Three-phase Induction Machine Research Articles

New Speed Control Scheme for a Three-Phase Induction Machines - (3~IM) Based on Sine Duty Cycle Modulation (SDCM)

This paper proposes a new control scheme for three-phase induction machines based on the sinusoidal duty cycle modulation control strategy combined with V/f control. This technique allows efficient open-loop control of inverter switches. The proposed diagram shows the main characteristics:1 0.1   ,0 50 ,Hzf 21.44 ,base KHzf  2 ,12ref V Vu  . In addition, it guarantees optimum operation of the inverter with the torque and speed parameters of the three-phase induction machine complying with current requirements:10rC Nmmax 6,5A/50Hz/ THD=1,2%

Diagnosis of Multiple Open-Circuit Faults in Three-Phase Induction Machine Drive Systems Based on Bidirectional Long Short-Term Memory Algorithm

Availability and continuous operation under critical conditions are very important in electric machine drive systems. Such systems may suffer from several types of failures that affect the electric machine or the associated voltage source inverter. Therefore, fault diagnosis and fault tolerance are highly required. This paper presents a new robust deep learning-based approach to diagnose multiple open-circuit faults in three-phase, two-level voltage source inverters for induction-motor drive applications. The proposed approach uses fault-diagnosis variables obtained from the sigmoid transformation of the motor stator currents. The open-circuit fault-diagnosis variables are then introduced to a bidirectional long short-term memory algorithm to detect the faulty switch(es). Several simulation and experimental results are presented to show the proposed fault-diagnosis algorithm’s effectiveness and robustness.

Experimental study on excitation phenomena of renewable energy source driven induction generator for isolated rural community loads

Induction machines (IMs) are one of the most popular electric machines due to their many advantages. It is well known that the IM can be utilized as a motor and generator at below and above synchronous speeds, respectively. However, an induction generator (IG) in the off-grid mode is not a self-started generator. A proper rating of the reactive power supply to the core of the generator and maintaining the rotor speed above the synchronous speed are key challenges in the off-grid mode for exciting the IG to generate the voltage and frequency at desired values. The voltage and frequency are dependent on the amount of reactive power supplied to the stator of the generator and the rotor speed. Since these two factors play a significant role, a key finding is presented in this paper by conducting various experiments on a three-phase IM and investigate the allowable upper and lower limits to avoid over and under-excitation issues during the self-excitation process. Additionally, different methods for the calculation of the required reactive power have been studied in this paper to identify the best method. The proposed study is advantageous for making effective use of IM as an IG for isolated rural applications.

Dynamic Simulation of Three Phase Induction Machines Based on Reduced Order Model for Power Systems Analysis

Induction machines are a crucial type of electrical equipment utilized as motors in various industries and single-phase forms in household applications. They make up more than 80% of the industrial motors used today. This paper presents a dynamic simulation of three-phase induction machines based on the (d-q) model, providing a clear and easy-to-understand explanation of the behavior of the induction motor in the synchronous reference frame. The simulation is implemented using SIMULINK/MATLAB software, and full-order model analysis is conducted for transient analysis. However, modeling induction machines as part of power system analysis can be done with a less detailed model than the full-order one. In this paper, a reduced-order model is employed to simulate the induction motor using MATLAB/SIMULINK. The results of the reduced-order system and the full-order framework are compared to investigate the model's limits, and the computational benefits of saving time during large power system simulations justify the relative decrease in accuracy. The use of a reduced-order model results in a significant reduction in computation time when simulating large and very large-scale power systems, with a much higher accuracy in transient analysis than the conventional steady-state model.

INDUCTIVE COUPLER FOR BATTERY CHARGING SYSTEM OF HEAVY ELECTRIC VEHICLES

This paper proposes a robust fault-tolerant control (FTC) for the dual three-phase (DTP) induction machines under failures controlled by a higher-order sliding mode control strategy. However, the DTP induction machine is increasingly used because of better reliability and a supply division. A passive and an active FTC law have been designed and tested on DTP. The proposed method not only realizes the FTC and the fault elimination but also provides a possible solution for emulating a traction system using a direct continue machine (DCM) supplied by a four-quadrant chopper. Therefore, the emulation system is based on a controlled DCM, which imposes the same behavior of the mechanical power train of an electric vehicle to the DTP. Simulation results are given to verify the robustness and good performance of the proposed fault-tolerant control scheme.

