Showing papers on "Induction motor published in 2012"
TL;DR: The analysis suggests that the dual (or triple) three-phase PMAC motor drive may be a favored choice for general aerospace applications, striking a balance between necessary redundancy and undue complexity, while maintaining a balanced operation following a failure.
Abstract: This paper presents an overview of motor drive technologies used for safety-critical aerospace applications, with a particular focus placed on the choice of candidate machines and their drive topologies. Aircraft applications demand high reliability, high availability, and high power density while aiming to reduce weight, complexity, fuel consumption, operational costs, and environmental impact. New electric driven systems can meet these requirements and also provide significant technical and economic improvements over conventional mechanical, hydraulic, or pneumatic systems. Fault-tolerant motor drives can be achieved by partitioning and redundancy through the use of multichannel three-phase systems or multiple single-phase modules. Analytical methods are adopted to compare caged induction, reluctance, and PM motor technologies and their relative merits. The analysis suggests that the dual (or triple) three-phase PMAC motor drive may be a favored choice for general aerospace applications, striking a balance between necessary redundancy and undue complexity, while maintaining a balanced operation following a failure. The modular single-phase approach offers a good compromise between size and complexity but suffers from high total harmonic distortion of the supply and high torque ripple when faulted. For each specific aircraft application, a parametrical optimization of the suitable motor configuration is needed through a coupled electromagnetic and thermal analysis, and should be verified by finite-element analysis.
779 citations
TL;DR: It is illustrated that comparisons between the different motors are difficult by the large number of parameters and the lack of a recommended test scheme, so it is proposed that a standardized drive cycle be used to test and compare motors.
Abstract: This paper presents a critical review of the drivelines in all-electric vehicles (EVs). The motor topologies that are the best candidates to be used in EVs are presented. The advantages and disadvantages of each electric motor type are discussed from a system perspective. A survey of the electric motors used in commercial EVs is presented. The survey shows that car manufacturers are very conservative when it comes to introducing new technologies. Most of the EVs on the market mount a single induction or permanent-magnet (PM) motor with a traditional mechanic driveline with a differential. This paper illustrates that comparisons between the different motors are difficult by the large number of parameters and the lack of a recommended test scheme. The authors propose that a standardized drive cycle be used to test and compare motors.
506 citations
TL;DR: In this paper, an improved finite control set-model predictive control (FCS-MPC) with an optimized weighting factor is presented, which is based on dividing the control interval into two parts.
Abstract: In this paper, an improved finite control set-model predictive control (FCS-MPC) with an optimized weighting factor is presented. The main goal of this paper is reducing the torque ripples when the FCS-MPC is implemented by means of the two-level inverter. For this purpose, the weighting factor is calculated via an optimization method. The optimization is based on dividing the control interval into two parts: active time for applying the active voltage vectors and zero time for applying the zero voltage. With this technique, the torque ripple is calculated as a function of weighting factor and it is optimized. The method is validated by simulations and experiments, using two-level inverter, at two speed regions (nominal speed and low speed). The results are compared with conventional FCS-MPC.
368 citations
TL;DR: In this article, three different motor drives for electric traction are compared, in terms of output power and efficiency at the same stack dimensions and inverter size, with reference to a common vehicle specification.
Abstract: Three different motor drives for electric traction are compared, in terms of output power and efficiency at the same stack dimensions and inverter size. Induction motor (IM), surface-mounted permanent-magnet (PM) (SPM), and interior PM (IPM) synchronous motor drives are investigated, with reference to a common vehicle specification. The IM is penalized by the cage loss, but it is less expensive and inherently safe in case of inverter unwilled turnoff due to natural de-excitation. The SPM motor has a simple construction and shorter end connections, but it is penalized by eddy-current loss at high speed, has a very limited transient overload power, and has a high uncontrolled generator voltage. The IPM motor shows the better performance compromise, but it might be more complicated to be manufactured. Analytical relationships are first introduced and then validated on three example designs and finite element calculated, accounting for core saturation, harmonic losses, the effects of skewing, and operating temperature. The merits and limitations of the three solutions are quantified comprehensively and summarized by the calculation of the energy consumption over the standard New European Driving Cycle.
