Cage Induction Machine Research Articles

Analysis of Squirrel Cage Induction Machine Based on the Magductance Modulator

Analysis of Squirrel Cage Induction Machine Based on the Magductance Modulator

Bearing Faults Diagnosis by Current Envelope Analysis under Direct Torque Control Based on Neural Networks and Fuzzy Logic—A Comparative Study

Diagnosing bearing defects (BFs) in squirrel cage induction machines (SCIMs) is essential to ensure their proper functioning and avoid costly breakdowns. This paper presents an innovative approach that combines intelligent direct torque control (DTC) with the use of Hilbert transform (HT) to detect and classify these BFs. The intelligent DTC allows precise control of the electromagnetic torque of the asynchronous machine, thus providing a quick response to BFs. Using HT, stator current is analyzed to extract important features related to BFs. The HT provides the analytical signal of the current, thus facilitating the detection of anomalies associated with BFs. The approach presented incorporates an intelligent DTC that adapts to stator current variations and characteristics extracted via the HT. This intelligent control uses advanced algorithms such as neural networks (ANN-DTCs) and fuzzy logic (FL-DTCs). In this paper, a comparison between these two algorithms was performed in the MATLAB/Simulink environment for a three-phase asynchronous machine to evaluate their effectiveness under the proposed approach. The results obtained demonstrated a high ability to detect and classify BFs, confirming the effectiveness of each algorithm. In addition, this comparison highlighted the specific advantages and disadvantages of each approach. This information is valuable in choosing the most suitable algorithm according to the constraints and specific needs of the application.

Comparison of Hyper-Reduction Methods Combined With POD: Model Order Reduction of a Squirrel Cage Induction Machine in Nonlinear Case

Comparison of Hyper-Reduction Methods Combined With POD: Model Order Reduction of a Squirrel Cage Induction Machine in Nonlinear Case

Image-Based Approach Applied to Load Torque Estimation in Three-Phase Induction Motors.

This paper presents a novel method for load torque estimation in three-phase induction motors using air gap flux measurement and the conversion of this type of time-domain signal into grayscale images for further processing as inputs for an inception-type convolutional neural network. The magnetic flux was measured employing a Hall effect sensor installed inside the machine, near the stator slots, and above the stator windings. In this case, the sensor was able to measure a resultant magnetic flux density, having both rotor and stator magnetic flux contributions. The present methodology does not require motor parameters for torque prediction. The proposed approach successfully estimated load torque using three optimizers across almost the entire motor load operational range, spanning from 1.5% to 93.9% of the rated load. Four model configurations achieved a mean absolute percentage error (MAPE) less than or equal to 3.7%. Specifically, two models for a 40 × 50 pixel image achieved MAPE of 3.7% and 3%, one model for a 40 × 25 pixel image achieved a MAPE of 3.5%, and one model for a 50 × 80 pixel image achieved a MAPE of 3.3%. This research has been experimentally validated with a 7.5 kW squirrel cage induction machine.

High Efficiency Squirrel Cage Induction Machines

This paper highlights the benefits of replacing the classical cast aluminum cage with a cast copper cage in the manufacture of future generation of high efficiency induction machines used as motors or generators. The numerical analysis carried out in the paper is based on a 2D plane-parallel finite element approach of the induction machine, the numerical results being discussed and compared with experimental measurements.

Dynamic Behavior of an Hybrid Wind – Fuel Cell Generation System: Active and Reactive Power Control

This paper reports the investigation on a detailed model of a real wind farm together with a fuel cell generation system based on hydrogen. The modeled wind farm is made up of squirrel cage induction machines and the developed fuel cell model is based on solid oxide type. The aim of the work is to analyze the symbiosis between the wind generation and a centralized energy storage system based on hydrogen for a particular wind farm embedded in the electric power system. With this aim, it has been developed an active and reactive power control system and it has been proposed an strategy for the generation of the reference current of the fuel cell.

Finite Element Analysis of a Three Speed Induction Machine

This paper deals with the Finite Element (FE) analysis of a special Three Speed Squirrel Cage Induction Machine (TSSCIM) with pole changing stator windings. Compared to classical multi-speed induction machines, the studied TSSCIM is designed so as to change in the same time the number of pole pairs (p) and the number of stator phases (m) so as to keep constant the product p x m. The numerical model of the machine used in this study is based on a 2D plane-parallel finite element approach and aims at finding some of the main steady state operation characteristics of the machine working both as motor and generator for three different running speeds. A comparison of the proposed TSSCIM with a classical inverter fed squirrel cage induction machine is also presented in order to underline some advantages and disadvantages of each solution.