NONLINEAR FAULT TOLERANT CONTROL OF DUAL THREE-PHASE INDUCTION MACHINES BASED ELECTRIC VEHICLES

This paper proposes a robust fault-tolerant control (FTC) for the dual three-phase (DTP) induction machines under failures and which is controlled by a higher-order sliding mode control strategy. However, the DTP induction machine is increasingly used because of its advantages such as better reliability and supply division, both passive and active FTC laws have been designed and tested on DTP. The proposed method not only realizes the FTC and the fault elimination as well but also provides a possible solution for emulating a traction system using a direct continue machine (DCM) supplied by a four-quadrant chopper. Therefore, the emulation system is based on a controlled DCM, which imposes the same behavior of the mechanical power train of an electric vehicle to the DTP. Simulation results are given to verify the robustness and good performance of the proposed fault-tolerant control scheme.

Discrimination Between Eccentricity and Interturn Faults Using Current or Voltage-Reference Signature Analysis in Symmetrical Six-Phase Induction Machines

Two common defects in induction machines (IMs) are eccentricity and interturn faults, which should be diagnosed to prevent performance degradation and further damage. A popular fault-detection approach is the current signature analysis (CSA), because of its simplicity and nonintrusiveness. Under closed-loop control, it is combined with analogous voltage-reference (VR) signature analysis (VRSA). However, by using these methods in three-phase IMs, it is difficult to discriminate between these faults, which cause similar symptoms. Multiphase machines provide remarkable advantages such as inherent tolerance to open-phase faults. Six-phase IMs are particularly attractive since they allow adopting three-phase converters. Among them, those with symmetrical spatial arrangement of the stator phases offer superior fault tolerance. Nonetheless, the distinction between eccentricity and interturn failures in these IMs has not been addressed so far. This article studies the discrimination between eccentricity and interturn faults in symmetrical six-phase (S6) IMs by CSA or VRSA. It is shown that, conversely to three-phase IMs and most other multiphase IMs, in S6 ones, these two types of failures can be easily distinguished: interturn faults considerably alter the currents or VRs in the so-called <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{x}$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{y}$</tex-math></inline-formula> plane, whereas eccentricity leads to current/voltage symptoms only in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{\alpha} _{\mathbf{1}}$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{\beta} _{\mathbf{1}}$</tex-math></inline-formula> plane. Experimental results confirm the theory.

Winding Design and Efficiency Analysis of a Nine-Phase Induction Machine from a Three-Phase Induction Machine

Multiphase machines are a hot research topic in control theory and industrial applications such as electric cars. However, the availability to buy them in the market is limited or null. For this reason, it is common to rewind it from a three-phase commercial machine. In this context, the aim of this paper is two-fold. First, to introduce a straightforward procedure to rewind a nine-phase induction machine from a three-phase one. For that purpose, a study of the three-phase induction motor was performed, which included selecting a new winding design, calculating stator coils, and simulating tests with ANSYS Maxwell software to validate the design. Secondly, a performance analysis comparing the power losses through experimental tests performed to obtain the electrical parameters of both nine-phase and three-phase topologies is presented.

Analysis and Implementation of Sliding Mode Controller-Based Variable Frequency Drive Using the SCADA System

Vector control of an asynchronous machine is traditionally accomplished by analogizing it to a separately excited DC machine. It provides decoupled torque and flux control that is perpendicular to each other, ensuring that neither vector interferes with the other. So, despite their close interconnection, torque and speed control are accomplished separately. The rotor flux is aligned with the direct axis of the synchronously rotating reference frame to achieve this. The PI controllers are critical in achieving the variable frequency drive (VFD) desired topology. The system employs three types of controllers: flux, speed, and torque. The flux controller is easy to tune, but the speed and torque controllers are more difficult to tune because the speed controller's output is the torque controller’s reference signal. Furthermore, there is no well-defined method for tuning the controllers in a vector control system. However, perfect tuning is required for the machine’s better dynamic behavior. It is clear from the above analysis that system identification is critical for tuning PI controllers. However, as an asynchronous machine, obtaining a decoupled system transfer function is extremely difficult. To solve this problem, the proposed system combines a seven-level pulse width modulation (PWM) inverter for vector control of a three-phase asynchronous nonstandard induction machine used in critical applications in nuclear power plants with a sliding mode control technique that eliminates the complexity of PI tuning. A second-order sliding mode controller could be used in the future to reduce the chattering and parameter variation effects. This controller can be enhanced with fuzzy logic principles to make it more robust and reliable, allowing it to be used in future drive designs for high-rating motors with critical applications.

