Inverter Driven Induction Motor Research Articles

Stray Loss Formulation for Inverter-Driven Induction Motors for a Wide Range of Switching Frequency and Motor's Loading

Stray Loss Formulation for Inverter-Driven Induction Motors for a Wide Range of Switching Frequency and Motor's Loading

Power quality improvement of large power induction motor drive using three-level front-end converter

PurposeThe purpose of this study is to provide the enhancement of power quality of a high power-rated voltage source inverter driven induction motor with a three-phase, three-level neutral point clamped converter placed at the front end, while a passive power filter is connected in shunt with it. The improvement in power quality can be achieved by reducing the total harmonic distortion in source current. The controllers were designed for the linearization of the high-power induction motor drive. A control method is presented for the regulation of the common DC-link voltage.Design/methodology/approachThe induction motor is modeled using its dynamic equations, and a decoupling controller is designed to linearize the nonlinear dynamics of the drive through feedback. The common DC-link voltage of the proposed front-end connected converter is monitored and controlled through a control method which feeds the pulse width modulated inverter that drives the induction motor. A passive power filter is designed to meet the reactive power requirement of the system in addition to improve the power quality.FindingsSimulations were carried out for the proposed topology of the drive mechanism, and the outcomes were analyzed by a comparative analysis of the drive system both in the presence of the passive filter as well as in the absence of the filter. The total harmonic distortion is found to be reduced enough to meet the standards with the designed filter, and the reactive power is also compensated considerably. The input power factor at the supply side is maintained almost to unity, and the DC-link voltage of the proposed circuit topology is maintained at the desired level. The overall performance of the drive system was found to be useful and economical.Originality/valueA new topology of a front-end connected three-level neutral point clamped converter to a high power-rated induction motor drive is proposed. The drive is fed by a pulse width modulated inverter with a common DC-link with the front end connected converter. A passive filter is designed with respect to the reactive power requirement of the system and connected in shunt to the converter at the supply side. Control schemes are designed and used for the drive system and also for the regulation of the common DC-link voltage of the proposed front end connected converter.

A Modified PWM Strategy With an Improved ANN Based MPPT Algorithm for Solar PV Fed NPC Inverter Driven Induction Motor Drives

A Modified PWM Strategy With an Improved ANN Based MPPT Algorithm for Solar PV Fed NPC Inverter Driven Induction Motor Drives

Performance of 7-level cascade H-bridge multi level inverter driven induction motor drive

In recent times, many of industrial applications require smooth control over a wide range of speeds or smooth torque control without effecting motor performance and efficiency. So, cascaded H-Bridge multilevel inverters convert the low or medium level voltage to medium or high level of output voltages. In this paper, a cascaded H-Bridge multilevel seven level inverter is operated by using sinusoidal pulse width modulation technique. This PWM technique will improves the smoothness of waveform by reducing the lower order harmonics. And analysed its performances like speed, torque, THD etc.

Core Loss Estimation for an Inverter-Fed Induction Motor With More Accurate Realisation of Material Non-Linearity and Impact of Hysteresis Minor Loops

The work presents a fast and accurate core loss evaluation method for inverter-fed induction machines. The proposed method takes into account the influence of time variation of magnetic permeability on the eddy current loss. Furthermore, the proposed method presents an accurate approach to precisely evaluate the hysteresis loss. The results obtained from the proposed method are compared with the existing methods for a 1.5kW inverter-driven induction motor. The method shows sufficiently high accuracy with reduced complexity and implementation-time for a wide range of inverter switching frequency and motor's loading.

Machine learning based multi class fault diagnosis tool for voltage source inverter driven induction motor

AC drives are employed in process industries for varying applications resulting in a wide range of ratings. The entire process industry has seen a paradigm shift from manual to automated systems. The major factor contributing to this is the advanced power electronics technology enabling power electronic drives for smooth control of electric motors. Induction motors are most commonly used in industries. Faults in the power electronic circuits may occur periodically. These faults often go unnoticed as they rarely cause a complete shutdown and the fault levels may not be large enough to lead to a breakdown of the drive. An early detection of these faults is required to prevent their escalation into major faults. The diagnostic tool for detection of faults requires real time monitoring of the entire drive. In this work, detailed investigation of different faults that can occur in the power electronic circuit of an industrial drive is carried out. Analysis and impact of faults on the performance of the induction motor is presented. A real time monitoring platform is proposed to detect and classify the fault accurately using machine learning. A diagnostic tool also is developed to display the severity and location of the fault to the operator to take corrective measures.

