Detecting faults in rotors of PM drives

In this paper, effects of the speed-controller bandwidth in permanent magnet synchronous machines are discussed. Motor current signature analysis has been used to detect rotor faults in synchronous machines.     

防止变压器短路损坏事故的技术措施

电力变压器是城乡电网的主要设备,但又是较脆弱的设备.近几年我市电网曾发生多起10 kV馈线短路,造成35 kV和110 kV电力变压器绕组变形损坏事故.究其原因,有些是制造厂家设计不良,压紧结构强度不足;有些则是运行部门管理维护不当,甚至是由于运行人员误操作所致.因此,防止变压器短路损坏事故的发生,必须采取综合的技术措施.     

Axial flux interior PM synchronous motor: parameters identification and steady-state performance measurements

This paper presents different measurement and identification approaches applied to a nonconventional permanent-magnet (PM) synchronous machine, namely, the novel axial flux interior PM (AFIPM) synchronous motor. The nonconventional geometry of the AFIPM motor requires a dedicated discussion on the parameter identification subject. In the paper, the standstill frequency-response test and the standstill time-response test on the AFIPM prototype are presented. On the basis of these tests, the d- and q-axes circuit parameters are chosen. To confirm the validity of the standstill tests, the load tests have also been performed. Furthermore, the load tests provide some preliminary AFIPM machine performance results and additional information on the saturation phenomena. The d- and q-axes equivalent circuits parameters obtained by the performed measurements are analyzed and compared. Finally, the most appropriate AFIPM machine model is selected.     

Predictive current control with current-error correction for PM brushless AC drives

The performance of the conventional predictive current control (PCC) when applied to a permanent-magnet brushless ac (PM BLAC) drive is analyzed. A technique is proposed to reduce the current errors that arise due to the inaccuracies in the system parameters and the nonideal behavior of the inverter during a steady-state operation. In addition, a current-regulated delta modulator is employed to achieve a fast dynamic response during a transient operation. The performance of the proposed PCC, which is simple to implement on a low-cost fixed-point DSP, is demonstrated experimentally.     

基于改进UPF滤波算法的稳态及短路电流下光学电流互感器信噪分离研究

我国大力发展特高压电网,对电流互感器的测量精度和速度提出了更高的要求。当输入电流信噪比低时,光学电流互感器(OCT)很难从频域角度进行滤波。因此提出无迹粒子滤波算法(UPF)来提高OCT的信噪分离能力,并针对传统UPF计算量大导致实时性较差的问题,采用基于全局采样的改进UPF滤波提高滤波的实时性。之后对电力系统发生三相短路下该滤波情况进行讨论,以改进UPF滤波中的残差作为阈值进行计算。最后在Matlab进行仿真验证,结果表明基于全局采样的改进UPF方法有效提高了输出信噪比和滤波精度,短路时也能快速、准确滤波,为继电保护装置提供电流。     

500kV母线短路故障的分析

描述了外高桥二厂"3.7"500 kV母线三相短路故障过程中系统的频率、潮流、电压和低压释放情况,并对此进行了分析,还仿真校核了系统短路电流和有关机组功角,提出了电网运行和管理的相关建议.     

Adaptive and robust speed control of interior permanent magnet synchronous motor drives

This paper presents a robust speed controller for field oriented controlled interior permanent magnet synchronous motor (IPMSM) drives. The proposed controller is designed using integral variable structure control (IVSC) combined with linear quadratic regulator (LQR). The LQR scheme is used to decide the optimal feedback gain to shape the system dynamics by tuning the IVSC switching plane to guarantee the robustness of the control algorithm. The complete drive is implemented in real-time using digital signal processor (DSP) control board DS1102. The tracking properties and robustness of the proposed scheme are examined through both simulations and experimental work. It guarantees accurate control performance in the presence of parameter variations, step speed change and load disturbances. The performance of IPMSM drive system with a conventional proportional-integral (PI) controller is presented in comparison with the proposed controller. The results show a significant improvement in both the transient and steady state responses over the conventional PI controller.     

Sensorless control of interior permanent-magnet machine drives with zero-phase lag position estimation

This paper presents an improved method to estimate rotor motion states for an interior permanent-magnet machine drive. This approach is based on the estimation of a saliency-based electromotive force (EMF) in the stationary reference frame using a state filter. The spatial information obtained from the estimated saliency-based EMF is used in an observer to estimate the motor motion states. By using the commanded torque as a feedforward input to the observer, the motion state estimation has zero-phase lag, providing a very-high-bandwidth estimate.     

缩短变电站10kV母线短路故障切除时间措施初探

列举了变电站10kV母线短路故障几率较高的原因,论述了10kV母线短路电流对开关柜和主变的危害,提出了缩短10kV母线短路故障切除时间的必要性和三种措施。一是缩短主变保护切除10kV侧开关的时间,二是装设简易母差保护,三是装设电弧光保护。比较了三种措施的优缺点,以及各自的适用范围。介绍了东莞供电局的应用情况。     

缩短变电站10 kV母线短路故障切除时间措施初探

列举了变电站10 kV母线短路故障几率较高的原因,论述了10 kV母线短路电流对开关柜和主变的危害,提出了缩短10 kV母线短路故障切除时间的必要性和三种措施.一是缩短主变保护切除10 kV侧开关的时间,二是装设简易母差保护,三是装设电弧光保护.比较了三种措施的优缺点,以及各自的适用范围.介绍了东莞供电局的应用情况.     

