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.     

PERFORMANCE ANALYSIS OF A HIGH STARTING TORQUE SINGLE-PHASE INDUCTION MOTOR

ABSTRACT

The objective of the work described is to make an assessment of the possible use of three-phase induction motor working as a single-phase motor. The analysis is performed on the proposed winding arrangement, introduced previously by same authors. The analysis includes all motor windings, whereas the conventional analysis is performed on the running winding only. The motor windings are analyzed through the stationary direct and quadrature axes. The magnetic field and E.M.F's of the motor are studied at starting, run-up and running operation. Hence, d-q axis equivalent circuits are deduced to represent the motor at different modes of operation, taking into consideration the core losses and sturation effects. Prediction of the run-up and running characteristics of the motor under investigation is achieved by solving the equations of equivalnet circuits in a simple manner. The predicted results are compared with the releavant experimental results. Good agreement has been achieved, and this confirms the validity of proposed analysis.     

谐波起动电动机的绕组分析

针对传统的三相笼型电动机和绕线型电动机不适应在水泥、煤炭等带式输送机等场合应用的问题,提出了一种改善起动性能的谐波起动电动机.探讨了其定子绕组和转子绕组的设计方法.     

转子甲类波绕组排列方法的探讨

为方便绕线型异步电动机的设计和接线操作,明确转子波绕组一端接线法十分必要。从电角度的观点出发确定三相绕组首端引出线位置。根据波绕组的连接规律进行各相带的槽号分配,进而利用Excel公式法编排绕组表。这种方法不但易于掌握,而且通过绕组表可直观的确定上下层整距、短距、引线线圈所在槽号,为绘制转子接线图和设计转子线圈奠定了基础。     

Analysis of a synchronous reluctance machine with an auxiliary single-phase winding

A three-phase synchronous reluctance machine having an axially laminated rotor structure and an auxiliary DC-source-fed single-phase control winding has utility as either a high-speed generator or a high-torque low-speed motor. This paper provides an understanding of its operation using electric circuit and electromagnetic field concepts in the process of which some insights are provided into the design of the windings, conditions for torque production and generation of electric power when operating in the motoring or generating modes. Some confirmatory experimental results of analytical developments are provided showing performance characteristics of an experimental machine.     

双馈异步发电机定转子绕组过热故障监测方法

双馈异步发电机(DFIG)在长期运行中很容易发生定转子绕组过热故障。以绕组温度为研究对象,在分析绕组过热故障成因的基础上,分别从电机热性能和参数辨识两方面进行检测。使用参数辨识法时,首先利用电机电磁数学模型辨识定转子绕组电阻,再根据电阻与温度之间的关系计算定转子温度,从而判断绕组是否过热。最后基于MATLAB软件仿真验证了定转子绕组参数辨识法的正确性,为DFIG诊断绕组过热故障提供理论支撑。     

六相双Y永磁同步电机绕组重构与分析

针对三相表贴式永磁同步电机振动噪声问题,本文考虑多相电机绕组结构,基于96槽16极槽极组合对六相双Y绕组结构重新排布,以同转子结构的双Y偏0°整距绕组的两种排布方式和双Y偏30°短距绕组排布方式下,对其绕组系数、磁动势谐波分布、电枢反应磁场结果进行比较分析,并与同结构三相短距绕组排布的永磁同步电机共四种模型下电磁力二维傅里叶分解结果比较分析,为六相双Y永磁电机设计提供借鉴。     

A brushless three-phase synchronous motor using the armature winding as both load and DC excitation winding

This paper presents a new brushless three-phase synchronous motor which has no exciter. The technique applied to the motor provides an effective way for conventional brushless synchronous motors to simplify the system configuration. The stator of the motor is equipped with a double-star connected armature winding which has two neutral points. The rotor is a cylindrical one, which is equipped with a two-phase field winding. The field winding is connected with shaft-mounted rectifiers. A dc voltage is applied to the two neutral points of the armature winding to obtain the rotor excitation when the motor is operated at synchronous speed. At that time. the armature winding acts as a stator dc exciting winding while also acting as a load winding. In this paper the principle and characteristics of the motor are described. and the experimental results are shown. It is confirmed that with a 2-kW experimental machine, the proposed motor has good performance. For example, by adjusting the stator dc current, this motor power factor can easily be controlled within a wide range.     

