Search

The effectiveness of a permanent magnet synchronous motor (PMSM) drive managed by an automatic voltage regulator (AVR) microcontroller using field oriented control (FOC) with space vector modulation (SVM) and a diode clamped multilevel inverter (DCMLI) is investigated. Due to its efficacy, FOC would be widely implemented for PMSM speed regulation. The primary drawbacks of a 3-phase classic bridge inverter appear to be reduced dv/dt stresses, lesser electromagnetic interference, and a relatively small rating, especially when compared to inverters. PMSMs have a better chance of being adopted in the automotive industry because of their compact size, high efficiency, and durability. The SVM idea states that an inverter's three driving signals are created simultaneously. Using MATLAB simulations, researchers looked into incorporating a DCMLI with a resistive load on an AVR microcontroller. Torque, current, and harmonic analysis were evaluated between the SVM and the inverter-driven PMSM drive in this research. In comparison to the prior art, the proposed PMSM drive has better speed and torque management, less output distortion, and less harmonic distortion. [ABSTRACT FROM AUTHOR]

Starting from the problem of studying the parametric robustness in the case of the control of a permanent magnet-synchronous motor (PMSM), although robust control systems correspond entirely to this problem, due to the complexity of the algorithms of the robust type, in this article the use of switched systems theory is proposed as a study option, given the fact that these types of systems are suitable both for the study of systems with variable structure and for systems with significant parametric variation under conditions of lower complexity of the control algorithms. The study begins by linearizing a PMSM model at a static operating point and continues with a systematic presentation of the basic elements and concepts concerning the stability of switched systems by applying these concepts to the control system of a PMSM based on the field-oriented control (FOC) strategy, which usually changes the value of its parameters during operation (stator resistance Rs, stator inductances Ld and Lq, but also combined inertia of PMSM rotor and load J). The numerical simulations performed in Simulink validate the fact that, for parametric variations of the PMSM structure, the PMSM control switched systems preserve qualitative performance in terms of its control. A series of Matlab programs are presented based on the YALMIP toolbox to obtain Pi matrices, by solving Lyapunov–Metzler type inequalities, and using dwell time to demonstrate stability, as well as the qualitative study of the performance of PMSM control switched systems by presenting in phase plane and state space analysis of the evolution of state vectors: ω PMSM rotor speed, iq current, and id current. [ABSTRACT FROM AUTHOR]

These surrogate models replace the machine model and estimate the output parameters of the machine based on the input parameters. Induction machines are one of the most important technical applications for both the industrial world and private use. The main purpose of this paper was to develop methods to reduce the computational effort in the design and optimization of IMs using the finite element method or analytical methods. From experimentally obtained results, it was demonstrated that the brought-in scheme attained high certainty in recognizing and discriminating among different IM conditions, i.e., a machine in good physical condition, a machine with one broken rotor bar, a machine with two broken rotor bars, a machine with damage on the bearing outer race, and a machine with an unbalanced mechanical load. [Extracted from the article]

This work presents a field oriented control (FOC) strategy (Fuzzy Logic (FL)) associated with PI controller applied to the control system of an permanent magnet synchronous motor (PMSM) powered by an inverter dedicated to electric vehicles, the major challenge of our research work is a control law for a permanent magnet synchronous motor more efficient in terms of rejection of disturbances; stability and robustness with respect to parametric uncertainties, A comparison of the performance of the proposed FOC with the FOC with the fuzzy-PI will be presented. The overall development scheme is summarized and an example illustrates features of the control approach performed on a 0.5 kW PMSM drive. The torque and the speed will be judged and compared for the two orders offered. As results, the behavior of the FOC based on fuzzy-PI controller is more efficient compared to the conventional vector control. [ABSTRACT FROM AUTHOR]