Sliding-Mode Current Control with Exponential Reaching Law for a Three-Phase Induction Machine Fed by a Direct Matrix Converter

The direct matrix converter (DMC) is considered to be an exciting power converter topology option for electric motor drives in industrial applications (elevators, hoists and cranes) and applications where size and weight are critical (e.g., the aerospace industry). Several control techniques have been developed to exploit the DMC’s benefits and achieve the desired performance with classic control techniques, such as field-oriented control and direct torque control, and more sophisticated ones, such as model predictive control and sliding mode control (SMC). SMC is attractive due to its robustness and fast response. However, this control strategy suffers from a phenomenon called chattering. Thus, a solution based on the exponential reaching law (ERL) is implemented to resolve this issue. The proposed method was validated using simulation and experimental results from tests on a three-phase induction machine.

A high-frequency modeling of AC motor in a frequency range from 40 Hz to 110 MHz

Introduction. Most electromagnetic compatibility models developed for the study of three-phase induction machines are generally valid for low and medium frequencies (&lt;&lt; 1 MHz). This frequency limit seems to be too restrictive for the overall study of conducted electromagnetic interference. In this paper, the model is using the proposed model and compared with experimental results in low and medium frequency. And then, the high-frequency modeling of induction motor is presented new method based on transfer function model. The proposed methodology is verified on an experimental and simulation, it’s suitable for prediction of the terminal overvoltage analysis and electromagnetic interference problems and common-mode and differential-mode currents. The novelty of the work consists to develop an improved high-frequency motor model based on transfer function to represent the motor high-frequency behavior for frequency-domain analyses in the frequency range from 40 Hz up to 110 MHz .The purpose of this work is to study the common-mode impedance and the differential-mode impedance of AC motor. The determination of these impedances is done for firstly both common and differential modes at low and medium frequency, and then common-mode and differential-mode characteristics at high frequency. Methods. For the study of the path of common-mode and differential-mode currents in typical AC motor (0.25 kW, 50 Hz) an identification method in high frequency for induction motor has been proposed based on the transfer function in differential-mode and common-mode configuration. The low and medium frequency model were presented in the first time based on equivalent circuit of electrical motor. Then, the common-mode and differential-mode impedances were defined in high frequency using asymptotic approach. This motor was studied by MATLAB Software for simulation and also experimental measurements. Results. All the simulations were performed using the mathematical model and the results obtained are validated by experimental measurements performed in the University of the Federal Armed Forces Hamburg in Germany. The obtained results of common-mode and differential-mode at low frequency, medium and high frequency are compared between simulation and experiment.

Low-cost DSP-based vibration data acquisition system for bearing fault detection in electric motors

This paper presents a low-cost DSP-based vibration data acquisition system with a high data storage capacity for fault detection in electric motors. An outer race bearing fault detection case study for a three-phase induction machine using vibration signals provided by the DSP-based acquisition system from a test rig is detailed. The fault detection scheme is performed based on Fast Fourier Transform (FFT) and Discrete Wavelet Transform (DWT).

Fault diagnosis for induction generator-based wind turbine using ensemble deep learning techniques

Fault diagnosis in induction machines (IM) require effective detection at early stages to prevent permanent machine failure. This requires fast sensing of disturbances as well as efficient diagnosis methods. Conventional signal measuring techniques are usually intrusive, sensitive, with a low signal-to-noise ratio, and may show limited performance at incipient fault stages. Moreover, traditional machine learning (ML) diagnosis techniques based on handcrafted feature extraction methods suffer from limitations that can be overcome by deep learning (DL) with automatic feature extraction capabilities. In this paper, an online, non-intrusive method is proposed for fault diagnosis in a three-phase IM based on infrared imaging. The proposed method integrates three convolutional neural network (CNN)-based DL models (Inception, Xception, and MobileNet) to identify IM health status, fault types, and stator Inter-turn faults (ITF) location and severity. Deep features obtained from these CNNs are merged through Discrete Wavelet Transform (DWT) resulting in spatial-time-frequency features. This fusion reduces the input features’ size and improves diagnostic accuracy. Merged features’ length is further reduced using the Principal Component Analysis (PCA) where these reduced features are then used for classification. Compared to DL-based diagnosis methods introduced in previous work, the proposed method shows superior performance. First, it uses the IR images directly without the need for clustering and segmentation steps, thus saving time and effort. Moreover, ensembled DL is applied via combining the three CNNs benefits altogether rather than applying an individual DL method. Finally, unlike the huge features’ number exhibited by previous studies, the proposed approach uses minimal features, thus reducing classification complexity and time while maintaining 100% classification accuracy.

