一种改善永磁同步发电机电压调整率的方案设计

针对永磁同步发电机无法通过调节励磁来调节输出电压的缺点,在永磁发电机的定子绕组上设计一套补偿绕组,当负载电流变化从而改变发电机的输出电压时,通过调节辅助励磁装置改变补偿绕组中电流的大小和方向,以抵消负载变化时电枢反应对气隙磁场的影响,从而保持输出电压的恒定,降低电压调整率.仿真计算表明,该方法可行.     

六相永磁同步发电机的整流稳压电路仿真

针对六相永磁同步发电机励磁不可调,转速的变化和负载电流的变化都将造成输出电压不稳定的缺点,对六相永磁同步发电机发出的六相交流电采用带平衡电抗器的双三相全控桥并联的开关式稳压整流电路进行整流,控制方式采用闭环控制,使得整流输出直流电压恒定,不随着发电机转速和负载电流的变化而变化.利用Matlab的Simulink和PSB两个工具箱建立了六相永磁同步发电机的整流稳压电路仿真模型对该整流电路进行了仿真.仿真结果表明该稳压整流电路输出直流电压值不随发电机输出电压变化而变化,负载电压稳定时间快、无尖峰、脉动小.     

稀土永磁同步发电机电辅助复合励磁系统的研究与设计

稀土永磁同步发电机具有结构简单、效率高等特点,但是在 d 轴电枢反应的作用下,永磁体的工作点产生动态变化,引起电压调整率要比电励磁发电机的电压调整率大得多.本文研究稀土永磁同步发电机电辅助复合励磁的系统,利用发电机输出端电压作为取样反馈信号,调节电辅助励磁电流,补偿 d 轴电枢反应.通过典型规格(7.5kVA)的样机实测表明,采用复合励磁的方法可以减小稀土永磁同步发电机电压调整率、提高运行性能.     

发电机负载能力差故障一例

一台200kW的柴油发电机组,经过大修,调试时,发现发电机负载能力差,即发电机一旦加上负载,其发电机端电压下跌。下面介绍这一故障的检修思路,供大家参考。 从电机学原理知,同步发电机端电压与驱动发电机转子的柴油机转速以及励磁电流相关。励磁电流不变时,发电机端电压随柴油机转速增加而增加;当柴油机转速不变时,发电机端电压随励磁电流的增加而增长。当负载增加时,柴油机转速必下降,为了保持发电机端电压不变,须增加励磁电流。自励恒压装置(见附图)就是使发电机端电压保持恒定的电器装置。     

永磁同步电机对拖试验电压降低问题研究

大型永磁同步电动机(PMSM)对拖做负载试验时,由于作为发电机运行的PMSM端电压随负载电流增加而降低,端电压低于负载回馈的电网侧电压导致无法继续加载的问题,本文提出永磁同步发电机输出端并联电容器的方法,以补偿因电机感性回路中滞后的无功电流导致的发电机端电压下降。根据发电机定子绕组电流计算直轴去磁电流Id,定量计算无功补偿的电容值,既可以满足PMSM加载的需求,也可以避免投入电容量过大导致发电机端电压过高对电机绝缘材料寿命的影响;建立了带电容补偿的PMSM对拖测试的仿真模型。仿真结果表明,电容补偿值计算正确,能有效升高发电机的端电压,实现PMSM的平稳加载。与其它加载方法相比,该方法工程造价低,并能够实际应用于PMSM的性能测试。     

电抗移相相复励励磁系统原理及设计

图1是常用的电抗移相相复励励磁系统(下简称相复励)线路图。电流互感器(4)付边提供的电压,与负载电流相对应,线性电抗器(3)把电枢绕组抽头电压或端电压移相约90°,和(4)提供的电压几何相加,经过桥式整流器(5)整流。给发电机的励磁绕组(2)供电。当发电机空载时,通过线性电抗器(3)提供励磁电源,建立空载电压;负载时,由(4)供给所需要的复励电流,进行电流补偿,由(3)移相,进行相位补偿,从而抵销负载电流电枢反应的去磁作用,保持电机端电压恒定。     

复合励磁稀土永磁同步发电机辅助电励磁部分的研究与设计

复合励磁稀土永磁同步发电机是一种能解决永磁发电机电压调节问题的新型发电机。该发电机转子由永磁发电机部分和辅助电励磁部分组成,它们共有一个电枢绕组。辅助电励磁部分采用爪极式结构,与永磁体同轴向,通过调节其磁场可调节输出电压,以达到稳定端电压的目的。探讨了该发电机辅助电励磁部分的基本结构和设计方法。实验分析表明,该辅助电励磁部分具有良好的调压功能,能实现端电压的稳定输出。     