The field-orientation dependent magnetoelectric coupling is experimentally studied for a rectangular Terfenol-D/PZT/Terfenol-D laminated structure. The considered magnetic field, namely the dc-bias magnetic field or the ac-excitation magnetic field, is allowed to be spatially re-orientated between two orthogonal geometric dimensions of the composite. In the study, the direction of the excitation can be fixed in the longitudinal (Scheme-I) or thickness (Scheme-II) directions, while considering the bias orientation. Alternatively, the bias field can be restricted to the longitudinal (Scheme-III) or thickness (Scheme-IV) directions, while the excitation orientation is considered. The variation in magnetoelectric coefficient as a function of the bias magnitude is studied with special attention paid to the field-orientation dependency. For the testing schemes of I and II, the direction of the dc-bias field can be re-oriented by forming an angle with the fixed direction of the ac-excitation field. As the angle changes from 0° to 90°, the magnetoelectric coupling evolves from L-T mode to S-T surface shear for Scheme-I, and from T-T mode to S-T thickness shear for Scheme-II. The bias-field-orientation dependence demonstrates a complex pattern due to the varying overall state of anisotropy in Terfenol-D. In Scheme-I with low bias magnitude, the orientation dependence can be represented by the measured effective longitudinal piezomagnetic coefficient. In addition, the optimal bias field for maximum magnetoelectric coefficient is observed to linearly increase with the bias orientation angle. Alternatively, the orientation dependence in Schemes III and IV is more predictable due to the barely changed overall state of anisotropy. In this case, Scheme-III shows that the magnetoelectric coefficient decreases monotonically with the orientation angle and Scheme-IV indicates that the maximum coefficient is attained at around 60°. The dependence of the magnetoelectric coupling on the excitation-filed orientation can be understood via analysis of the resultant magnetostriction in Terfenol-D with assumed effective magnetization, which may depart from the bias field due to the strong demagnetization effect. The analysis is supported by the computed field-orientation dependence of the magnetostriction in Terfenol-D. [ABSTRACT FROM AUTHOR]

In this paper, an advanced integrator is proposed for the estimation of stator flux in a direct torque control (DTC) drive. A two‐level lookup table‐based direct torque‐controlled interior permanent magnet synchronous motor (IPMSM) drive is implemented. DTC has the inherent disadvantage of DC drift and saturation in stator flux estimation due to a pure integrator. In the proposed work, a different approach to estimate stator flux is reported overcoming the constraints of a pure integrator in DTC. An advanced integrator with an adaptive controller is implemented to determine the stator flux and enrich the performance of the drive. A comparison of transient and steady‐state analysis is carried out when IPMSM is fed by a low‐pass filter‐based DTC and proposed stator flux estimator‐based DTC. To make the system mechanically robust, stator current‐based model reference adaptive control is executed to estimate the motor speed. A mathematical derivation for the stability study of the adaptation mechanism is carried out using Popov's hyperstability criteria. The proposed algorithm is implemented in the MATLAB/Simulink environment and the soundness of the proposed work is presented by simulation results. Moreover, the experimental analysis using dSPACE1104 justifies the simulation results of the proposed system. [ABSTRACT FROM AUTHOR]

Globally abundant wave energy for power generation attracts ever increasing attention. Because of non-linear dynamics and potential uncertainties in ocean energy conversion systems, generation productivity needs to be increased by applying robust control algorithms. This paper focuses on control strategies for a small ocean energy conversion system based on a direct driven permanent magnet synchronous generator (PMSG). It evaluates the performance of two kinds of control strategies, i.e., traditional field-oriented control (FOC) and robust adaptive control. The proposed adaptive control successfully achieves maximum velocity and stable power production, with reduced speed tracking error and system response time. The adaptive control also guarantees global system stability and its superiority over FOC by using a non-linear back-stepping control technique offering a better optimization solution. The robustness of the ocean energy conversion system is further enhanced by investigating the Lyapunov method and the use of a DC-DC boost converter. To overcome system complexity, turbine-generator based power take-off (PTO) is considered. A Matlab/Simulink study verifies the advantages of a non-linear control strategy for an Oscillating Water Column (OWC) based power generation system. [ABSTRACT FROM AUTHOR]

In this study, the speed-sensorless improved field oriented control (FOC)-based induction motor (IM) drive has been presented. In addition to the rotor fluxes and rotor mechanical speed required for speed-sensorless FOC, the load torque, the stator resistance, and the rotor resistance are estimated by the switching extended Kalman filter (SEKF) with improved memory requirement and design stage which use the measured stator currents and voltages as inputs. The performance of FOC is improved by the feedforward control of the estimated load torque. In addition, the estimation errors caused by the parameter variations are reduced with the estimations of the stator and rotor resistances. The proposed speed-sensorless IM drive is tested by challenging scenarios in simulations. The results obtained demonstrate that the improved FOC-based IM drive has a high performance. [ABSTRACT FROM AUTHOR]