Torque fluctuation and critical clearing time in wind power generation by induction machines.

Squirrel cage induction machines represent a common solution widely adopted in wind generation. The induction machine is simple, reliable, cheap and requires very little maintenance. Some problems are, however, connected with the use of induction machines in wind power generation systems. In particular two effects have to be taken into account: the torque fluctuations at the generator shaft and the critical clearing time (CCT). Both problems represent a serious limitation for weak networks in which the first effect can cause flicker effect while the CCT is very short. In the paper a full modelling of a wind energy plant constituted by n machines is presented. Using the set-up model the behaviour of the plant for a different number of connected machines is analysed. In particular, the system stability connected with voltage sags and network faults is studied

Dynamic Modelling of Wind Farms: a Comparative Study Between Two Modelling Approaches.

World’s energy needs have encouraged wind power sources. An increasing number of wind farms are being connected to the power grid and accurate wind farm models need to be developed to study the dynamic behaviour of them. This paper reports an investigation to compare two different modelling approaches of a real wind farm. This study is applied to the dynamic model of a real wind farm located at El Perdón, in Navarre, (Northern Spain). It consists of 30 Squirrel Cage Induction Machine (SCIM) wind generators of 660 kW and a nominal voltage of 690V. The wind farm feeds three local loads at 66 kV and is connected through two transformers to the network of 220KV.

A Two-Step Continuous-Control-Set MPC for Modular Multilevel Converters Operating With Variable Output Voltage and Frequency

This paper presents a new enhanced single-stage two-step Continuous Control Set Model Predictive Control (CCS-MPC) algorithm, for Modular Multilevel Converters (MMCs) operating with variable output frequency at the AC port. The proposed two-step CCS-MPC allows the implementation of feed-forward compensation of the one-step ahead perturbations at the AC side, using an algorithm based on the Moore-Penrose pseudoinverse matrix. Limitations of the current and voltages in the MMC clusters are implemented to avoid overmodulation and overcurrents, being the solution of the constrained CCS-MPC online solved using the active-set method. Without losing generality, the experimental validation of the single-stage CCS-MPC is performed using an 18-cell MMC prototype, driving a 7.5 kW cage induction machine operating in a wide speed range. A dSPACE MicroLabBox platform is used to control the MMC-based drive by implementing the CCS-MPC algorithm, the modulation stage and the active-set method. It is experimentally demonstrated that the compensation of the low-frequency perturbations allows a considerable reduction in the required circulating currents at the low-frequency operation of the drive. Reduction in the capacitor voltage ripple, improved efficiency, and a smaller Total Harmonic Distortion (THD) in the output currents are also achieved with the proposed single-stage two-step CCS-MPC.

Parameter identification of squirrel cage induction machine using Linear Kalman filter

In the industrial environment, the induction machine is generally the most used, given its low cost, its efficiency, and its reliability. To obtain optimal operation, it is essential to collect values of its parameters (stator and rotor resistances and inductions). This data can be used to prevent breakdowns and ensure these machines’ rational use. In this context, this article proposes a new method to estimate the internal parameters of these machines using the KALMAN FILTER. Simulations under the MATLAB environment have been developed. Their results show that the estimated parameters are close to the nominal ones.

Development of a Novel High Strength Aluminum-Cerium Based Rotor Alloy for Electric Vehicle Induction Motor Applications

<div class="section abstract"><div class="htmlview paragraph">To increase vehicle range, light weighting of electric vehicles has been extensively researched and implemented by using aluminum intensive solutions. With regards to traction motors, aluminum alloys that have a desired combination of high electrical conductivity and strength are required for high power output and efficiency. In this research, a novel Al-Ce based alloy, with minor additions of Si and Mg for strengthening, was investigated in different heat treatment tempers to maximize mechanical properties while maintaining a high electrical conductivity. This new alloy system appears to have addressed the classic conundrum of the inverse relationship of mechanical performance verses electrical conductivity for traditional aluminum alloy systems. The results suggest that the Al-Ce-Si-Mg alloy had yield strength in excess of 120 MPa and electrical conductivity of at least 50 %IACS in the T5 and T6 conditions. Simulations of a squirrel cage induction machine show that this combination of properties resulted in similar motor performance to other rotor Al alloys. As a result, the Al-Ce-Si-Mg alloy is a promising alternative to the near pure Al or Cu-based alloys that are currently used in induction motor rotor castings.</div></div>

