基于PSO优化LS-SVM的异步电动机振动故障诊断

为了提高异步电动机振动故障诊断的准确性,提出了基于粒子群算法优化最小二乘支持向量机的异步电动机振动故障诊断方法。先通过实验室对异步电动机各类故障的振动进行测试,对测试数据进行预处理,选择异步电动机不同位置振动信号的特征频率作为系统的输入,然后利用训练好的粒子群算法优化后的最小二乘支持向量机进行异步电动机振动的故障诊断。最终结果与其他诊断方法对比表明：该方法克服了样本训练时间较长并容易陷入局部收敛的缺点,同时诊断的准确率较高,有效地避免了异步电动机故障的误诊断。     

A review of RFO induction motor parameter estimation techniques

An induction motor is the most frequently used electric machine in high performance drive applications. Control schemes of such drives require an exact knowledge of at least some of the induction motor parameters. Any mismatch between the parameter values used within the controller and actual parameter values in the motor leads to a deterioration in the drive performance. Numerous methods for induction machine online and offline parameter estimation have been developed exclusively for application in high performance drives. This paper aims at providing a review of the major techniques used for the induction motor parameter estimation. The paper is illustrated throughout with experimental and simulation examples, related to various parameter estimation techniques.     

Dynamic model of an integral-cycle controlled single-phaseinduction machine

A dynamic machine model of an integral-cycle-controlled single-phase induction motor is derived by properly choosing a stationary d-q reference frame. The approach highlights the mode transition which occurs in the integral-cycle operation. By utilizing the model it is revealed that two types of capacitor connection to the machine windings are equivalent, and that the integral-cycle controlled single-phase induction machine switches its operation between two distinct modes. A comparison of simulated to test results indicates that with the integral-cycle control, a complicated motor behavior may occur due to the irregular current waveform in its operation     

A new energy recovery double winding cage-rotor induction machine

This paper proposes a new double winding induction machine and its speed control methods. The machine consists of two stator windings and one cage rotor. One stator acts as a motor and the other as a generator. By controlling the voltage supplied to the secondary or the generator winding, the rotor speed can be adjusted. The machine has a similar speed control characteristic to that of a slip-ring induction motor equipped with the rotor energy recovery scheme. The construction, principle, equivalent circuit, and speed control schemes of the new machine are presented. The performance characteristics of the machine are analyzed using the equivalent circuit and verified by experimental results.     

Steady-state analysis of a three-phase induction motor with theSmith connection

This letter presents a steady-state analysis of the single-phase operation of a three-phase induction motor with the Smith connection. The motor performance, such as the phase voltages, phase currents, and torque, can be obtained quantitatively. The theoretical analysis is verified by experiments performed on a small induction machine     

Machine modeling and universal controller for vector-controlled induction motor drives

Developments of machine model and a universal controller for vector-controlled induction motor drives are presented in this paper. The machine representations associated with vector-control methods referring to various frames, including stator, rotor, and air-gap flux frames, can be derived simply by selecting different state variables; thereby clearly identifying the relationship between machine modeling and vector control. Moreover, a universal vector controller for induction motor drives fed by a voltage-controlled voltage source inverter is presented. It is shown in this paper that various vector controllers, including rotor flux-oriented controller, stator flux-oriented controller and air-gap flux-oriented controller, can be realized by simply changing few parameters. It is demonstrated by experimental results that the developed universal vector controller for various vector-control approaches can be implemented using the same hardware with a minor change to software associated with parameters; and thereby confirming the theoretical analysis.     

A thermometric approach to the determination of iron losses insingle phase induction motors

This contribution describes a novel technique for evaluating the iron loss density distribution in a single phase induction motor using the temperature time method. This is achieved by measuring the temperature gradient which exists at any point within the machine when it is isolated from the supply. This method was used when the motor was lightly loaded. The measurements were carried out on a 200 W, 220 V, 4-pole, 1.6-A single phase induction motor     

Performance analysis of a composite dual-winding reluctance machine

The electromagnetic energy conversion process of a composite dual-winding asynchronous reluctance machine is presented. The mechanism of torque production is explained using the magnetic fields distributions. The dynamic model developed in dq-rotor reference frame from first principles depicts the machine operation and response to sudden load change. The device is self-starting in the absence of rotor conductors and its starting current is lower than that of a conventional induction machine. Although the machine possesses salient pole rotors, it is clearly shown that its performance is that of an induction motor operating at half the synchronous speed. Hence the device produces synchronous torque while operating asynchronously. Simple tests were conducted on a prototype demonstration machine and the results obtained are seen to be in tune with the theory and the steady-state calculations.     