The field-orientation dependence of magnetization reversal and spin wave modes in nanorings has been investigated by focused magneto-optical Kerr effect spectroscopy, Brillouin spectroscopy, and micromagnetic simulations. The samples studied are periodic arrays of 150 nm wide Ni80Fe20 rings with long axes of 850, 1200, and 1500 nm, and respective short axes of 550, 700, and 900 nm. For the smallest ring, the onion-to-vortex transition is observed for both the applied magnetic field directed along, and 5° from its magnetization easy axis. In contrast for the two larger rings, this transition is not observed for the field in the latter orientation. Splitting of spin wave modes is observed for the transition from the onion to vortex state. Micromagnetic simulations of magnetization reversal and spin waves are in good agreement with experiments. The simulated temporal recording of magnetization distributions during transition reveals that different switching mechanisms result from different applied magnetic field orientations. [ABSTRACT FROM AUTHOR]

A new model predictive torque and flux controller is proposed, which controls the electromagnetic torque and rotor (rather than the stator) flux magnitude. Analytical expressions for the weighting factors are derived that ensure that the proposed controller achieves the same closed-loop performance as predictive current control. In particular, the same low current and torque distortions result, without requiring an outer field-oriented control loop. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a speed sensorless control scheme named as finite control set-model predictive current control (FCS-MPCC) using a modified fictitious ohmic quantity (R) based model reference adaptive system (MRAS) for grid-connected doubly-fed induction machine (DFIM) drive. The variables of the reference model of this speed sensorless scheme (R-MRAS) are represented in stationary reference frame while those for the adaptive model are denoted in synchronously rotating reference frame. The sensorless formulation thus obtained is completely independent of any stator/rotor resistance terms. The scheme is also devoid of any stator/rotor flux estimation. Moreover, the intuitiveness of FCS-MPCC brings in additional flexibility in comparison to the conventional control techniques like field oriented control (FOC) and direct torque control (DTC). The overall scheme demonstrates faster execution time than FOC/DTC based control of DFIM drive. The proposed control algorithm is simulated and tested for limited speed range application in MATLAB/Simulink. The validation of simulation results are further done by experimentation on a dSPACE-1103 based DFIM laboratory setup. Highlights • In this paper, MRAS based sensorless speed estimation of DFIM drive by FCS-MPCC is reported. • The estimation scheme insensitive to the changes in machine parameters. • The overall scheme demonstrates faster execution time than FOC/DTC based control of DFIM drive. [ABSTRACT FROM AUTHOR]

In this study, a sensorless hybrid control scheme for brushless direct current (BLDC) motors for use in multirotor aerial vehicles is introduced. In such applications, the control scheme must satisfy high-performance demands for a wide range of rotor speeds and must be robust to motor parameter uncertainties and measurement noise. The proposed controller combines field-oriented control (FOC) and direct torque control (DTC) techniques to take benefit of the advantages offered by each of these techniques individually. Simulation results demonstrate the effectiveness of the proposed control scheme over a wide range of rotor speeds as well as good robustness against parameter uncertainties within -5 to + 10% for inductance and -5 to + 5% for resistance parameters. The proposed hybrid controller is robust also against noise in voltage and current measurements. In order to verify the results from simulation, the proposed hybrid controller is implemented in hardware using the TI C2000 Piccolo Launchpad and TI BOOSTXL-DRV8305EVM BoosterPack. Testing is done with a Bull Running motor typically used in aerial drones. Testing experiments demonstrate that the hybrid controller reduces the rotor speed ripple when compared to DTC while operating in steady-state mode and decreases the response time to desired speed changes when compared to FOC. [ABSTRACT FROM AUTHOR]

The doubly fed induction machine has been traditionally adopted in adjustable-speed ac power generation drives in order to take advantage of the reduced rating for the power electronic interface. Aside this well-established application where the doubly fed induction generator (DFIG) is controlled by a back-to-back converter, recent literature records a growing interest toward un-conventional DFIG drives for dc power generation, combining DFIG high control freedom with simplified power electronic interfaces to achieve an overall cheap and fully controllable system. Despite several concepts have been demonstrated on small-scale rigs, there is a lack of systematic comparison among different topologies and control solutions. This paper bridges this gap by providing a review of recent topologies, their control, design and performance, and operation issues. As major novelties, this paper includes off-spec performance comparison of different torque-ripple mitigation strategies, discussion of sizing requirements for generator and power electronics, fundamental aspects of the behavior under voltage dips, and priorities and challenges for future research on the subject. [ABSTRACT FROM AUTHOR]

In this paper, a speed estimation method is presented, which is based on a flux observer for air-gap field orientation control (AFOC) of an induction motor (IM) drive that utilizes both air-gap flux and stator current. The stator current is obtained using Hall effect current sensors. The air-gap flux observer design was established using the Lyapunov stability theory, and the estimated rotor speed was derived from the developed flux estimator. The gain matrix parameters of the observer were adjusted by a fuzzy logic control (FLC) strategy. The MATLAB\Simulink® toolbox was used to simulate this system and all the control algorithms were realized using a TI DSP 6713-and-F2812 card to generate pulse-width modulation (PWM) signals for the power stage to actuate the motor and validate the approach. Both the simulations and experimental results verified the effectiveness of the proposed system. [ABSTRACT FROM AUTHOR]