354 citations
TL;DR: In this paper, a fault-tolerant control scheme for multiphase induction motor drives is presented and assessed, which is valid either in transient or steady-state operating conditions.
Abstract: In this paper, a control scheme for multiphase induction motor drives is presented and assessed. This control scheme ensures the operation of a multiphase drive under an open-circuit phase fault that can occur in one or more phases at the same time. A fault-tolerant control strategy is developed. The mathematical analysis is based on the space vector representation of the multiphase system and is valid either in transient or steady-state operating conditions. The feasibility of the drive is verified by means of experimental tests carried out on a prototype of seven-phase induction motor.
320 citations
TL;DR: A sensorless three-level neutral-point-clamped inverter-fed induction motor drive is proposed and Fuzzy logic control and the speed-adaptive flux observer are introduced to enhance the performance of the system.
Abstract: A sensorless three-level neutral-point-clamped inverter-fed induction motor drive is proposed in this paper. The conventional direct torque control (DTC) switching table fails to consider the circuit limitations, such as neutral-point-balance and smooth vector switching, caused by the topology of a three-level inverter. Two kinds of modified schemes for three-level DTC are proposed to solve these problems. They also provide performance enhancement while maintaining robustness and simplicity. Fuzzy logic control and the speed-adaptive flux observer (with novel gain and load toque observation) are introduced to enhance the performance of the system. The issue of large starting current is investigated and solved by introducing the technique of preexcitation. A 32-bit fixed-point DSP-based motor drive is developed to achieve high-performance sensorless control over a wide speed range. The effectiveness of the proposed schemes is confirmed by simulation implementation and experimental validation.
256 citations
TL;DR: A new signature for detection of rotor faults in induction motors, such as eccentricity and broken rotor bars, that uses the external magnetic field analysis based on the variations of axial flux density in the presence of these faults is presented.
Abstract: This paper presents a new signature for detection of rotor faults in induction motors, such as eccentricity and broken rotor bars, that uses the external magnetic field analysis. The proposed method is based on the variations of axial flux density in the presence of these faults. The low frequency part of the magnetic field spectrum is particularly analyzed. The analysis is realized through a machine modeling based on permeance circuit under eccentricity fault and also by machine modeling based on coupled magnetic circuit theory under broken rotor bars fault. Analytical relations which describe the machine operation under broken bars fault highlight the influence of speed variation to modify the low frequency components of the external magnetic field. The theoretical results have been validated by experimental measurements. In particular, an inverse stator cage induction machine have been used to measure the bar currents under healthy and faulty cases.
229 citations
TL;DR: This paper presents a precisely matched comparative analysis of three alternative PI, and a hysteresis-based, current regulation strategies, suitable for use in a “standard” vector control IM drive, showing that properly tuned, all four strategies have essentially the same performance.
Abstract: Dynamically accurate torque control is an essential prerequisite for higher performance motor drive systems. For ac induction motors (IMs), the two most established strategies are direct torque control (DTC) and vector or field orientated control. DTC directly switches the inverter to regulate torque without requiring explicit stator current regulation. However, it suffers from variable switching frequency and is more challenging to implement in digital controllers. Vector control separately regulates the “torque” and “flux” producing components of the motor stator current and is readily suited to a digital implementation with a constant switching frequency. However, it requires accurate current control to be effective, typically achieved using a linear current regulation system. The principles of linear current regulation are well established and have been researched intensively over many years. However, their quantitative design is still an uncertain mix of theory and practice, including in particular how to best set the regulator gains. This paper addresses this issue, by presenting a precisely matched comparative analysis of three alternative PI, and a hysteresis-based, current regulation strategies, suitable for use in a “standard” vector control IM drive. The results show that properly tuned, all four strategies have essentially the same performance, suggesting that the choice between them needs really only be made on the basis of convenience of implementation and/or cost.
190 citations
TL;DR: The proposed MRAC-based speed sensorless vector control drive as well as the stator resistance estimation technique has been simulated in MATLAB/SIMULINK and experimentally validated through a dSPACE-1104-based laboratory prototype.