Electric Machine Bearing Health Monitoring and Ball Fault Detection by Simultaneous Thermo-Mechanical Fibre Optic Sensing

This article reports the use of fiber Bragg grating (FBG) sensors for electric machines' in-service bearing condition monitoring. The proposed method enables simultaneous extraction of thermal and mechanical information on the bearing operational status for health monitoring and fault diagnosis purposes. The work first reports the instrumentation, calibration and the measurements interpretation methods of an FBG array sensor fitted to the drive-end bearing of an operating inverter driven induction motor. Experimental tests are then undertaken on a purpose build test rig to evaluate the proposed in-situ sensing scheme's performance under healthy and faulted bearing conditions. The results demonstrate that the measurements acquired by individual FBG sensors fitted in the bearing architecture contain concurrent thermal and mechanical information, which can be clearly differentiated to enable understanding of the examined motor bearing's thermal only and mechanical only operating conditions. Furthermore the in-situ measurements obtained in fault conditions are shown to contain clearly defined time and frequency domains fault signatures, which can enable unambiguous fault diagnosis and trending.

An Approximate Estimation Approach of Fault Size for Spalled Ball Bearing in Induction Motor by Tracking Multiple Vibration Frequencies in Current.

Fault size estimation is of great importance to bearing performance degradation assessment and life prediction. Until now, fault size estimation has generally been based on acoustic emission signals or vibration signals; an approach based on current signals has not yet been mentioned. In the present research, an approximate estimation approach based on current is introduced. The proposed approach is easy to implement for existing inverter-driven induction motors without complicated calculations and additional sensors, immune to external disturbances, and suitable for harsh conditions. Firstly, a feature transmission route from spall, to Hertzian forces, and then to friction torque is simulated based on a spall model and dynamic model of the bearing. Based on simulated results, the relation between spall size and the multiple characteristic vibration frequencies in friction torque is revealed. Secondly, the multiple characteristic vibration frequencies modulated in the current is investigated. Analysis results show that those frequencies modulated in the current are independent of each other, without spectrum overlap. Thirdly, to address the issue of which fault features modulated in the current are very weak, a fault-feature-highlighting approach based on reduced voltage frequency ratio is proposed. Finally, experimental tests were conducted. The obtained results validate that the proposed approach is feasible and effective for spall size estimation.

Developed operation of inverter fed induction motor to drive the electric vehicle

This paper focuses on increasing the operating efficiency of the inverter drive induction motor for electric vehicles. The vehicle speed control is achieved by changing the frequency from 5 Hz to 100 Hz. In this work, characteristics of the inverter control induction motor drive are established. The mathematical analysis is developed by the computer programs. The computed characteristic curves are obtained. Due to the difficulty of obtaining an actual electric vehicle in the lap, a fan load equivalent to the electric vehicle is used. The load characteristics are measured at different applied voltages for energy saving.

A Simulink / MATLAB Model of a Three-Phase Sinusoidal PWM Inverter Driven Induction Motor

A three-phase voltage source inverter driven induction motor dynamic model developed using Simulink / MATLAB is presented. The presented model is derived from the d-q motor model. A modular approach is used in the construction of the motor-drive system model. The model presented is useful for studying both the steady-state and transient behavior of the motor drive system. The developed model enables the user to access all parameters of interest. Modifications can be made to the system model in order for it to be used with other motor drive system topologies. The model has benefits for use by undergraduate student researchers, and professors when used as a teaching tool in undergraduate courses.

Performance of a Classifier Based on Time-Domain Features for Incipient Fault Detection in Inverter Drives

In the field of industrial informatics and fault diagnostic applications, an important topic is about detecting and locating fault in an industrial machinery in its incipient stage. This enables avoiding severe faults that are often followed by unscheduled process interruptions and escalated maintenance cost. Inverter-driven induction motor drives, among other irregularities, suffer from degradation of switching device (such as insulated gate bipolar transistor (IGBT)) junctions giving rise to spurious resistance at those junction points. The present research attempts to identify those incipient yet progressive faults from motor current signature by a time-domain computation technique for feature extraction followed by the use of support vector machine classifier. Additionally, it is observed that spurious resistance faults in an inverter can be grouped in a particular pattern using mean current vector distribution. Different experimental results confirm that the proposed method is robust to change in motor parameters and load while giving satisfactory classification accuracy.