新型接法的三绕组单相电动机

在单相供电系统中,当电动机额定功率大于0.5 kW时,采用普通单相感应电动机是不经济的,为此提出一种新型连接方式的三绕组单相感应电动机,该接法对Y接法三相感应电动机的6个出线头进行改接,并与2个电容器相连接,改变了绕组中电流的相位,使三相电机在单相供电系统中实现接近对称运行。采用对称分量法研究该连接方式下电机对称运行需要满足的条件,讨论对称运行条件下电容的选择及其对电机性能的影响,推导了该电机性能计算的具体方法。针对该连接方式进行试验研究,并与三相对称运行进行比较。样机试验证明,新型接法三绕组电机的效率接近三相电动机在三相电源上对称运行的效率,且具有更高的功率因数,可替代普通单相感应电动机。     

Brushless self-excited three-phase synchronous generator without exciter

This paper describes principles together with analytic and experimental studies of an exciterless, brushless, and self-excited three-phase synchronous generator which was devised by authors. Since traditional brushless and dc self-excited three-phase synchronous generators without exciter did not have the self-exciting function by series characteristic component proportional to the load current inside the generator, they need auto-voltage regulating equipment or a transformer with three windings and condensers to obtain constant voltage characteristics. It also has the following problem in the case of two-pole traditional generator: oscillatory tension is generated at the shaft of the rotor caused by the magnetic force between magnetic poles of stator and rotor windings, and it causes mechanical vibration and noise. This paper proposes a new brushless and self-excited three-phase generator solving the aforementioned problems: the ratio of poles of the windings for providing power to load (armature and field windings) to the windings for supplying exciting power (stator and rotor exciting windings) is 1 to 5. Then oscillatory tension does not generate theoretically. Furthermore, a self-exciting three-phase generator using the 5th-harmonic component of armature reaction which makes series characteristic component proportional to the load current, currently is available. In this paper, the winding construction, the electric circuit, and the principle of the aforementioned generator are described, and the experimental results of the trial-produced generator show that the three-phase terminal voltage waveforms are almost sinusoidal and also balanced, and the voltage can be kept almost constant for the change of load. This generator has high reliability because of its simple construction.     

九相永磁同步推进电机系统主动切套运行控制策略

主动切套运行是多套多相电机特有的一种对称故障运行方式,可根据负载率选择最佳的运行绕组套数,以优化电机系统效率。本文以三套三相绕组构成的九相永磁同步推进电机系统为研究对象,研究了电机主动切套的控制方法,通过考虑切套前后推进电机本体及其逆变器损耗的变化,得到九相永磁同步推进电机系统全转矩范围内损耗最小的切套运行方式。通过对9kW九相永磁同步推进电机原理样机进行Simulink仿真计算,验证了理论分析的正确性。     

三相无刷同步发电机转子绕组不同连接方式可靠性分析

电励磁三相无刷隐极同步发电机可通过改变励磁绕组电流大小改变气隙磁场强度,从而实现宽范围电压调节。转子绕组是三相无刷隐极同步发电机的重要组成部分,其一般采用同心式绕组。并联支路数为1的转子绕组极间、重间连接后,引出线正端与负端在铁心端面固定并直接引出。而并联支路数大于1的转子绕组不仅需要极间、重间连接,还需选择恰当的并联连接方式。不同的连接方式直接影响转子绕组的复杂性与可靠性。以10极5 MW三相无刷隐极同步发电机为例,对并联支路数为2的转子绕组不同连接方式进行比较。结合工艺性与可操作性,选择最优转子绕组连接方式,制作了发电机转子绕组以及样机。结果表明,该连接方式简单可靠,可提高产品工艺性,有效避免转子绕组绝缘故障。     

Dual stator winding induction machine drive

A new dual stator winding induction machine drive is described in this paper. The proposed induction machine consists of a standard squirrel-cage rotor and a stator with two separate windings wound for a dissimilar number of poles. Each stator winding is fed from an independent variable-frequency variable-voltage inverter. The proposed drive offers such advantages as speed sensorless operation, better reliability, and more flexibility to manipulate the resultant torque-speed curve of the motor. In the proposed drive, zero-speed operation is achieved by independently controlling the two sets of stator currents, hence, maintaining a minimum electrical frequency independent of the mechanical speed. This feature is especially important to minimize the negative impact of the stator resistance influence at low-speed operation and it greatly simplifies the implementation of speed sensorless control schemes. The drive is well suited for either constant volts per hertz or field-oriented (FO) operation. Circulating harmonic currents, common to most dual stator machines, are eliminated by the dissimilar pole number in each stator winding     

无轴承同步磁阻电机最小二乘法转子位移自检测策略

位移传感器是无轴承同步磁阻电机悬浮运行时转子位置闭环可控的关键部件,但装配多个位移传感器阻碍了无轴承同步磁阻电机的低成本实用化和结构简单化,由此提出最小二乘法转子位移自检测（无传感器）策略。基于电机悬浮绕组和转矩绕组的磁链、电压和电流状态方程,重构最小二乘法转子位移检测模型,通过采样两套绕组电压和电流,应用最小二乘递推算法对转子位移进行在线辨识。仿真实验表明,该方法能准确实现无传感器工况下转子位移自检测,检测系统有较强的负载扰动适应性。     