Abstract: In this paper, a new model reference adaptive controller (MRAC) for the speed estimation of the vector-controlled induction motor drive is presented. The proposed MRAC is formed using instantaneous and steady-state values of X (= v* × i where v = voltage and i = current vector in synchronously rotating reference frame), which is a fictitious quantity and has no physical significance. This formulation is not only simply realizable but also made the sensorless drive stable in all the four quadrants of operation. Speed estimation does not involve computation of stator or rotor flux. Requirement of no additional sensors makes the drive suitable for retrofit applications. A simple modification of the controller can estimate the stator resistance in all the four quadrants of operation, if speed signal is available. The proposed MRAC-based speed sensorless vector control drive as well as the stator resistance estimation technique has been simulated in MATLAB/SIMULINK and experimentally validated through a dSPACE-1104-based laboratory prototype. A study on stability of such systems is also added.
190 citations
TL;DR: In this paper, a three-phase, five-level inverter topology with a single-dc source is presented by cascading a 3-level flying capacitor inverter with a flying H-bridge power cell in each phase.
Abstract: In this paper, a new three-phase, five-level inverter topology with a single-dc source is presented. The proposed topology is obtained by cascading a three-level flying capacitor inverter with a flying H-bridge power cell in each phase. This topology has redundant switching states for generating different pole voltages. By selecting appropriate switching states, the capacitor voltages can be balanced instantaneously (as compared to the fundamental) in any direction of the current, irrespective of the load power factor. Another important feature of this topology is that if any H-bridge fails, it can be bypassed and the configuration can still operate as a three-level inverter at its full power rating. This feature improves the reliability of the circuit. A 3-kW induction motor is run with the proposed topology for the full modulation range. The effectiveness of the capacitor balancing algorithm is tested for the full range of speed and during the sudden acceleration of the motor.
188 citations
TL;DR: A new anti-windup PID controller is proposed to improve control performance of variable-speed motor drives and is experimentally applied to the speed control of a vector-controlled induction motor driven by a pulse width-modulated voltage source inverter.
Abstract: The windup phenomenon appears and results in performance degradation when the proportional-integral-derivative (PID) controller output is saturated. Integral windup is analyzed on the PI plane, and a new anti-windup PID controller is proposed to improve control performance of variable-speed motor drives and is experimentally applied to the speed control of a vector-controlled induction motor driven by a pulse width-modulated voltage source inverter. The steady-state value of the integral state is predicted while the PID controller output is saturated, and this value is utilized as an initial value of the integral state when the PID controller begins to operate in a linear range. Simulation and experiments result in more similar speed responses against load conditions and step reference change over conventional anti-windup schemes. Control performance, such as overshoot and settling time, is very similar to that determined by PID gain in the linear range.
TL;DR: A novel approach to detect and classify comprehensive fault conditions of induction motors using a hybrid fuzzy min-max (FMM) neural network and classification and regression tree (CART) is proposed.
Abstract: In this paper, a novel approach to detect and classify comprehensive fault conditions of induction motors using a hybrid fuzzy min-max (FMM) neural network and classification and regression tree (CART) is proposed. The hybrid model, known as FMM-CART, exploits the advantages of both FMM and CART for undertaking data classification and rule extraction problems. A series of real experiments is conducted, whereby the motor current signature analysis method is applied to form a database comprising stator current signatures under different motor conditions. The signal harmonics from the power spectral density are extracted as discriminative input features for fault detection and classification with FMM-CART. A comprehensive list of induction motor fault conditions, viz., broken rotor bars, unbalanced voltages, stator winding faults, and eccentricity problems, has been successfully classified using FMM-CART with good accuracy rates. The results are comparable, if not better, than those reported in the literature. Useful explanatory rules in the form of a decision tree are also elicited from FMM-CART to analyze and understand different fault conditions of induction motors.
TL;DR: A genetic algorithm (GA) optimized ANN-based MPPT algorithm implemented in a stand-alone PV system with direct-coupled induction motor drive to eliminate dc–dc converter and its accompanying losses is proposed.