An Improved Dual DTC of Double-Inverter-Fed WRIM Drive With Reduced Torque Ripple by Emulating Equivalent 3L NPC VSC

Wound rotor induction machine (WRIM) connected to stator and rotor voltage source converters (VSCs), known as the double-inverter-fed WRIM drive, can be viewed as two virtual squirrel cage induction machine drives, when seen from air-gap. In this article, this feature of WRIM is explored to develop an improved dual direct torque vontrol (DDTC) technique such that, two individual and independent conventional DTC controllers can be directly employed to control the stator and rotor VSCs. The improved technique is inculcated with all the benefits of conventional DTC controller, especially the benefit of zero dependence on rotor position. Furthermore, the increased torque ripple with the conventional DTC controllers is mitigated by modifying the switching tables (STs) such that, the voltage vectors emulated in the air-gap are equivalent to a 3-level neutral point clamped VSC. The STs are developed by analyzing the WRIM as an open-end winding induction machine (OEWIM). To demonstrate the performance of the proposed DDTC technique, the experimental results obtained from 3 kW WRIM are presented, under various transients and steady-state conditions. The reduction in the torque ripple is demonstrated by estimated torque ripple waveforms, at different speeds.

Improved control scheme of a dual star induction generator integrated in a wind turbine system in normal and open-phase fault mode

A robust control scheme of a wind turbine system (WTS) based on a dual star induction generator (DSIG) in normal and open-phase fault (OPF) mode is presented in this paper. The strong point of this generator that recently attracted the attention of several researchers especially in wind energy field is that it combines the advantages of the squirrel cage induction machine and those of multiphase ones. This research is carried out to reach two main objectives. Firstly, in order to ensure a robust control of the DSIG-based WTS with a low effect of chattering phenomenon, an improved control scheme based on super-twisting continuous sliding mode controllers (STCSMC) is proposed. The second objective is to verify, by an OPF test, the ability of the DSIG to operate in degraded conditions. Finally, simulated results show that more robust control is achieved and that the DSIG-based WTS continues to provide suitable electrical energy to the grid without remarkable effects.

Effects of induction machine parameters on its performance as a standalone self excited induction generator

A squirrel cage induction machine (SCIM) when aggregated with relevant capacitances and a prime mover, acts as self-excited induction generator (SEIG). As it hosts energy conversion the parameters of SCIM have considerable impact on the power extraction capability of SEIG. An aspect which is missing from the available research on SEIGs is evaluation of the affects of its rotor’s moment of inertia (J) and per-phase stator winding resistance (Rs) on performance indices. This work investigates the impacts of these factors on a SCIM’s performance as series compensated, short shunt SEIG. The study considers two distinctly designed SCIMs, in terms of J and Rs, operated as SEIG. In order to simulate their performance a stationary reference frame dq model including non-linear saturation and cross coupling effects is developed and verified experimentally. Several key investigations based on series capacitance selection, losses and efficiency, on-load performance with different power factor loads, transient performance with load perturbation and variable speed operation are carried out. The study reveals that SEIG with high J and lower Rs gives considerably better performance than its counterpart. The conclusions reported in the study are important especially for standalone/off grid application of SEIGs.

A comparative study for stator winding inter-turn short-circuit fault detection based on harmonic analysis of induction machine signatures

This article deals with inter-turn short-circuit fault detection in stator windings of squirrel cage induction machines. The main aim is to perform harmonic analysis of different electrical signatures namely the stator phase current, external magnetic flux and electromagnetic torque at different levels of mechanical load in order to develop an efficient fault detection approach of this kind of defect in induction machines. The proposed approach is based on the analysis of saturation related harmonics at rank 3k1fs, where k1 is an odd number, and magnetomotive force (MMF)-related harmonics at rank (6k2±1)fs, with k2=1,2,… in stator phase current and stray flux and harmonics at rank 2k2fs in electromagnetic torque. The amplitudes of these last harmonics in healthy condition are compared with 3% power supply unbalance, 16.6% (40 turns) and 33% (80 turns) levels of inter-turn short-circuit fault in frequency range from 0 Hz to 2500 Hz under different levels of mechanical load. Besides, the stand-still test is also investigated in this work. Simulation study is carried out based on 2.2kW squirrel cage IM using finite element method (FEM). This method provides accurate and inexpensive tool for evaluating the performance of induction machine under healthy and faulty conditions. The obtained results demonstrate that the stray flux is the most sensitive signature to the stator winding inter-turn short-circuit fault, and it is robust against the power supply unbalance in comparison with both stator current and electromagnetic torque.

