变频器谐波问题的探讨

从谐波的概念入手，结合变频器的内部结构的相关知识，详细地分析了变频器谐波产生的原因及其危害，提出了抑制谐波的常用方法，提出了可供参考的解决方案。     

电力系统电能质量的测试与治理

通过对35kV配电系统电能质量的定量测试与分析,提出了无功补偿的治理方案并加入实施,提高了功率因数,避免了系统谐振,改善了电网质量。     

天钢集团中板厂SVC动态无功补偿和谐波滤波系统

天津钢铁集团中板厂的负载为冲击性交-交变频机,交-交变频机的谐波除了特征谐波外,还有大量旁频。电网中谐波电流大,功率因数低,电压波动超标。SVC系统为FC TCR系统,通过测试负载电流和普通直流机负载电流,分析频率特性,得出交交变频机的谐波滤波可以按照直流机的滤波装置来设计,同时TCR本身产生的谐波必须予以考虑。     

Optimal bounded control of harmonically and stochastically excited strongly nonlinear oscillators

A procedure for designing optimal bounded control to minimize the response of harmonically and stochastically excited strongly nonlinear oscillators is proposed. First, the stochastic averaging method for controlled strongly nonlinear oscillators under combined harmonic and white noise excitations using generalized harmonic functions is introduced. Then, the dynamical programming equation for the control problem of minimizing response of the systems is formulated from the partially completed averaged Itô equations by using the dynamical programming principle. The optimal control law is derived from the dynamical programming equation and control constraint without solving the dynamical programming equation. Finally, the stationary probability density of the amplitude and mean amplitude of the optimally controlled systems are obtained from solving the reduced Fokker–Planck–Kolmogorov equation associated with fully completed averaged Itô equations. An example is given to illustrate the proposed procedure and the results obtained are verified by using those from digital simulation.     

三相电压型低谐波PWM整流器主电路参数间的关系

三相电压型低谐波PWM整流器主电路的多个参数之间的关系较为复杂，在仿真和实验中，若给出的参数不合理，则变换器不能正常工作，从而给仿真和实验带来一定困难。文章在考虑了输入电阻的情况下，给出了功率因数角为任意值时，主电路各参数和控制参数间的稳态关系及一些参数的约束关系。上述关系对于分析和设计被研究电路具有很好的指导意义，文中的公式通过了仿真验证。     

Reasoning about Action Systems using the B-Method

The action system formalism has been succesfully used when constructing parallel and distributed systems in a stepwise manner within the refinement calculus. Usually the derivation is carried out manually. In order to be able to produce more trustworthy software, some mechanical tool is needed. In this paper we show how action systems can be derived and refined within the B-Toolkit, which is a mechanical tool supporting a software development method, the B-Method. We describe how action systems are embedded in the B-Method. Furthermore, we show how a typical and nontrivial refinement rule, the superposition refinement rule, is formalized and applied on action systems within the B-Method. In addition to providing tool support for action system refinement we also extend the application area of the B-Method to cover parallel and distributed systems. A derivation towards a distributed load balancing algorithm is given as a case study.     

一种消除强谐波干扰的有效方法

谐波干扰是一种常见的干扰。本文提出了一种消除强谐波干扰的方法，它实现简单、速度快，尤其适用于对速度和实现有限制的场合。仿真结果证明了该方法消除谐波干扰和进行谐波恢复的有效性。     

酒精代谢的数学分析

本文从生物学角度出发,根据微分方程理论.结合给定的数据,经过合理的假设,建立了血液中酒精的浓度随时间变化的基础模型。并针对不同的饮酒方式和饮酒量,分别建立了相应的模型。用拟合的方法确定参数,准确地模拟出酒精浓度变化趋势的曲线,拟合结果与原始数据吻合程度较高。同时,对一些实际问题也给出了合理的解释。     

三次谐波检测无刷直流电机转子位置的研究

论述了一种用三次谐波检测转子位置的新方法。与传统的反电动势法检测转子位置相比较，三次谐波法实现简单，可检测速度范围更宽，不需要深度滤波。文中抛弃了将三次谐波直接输入DSPA／D口的传统做法，而是将反映三次谐波相位信息的方波输入DSP的I／O口，利用DSP强大的数据处理功能，提出了用软件实现数字锁相功能和对换相时刻的准确估计，去除了传统的硬件积分方法；提出用模拟相电压代替传统的端电压作为辅助检测信号；从而简化了硬件电路，提高了转子位置估计的精度和可靠性。实际试验表明，这种方法能够准确而快速的估计转子位置，动静态特性良好，整个系统结构紧凑，可靠性高。     

高效全固化钛宝石腔内倍频蓝光和四倍频紫外激光器的研究

用半导体抽运的Q开关YLF倍频激光器抽运钛宝石晶体，在平凹腔内加入组合的石英双折射滤光片压缩线宽，用LBO晶体腔内激发二次谐波，聚焦到BBO上产生四次谐波深紫外光。在抽运功率3．8w时，输出610mW．416nm蓝光。用长焦距的透镜聚焦二次谐波．得到64mW，208nm的紫外激光。基频光的谱线宽度是决定倍频效率的关键因素。实验观察到激光器的频谱宽度与双折射滤光片的带宽有一个数量级的差别，考虑到模式竞争和增益饱和效应，数值模拟了加入双折射滤光片后的钛宝石激光器的实际线宽，结果与实验中测量的数据基本一致。实验还分析了基频光的线宽对二次谐波效率的影响、二次谐波的线宽对四次谐波效率的影响、基频光的波长对四次谐波激发效率的影响。