A cast copper rotor induction motor for small commercial EV traction: Electromagnetic design, analysis, and experimental tests

According to the demands of the small commercial electric vehicle (EV) traction driving system, an 18kW inverter-driven induction motor (IM) with a die-casting copper squirrel cage rotor for traction drive was designed and evaluated. The 2D finite element model of the designed IM was built by considering the nonlinearity of core materials, and the geometric parameters of the motor were optimized. The operational performance of torque versus speed characteristics and the efficiency over the speed range under the rated (continuous) and overload condition were investigated. Finally, the designed inverter-driven IM was developed and the performance of the IM operating in three typical modes were tested respectively. The experimental results of the designed motor operating in various driven mode were compared with that of 2D FEM. All the results proved that the designed inverter-driven IM could meet the target specification of the small commercial EV.

Seven Level Inverter Fault Mitigation Using Redundant Cell for Induction Motor Drive

<span lang="EN-US">Fault identification is as much important as prior knowledge to mitigate the faults that might occur in inverter driven induction motor drives. In this paper, seven-level multi level inverter was taken up for testing of mitigation using redundant cell and the results were compared with five-level inverter to exhibit the performance of mitigation policy. This paper presents analysis of inverter feeding an induction motor drive when switch open and short fault occurs. When the fault occurs, the redundant cell activates and thus the drive system operates. In this paper, the function for redundant cell was explained with the results of drive system simulated in Matlab/Simulink.</span>

Low complexity predictive torque control strategies for a three‐level inverter driven induction motor

Iterative and complex prediction loop is a challenge for the implementation of finite-state predictive torque control (FS-PTC) of motor drive. The complexity is due to the complex torque calculations, number of available voltage vectors (which are called as prediction vectors), and weighting factor tuning for torque and flux errors in the cost function. One way to reduce the complexity is an equivalent reference stator flux vector calculation (RSFVC) from torque and flux references, which also solves the problem of weighting factor tuning. Along with a new stator flux based RSFVC technique, a reduced number of prediction vectors are proposed in this study to reduce the number of iteration of the prediction loop. The position of the stator flux and sign of the stator flux-error are considered to lessen the number of prediction vectors. Hence, the implementation challenges of FS-PTC algorithm are overcome. The performance of the proposed technique is investigated for two types of RSFVCs: one is based on the stator flux, and another one is based on the rotor flux. Experimental results verify that the proposed low complexity FS-PTC strategies retain the advantages of a conventional FS-PTC.

인버터 입력전류 분석을 이용한 유도전동기 고장진단

운전 중인 유도전동기에 고장이 발생하면, 구동장치 등 전체 시스템에 2차적인 고장을 유발 시킬 수 있다. 이 경우 구동시스템의 신뢰도와 안전성이 저하되고, 경제적인 손실을 초래할 뿐만 아니라, 인명 피해의 위험 등 많은 문제가 발생할 수 있다. 따라서 유도전동기의 고장징후를 조기 감지하여 전체 시스템 고장을 방지할 수 있도록 하는 유도전동기 고장진단 방법이 필요하다. 본 논문은 유도전동기에서 고정자권선의 부분 단락과 회전자 바의 균열이 발생하는 경우, 인버터 입력전류를 분석하여 고장징후를 조기 감지하는 유도전동기 고장진단 방법을 제안한다. 제안한 고장진단 방법은 고정자 전류 3개를 모두 센싱해야 하는 기존 고장진단 방법과 달리, 인버터 입력전류 센서 한 개만으로 유도전동기 고장진단이 가능하다. 또한, 정상전류 주파수성분과 고장전류 주파수성분이 서로 분리되어 나타나는 인버터 입력전류 특성을 통해 기존 고장진단 방법보다 비교적 쉽고 확실한 고장진단이 가능하다. 시뮬레이션을 통하여 제안한 유도전동기 고장진단 방법의 우수성과 유효성을 확인한다. It is well known that since abrupt faults in induction motors tend to lead to subsequent faults and deterioration of the drive apparatus, motor faults may lead to several operating restrictions, such as security problems and economic loss. A lot of research has been done in the area of diagnosis to detect machine faults and to prevent catastrophic hazards in the motor drive system. This paper presents a new method of motor current signature analysis in which the DC-link current of the inverter-driven induction motor system, where a single current sensor is employed instead of three AC current sensors, is measured, and fast Fourier transform analysis is performed. This proposed method makes it possible to easily discern and clearly separate the motor fault current signature from the normal operation current flowing through the stator and rotor windings.