TL;DR: It is illustrated that the machines operate under highly saturated conditions at high torque and that care should be taken when selecting the correct analysis technique, by divergent results when using I-Psi loops and dq techniques to calculate the torque.
Abstract: In this paper, different analysis and design techniques are used to analyze the drive motor in the 2004 Prius hybrid vehicle and to examine alternative spoke-type magnet rotor (buried magnets with magnetization which is orthogonal to the radial direction) and induction motor arrangements. These machines are characterized by high transient torque requirement, compactness, and forced cooling. While rare-earth magnet machines are commonly used in these applications, there is an increasing interest in motors without magnets, hence the investigation of an induction motor. This paper illustrates that the machines operate under highly saturated conditions at high torque and that care should be taken when selecting the correct analysis technique. This is illustrated by divergent results when using I-Psi loops and dq techniques to calculate the torque.
TL;DR: Results indicate that using time domain features can be effective in accurate diagnosis of various motor bearing faults with high precision and low computational burden.
Abstract: This paper proposes a systematic procedure based on a pattern recognition technique for fault diagnosis of induction motors bearings through the artificial neural networks (ANNs). In this method, the use of time domain features as a proper alternative to frequency features is proposed to improve diagnosis ability. The features are obtained from direct processing of the signal segments using very simple calculation. Three different cases including, healthy, inner race defect and outer race defect are investigated using the proposed algorithm. The ANNs are trained with a subset of the experimental data for known machine conditions. Once the network is trained, efficiency of the proposed method is evaluated using the remaining set of data. The obtained results indicate that using time domain features can be effective in accurate diagnosis of various motor bearing faults with high precision and low computational burden.
TL;DR: An artificial neural network (ANN) based adaptive estimator is presented in this paper for the estimation of rotor speed in a sensorless vector-controlled induction motor (IM) drive and validated through computer simulation using MATLAB/SIMULINK.
Abstract: An artificial neural network (ANN) based adaptive estimator is presented in this paper for the estimation of rotor speed in a sensorless vector-controlled induction motor (IM) drive. The model reference adaptive system (MRAS) is formed with instantaneous and steady state reactive power. Selection of reactive power as the functional candidate in MRAS automatically makes the system immune to the variation of stator resistance. Such adaptive system performs satisfactorily at very low speed. However, it is observed that an unstable region exists in the speed-torque domain during regeneration. In this work, ANN is applied to overcome such stability related problem. The proposed method is validated through computer simulation using MATLAB/SIMULINK. Sample results from a laboratory prototype (using dSPACE-1104) have confirmed the usefulness of the proposed estimator.
20 May 2012
TL;DR: In this article, the IEC 60034-2-3 standard specifies test methods for determining harmonic losses of VSD-fed motors, supplementing the methods intended for operation on sinusoidal supply.
Abstract: Premium efficiency motors are now mandatory in North America, but new higher efficiency classes are being introduced. Motors of IE4 Super-Premium Efficiency Class are already available in the market, and a new IE5 Ultra-Premium Efficiency Class is being considered. Within the IE4 Super-Premium Class, line-start permanent-magnet motors (LSPMs) are a recent entrance in the industrial motor market. Its steady-state performance is outstanding, but as in all technologies, there are some associated issues, both for retrofitting or new applications. The LSPM efficiency can be measured according to the input-output (or direct) method specified in the IEEE 112 or IEC 60034-2-1 standards, but if the losses are to be segregated, for example, to allow proper temperature correction, it is important to evaluate if the specified test methods can be applied to this sort of machine. Due to the significant promotion and penetration of variable-speed drives (VSDs) in industrial motor driven systems, the motor tolerance and operation limits to such devices are addressed in this paper. The proposed IEC 60034-2-3 Standard specifies test methods for determining harmonic losses of VSD-fed motors, supplementing the methods intended for operation on sinusoidal supply. In this paper, the referred issues will be addressed in detail, and experimental results on the application of the IEC 60034-2-1 and IEC 60034-2-3 standards to IE2, IE3, and IE4 class motors are presented and discussed, with the focus on the LSPM Super-Premium technology. A comparative technical and economical analysis of commercial IE2, IE3, and IE4 class motors is presented, including an in-field example of replacement of a squirrel-cage induction motor by an LSPM.
