verification of the hybrid driving technique for this motor. In order to benefit from the resonance operating conditions of ultrasonic motors and the structural superiority of inertial type piezoelectric motors, we blend these two drive methods as the new hybrid technique. Translational and rotary motions of mobile element are produced by inertial drive while the stator is excited with rectangular signals at longitudinal and torsional resonance frequencies, respectively.     

电动伺服非正弦振动系统在板坯连铸机上的应用

介绍了连铸机振动装置的发展趋势。由于电动伺服非正弦振动系统具有高同步性、精密控制、运行可靠、维护方便、节能等优点,在板坯连铸机使用后可较好地改善板坯质量,提高产量。     

基于C8051F单片机的非正弦波功率表的研制

提出了一种以C8051F高速片上系统单片机为核心的非正弦波功率表的设计。分析了它的测量原理,并进行了误差分析。它具有成本低,频率范围宽,测量精度高等特点。     

连铸结晶器非正弦振动系统模糊神经网络跟踪控制

针对结晶器非正弦振动液压伺服系统参数易变、模型不确定这一特点，对模型未知的系统用神经网络模型逼近，并采用改进的递阶遗传算法对神经网络的权值和结构同时进行训练，实现系统模型的精确辨识；将模糊控制与神经网络相结合，提出一种模糊神经网络控制方法，实现连铸结晶器非正弦振动系统的跟踪控制。仿真验证了该方案能提高非正弦振动系统跟踪控制性能和鲁棒性，且易于工程实现。     

非正弦时域正交调制性能分析及仿真

给出基于时限椭圆球面波函数的非正弦时域正交调制解调的数学模型,从理论上推导调制信号的频带利用率、功率谱特性以及AWGN信道下的差错性能,给出功率谱及误码率的数学表达式,进行仿真并与理论推导结果进行比较,验证理论推导的正确性,为通信系统设计和应用提供理论和实验依据。