Reduced order field-circuit modeling of squirrel cage induction machines for automotive applications

PurposeThe aim of the paper is to investigate the impacts of simplifications of a reduced-order simulation model of squirrel cage induction machines (SCIMs) by numerical experiments.Design/methodology/approachDesign of setups to isolate the main influences on the results of the reduced-order model of SCIMs. Results of time-stepping finite element calculations are used as benchmark.FindingsWhereas neglecting eddy current effects and the assumption of a sinusoidal rotor current distribution leads to acceptable deviations in regular inverter operation, the sampling and interpolation of the machine parameters in a two-axis coordinate system considerably deteriorate the model accuracy. Using a polar coordinate system for this purpose is expected to significantly improve the model quality.Originality/valuePreparing the ground for a successful, both fast and accurate simulation model of SCIMs as parts of electrified drivetrains.

Detection of Broken Rotor Bars in a Cage Induction Machine Using DC Injection Braking

In this paper, an effective procedure for broken rotor bar (BRB) fault detection in a three-phase squirrel-cage induction machine (SCIM) is proposed. This approach relies on a motor current signature analysis (MCSA) by observing the specific fault-related current component generated by applying the DC injection braking method. Unlike the traditional MCSA, which is commonly focused on the detection of BRB sidebands around the fundamental current component, the proposed methodology introduces a new BRB feature in the current spectrum which makes it much easier for identification. The distinctive time-frequency evolution pattern of this feature provides the reliable identification of BRBs, even under no-load operating conditions, thus overcoming the major drawback of traditional MCSA-based methods. Fault severity classification is easily performed through the magnitude inspection of the BRB fault-related current component. In addition, the proposed approach does not require high-complexity signal processing algorithms to achieve reliable results. The proposed concept is presented theoretically, assisted by a magnetically coupled multiple circuit model of the SCIM, both with healthy and faulty rotor bars. Finally, the experimental tests validate the proposed methodology and demonstrate its effectiveness and usefulness.

On Medium Frequency Differential Mode Resonance Effects in Doubly Fed Induction Machines

During synchronization phase of a doubly fed induction machine prototype abnormal high voltages were recorded at stator terminals. By evaluating the measured curves, and the frequency response of a similar machine, these overvoltages could be traced back to differential mode resonance effects within the machine itself. The effect of differential mode resonance is not restricted to doubly fed induction machines but also occurs in other machine types such as squirrel cage induction machines. If not considered in the insulation design, such abnormal voltages will lead to a premature ageing of the insulation. Depending on the operating conditions, premature failures may occur. The measured data presented in the article give an illustrative example what could happen if windings of electric machines are excited near series resonance frequency. As the occurence of this effect becomes more probable the higher the switching frequency of the converter, it is thoroughly important to be aware of it.

Stator Current Spectral Content of Inverter-Fed Cage Rotor Induction Motor

The paper analyzes the influence of the number of rotor bars on the stator current spectral content in a three-phase cage induction motor fed by a pulse-width modulated (PWM) inverter. It is shown that each of the higher-order time harmonics in the supply voltage produces space harmonics in a rotating magnetic flux density wave, which results in induced rotor slot harmonics (RSHs) in the stator current spectrum. The conditions for the existence of these space harmonics are identical to those applying to a mains-fed motor. In other words, the number of rotor bars of a mains-fed motor yielding an RSH-free stator current spectrum produces the same stator current spectrum even in case the motor is inverter-fed. Additionally, to minimize the adverse effects of RSHs in the stator current spectrum, one must consider not only the number of rotor bars, but also its relationship with the frequency modulation ratio of the PWM inverter. Analytical predictions are presented to illustrate these results supported both by numerical simulations of the induction motor modelled through the winding function theory and experimentally taking the case a two-pole cage induction machine as a case study.