A new phase-delay-free method to detect back EMF zero-crossing points for sensorless control of spindle motors

This paper introduces a new rotor position detecting method for the sensorless control of spindle motors in hard disk drives. The method applies a digital filtering procedure to identify the true and false zero-crossing points of phase back electromotive forces, the latter of which are caused by the terminal voltage spikes due to phase commutations. The proposed method is phase-delay free and independent of motor parameters. It is especially suitable for high-speed sensorless brushless dc motors. We used the method to drive many kinds of spindle motors for different hard disk drives. The experimental results confirmed the effectiveness of the proposed method in a wide speed range.     

THE DESIGN AND IMPLEMENTATION OF SELF-COMMISSIONING TECHNIQUES FOR A VECTOR-CONTROLLED INDUCTION MOTOR DRIVE

ABSTRACT

This paper presents the design and implementation of self-commissioning techniques for a vector-controlled induction motor drive. Two key techniques are involved in the self-commissioning of a vector-controlled induction motor drive. The identification of the electric and mechanical parameters of motor and load, and the tuning of controller parameters that are to meet performance specifications in the various vector control loops, are proposed. The proposed techniques are further verified by experiments. Close simulation and experimental results are obtained.     

Adaptive controller design for a synchronous reluctance motor drive system with direct torque control

The design and implementation of adaptive controllers for a sensorless synchronous reluctance drive system with direct torque control is proposed. Two adaptive control algorithms, which include adaptive backstepping control and model-reference adaptive control, are proposed to improve the performance of a sensorless direct torque control synchronous reluctance motor drive system. A digital signal processor, TMS320-C30, is used to execute the rotor position estimating technique and the adaptive control algorithms. The system shows good transient responses, good load disturbance responses and good tracking responses. Several experimental results validate the theoretical analysis. The advanced controller design for a sensorless synchronous reluctance motor drive with direct torque control is proposed.     

Controller design and FPGA implementation of a speed‐sensorless vector‐controlled induction motor drive based on stability consideration

Abstract

The purpose of this paper is to determine the controller parameter tuning range for a speed sensorless vector‐ controlled induction motor drive from the system stability point of view. The tuning rules for conventional PI controllers are mostly based on experience. Trial‐and‐error procedures are used to tune the values of the controller parameters. The relationship between the tuned controller parameters and the stable operating range of the control system is generally not known. This paper starts from establishing complete dynamic models for a sensorless vector‐controlled induction motor drive. The nonlinear dynamic models are linearized around a chosen operating point. The characteristic equation is then derived, which is used to determine the values of the controller parameters corresponding to the marginal system stability. Based on these critical values, the tuning ranges of the controller parameters are obtained, which assures stable operation of the drive in the entire operating region and provides a reference for controller parameter tuning. The proposed method is further extended to include the effect of parameter sensitivity due to motor parameter variation. An experimental setup based on a DSP‐FPGA system is implemented. The simulation and experiments confirm the validity of the proposed approach.     

Space and time harmonics related problems and their mitigation for position and speed sensorless slip-ring induction motor drives applications

There have been renewed interests in slip-ring induction machines due to their increasing use in both grid connected and stand-alone wind power generation schemes. Despite the squirrel cage induction generators’ advantages of being brushless, low-cost, needing less maintenance and having inherent overload protection, the biggest advantage of variable-speed wound rotor induction machines is in its doubled energy capture. Also in high power induction motor drives such as static Kramer drives or static Scherbius drives use of wound rotor induction motors is a must. Thus it becomes necessary to measure the speed of the machine for closed loop control for such high performance drives. Recently, a sensorless position and speed estimation scheme was proposed for wound rotor wind power generator. In this paper, the limitation of the scheme caused by space and time harmonics have been investigated. Simulation results have been presented to explain the mechanism of the space and time harmonics caused distortion of current. Experimental results showing the deterioration of speed detection scheme at light load for a slip-ring induction motor have been presented. Finally, improvements have been applied experimentally to obtain better speed estimation.     

Sensorless permanent-magnet synchronous motor drive using a reduced-order rotor flux observer

A sensorless permanent-magnet synchronous motor (PMSM) drive is developed. A second-order Luenberger observer is used to estimate the position of the rotor flux and hence the rotor speed. The observer is computationally efficient as it has a simple structure and does not involve mechanical parameters. An integral-feedback method is adopted for the estimation of the rotor speed. The inner current loop is realised using a decoupling and diagonal internal model control algorithm. Details of the sensorless control system are given and the feasibility of the proposed method is verified through simulation and experiments. Satisfactory estimation accuracy is obtained even when the drive operates at very low speeds and also during rotor speed reversals.     