01 Sep 2012
TL;DR: In this paper, a fully decoupled current control which allows an independent input, output, and internal balancing current control is presented to equalize the energy stored in the nine converter arms, including average, horizontal, vertical and diagonal balancing control loops.
Abstract: The Modular Multilevel Matrix Converter (M3C) is a Modular Multilevel Converter topology which is suitable for high power low speed drive applications. This paper presents a fully decoupled current control which allows an independent input, output and internal balancing current control. To equalize the energy stored in the nine converter arms, an energy and balancing control is presented which includes average, horizontal, vertical and diagonal balancing control loops. Simulation results are used to verify the function of the M3C together with an induction motor drive system. Additionally, the proper function of the recently constructed arm PCB working as single phase multilevel STATCOM is presented. This PCB will be used for each arm in the laboratory prototype of the M3C in the near future.
TL;DR: This paper describes a set of experimental tests on a dual three-phase induction machine for fault-tolerant applications and different winding configurations are investigated and compared in case of both open-circuit and shortcircuit faults.
Abstract: This paper describes a set of experimental tests on a dual three-phase induction machine for fault-tolerant applications. Both three-phase and six-phase machine operations are considered. Different winding configurations are investigated and compared in case of both open-circuit and short-circuit faults. Experimental tests for each configuration are reported at no-load and under load operating conditions.
TL;DR: The paper deals with analytical method of design and prediction of performance characteristics for induction motors with solid steel rotor coated with copper layer and the equivalent impedance of the rotor has been derived on the basis of the distribution of the 2-D electromagnetic field.
Abstract: The paper deals with analytical method of design and prediction of performance characteristics for induction motors with solid steel rotor coated with copper layer. On the basis of the distribution of the 2-D electromagnetic field, the equivalent impedance of the rotor has been derived. The edge effect and nonlinear magnetic permeability of solid steel have been included. The presented analytical method has been verified with laboratory test results. A 300 kW, 60 000-rpm, three-phase solid-rotor induction motor for the next generation air compressor has been investigated. The accuracy of analytical approach is acceptable and can be recommended for rapid design of solid-rotor induction motors.
TL;DR: The real-time implementation of a bi input-extended Kalman filter (EKF)-based estimator to overcome the simultaneous estimation problem of the variations in stator resistance Rs and rotor resistance Rr' aside from the load torque tL and all states required for the speed-sensorless control of induction motors (IMs) in the wide speed range.
Abstract: This paper presents the real-time implementation of a bi input-extended Kalman filter (EKF) (BI-EKF)-based estimator in order to overcome the simultaneous estimation problem of the variations in stator resistance Rs and rotor resistance Rr' aside from the load torque tL and all states required for the speed-sensorless control of induction motors (IMs) in the wide speed range. BI-EKF algorithm consists of a single EKF algorithm using consecutively two inputs based on two extended IM models developed for the simultaneous estimation of Rr' and Rs. Therefore, from the point of real-time implementation, it requires less memory than previous EKF-based studies exploiting two separate EKF algorithms for the same aim. By using the measured stator phase voltages and currents, the developed estimation algorithm is tested with real-time experiments under challenging variations of Rs , Rr', and tL in a wide speed range; the results obtained from BI-EKF reveal significant improvement in the all estimated states and parameters when compared with those of the single EKFs estimating only Rr' or Rs.
TL;DR: An analysis by which the stability of a multiple-input-multiple-output system of simultaneous speed and stator resistance estimators for sensorless induction motor drives can be successfully predicted is presented.
Abstract: This paper presents an analysis by which the stability of a multiple-input-multiple-output system of simultaneous speed and stator resistance estimators for sensorless induction motor drives can be successfully predicted. The instability problem of an adaptive flux observer (AFO) is deeply investigated. In order to achieve stability over a wide range of operation, a design of the observer feedback gain is proposed. Furthermore, closed-loop control systems of the independent use of the two estimators are developed. Therefore, all gains of the adaptive proportional-integral controllers are selected and generalized to provide good tracking performance as well as fast dynamic response. The performance of the AFO using the proposed gains, with a sensorless indirect-field-oriented-controlled induction motor drive, is verified by simulation and experimental results. The results show a good improvement in both convergence and stability, particularly in the regenerative mode at low speeds, which confirm the validity of the proposed analysis.