A solid state direct on line starter for medium voltage inductionmotors with minimized current and torque pulsations

This paper describes a thyristorized static switch which is designed and implemented specifically for frequent direct-on-line starting of medium voltage large induction motors. The circuit configuration chosen utilizes back-to-back connected series thyristor strings on two of the supply lines. Both the starting current and the torque pulsations of the induction motor are minimized by a controlled, nonsimultaneous switching of motor phases to the supply. This reduces the electrical stresses on the power system and the mechanical stresses on the shaft as compared to conventional switching elements. The optimum switching strategy is found by the use of a hybrid mathematical model in ABC/dqO form. The validity of the results obtained for medium voltage, squirrel-cage induction machine are verified by the use of a physical simulator consisting of a low voltage, small induction machine and a shaft torque measuring system. The system has been in operation successfully in an iron and steel plant since 1991     

Analysis of a three-phase induction machine including time andspace harmonic effects: the a, b, c reference frame

This paper presents a mathematical modeling that uses the concept of harmonic inductances to derive voltage and torque equations of a three-phase induction machine using a, b, c and A, B, C formulation. Phase currents and electromagnetic torque are obtained by numerical integration of equations considering any supply voltage waveform. Two cases were studied-operation of induction motor supplied with sinusoidal waveform, and operation of an induction motor supplied by a three-phase inverter     

Performance analysis of a three-phase induction motor under mixed eccentricity condition

A substantial proportion of induction motor faults are eccentricity related. In practice, static and dynamic eccentricities happen to exist together. With this point in mind, an analytical approach to evaluate the performance of a three-phase induction motor under mixed eccentric conditions is presented in this paper. A clear and step-by-step theoretical analysis, explaining completely the presence of certain harmonics in the line-current spectrum in the presence of eccentricity, is discussed. More importantly, it is shown for the first time that a link exists between the low- and high-frequency elements of these harmonics. It is also shown that these high-frequency components are not very strong in all types of machine. These results will be useful in generating rules and laws to formulate online tools for machine condition monitoring. Finite-element results to substantiate the inductance values used in the simulation are also included. The analysis is validated by the line-current spectrum of the eccentric machine obtained through simulation using the modified winding-function approach (MWFA) and experimentation.     

感应淬火技术在汽车零件制造中的应用

传统的低层次的PLC控制淬火机床机械动作和单一时间控制模式难以保证结构复杂的汽车零件淬火质量，而计算机软硬件智能化思想改变了传统的工业控制面貌，使我国淬火装置水平达到了一个全新的境界。     

A laboratory model for harmonic measurements in windpowergenerators

In this letter we present the principles of an integrated control and measurement system which is linked to a DC servo motor used to drive a single-phase induction machine. The role of the DC servo motor is to model the drive from the turbine of a wind energy conversion system (WECS). This drive is in turn physically connected to a single-phase induction machine that is in turn linked to an external single-phase supply and various loads applied. Measurements of the harmonic components from the system are obtained from a desktop computer with analog to digital interface cards running programs developed under LabVIEW software. The system demonstrates the greatest change in harmonic components just before onset of power generation and thereafter settles to a constant level. Work is planned to expand the system to include more nodes, three phase capabilities, and reactive power electronic control     

An induction machine model for predicting inverter-machineinteraction

The conventional qd induction motor model typically used in drive simulations is very inaccurate in predicting machine performance, except perhaps for the fundamental component of the current and the average torque near rated operating conditions. Predictions of current and torque ripple are often in error by a factor of two to five. This work sets forth an induction machine model specifically designed for use with inverter models to study machine-inverter interaction. Key features include stator and rotor leakage saturation as a function of current and magnetizing flux, distributed effects in the rotor circuits, and a highly computationally efficient implementation. The model is considerably more accurate than the traditional qd model, particularly in its ability to predict switching frequency phenomena. The predictions of the proposed model are compared with those of the standard qd model and to experimental measurements on a 37 W induction motor drive     