复合励磁永磁同步发电机研究

0 引言 随着第三代永磁钕铁硼的热稳定性和耐腐蚀性的改善,以及价格的降低,世界各国都在开发民用的稀土永磁发电机。对于一般的稀土永磁发电机,由于稀土永磁体的高矫顽力使发电机的输出电压无法调节,当负载或转速变化时,这类发电机保持恒压是比较困难的,因此电压调节困难阻碍了永磁发电机的技术发展和应用。而普通电励磁同步发电机由于可以方便地调节直流励磁。所以在磁场调节方面具有永磁发电机达不到的优势。     

复合励磁稀土永磁同步发电机辅助电励磁部分的研究与设计

复合励磁稀土永磁同步发电机是一种能解决永磁发电机电压调节问题的新型发电机。该发电机转子由永磁发电机部分和辅助电励磁部分组成，它们共有一个电枢绕组。辅助电励磁部分采用爪极式结构，与永磁体同轴向，通过调节其磁场可调节输出电压，以达到稳定端电压的目的。探讨了该发电机辅助电励磁部分的基本结构和设计方法。实验分析表明，该辅助电励磁部分具有良好的调压功能，能实现端电压的稳定输出。     

GEC 900MW发电机自动励磁调节器简介

自动励磁调节器(AER)提供和调节主励磁机磁场的励磁电流,以调节主发电机端电压。该AER有A、B两个通道,每个通道(包括一个外电压和一个内电流回路)能够满足发电机端电压的全部调节。AER的三相电源是由PMG永磁机(与励磁机装在同一轴上的副励磁机)提供。现将有关回路简介于下。a.参考电压电路该电路同时提供一个稳压源给相加点和一个供运行人员调节的电动变阻器(70V)。自动励磁调节电位器一实现参考电压定值为发电机额定端电压90%-105%范围内调     

无刷双馈电机在独立电源系统中应用的仿真研究

分析了无刷双馈电源系统变速恒频的运行原理,结合独立电源系统的特点,建立了系统在空载和带负载状态下的数学模型;对系统空载至负载、转速突变、负载突变等情况进行了仿真研究,分析了系统动态特性;通过仿真验证,可以实现变速恒频发电,而且通过电压的标量控制可以实现系统输出电压的恒定。     

Inrush currents of induction generators due to abrupt connection to utility power networks

The squirrel-cage-type induction generator is suitable for small water power stations and wind power stations because of its simple and rugged structure, and low construction cost. However, the transient rush current flows into the primary and secondary windings when an induction generator is connected abruptly to a utility power network. The inrush current causes the voltage fluctuation in the power system. Therefore, electric power companies need a control method with low cost of the inrush current of the induction generator. Many properties of the inrush current must be known in detail. The factors affecting inrush currents are system voltages, control of the system voltage phase angle, rotary speed, residual magnetism of the core, and residual electric charge of the primary windings. In this paper, the inrush current is analyzed by the instantaneous value symmetrical coordinates. The experimental study of the inrush current using phase control equipment and a small induction generator is presented. The conclusions of this investigation are summarized as follows: (1) The factor that gives the strong influence on the inrush current is the voltage phase angle. (2) Although rotary speed changes from 0.9 to 1.15 times as much as the synchronous speed, the maximum value of the inrush current is nearly constant. (3) The maximum amplitude of the inrush current is definitely seen in the first or second wave.     

Dynamic stability study of an isolated wind-diesel hybrid power system with wind power generation using IG,PMIG and PMSG: A comparison

This paper presents a comparative study of reactive power control for isolated wind-diesel hybrid power system in three different cases with wind power generation by induction generator (IG), permanent-magnet induction generator (PMIG) and permanent-magnet synchronous generator. The synchronous generator (SG) is used with diesel engine set. A mathematical model of the system based on small signal analysis, is developed considering reactive power flow balance equations. The variable reactive power needed by the system is provided by a static synchronous compensator (STATCOM) when wind power generation is done by IG and PMIG. When permanent-magnet synchronous generator (PMSG) is used for wind power generation, the variable reactive power demand is fulfilled by a voltage source converter (VSC) which is on the load side. A new mathematical approximation model for VSC connected with PMSG is proposed such that the voltage source converter fulfills the increased reactive power requirement of load and also increases its active power equal to the increased input wind power. Proportional and integral (PI) gains of the STATCOM and VSC controllers are optimized using integral square error criterion (ISE). The dynamic responses of the system for small (1%) step increase in load reactive power with and without 1% step increase in input wind power are shown. The paper also shows the dynamic responses of the system for random step change in load reactive power plus random step change in input wind power. The MATLAB/SIMULINK environment is used for simulation.     