Diagnosis of airgap eccentricity fault in the inverter driven induction motor drives by transformative techniques

Summary In the present paper, the airgap eccentricity fault of the induction motor has been diagnosed by digital signal processing transformative techniques in the inverter driven induction motor drives. The airgap eccentricity fault has been diagnosed in the transient condition by time domain as well as time-frequency domain techniques with the help of a proposed dynamic simulation model. In the past, many signal processing techniques had been used for various induction motor fault detection purpose such as fast Fourier transform, Hilbert transform, short term Fourier transform, etc. But, all techniques faced some sort of disadvantages. Therefore, in this paper, all shortcomings of the previous used signal processing techniques have been solved by newly wavelet transform's approximation signal. The low frequency approximation signal has been used to diagnose the eccentricity fault in the transient condition. Therefore, early fault diagnosis of the motor is possible and averted the motor before reaching in the ruinous conditions. As a result, the industries may save large revenues and unexpected failure conditions. The obtained results clearly demonstrate that the developed diagnostic technique may reliably separate airgap eccentricity fault in many stages.

A Fault-Tolerant Dual Three-Level Inverter Configuration for Multipole Induction Motor Drive With Reduced Torque Ripple

Multilevel inverters are gaining more attention in ac drive application due to their many attractive features. In the case of conventional neutral-point-clamped (NPC) or flying capacitor multilevel inverter configurations, active switches are connected in series to produce multilevel output voltage waveform. Therefore, if any one switch fails, the entire configuration has to be shut down; this will reduce the reliability of the system. A dual three-level inverter configuration for induction motor drive is proposed in this paper to improve reliability of the system. This topology is developed by feeding four-pole induction motor stator winding with four conventional two-level inverter modules. A level-shifted carrier-based third harmonic injection pulsewidth-modulation technique is used to produce the gating signals for the proposed configuration. By providing proper phase shift between carrier waves, multilevel voltage waveform is produced across the total motor phase winding, and first center band harmonics are also canceled. Thereby, the torque ripple will be considerably reduced compared with conventional NPC five-level inverter-driven induction motor drive. Finite-element analysis (FEA) is used to estimate the torque ripple when induction motor is supplied by the proposed configuration and conventional five-level NPC inverter configuration to show the effectiveness of the proposed converter. The proposed configuration is simulated using MATLAB/Simulink and experimentally verified using a laboratory prototype with a 5-hp four-pole induction motor drive.

Transient Model and Detection of Stator Inter-Turn Fault In Inverter Driven Induction Motor Drives by Time Domain Technique

Transient Model and Detection of Stator Inter-Turn Fault In Inverter Driven Induction Motor Drives by Time Domain Technique

Wavelet-fuzzy speed indirect field oriented controller for three-phase AC motor drive – Investigation and implementation

Three-phase voltage source inverter driven induction motor is used in many medium- and high-power applications. Precision in speed of the motor play vital role, i.e. popular methods of direct/indirect field-oriented control (FOC) are applied. FOC is employed with proportional–integral (P-I) or proportional–integral–derivative (P-I-D) controllers and they are not adaptive, since gains are fixed at all operating conditions. Therefore, it needs a robust speed controlling in precision for induction motor drive application. This research paper articulates a novel speed control for FOC induction motor drive based on wavelet-fuzzy logic interface system. In specific, the P-I-D controller of IFOC which is actually replaced by the wavelet-fuzzy controller. The speed feedback (error) signal is composed of multiple low and high frequency components. Further, these components are decomposed by the discrete wavelet transform and the fuzzy logic controller to generate the scaled gains for the indirect FOC induction motor. Complete model of the proposed ac motor drive is developed with numerical simulation Matlab/Simulink software and tested under different working conditions. For experimental verification, a hardware prototype was implemented and the control algorithm is framed using TMS320F2812 digital signal processor (dsp). Both simulation and hardware results presented in this paper are shown in close agreement and conformity about the suitability for industrial applications.

Premature Wear and Recurring Bearing Failures in an Inverter-Driven Induction Motor—Part I: Investigation of the Problem

This paper provides an analysis about early incipient and recurring failures in three-phase induction motor bearings when driven by pulsewidth modulation (PWM) inverters, focusing on a real industrial process. The potential problems preliminarily defined were first discussed on a theoretical basis and afterward experimentally assessed by means of vibration, stator current, and common-mode current data acquisition and analysis. Over the investigation, it was concluded that the presence of common-mode currents at the verified levels could cause damages to the motor bearings, which was confirmed when the machine stopped working due to another bearing failure.