Sensorless speed estimation in induction motor drives by using the space vector angular fluctuation signal

A sensorless speed estimation method for real-time application in induction motor drives under steady-state condition is proposed. Speed harmonic component in the space vector angular fluctuation (SVAF) signal, which is caused by both dynamic and static eccentricity, is used for speed estimation. The SVAF signal is obtained from the stator currents of the induction motor. The extraction of speed information using digital signal processing techniques is considered. Experimental results are given to demonstrate the validity of the speed estimation method on an induction motor driven by an inverter.     

Initial rotor position estimation and sensorless direct torque control of surface-mounted permanent magnet synchronous motors considering saturation saliency

For a practical direct torque-controlled (DTC) permanent magnet synchronous motor (PMSM) drive system, the information of the initial rotor position, which is usually obtained by a mechanical position sensor, is essential for starting under the full load. To avoid the disadvantages of using mechanical position sensors, great efforts have been made on the development of sensorless control schemes. An initial rotor position estimation strategy is presented for a DTC PMSM drive based on a nonlinear model of PMSM incorporating both structural and saturation saliencies. In the new scheme, specially designed high-voltage pulses are applied to amplify the saturation saliencies. The peak currents corresponding to the voltage pulses are used, in combination with the inductance patterns, to determine the d-axis position and the polarity of the rotor. The presented initial rotor position identification strategy has been implemented in a sensorless DTC drive for a surface-mounted PMSM. Experiments are conducted to confirm the effectiveness of the method and the performance of the drive system.     

Design of a traveling wave type ultrasonic motor

The purpose of the present paper is to establish a method of design for a traveling wave type ultrasonic motor. This method is based on two models for the ultrasonic motor. A two-dimensional elastic contact model is used for estimating the friction drive between the rotor and vibrator of the motor. Moreover, an electrical equivalent circuit is used to estimate the interaction between the electrical and mechanical parts of the vibrator. The proposed method is applied to the design of a prototype motor. To determine applicability of the method, the load characteristics of the prototype motor are measured. The measured characteristics agree with the required ones which are specified in advance. As a result, the validity of the proposed method is experimentally confirmed     

Sensorless Monitoring of a Motor-Drive Machanical System Based on Adaptive Signal Decomposition

1IntroductionSensorless techniques have been successfully applied to motor speed measurement, noise and vibra-tion identification, and machinery fault diagnosis. Although a variety of relevant techniques such asvibration analysis are nowavailable for the monitoring and diagnosis of a mechanical system, studiesof the sensorless techniques have been followed with great interest by many researchers. In the tech-nique, since the motor is regarded not only as a drive motor to provide mechanical ene…     

A novel sensorless control method for brushless DC motor

The authors present the theory and implementation of a novel sensorless control method for the interior permanent magnet (IPM) brushless DC motor (BLDCM). The proposed new sensorless technique can accurately detect the zero-cross point (ZCP) of back electromotive force (BEMF), which is based on a comparison of the terminal voltage of the un conducting phase during the first and second part of a pulse width modulation (PWM) cycle. Compared with the conventional BEMF sensorless approach, the proposed new sensorless method solves the problem of the sensorless BLDCM drives at very low speeds. Experimental results confirm the validity of the new method.     

Design and implementation of an industrial vector-controlled induction motor drive

Vector-controlled induction motor drives are quite popular in the industry in applications that demand high dynamic performance. This paper describes the implementation of a complete industrial vector-controlled drive for a 30 kW induction motor. The control algorithms for the drive are implemented using a TMS320F28335 Digital Signal Controller (DSC). Various monitoring and protection functions for the drive are implemented using a Cyclone IV FPGA that communicates with the DSC, and acts as the master controller for the drive. The FPGA also communicates with a Human–Machine Interface to provide a simple graphical control interface to the operator.     

Predictive-space vector PWM current control method for asymmetrical dual three-phase induction motor drives

The interest in multiphase drives has re-emerged in the last decade, being the asymmetrical dual threephase induction motor drive one of the most popular options. Predictive control techniques, already implemented in three-phase drives, have been recently adapted to the multiphase case. Schemes proposed so far have demonstrated high performance at the expenses of a higher degree of computational cost and illdefined switching frequency. In this study, a predictive space vector PWM (SVPWM) current control technique with fixed switching frequency is proposed for asymmetrical dual three-phase AC drives. Fast torque and current response are achieved similar to those obtained using conventional predictive current control techniques. Electrical noise suppression is favoured as in PWM current control methods. Experimental results are provided to examine the benefits of the proposed control method.     