无刷双馈风力发电系统的转速自抗扰控制

针对变速、恒频风力发电系统具有非线性、强耦合的特点,结合无刷双馈电机的结构特点及基本理论,导出其在发电状态下的转子速由轴电压、电流方程式,并以此为基础构建了无刷双馈发电机（brushlessdoubly—fedgenerator,BDFG）在双同步坐标系下的数学模型。对控制绕组子系统对应的转子磁链进行观测,引入自抗扰控制（active—disturbancerejectioncontrol,ADRC）策略实现转速解耦控制,使发电机转速跟踪风速变化,获得最佳叶尖速比;调节控制绕组频率,在低风速下可达到最大风能跟踪控制和变速恒频发电的目的。仿真结果表明：磁链观测器能较准确估计控制绕组子系统对应的转子磁链,ADRC受系统参数变化的影响较小,具有较强的鲁棒性和适应性,改善了系统的控制品质,验证了控制策略的可行性。     

滞环控制双绕组感应发电机励磁控制系统

设计了双绕组感应电机发电系统.在电机定子上设置了功率绕组和控制绕组,前者接负载,后者接励磁调节器,采用控制绕组电压定向矢量控制,使用滞环控制器触发驱动逆变桥,实现了对端电压良好的控制.也不会给电网系统带来无功负担.在变负载和转速情况下,对端电压动态和稳态性能进行实验分析证明.该系统动态响应速度快,稳态性能良好.     

变速直驱永磁风力发电机控制系统的研究

在直驱永磁风力发电系统中,永磁发电机的输出电压的幅值和频率随风速的波动而变化,不可直接并网。根据风力机运行特性和最佳风能利用原理,本文设计了由不可控AC/DC整流器和可控DC/AC逆变器组成的控制系统,通过控制逆变器的输出电压或电流实时跟踪给定值,来控制永磁发电机电磁转矩,实现最大风能的获取和无功功率可调。本文在理论上分析了方案的可行性,并搭建了基于DSPTMS320LF2407的实验室硬件平台。     

Grid integration improvement for single-phase inverters of small wind turbines under distorted voltage conditions

In this work, an enhanced control method for the grid-tied single-phase inverter in small wind turbines based on PMSG (permanent-magnet synchronous generator) under grid voltage distortion is introduced. Composite observers are designed for decomposing harmonic and fundamental components of the grid current and voltage accurately, which facilitate current control action and synchronize the inverter with the grid. Grid voltage phase angle is detected by an advanced PLL (phase-locked loop) scheme based on the grid voltage fundamental component. The inverter current is adjusted by multi-PR (proportional-resonant) controllers, where its harmonic components are regulated to zero resulting in a sinusoidal grid current. In this scheme, the DC-link voltage is maintained at constant by a DC boost converter, while generator output power is controlled by the grid-tied inverter. An MPPT (maximum power-point tracking) operation of wind turbine is obtained, with which generator speed is estimated from the input voltage and current of the DC boost converter, thus avoiding the use of an expensive and complex mechanical sensor. The presented method is proved through experimental investigation, where experimental results show that the THD (total harmonic distortion) of grid current is about 3% under 12.25% THD of the grid voltage.     

基于负载电流补偿与转速反馈的飞轮储能系统控制策略

为缓解电动汽车快速充电对电网的冲击,研究在直流快速充电站(DC fast charging station,DC-FCS)应用永磁同步电机(permanent magnet synchronous motor,PMSM)式飞轮储能系统(flywheel energy storage system,FESS)。在传统PMSM双闭环控制的基础上提出基于负载电流补偿与转速反馈的控制策略。首先建立电动汽车直流快速充电站负荷数学模型,对其冲击特性进行分析。然后阐明所提飞轮储能系统控制策略,并设计配有PMSM-FESS的直流快速充电站控制系统。最后在Matlab/Simulink软件平台上搭建配有FESS的快速充电站系统仿真模型。仿真结果表明：所提PMSM-FESS控制策略可有效限制电网功率上升速率,补偿快速充电站母线电压跌落;即使面临多台电动汽车短时间连续接入的情形,所提控制策略仍可有效缓解直流快速充电站对电网的冲击,降低直流母线电压跌落幅度。     

小型并网运行的单相永磁同步发电机的设计

单相永磁同步发电机在民用发电系统中有一定的应用,然而单相电机的理论和工程应用主要集中在单相异步电动机。本文设计了并网运行的10KW单相永磁同步发电机,首先根据电磁负荷确定基本尺寸,应用磁路法对转子永磁体进行了设计,根据电机的相量图分析了移相电容的选取,对电机的两相绕组和谐波抑制进行分析设计,分析了斜槽对减小电压波形畸变率和负载转矩脉动的作用,最后通过场路耦合有限元方法计算了样机的运行特性。     

Inverterless high-power interior permanent-magnet automotive alternator

This paper describes a high-power brushless interior permanent-magnet (PM) automotive alternator which does not use an inverter. The "inverterless" alternator is designed with a high back electromotive force voltage and high reactance, and acts as a constant current source over much of its wide constant power operating speed range. In this configuration, a switched-mode rectifier can be used to regulate the dc output voltage and current, which avoids the complexity and high cost of an inverter. An analysis of the modeling and performance of interior PM machines in this inverterless topology is described. Experimental results showing an outstanding constant power speed range are presented for a 6-kW concept demonstrator machine tested using a three-phase resistive load to simulate inverterless operation.