TL;DR: In this paper, a 3D coupled-field finite element method was used in simulation of temperature distributions in air-cooled asynchronous induction motors, where the temperature rise in motors is due to Joule's losses in stator windings and squirrel cages, and heat dissipation by air convection and solid conduction.
Abstract: This paper investigates a 3-D coupled-field finite-element method (FEM) used in simulation of temperature distributions in air-cooled asynchronous induction motors. The temperature rise in motors is due to Joule's losses in stator windings and squirrel cages, and heat dissipation by air convection and solid conduction. The Joule's losses calculated by 3-D eddy-current field analysis are used as the input for the thermal field analysis, which is deeply dependent on accurate air fluid field analysis. Moreover, a novel multi-component fluid model is proposed to deal with the influence of rotor rotation upon the air convection. A test prototype is designed and manufactured. The good agreement of the temperature distributions between the simulated and measured results validates the proposed methodology.
TL;DR: In this article, a fuzzy logic hysteresis comparator-based direct torque control (DTC) scheme of an induction motor (IM) under varying dynamic conditions is presented. But, the performance of the proposed drive is tested in both simulation and experiment, a complete simulation model is developed using MATLAB/Simulink.
Abstract: This paper presents a fuzzy logic hysteresis comparator-based direct torque control (DTC) scheme of an induction motor (IM) under varying dynamic conditions. The fuzzy logic controller (FLC) is used to adjust the bandwidth of the torque hysteresis controller in order to reduce the torque and flux ripples and, hence, to improve motor dynamic response. The effects of torque hysteresis bandwidth on the amplitude of torque ripples of an IM are also discussed in this paper. Based on the slopes of motor-estimated torque and stator current, an FLC is designed to select the optimum bandwidth of the torque hysteresis controller. This paper also proposes a simpler algorithm than the conventional trigonometric function-based algorithm to evaluate the sector number (required for DTC scheme) of the stator flux-linkage space vector. The proposed algorithm reduces the computational burden on the microprocessor. In order to test the performance of the proposed FLC-based DTC scheme for IM drive, a complete simulation model is developed using MATLAB/Simulink. The proposed FLC-based DTC scheme is also implemented in real time using DSP board DS1104 for a prototype 1/3 hp motor. The performance of the proposed drive is tested in both simulation and experiment.
TL;DR: In this paper, a systematic cascade explicit model predictive control framework for field-oriented control (FOC) of electrical drives is presented. But the performance of the proposed closed-loop system is limited by the sensitivity of traditional feed-forward loops to system parameters.
Abstract: Field-oriented control (FOC) has proven effective for controlling ac drives with good dynamic performance. However, operation at low-switching frequencies and the sensitivity of traditional feedforward loops to system parameters pose severe limitations on the achievable performance and require a tedious tuning procedure. In this paper, we present a systematic cascade explicit model predictive control framework for the FOC of electrical drives, resolving the aforementioned issues while being sufficiently simple to be widely implemented on various ac drive systems. The resulting closed-loop system exhibits high dynamic performance for all operating points, even at low-switching frequencies. We present experiments with a permanent-magnet machine and an induction motor, demonstrating the practical feasibility and the merits of the proposed framework over traditional controller designs for electrical drives.
TL;DR: In this paper, a dynamic space-vector model is applied to loss-minimizing control in induction motor drives, which takes hysteresis losses and eddy-current losses as well as the magnetic saturation into account.