Enhanced current control of high-speed PM machine drives throughthe use of flux controllers

This paper compares various types of current controllers, including a novel method based on flux control. A proportional integral (PI) control method is used initially, to control the current in a high-speed permanent-magnet synchronous machine. The performance of this simple PI loop is presented, Various improvements to the PI controller are investigated, and the change in performance examined. A new current control scheme based on a flux-linkage model of the machine is introduced. The performance of the model-based control is demonstrated and compared with the performance of the PI current controller. Factors affecting the accuracy of the model-based control are given. By incorporating these factors into the model, the performance of the flux controller is further enhanced     

低压系统短路电流快速分断控制实现的研究

本文分析了实现低压系统短路故障早期检测的主要难题,设计了基于短路故障早期检测模型的短路电流快速分断控制系统并进行了有效验证,解决了短路故障早期检测理论的实际应用问题。同时,为开发智能型保护电器提供了一个有效的试验验证方法。     

A saturating lumped-parameter model for an interior PM synchronousmachine

This paper presents a lumped-parameter magnetic model for an interior permanent-magnet synchronous machine. The model accounts for the effects of saturation through a nonlinear reluctance-element network used to estimate the q-axis inductance. The magnetic model is used to calculate inductance and torque in the presence of saturation. Furthermore, these calculations are compared to those from finite-element analysis with good agreement     

The steering effect PM motor drives for automotive systems

The steer-by-wire (SBW) system requires the use of enhanced fuel economy, assist action given two motor drives, the first for the mechanical steering system and the second for the torque feedback to the steering wheel. An interior permanent magnet (IPM) synchronous motor is used for the steering actuator whereas a fractional-slot surface-mounted permanent magnet (SPM) synchronous motor is used for the torque feedback.     

Achieving a constant power speed range for PM drives

Flux weakening has long been a standard approach in obtaining a constant power speed range for traction drives with commutator motors. There is much interest in using permanent magnet (PM) commutator motors or, preferably, electronically commutated PM motors for such applications. Some PM motor designs, such as those using inset or buried magnets, have been proposed to achieve flux weakening. This paper questions the desirability of the flux weakening approach for a number of applications where energy efficiency is of prime importance, such as in electric vehicles. For an acceptable increase in the rating of some of the semiconductor devices, standard PM commutator motors and switched PM motors with surface-mounted magnets can be used and a significant reduction in power loss can be achieved     

Air conditioner response to transmission faults

This paper describes two multi-phase faults events which occurred during periods of high air conditioning use. There was a significant loss of load in these events which is attributed to air conditioner motor protection. The overall response of the transmission system is simulated using induction motor models based on the characteristics of a typical residential air conditioner compressor motor. The sensitivity of factors such as fault location, fault duration and excitation system performance is also investigated     

电网短路故障下DFIG的电磁特性研究

对电网短路故障下双馈感应发电机（Doubly Fed Induction Generator,DFIG）的电磁特性进行研究以提高DFIG的故障穿越能力。在对实际电网进行简化的基础上,利用电路理论的换路原理以及KVL、KCL定律分别对电网三相短路故障发生时和切除时DFIG定子磁链的动态特性进行了理论研究;仿真分析了电网不同地点、不同短路故障类型下DFIG定子磁链和转子电流的变化特性。研究结果表明,电网短路切除时DFIG定子磁链发生突变,在线路电阻电抗比较小的情况下定子磁链跃变为稳态值而不出现暂态直流分量,从而短路切除时转子中不会出现暂态冲击电流。理论研究与仿真分析表明,短路发生时与切除时DFIG具有不同的电磁动态。     

控制和降低短路电流水平措施在华东电网的应用

分析了华东500 kV主环网短路电流水平。总结、归纳和分析了华东电网近年来应对短路容量超标矛盾的经验和措施。描述了2006~2007年华东电网控制和降低枢纽变电站短路电流水平的方案。     

Selection of short-circuit protection and control for Design Emotors

The purpose of this article is to give users of Design E motors electrical application information concerning the selection of the appropriate motor disconnecting means, motor branch-circuit short-circuit protection, motor circuit conductor, motor controller and motor overload protection, and guidance concerning torque characteristics. The authors describe how motor efficiency is increased and how the design changes related to increased efficiency affect the mechanical and electrical characteristics of motors. They also review the requirements of Article 430 of the 1996 National Electrical Code and provide generic application tables that compare the protection and control requirements of Design E motors with those of Designs B, C, and D     

串联谐振型FCL对高压断路器开断短路故障的影响

基于串联谐振型故障限流器的等效分析模型,分别针对短路出线故障和近区故障,详细研究了限流电感及其并联杂散电容对短路电流,断路器瞬态恢复电压第一个峰值以及瞬态恢复电压上升率的影响,并综合以上指标得到了断路器苛刻度的变化规律.研究表明,选取合适的限流电感、采取合理的措施改变限流电感并联杂散电容能够有效地降低断路器的苛刻度,有利于断路器对短路故障的开断.