Simple position sensorless starting method for brushless DC motor

Position sensorless methods for brushless DC motors based on back-EMF zero crossing suffer from a starting problem since there is no back-EMF at standstill. A simple method by which the motor is started from standstill up to a speed wherein sensorless methods will be able to detect the correct commutation instants is proposed. The proposed method relies on a difference of line voltages measured at the terminals of the motor. It is shown that this difference of line voltages provides an amplified version of an appropriate back-EMF at its zero crossings. It is further demonstrated that this information can be used to trigger devices so as to develop an accelerating torque from zero speed. This method is simple to implement and it can reliably start the motor even with load. The effectiveness of the proposed method is demonstrated through simulation and hardware results.     

A New Sensorless Technique for the Speed Detection of an Induction Motor

1IntroductionSpeeddetechonofmotorsplaysanincreasinglyilnPortantpartinmodemmotorapplications.Amongavarietyoftechniquesareavailable,sensoriesstechniquehasbeenfollowedwithgreatinterestformanyresearherssinceitwaspresentedatthelniddleofl98o's.Inthistechl1ique,themotorisregardednotonlyasadriveInotortoprovidemechanicalenergytothelnotorsysteln,butalsoisregardedasasellsorfromwhichthespeedinformahoncanbeobtained,noadditiOna1transducerorsensorrequired.Voltage-basedlnethodalldcurrent-basedlnethodhavebee…     

半导体精密控温技术在航天器包装容器的应用

目的 对某型号航天器包装容器进行温控系统设计,以达到航天器高精度控温的要求.方法 对总体保温布局进行设计,优化被动保温结构,采用半导体控温方式,利用Ansys Workbench进行稳态和瞬态热力学分析.通过试验测试,验证保温结构设计和热力学分析结果的合理性.结果 在外部施加热源温度36℃和0℃情况下,随着热源区域的远离,包装容器内部的温度也趋于平稳,内部装载产品区域温度基本能维持在20.99～22.662℃.实际试验结果显示箱内温度变化不大于±1℃,比传统的空调控温精度高出70％左右.结论 通过优化箱体的被动保温结构,采用半导体精密控温,可以满足未来航天器小型化、高精度运输要求.     

Automatic induction machine parameters measurement using standstill frequency-domain tests

A new method to measure the induction machine equivalent circuit parameters is proposed. The method is based on three frequency-domain tests, performed at standstill, avoiding then the locked-rotor and no-load tests. The proposed algorithm can be implemented in standard motor drives in order to automatically perform self-commissioning. Furthermore, the proposed method allows a direct measurement of the iron saturation. Experimental results are presented to validate the measurement method and the machine equivalent circuit.     

Practical sensorless control for inverter-fed BDCM compressors

Brushless DC motors (BDCMs) possess higher efficiencies than the conventional induction motors and BDCMs have therefore been used widely in inverter-fed compressors. Since the Hall position sensors cannot work well in the high-temperature environment of refrigerants, sensorless control schemes play an important role in the application of inverter-fed BDCM compressors. Sensorless control for actual BDCM compressor is proposed and implemented. First, the sensorless circuits used have been analysed in detail to find the design rules of the circuit parameters for various compressor motors. Then, the limitations of sensorless control are discussed to develop a practical speed controller for BDCM compressors. The developed starting strategy and sensorless algorithms are presented and digitally implemented. Finally, some experimental results are displayed to demonstrate the proposed sensorless speed control for BDCM compressors.     

Recent advances in permanent magnet brushless DC motors

This paper deals with the latest developments in Permanent Magnet Brushless DC (PMBLDC) motor drives. A comprehensive account of the state-of-the-art on types of construction of the motor, closed loop controllers in position, speed and current/torque control and recent trends in inverters, sensors etc. are given. Techniques for mechanical sensors elimination are discussed in detail. Special efforts made to reduce torque ripples, noise and vibrations are described. The impact of microelectronics through integrated chips used in the control of PMBLDC motor drives is given. The increasing applications of this drive due to improved performance and its cost reduction are also enlisted.     

Adaptive backstepping motion control of induction motor drives

Abstract

In this paper, an adaptive backstepping controller is proposed for position tracking of a mechanical system driven by an induction motor. The mechanical system is a single link fixed on the shaft of the induction motor such as a single‐link robot. The backstepping methodology provides a simpler design procedure for an adaptive control scheme and provides a method to define the sliding surface if the robust slidingmode control is applied. Thus, the backstepping control can be easily extended to work as an adaptive sliding‐mode controller. The presented position control system is shown to be stable and robust to parameter variations and external disturbances. The effectiveness of the proposed controllers is demonstrated in experiments.