Double Three-phase Induction Machine Modeling for Internal Faults Simulation

Multi-phase induction motors present excellent characteristics for faulty tolerant operation. Among them, six-phase induction motors, which are among the most used, exhibit two types of configuration: the double three-phase and the six-phase with single neutral. The double three-phase presents the advantage of reducing harmonics with its symmetric winding. This article presents a new modeling of the double three-phase induction machine for internal faults simulation. The developed model is composed by two sets of three-phase stator windings forming two stars. The model considers an arbitrary displacement (α) between stator stars, allowing the simulation of this type induction machines with different configurations, with 60° displacement used herein. The simulations of internal faults, such as stator windings or rotor faults, are both considered in the proposed model, allowing the machine study under abnormal conditions. The double three-phase induction machine model was fully implemented in real coordinates, making it possible to simulate stator and rotor faults without being necessary to change system equations coordinate. Several examples allow verifying the characteristics of the proposed model and its application for internal fault analysis. Experimental results are also presented to validate the obtained simulation results.     

Improved designs of disk induction motors of block-module type for extreme environments

The construction of new disk induction motors of block-module type, which are a part of motor-transformer units (MTUs), are considered. The induction motors are intended for operation in hermetic objects under extreme conditions: a gas, steam-to-gas, and liquid environment at high pressures (up to 150MPa) and temperature (up to +600°C). The primary winding of the transformer part of the unit is connected to a three-phase network, and the secondary z-phase bar winding is located in Z grooves of the magnetic conductor of a transformer closed on one side by a short-circuited ring. The motor part of the unit contains an induction motor with a short-circuited rotor and stator with bar uninsulated winding connected to the transformer secondary winding; on the opposite side, it is closed by a short-circuited ring. The induction motor can be implemented with a disk short-circuited rotor located between two disk stators with bar windings. The bars of the transformer secondary winding are connected with Z bar-shaped hermetic lead-ins installed in a hermetic partition. Each bar-shaped hermetic lead-in is connected at the other end with n bars of the stator winding through intermediate conductive arc-shaped segments adjoining the stator. The operating principle and operation features of new disk induction motors of block-module type are considered.     

用电池-指针万用表确定三相交流异步电动机相序和转向

三相交流异步电动机的旋转方向决定于其电源相序和定子三相绕组与电源相序的对应连接。根据负载要求的电机转向,用直流感应法确定三相交流异步电动机绕组的相序,从而确定三相绕组与三相电源正确的对应连接关系。对该方法的原理和实用性进行了介绍。     

A General Analytical Method for a Three‐Phase Line‐Start Permanent‐Magnet Synchronous Motor

A line‐start permanent‐magnet synchronous motor (LSPMM) consists of a stator with symmetrical three‐phase armature windings and a salient pole rotor with a permanent magnet for excitation and a starting winding similar to the squirrel‐cage winding of an induction motor. In this paper, a general analytical method based on tensor analysis is proposed for practical performance calculation of a three‐phase LSPMM. The general equation for the currents of the three‐phase LSPMM is derived from the transient impedance tensor expressed in polyphase symmetry axes, and the general equation for vibratory and nonvibratory torques is derived from the current equation. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 185(4): 60–68, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21284     

Diagnosis of Short‐Circuit Faults in Stator Winding Inside Low‐Voltage Induction Motor Using Impulse Voltage Test

Short‐circuit faults in windings due to the deterioration of insulation is among the most common faults in motor drive systems. An easy and effective fault diagnosis method is urgently required to ensure highly reliable operation. This paper proposes a novel method for the diagnosis of short‐circuit faults in stator winding inside a low‐voltage induction motor without removing the rotor, by performing an impulse voltage test. As the rotor does not need to be removed from the motor in this novel diagnosis method, the method can be put to practical use. In this study, first, several impulse voltage tests are carried out on the stator windings of motors. Second, the values of two features that represent the characteristics corresponding to the condition of the motor are calculated, and it is found that the shape of the feature distribution does not depend on the rotor position but on the condition of the winding. Third, the distance between the feature distribution for the healthy motor and features obtained from a target motor is calculated. On the basis of this distance, the condition of the stator winding inside the induction motor is determined. The effectiveness of the proposed diagnosis method is verified by performing experiments that involve several motors with healthy and faulty windings.     

无起动绕组永磁同步电机初始定位及起动策略

永磁同步电机采用转子表面叠装永磁体励磁,具有起动电流小的优点,但是起动比较困难,特别是无起动绕组时更是如此。基于无轴承永磁同步电机转矩产生原理,针对其无起动绕组的特点,在加入悬浮子系统之前,研究了永磁同步电机无起动绕组的起动问题。提出一种通用的优化起动策略,给出准确实现转子初始定位的充要条件、定位相序的优化方法以及基于转子磁场定向控制策略的起动方法。实验结果表明,采用该起动策略,可以在无起动绕组情况下,使永磁同步电机快速、可靠起动,并进入稳定运行状态,而且起动电流很小,具有安全、可靠的优点。