单相自激式异步发电机负载并联电容恒压研究

提出采用负载并联电容方法解决单相自激式异步发电机输出电压不稳的难题。给出了并联电容值的确定方法．通过实验验证了该方法的正确性。     

逐波机电王国巾帼不让须眉--记后勤工程学院副教授、全军后勤重大科技成果奖获得者王维俊

王维俊,女,副教授,1964年3月生于湖北武汉,1986年从重庆大学特种电机专业毕业后被分配到解放军后勤工程学院任教;1996年获得重庆大学硕士学位.后一直在解放军后勤工程学院自动化系从事教学与科研工作,现任系电工电子教研室副主任,研究生导师。 科研成果:1990年至1999年在科研工作方面,先后负责并完成了“单相自激式异步发电机—电动机体系研究”、“单相自激式异步发电机研究”、“发电机带动态负载能力的研究”、“变压器节能论证”、”电机风冷系统研究”、”多功能防盗报警系统研究”、“红外/微波探测器研究”、“高速异步电机论证”共八项科研项目.获一项全军科技进步一等奖,两项科技进步三等奖,一项“九五”全军重大科技成果奖,两个项目经专家认定,已达到国际先进水平,有国家公开发明专利两项。在国内外期刊及学术会议上共发表论文30多篇。     

高效能单相异步发电机的简化分析方法

本文应用双旋转磁场理论对高效能单相异步发电机进行了分析,证明单相异步发电机只能获得负序圆形旋场,推导出为获得圆形旋转磁场主副绕组有效匝比K与负载功率因数cosψ的关系。研究转速不变情况下,为保证电压恒定,电容C与频率f的变化规律,并计算在允许电压调整率及频率变化范围内,单相异步发电机带纯电阻负载时的最大输出功率。关键词:双旋转磁场单相异步发电机     

阻感性负载下单相离网逆变器稳定性分析与控制

独立运行的单相全桥逆变器通常工作于电压源模式,将直流源侧能量传送至交流负载侧。由于负载的多样性,系统具有复杂的动态特性。阻感性负载(如电机、空调等)连接至逆变器交流输出时,系统出现振荡失稳现象。首先,建立单相逆变器系统数学模型,并结合比例-谐振(PR)控制器特征对模型进行线性化处理,得出了单相逆变器系统的输出阻抗表达。其次,采用阻抗比判据方法,绘制阻抗比的奈奎斯特曲线,确定了系统不稳定运行的拒绝域,从而解析性地得到了感性负载、控制系数、滤波电容等对拒绝域的影响。结果表明,在实际运行参数范围内,随逆变器的比例系数、滤波电感的减小,或者滤波电容、滤波电感串联电阻的增大,阻感性负载下的单相逆变器趋于稳定,可得到稳定的输出电压波形。     

带感性负载时三相永磁同步发电机电压特性及设计研究

对带感性负载三相永磁同步发电机的电压特性进行了研究分析,提出了合理设计电机参数可有效减少电压变化率的永磁同步发电机设计理论。对不同xd/xq比值的永磁同步发电机的电压变化率进行了仿真计算,设计了一台12kW三相永磁同步发电机样机,实际结果验证了设计理论的有效性及实用性。     

自激异步发电机投切负载的暂态过程分析

投切负载是异步发电机运行中的重要暂态过程,对其进行分析可以为优化电机运行方案和合理设计电机保护措施提供理论支持。以异步发电机ab0坐标系下的暂态等值电路为基础,列写异步发电机空载运行和带电阻负载运行情况下的自治状态方程。首先用非线性电路理论判断自治状态方程稳定性,再用4阶Runge-Kutta法分别求解投切负载时的状态方程,得到各状态变量的瞬时数值。把计算数据从ab0坐标系转换到abc坐标系下,根据各时刻数值画出波形得到异步发电机投切负载时的暂态过程。给出相一致的实验结果和仿真计算结果,验证了所用分析方法的正确性。     