Abstract: This paper applies a dynamic space-vector model to loss-minimizing control in induction motor drives. The induction motor model, which takes hysteresis losses and eddy-current losses as well as the magnetic saturation into account, improves the flux estimation and rotor-flux-oriented control. Based on the corresponding steady-state loss function, a method is proposed for solving the loss-minimizing flux reference at each sampling period. A flux controller augmented with a voltage feedback algorithm is applied for improving the dynamic operation and field weakening. Both the steady-state and dynamic performance of the proposed method is investigated using laboratory experiments with a 2.2-kW induction motor drive. The method improves the accuracy of the loss minimization and torque production, it does not require excessive computational resources, and it shows fast convergence to the optimum flux level.
TL;DR: Experimental results show that the proposed hybrid SHEPWM scheme could meet the modulation index need of the motor and reduce the common-mode voltage in the drive, and the two SHEP WM schemes could transition smoothly.
Abstract: This paper proposes a hybrid selective harmonic elimination pulsewidth modulation (SHEPWM) scheme for common-mode voltage reduction in three-level neutral-point-clamped inverter-based induction motor drives. The scheme uses the conventional SHEPWM (C-SHEPWM) to control the inverter at high frequency (≥ 0.9 motor rated frequency) and uses the modified SHEPWM (M-SHEPWM) to control the inverter at low frequency. It also uses a scheme to ensure the smooth transition between the two SHEPWM schemes. As a result, at high frequency, the C-SHEPWM provides the required high modulation index for the motor, while at low frequency, when a passive filter is less effective for common-mode voltage reduction, the M-SHEPWM is used to suppress the common-mode voltage. Experimental results show that the proposed hybrid SHEPWM scheme could meet the modulation index need of the motor and reduce the common-mode voltage in the drive, and the two SHEPWM schemes could transition smoothly.
TL;DR: In this article, the authors present and implement a procedure to estimate the parameters of a five-phase induction machine, which can be also extended to other multiphase machines with higher phase numbers.
Abstract: Multiphase drives are advantageous when high overall system reliability and the reduction in the total power per phase are required. The control strategies for these applications require a good knowledge of the machine parameters to ensure a high quality of the dynamic and steady-state drive performance. Multiphase machines are still not common in industry and it appears that very little work has been done so far in relation to parameter identification techniques. This paper presents and implements a procedure to estimate the parameters of a five-phase induction machine, which can be also extended to other multiphase machines with higher phase numbers. The method is based on standstill time-domain tests and recursive least-squares algorithms. Experimental results are provided to illustrate the developed identification method using tests on two different five-phase induction machines. Correlation with corresponding parameters obtained in Part 1 of this paper is established, where electrical parameters of the same two five-phase inverter-fed induction motor drives were identified using various procedures, based on sinusoidal excitation of the machine.
TL;DR: This paper deals with the use of the instantaneous active and reactive power signature analyses and their derived signals-the instantaneous power factor and phase angle - for discriminating broken rotor bars and airgap eccentricity conditions from mechanical load oscillation effects in operating three-phase squirrel cage induction motors.
Abstract: This paper deals with the use of the instantaneous active and reactive power signature analyses and their derived signals-the instantaneous power factor and phase angle - for discriminating broken rotor bars and airgap eccentricity conditions (rotor faults) from mechanical load oscillation effects in operating three-phase squirrel cage induction motors. Both simulation and experimental results are presented to show the effectiveness and the merits of the proposed approach that offers the possibility to distinguish between the three conditions by comparing the signature analyses of two different quantities for each abnormality condition.
TL;DR: In this paper, a Markov reliability model of induction motor drives operating under field-oriented control is presented, which includes faults in the power electronics, machine, speed encoder, and current sensors.
Abstract: This paper presents a Markov reliability model of induction motor drives operating under field-oriented control. The model includes faults in the power electronics, machine, speed encoder, and current sensors. The procedure can be extended for more detail, to other machines and to other drive topologies. To develop the model, faults are first identified, and then, a simulation model of the setup is developed and experimentally verified. Faults are injected into the model in sequential levels and the system performance is assessed after each fault. Fault coverage-the probability that the system survives given a fault has occurred-is studied. A complete Markov reliability model is developed to assess the mean time to failure of the system and other reliability factors. This analysis is shown to be simple and useful for assessing the reliability of motor drives and is expected to help in designing fault-tolerance mechanisms for specific drives, where reliability can be evaluated after every design.