凸极同步电动机直接转矩控制的研究

在分析凸极同步电动机数学模型的基础上,详细推导并分析电磁转矩与转矩角之间的关系,理论证明凸极同步电动机直接转矩控制系统的可行性。提出励磁电流控制思想,加快系统的动态响应,补偿阻尼绕组对电动机动态性能的影响。基于Matlab7．0．1软件建立凸极同步电动机直接转矩控制系统的仿真模型,仿真结果证明该控制思想的有效性和良好的动态性能。     

电励磁同步电动机直接转矩控制系统

在建立凸极同步电动机数学模型的基础上,分析推导了电磁转矩与转矩角之间的关系,提出了阻尼绕组补偿的励磁电流控制思想.基于此控制思想设计了具有高动态性能的直接转矩控制系统,并利用Matlab 7.0构造了仿真模型,仿真结果表明该系统具有良好的静、动态性能.     

电压型逆变器供电六相双Y移30°绕组同步电动机的动态数字仿真

分别建立六相电压型逆变器和六相双丫移30°绕组同步电动机的动态仿真数学模型.为了便于考虑变频器和电动机之间的接口,以及深入分析转子阻尼绕组对系统动态性能的影响,定子采用基于线电压的静止a—b—c模型,转子采用多回路模型,并对电动机的空载软起动过程进行了仿真和分析。数字仿真的结果表明,六相双丫移30°绕组同步电动机转矩脉动小,有利于系统的稳定运行,在电力推进等领域将得到重要应用。     

同步电动机任意设定转速的无源性跟踪控制

建立了同步电动机基于E-L(Euler-Lagrange)方程的无源性控制数学模型,基于此模型,针对任意时变且未知的负载转矩,对任意设定的期望转速,通过设计负载转矩估计器和期望轨迹设计器,给出了同步电动机无源性转速跟踪控制器的一般设计方法.这种控制器无需转子阻尼绕组电流观测器,无需磁场定向.仿真证明这种控制器能很好地实现期望的跟踪控制目标,具有较好的跟踪控制效果.     

双三相同步电动机的数学模型及仿真

建立六相双Y移30°绕组同步电动机的状态空间数学模型,为了便于计算全阻尼绕组电流,定子采用d-q坐标变换,转子采用多回路模型,并对电动机带螺旋桨负载的起动过程进行了仿真和分析。仿真结果验证了模型的有效性,同时表明这种双三相同步电动机起动性能良好,转矩脉动较小,非常适合船舶电力推进系统的应用。     

稀土永磁同步电动机动态转矩分析

采用数字仿真技术分析稀土永磁同步电动机在受到周期性负载时的同步转矩系数及阻尼转矩系数，给出了电机各参数对动态转矩的影响。     

运控电机之无刷直流电动机

近代无刷直流电动机(BLDCM)没有滑动电接触,具有调速方便和转矩控制性能好等类似直流电动机的特性,已成为近代运控电动机的主流.但是它本质上是具有自同步功能的交流永磁同步电动机,与真正的直流电动机相比较仍有二个弱点,一是绕组电感限制电动机的极限功率输出,二是电枢交流电流实时检测和控制不方便.提出了新一代BLDCM的设想,即具有理想直流电枢绕组电路的电子换向电动机,并对其旋转磁场-机械特性和转矩控制性方式进行了分析,有助于对其本质的理解.     

隐极发电机阻尼绕组和槽楔对励磁转矩的影响

为了说明在外部稳态不对称情况下,阻尼绕组和阻尼槽楔对同步隐极发电机励磁绕组恒定电磁转矩和二次谐波电磁转矩的影响。首先,在同步隐极发电机正序等效电路和负序等效电路以及正序磁场恒定电磁转矩和负序磁场恒定电磁转矩分析的基础上,推导出一种新型研究同步隐极发电机恒定电磁转矩的解析方法。然后,在磁场相互作用分析的基础上,提出一种分析同步隐极发电机励磁绕组二次谐波电磁转矩的新方法,并用该方法分析了电流不对称度、阻尼绕组和阻尼槽楔对同步隐极发电机励磁绕组二次谐波电磁转矩幅值的影响。最后,为了验证解析分析的正确性,采用时步有限元法进行仿真计算,有限元数值算法的结果与解析分析结果具有良好的一致性。     

自起动永磁同步电动机稳态运行鼠笼电流分析

通过理论分析和有限元仿真,对定子绕组采用△联接的自起动永磁同步电动机的气隙磁场、转子阻尼绕组的电流、转矩、转速、损耗等进行分析,可以得出定子绕组采用△联接时,不仅会大大增加稳态运行时的转子铜耗,还会引起转矩、转速的波动。因此,定子绕组应慎用△联接。将△联接与Y联接的电机做了对比分析。     

ALA转子磁阻同步电动机的动态不稳定性

采用小信号分析法研究了ALA转子磁阻同步电动机开环运行时的动态不稳定性问题 ,导出了ALA转子磁阻同步电动机电磁阻尼转矩系数的解析表达式 ,分析了电动机在小值振荡条件下的电磁阻尼特性 ,提出ALA转子电动机的动态不稳定性在电动机电源频率略大于电动机振荡的自然频率时产生。理论分析与实验结果相符。     