单相异步发电机在小风力机中的应用

单相异步发电机有许多优点，最大缺点是电压随负载变化波动很大，对实际使用的带来不少困难，本文提出了单相异步发电机设计特点及其稳压方法，实验结果表明，小型风力机配套发电机单相异步发电机有前途的。     

阳光电源太阳能并网逆变器成功中标武汉新火车站项目

近日，河北凯翔科技有限公司为泰安伊万福电机有限公司生产了一套阻感一体式发电机组测试系统，目前验收合格后已运抵需方交付使用。该测试系统主要用于测试发电机组的输出功率与带载能力，发电机测试系统由测试台，感性负载柜，     

对感性负载运行节电的分析

经过多年实践，我们认为提高感性负载的负荷率，实行满负荷运行是降低负载无功功率，提高功率因数的最简便最有效的方法。在电力系统中，大部分用电设备为感性负载，其消耗电网的无功功率，异步电动机约占总数６０％以上，变压器占２０％左右，其余为架空线、整流设备、电抗器等。设计时电动机最高效率大约出现在７５％额定电流处，而功率因数却在额定电流附近最高；变压器负荷率在５０％～１００％时效率可达９５％以上，功率因数也是在这样的负载率下最高。因此，提高感性负载的负荷率，使它们运行时接近或达到设计要求是降低设备无功功率…     

高效能单相异步发电机

本文根据单相异步发电机有负载、励磁和调磁三项功能系统的实际情况,较全面地分析了如何协调它们,合理设计以获得性能优异的单相异步发电机。     

Fuel-efficient Induction Generator Based Diesel Generator Set for Stand-alone Supply Systems

This article proposes a fuel-efficient, diesel engine driven, self-excited induction generator based diesel generator set for stand-alone supply systems. The system uses a static compensator along with a battery energy storage system. The static compensator with a battery energy storage system provides the voltage control, load compensation, harmonics elimination, load balancing, and reactive power compensation. The fuel efficiency of the generator is improved by loading the generator continuously between 80% and 100% of its rated capacity. The battery energy storage system takes the power from the generator during light load periods and supplies the power to the load during overloads. In addition, a continuous loading of the generator eliminates the problem of frequency variation of the induction generator under varying loads. The proposed system is designed to feed both three-phase as well as single-phase loads. A zigzag transformer is used for neutral current compensation. A power balance theory based control algorithm has been used to estimate the reference source currents.     

Smith联接的单相自励感应发电机

针对需要单相电源的场合时有采用三相异步电机自动单相运行这种工况,对自励发电运行方式进行了分析.利用对称分量法导出了Smith联接的单相自励感应发电机对称运行条件及性能计算公式.计算表明:Smith联接的三相感应电机单相自励发电运行时,电压变化率较大,且离开平衡点负序电流迅速增加;利用最优化方法确定三相自励感应发电机不对称运行时的稳态工作点简单有效.实验结果与理论计算基本一致.     

Smith联接的单相自励感应发电机

针对需要单相电源的场合时有采用三相异步电机自动单相运行这种工况，对自励发电运行方式进行了分析。利用对称分量法导出了Smith联接的单相自励感应发电机对称运行条件及性能计算公式。计算表明：Smith联接的三相感应电机单相自励发电运行时，电压变化率较大，且离开平衡点负序电流迅速增加；利用最优化方法确定三相自励感应发电机不对称运行时的稳态工作点简单有效。实验结果与理论计算基本一致。     

Operating performance of static series compensated three-phase self-excited induction generator

The performance of three-phase self-excited induction generator (SEIG) is investigated with static synchronous series compensator (SSSC) and static compensator (STATCOM) to feed static and dynamic loads. The employed compensators are three-phase, Insulated Gate Bipolar Transistor (IGBT) based, Pulse Width Modulation (PWM) operated, Current-Control Voltage Source Converter (CC-VSC). The proposed control techniques employ proportional-integral (PI) controller to generate the reference current. With the designed parameters and control, the SSSC is found effective to regulate load voltage during sudden change of the loads. The SSSC also provides stable operation with dynamic induction motor load and mitigates the unstable and oscillating behavior that is resulting during the operation of compensated SEIG with dynamic motor load. The presented results prove that both SEIG–SSSC and SEIG–STATCOM systems provide satisfactory performance.     