Bus transfer of multiple induction motor loads in a 400 megawattfossil power plant

A computer model capable of simulating multiple induction motors during bus transfer is described and its results compared with field tests. Optimum switching times are specified based on bus residual voltage and phase angle that will maintain motor inrush currents below ANSI/NEMA criteria. Recent papers have documented the inadequacy of the ANSI/NEMA resultant V/Hz criteria for assuring that motor-shaft torques remain below acceptable levels following bus transfer. The presented results support these findings, but indicate that the combination of high and low-inertia motors fed from the same bus will reduce motor peak-shaft torques when compared to individual transfer of low-inertia motor/pump units alone     

Efficiency testing of motors powered from pulse-width modulatedadjustable speed drives

This is a report of efficiency testing of an induction motor powered from three different pulse width modulated adjustable speed drives. The motor was operated at a range of speeds and torques, and each drive was operated at the highest, lowest, and an in-between carrier frequency. The motor was a typical NEMA design B motor, and the drives were typical, industrial scalar drives using the default volts/Hz setting. The testing showed that the drive efficiencies remained above 90% until torque was lowered to below 20% of rated torque. Combined motor and drive efficiencies remained above 80% until speeds or horsepower loads were lowered to below 20% of rated torque. The test was performed using a unique data acquisition scheme that permitted acquisition of a large number of torque settings for each speed selection     

A maximum efficiency-photovoltaic-induction motor pump system

It is not economically viable to connect remote areas to the national electric grid, so pumping systems based on photovoltaic energy sources are suitable for these areas. The induction motor is more rugged, reliable, and maintenance free than d.c. motors. In this paper, a pumping system based on an induction motor driven by a voltage source inverter is investigated. Two control strategies are considered. First, the system is controlled to operate on the maximum power line of the PV array, with variable water discharge Q. Second, the induction machine is controlled to operate at maximum efficiency. The operating characteristic of the array is thus controlled to match the voltage and current required by the motor. Comparison is carried out between the two operating schemes.     

Symbolically aided model development for an induction machine in virtual test bed

A new phase-domain induction machine model for use in power system dynamic simulation is developed with the aid of a symbolic tool. The symbolic tool can automatically construct a time-domain power system component model in the resistive companion form (RCF) that is widely used in time-domain simulators. The automatic differentiation technique (ADT) is utilized within the context of a symbolic modeling language, and the tool has been implemented for the virtual test bed (VTB) simulation environment. The new induction machine model was used to study start-up transients of an induction motor. The new model was verified by comparing the simulation results to those obtained from a standard d-q model. This paper also demonstrates that a symbolically assisted technique can provide an efficient and rapid path for developing complex nonlinear device models for power system simulations.     

PSPICE simulation of single-phase induction motors

Dynamic analysis of a single-phase induction motor is studied using PSPICE software. The machine dynamics are presented by a set of nonlinear time-varying differential equations. The equations which define the motor operation are represented in an orthogonal system. The electric circuit presenting this set of equations is determined and solved by PSPICE software for simulation of the motor. The simulation results are compared with those obtained by EMTP and the experiment. Good agreements are observed for both cases     

A discrete adaptive induction position servo drive

A discrete adaptive induction position servo is designed and implemented. In the proposed servo system, the dynamic model of the indirect field-oriented induction motor is estimated from measurements using the stochastic approach. Based on this model, a PI speed controller and a P position controller are designed using pole-placement and root-locus techniques. In order to reduce the effects of machine and load parameter variations on the performance of the indirect field-oriented induction motor servo drive, an adaptive controller is augmented in which a reduced reference model, which defines the desired following control performance, is chosen and the adaptive control signal is synthesized. The proposed adaptive controller has the advantages of being easy to design and implement. Simulation and experimental results show that good following and regulating control performances are achieved. Moreover, the performances are rather insensitive to parameter variations