Impact of Aspect Ratios of Solid Rotor, Large Air Gap Induction Motors on Run-Up Time and Energy Input

This article introduces a unique three-phase induction machine with a large air gap and a copper-coated iron cylinder. The motor is built in an X-ray tube for medical applications where key performance indicators are the start-up time, generated rotor, and total energy during the run-up. The common equivalent circuit for induction motors is utilized to systematically analyze the effect of the rotor protrusion length variation on these key performance indicators by means of three-dimensional (3D)-FEA. However, due to the large air gap and dominating winding head standard evaluation tools, such as the no-load and locked-rotor tests do not provide accurate circuit parameters. Thus, a combined no-load and locked-rotor test evaluation is introduced. Furthermore, to avoid the time and computational effort of time-stepping 3D-FEA, time harmonic and static 3D-FEA is introduced. To validate these simplified 3D-FEA simulations, results are compared with the selected time-stepping 3D-FEA results. Experimental results verify the 3D-FEA results. After establishing a routine to identify accurate equivalent circuit parameters by means of 3D-FEA, the parameters for three different stator lengths each combined with six different rotor lengths are identified. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V/f</i> -controlled run-up simulations are then conducted to generate the results. Results quantify the tradeoff between start-up time, generated rotor, and total energy depending on the rotor protrusion, e.g., the start-up time is indirectly proportional to the rotor protrusion and directly proportional to the rotor frequency (the relative frequency between stator field and rotor speed). The effect of the rotor temperature, which can reach up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim 390^\circ \,$</tex-math></inline-formula> C, on the results is included.

Self-Adaptive Fault-Tolerant Control of Three-Phase Series-End Winding Motor Drive

This article proposes a simplified fault-tolerant control (FTC) method for three-phase series-end winding motor drive, which has four bridges to achieve high voltage utilization and increased degrees of control freedom. Seven fault types are analyzed and the corresponding voltage/current derating is calculated. The proposed self-adaptive fault-tolerant strategy applied for the first fault category acts in both healthy and faulty conditions, which avoids the risk of delay and error caused by fault diagnosis, and achieves smooth fault-tolerant transition. Compared with existing FTC methods for the same structure, the proposed control strategy can achieve obviously better voltage utilization. In addition, to further exploit the maximum speed potential in the linear modulation zone, the improved common-mode voltage injection is adopted. The performance of the proposed fault-tolerant method is validated experimentally in an open-end three-phase induction machine system with the open-circuit fault.

Control Strategy of a Five-Phase Induction Machine Supplied by the Current Source Inverter With the Third Harmonic Injection

In the five-phase induction machine (IM), it is possible to better use the electromagnetic circuit than in the three-phase IM. This requires the use of an adequate converter system which will be supplied by an induction machine. The electric drive system described, in this article, includes the five-phase induction machine supplied by the current source inverter (CSI). The proposed novelty—not presented previously—is the control system structures for the five-phase IM, which is supplied by CSI. The proposed control systems allow for independent control of IM state variables in the first and the second system plane to inject the third harmonic. However, the third harmonic must be suitably associated with the fundamental harmonic. In the proposed solution, the machine vector model is not transformed into the ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d–q</i> ) coordinate system that is connected to the rotor flux vector but utilizes the stationary system ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α–β</i> ). The nonlinear model linearization is based on the demonstrated nonlinear variables transformation for i-orthogonal ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α–β</i> ) (i) planes. Voltage control is applied to the control system structure. The control variables of the five-phase IM are the voltage in the dc link and the angular speed of the output current vector. In the control strategy, the control variables are determined for both system planes. Therefore, the transformation of these control variables to the dc link of CSI is proposed. The proposed control structure allows for independent control of variables in the first and second system planes. It leads to the possibility to increase the value of electromagnetic torque up to 12% for the five-phase IM, which has not been used before in the case of the machine supplied by the CSI. All theoretical issues are confirmed by experimental tests in the 5.5 kW five-phase IM.