Fundamental characteristics of a brushless and self-excited sinusoidal-wave single-phase synchronous generator having a two-phase field winding excited by a half-wave rectified current

It is desired from the viewpoints of maintenance and construction to make single-phase synchronous generators of brushless and self-excited types. A novel brushless and self-excited single-phase synchronous generator was devised by one of the authors. The stator exciting current is made to flow simultaneously with the load current in the armature winding. Thus, the iron core for the magnetic circuit can be both for the synchronous generator itself and for the exciter. Experimental studies of the brushless and self-excited single-phase synchronous generator of which the rotor winding is used as a rotor exciting winding and a field winding are described in this paper. In the proposed generator, the rotor is provided with a balanced two-phase field winding to improve the voltage wave distortion. The terminal voltage of this generator can be kept constant in spite of the load variation. Therefore, the proposed synchronous generator can be expected to be used widely.     

自励异步发电机负载对端电压和频率的影响

从异步发电机稳态运行的等效电路数学模型出发，推导了回路阻抗方程，令回路阻抗值为零，作为异步发电机稳定运行的条件。利用变量轮换直接优化方法计算励磁电抗和定子频率，进而计算出不同负载下的端电压值。此法稳定性好且编程简单。给出了异步发电机的端电压和定子频率随负载变化的曲线以及外特性曲线。计算结果说明负载对异步发电机的端电压影响较大，而对定子频率影响较小，且影响随负载性质改变而不同。计算结果与实验结果的一致性说明了分析方法的准确性。     

自励异步发电机负载对端电压和频率的影响

从异步发电机稳态运行的等效电路数学模型出发,推导了回路阻抗方程,令回路阻抗值为零,作为异步发电机稳定运行的条件。利用变量轮换直接优化方法计算励磁电抗和定子频率,进而计算出不同负载下的端电压值。此法稳定性好且编程简单。给出了异步发电机的端电压和定子频率随负载变化的曲线以及外特性曲线。计算结果说明负载对异步发电机的端电压影响较大,而对定子频率影响较小,且影响随负载性质改变而不同。计算结果与实验结果的一致性说明了分析方法的准确性。     

Dynamic behavior of a single-phase self-excited induction generator using a three-phase machine feeding single-phase dynamic load

This paper is motivated to analyze the transient behavior of a single-phase self-excited induction generator (SEIG) using a three-phase machine due to switching of single-phase dynamic load like induction motors. The generator consists of a three-phase star connected induction machine excited with three-capacitors and a single-phase induction motor (IM) load. The developed dynamic models of the SEIG and the motor are based on stationary reference frame d–q axes theory incorporating the effect of cross-saturation in the magnetic circuit of the machine and the equations of excitation capacitors are described by three-phase abc model. The system suffers from heavy transients during switching of induction motor and becomes unstable. These problems may be due to resonance caused by series capacitors and the inductive motor load. The use of damping resistors across one series capacitor is proposed to damp out the starting transients for the stable operation. The motor can be started up successfully using the damping resistor. The variation of the damping resistance with the increase in load on the motor after successful starting to maintain constant terminal voltage has been presented. The eigenvalue technique is also employed to examine the transient conditions in the studied SEIG-IM system. The simulated and experimental results are presented for both the unsuccessful and successful starting of the motor. These results are in close agreement with each other, which show the effectiveness of the approach.     

Improved Steady State and Transient Performance With Optimum Excitation of Single-Phase Self-Excited Induction Generator

This article deals with the performance prediction and analysis of the two winding single-phase self-excited induction generator (single-phase SEIG). A methodology of selection of capacitors for optimum excitation of the single-phase SEIG scheme is explained. Appropriate dynamic model of the system is developed incorporating the cross-saturation effect. This dynamic model is used for simulating realistic transients, such as no-load and on-load excitation, load perturbation, short-circuit condition, and re-excitation. Simulation results are confirmed by experimental investigation, thus providing verification of the derived model. The results are analyzed to obtain useful guidelines toward system improvements under such transients.