交－交变频大功率同步电动机阻尼绕组设计的分析研究

通过建立带阻尼绕组的大功率交－交变频凸极同步电动机的多回路数学模型，研究了在负载突然变化，不同阻尼绕组结构、导条根数、阻尼节距时，电动机的功角振荡、阻尼绕组瞬态电流、损耗等情况。结果表明；大功率交－交变频凸极同步电动机应设置成全阻尼绕组，且在极面上阻尼条靠近ｄ轴布置比阻尼条均匀布置要好。电机实际运行情况验证了结论的正确性。     

阻尼绕组对磁场定向控制交－交变频同步电机动态行为的影响

本文在交－交变频磁场定向控制同步电机调速系统数学模型的基础上，研究了阻尼绕组对交－交变频同步电机动态行为的影响．结果指出．阻尼绕组能有效地抵消动态电枢反应，加快定子电流响应，提高电机的过载能力．从改善系统的动态特性出发，应选择全阻尼结构。     

Classical analysis of static stability of a salient-pole synchronous motor

Sufficient conditions for static stability of a salient-pole synchronous motor are found by two methods. The equivalence of these methods is proved. The synchronous motor is demonstrated to be statically unstable under superconductivity conditions, even if it is equipped with a damper winding.     

A New Brushless Half-Speed Synchronous Motor with Q-Axis Squirrel-Cage Damper Winding Driven by Voltage Source Inverter

A new brushless half-speed synchronous motor combined with a voltage source inverter is presented. The diode is inserted into one phase of the stator winding, and then the stationary magnetic field is superimposed on the revolving field. The rotor structure of the proposed motor is composed of the quadrature-axis (q-axis) squirrel-cage damper windings on the salient poles. By superimposing a stationary magnetic field on the stator, the motor is compelled to run at exactly half synchronous speed. For purposes of direct comparison the machine is tested with various configurations of damper windings. The experimental results are shown, and it is proved that the motor has excellent performance. The proposed brushless synchronous motor is very simple, robust, and maintenance-free.     

Steady-state analysis of a self-controlled synchronous motor

This paper deals with a simple mathematical model for steady-state analysis of a self-controlled synchronous motor in terms of d,q variables. The flux linkage of the damper winding is considered constant under steady-state conditions. With the input voltage to the synchronous motor and the machine equations in d,q form, torque-current and speed-current relations are developed. The computed results are given and discussed in detail for a 3 kVA, three-phase, 400 V, four-pole, inverter fed synchronous motor and it is shown that this system has the same characteristics as a conventional DC motor.     

基于精确线性化解耦的永磁同步电机空间矢量调制系统

从永磁同步电机的定子磁链模型出发，应用精确线性化理论，实现永磁同步电机输入输出线性化与解耦。将永磁同步电机动态解耦成二阶线性转速子系统和一阶线性磁链子系统，结合磁链扇区判断方法和线性化解耦后的实际系统输入来确定目标空间电压矢量，实现了永磁同步电机调速系统的转速和磁链动态解耦控制。仿真和实验结果表明，基于精确线性化解耦的永磁同步电机空间矢量调制系统具有理想的速度跟踪性、良好的鲁棒性和低速性。     

自控式同步电动机的数学模型及稳态运行的分析

本文建立了一种较为完整的自控式同步电动机的数学模型,该模型采用多回路法处理阻尼绕组,可以计算阻尼条中的电流,还可考虑平波电抗器电感和高次谐波磁场的影响。本文提出了自控式同步电动机稳态运行的数值解法,对一台实验机组的稳态运行性能进行了计算,并与实验结果作了比较。     

交交变频器-多相同步电动机稳态和似稳态等效电路模型

在分析交交变频器-多相同步电动机调速系统运行的基础上,提出将多相同步电动机的d、q轴变量分解为低频分量(含非周期分量)和高频分量分别加以处理,并忽略转子回路对高频分量的电阻和阻尼绕组对低频分量的作用的分析方法,建立了适合于交交变频器-多相同步电动机系统稳态和似稳态分析的等效电路模型.试验结果证明了该模型的正确性.     

Verification of effect of damper windings on the transient condition of synchronous generator

This paper describes the results of an experimental investigation on the effects of the damper winding of a four‐pole synchronous generator at a synchronous generator transient. It is known from simulations that the damper winding acts effectively under synchronous generator transient conditions. However, experimental proof has not been obtained yet. Thus, experiments on damper effects were conducted using a laboratory‐scale power system. The damper winding of the tested generator consisted of five damper bars for each pole; the number of working damper bars could be changed manually. The damper currents at each bar were measured by a Rogowski coil. FFT analysis was applied to both the damper currents and armature currents under different operating conditions. The relationships between damper currents in the rotor and armature currents in the stator were made clearer than before. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(2): 33–42, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21278     

Mill motors for adjustable-speed AC drives

The use of AC adjustable-speed drives for rolling mill applications is addressed. AC motor characteristics and how they relate to adjustable-speed mill drives are described. A review of AC motor theory highlighting distinctions between induction and synchronous machines along with comparisons to DC motor performance is included. Constant power speed range performance and limitations, damper winding requirements, and the selection of motor variables such as terminal voltage and frequency are discussed