Brushless Synchronous Generator-Unidirectional Rectifier for Offshore Wind Energy Conversion System

This paper presents the variable speed applications of a recently developed generator named Brushless Induction Excited Synchronous Generator (BINSYG) for offshore wind power applications. The machine is basically a Synchronous generator (SG) with its excitation fed from a three-phase Induction Machine (IM). Both the machines are embedded in the same machine frame and share the same magnetic core. The SG feeds power to the dc grid via a five-level Unidirectional Dual Flying Capacitor Active Neutral Point Converter. The converter is controlled such that the Total Harmonic Distortion (THD) of the current flowing through the stator of SG is below 5% and at unity power factor at SG terminal. The excitation developed by IM-type exciter is adjusted using a new control strategy that is proposed for Voltage Source Inverter, such that BINSYG can operate at wide speed range necessary for Wind Energy Systems (WES). The complete system is controlled without using ac voltage sensors and speed encoders. The proposed WES with its control algorithm is first modelled in MATLAB/Simulink. Further, rapid control prototyping verification in the form of real-time results using OPAL-RT is presented for a small scale (5.5 kVA) BINSYG feeding power to a 750 V dc grid.

Static and Dynamic Simulation of an Induction Motor Using Matlab/Simulink

Industries are adequately configured with the operational devices that are required to develop induction motors. Engineers should precisely comprehend the kind of equipment that is constructed, as with every other production system, and should start by having the goal in their perspective. An adaptable simulation of an induction motor with a protective scheme is presented. The adaptable simulation assists engineers in accurately designing motors that meet all protective standards for certain purposes. This work achieved simulations of induction motors in stable and unstable conditions. An extensive study was performed to determine the optimum design of an induction motor. This paper attempts to provide engineers with a thorough grasp of the adaptable modelling of an induction motor. In this work, a direct dq0-direct axis algorithm is presented to implement both static and dynamic modelling of a three-phase induction machine due to possible faults and high-performance requirements in induction machines. The proposed algorithm was tested against several conventional methods, and it was observed that under the stable condition of the machinery, the proposed algorithm could remove any developing faults. This conserves time and minimises the labour required of the operator, which makes the proposed algorithm more efficient. Furthermore, the machine is demonstrated in a steady-state performance with respect to the current, active power, efficiency, reactive power, power factor, and speed when the torque loads range from 0 to 125% of its nominal torque. The transient behaviour of the machine was shown through the current, electromagnetic torque, electromagnetic torque versus speed, and speed under no-load, half-load (50%), and full-load (100%) conditions. Finally, the results of the proposed technique were compared to the results of the measured parameters. It was observed that when the load changed from a half load (50%) to a full load (100%), then the supply voltage was suddenly halved with the load at full load (100%). It was observed that the proposed algorithm provides accurate estimates with a deviation of not more than +/−2% from the measured parameters.

Velocity Sensor Fault-Tolerant Controller for Induction Machine Using Intelligent Voting Algorithm

Nowadays, induction machines (IMs) are widely used in industrial and transportation applications (electric or hybrid ground vehicle or aerospace actuators) thanks to their significant advantages in comparison to other technologies. Indeed, there is a large demand for IMs because of their reliability, robustness, and cost-effectiveness. The objective of this paper is to improve the reliability and performance of the three-phase induction machine in case of mechanical sensor failure. Moreover, this paper will discuss the development and proposal of a fault-tolerant controller (FTC), based on the combination of a vector controller, two virtual sensors (an extended Kalman filter, or EKF, and a sliding mode observer, or SMO) and a neural voting algorithm. In this approach, the vector controller is based on a new structure of a back-stepping sliding mode controller, which incorporates a double integral sliding surface to improve the performance of the induction machine in faulty operation mode. More specifically, this controller improves the machine performance in terms of having a fast response, fewer steady-state errors, and a robust performance in the existence of uncertainty. In addition, two voting algorithms are suggested in this approach. The first is based on neural networks, which are insensitive to parameter variations and do not need to set a threshold. The second one is based on fuzzy logic. Finally, validation is carried out by simulations in healthy and faulty operation modes to prove the feasibility of the proposed FTC.

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.