Three-phase interior permanent magnet synchronous motor (IPMSM) drive systems have gotten widely used recently in various applications due to their speed regulation characteristics and high power density. Compared with classical field-oriented control (FOC) and flux-weakening control, model predictive control (MPC) technique is more efficient and effective in achieving excellent performance without complicated controller tuning, but with explicit constraints. Yet, the optimum application of the MPC algorithm in a machine control system is still in the exploratory stage. In order to lower the current and torque ripples, this paper retains a modulator, but replaces all the proportional integrate control loops, which are contained in the conventional FOC systems with a single MPC controller. Moreover, we adopt a brand-new linearization approach to tackle the strong coupled nonlinear IPMSM mathematical model, obtaining an improved linear plant model, which is suitable for the motor with constant load torque. When it comes to flux-weakening control, the required d-axis current is calculated, after which it is used as the input of the proposed MPC controller, abandoning the previous natural field weakening method. Finally, for the purpose of lowering the dynamic speed and current overshoot, a further constraint in the change rate of manipulated variables is discussed. The improved control algorithm has been verified in both simulation and experiment. [ABSTRACT FROM AUTHOR]

This paper focuses on the presentation of an effective predictive flux control (PFC) approach for an induction motor (IM) drive. The finite control set (FCS) principle is used in order to select the inverter voltages and thus there is no need to use the pulse width modulation (PWM) strategy. The proposed control approach uses a cost function formulation in which there is no need for tuning the value of the weighting factor which is inherently present in the classic predictive torque control (PTC) approach, and thus the computational burden is effectively reduced. The proposed PFC approach is derived based on the rotor field orientation principle in which the stator flux components are utilized as control variables instead of utilizing the stator current components as adopted in the classic RFO technique. In order to get better-predicted signals with limited noise content, the stator flux is estimated using an effective flux estimator instead of using the machine voltage model. An effective online identification procedure for the stator transient inductance is proposed and analyzed in a systematic manner, which has led to an improvement in the rotor flux orientation, and thus the robustness of the controller is enhanced. The performance of the drive is tested during the normal speed operation and then during the field weakening operation. The obtained results confirm the validity of the proposed PFC control approach and the effectiveness of the identification procedure in achieving correct and precise rotor field orientation which consequently results in improving the overall dynamic performance of the drive. [ABSTRACT FROM AUTHOR]

Permanent magnet ac motors have been extensively utilized for adjustable-speed traction motor drives, due to their inherent advantages including higher power density, superior efficiency and reliability, more precise and rapid torque control, larger power factor, longer bearing, and insulation life-time. Without any proportional-and-integral (PI) controllers, this paper introduces novel first- and higher-orderfield-oriented sliding mode controlschemes. Compared with the traditional PI-based vector control techniques, it is shown that the proposed field oriented sliding mode control methods improve the dynamic torque and speed response, and enhance the robustness to parameter variations, modeling uncertainties, and external load perturbations. While both first- and higher-order controllers display excellent performance, computer simulations show that the higher-order field-oriented sliding mode scheme offers better performance by reducing the chattering phenomenon, which is presented in the first-order scheme. The higher-order field-oriented sliding mode controller, based on the hierarchical use of supertwisting algorithm, is then implemented with a Texas Instruments TMS320F28335 DSP hardware platform to prototype the surface-mounted permanent magnet ac motor drive. Last, computer simulation studies demonstrate that the proposed field-oriented sliding mode control approach is able to effectively meet the speed and torque requirements of a heavy-duty electrified vehicle during the EPA urban driving schedule. [ABSTRACT FROM AUTHOR]

This paper discusses the synchronous operation of a brushless doubly fed reluctance machine (BDFRM). Basic operation theory of a ducted rotor BDFRM is reviewed, and mathematical analysis relating to synchronous operation is presented. Corresponding control strategy for synchronous speed operation is discussed. A prototype machine is built and implemented as a motor drive. Subsequently, the BDFRM drive is tested in synchronous mode of operation at varying speed levels and loads. [ABSTRACT FROM AUTHOR]

The magnetic configurations and magnetic reversal processes in arrays of geometrically identical rounded rectangular Co rings have been investigated. Magnetic imaging reveals a range of configurations, including diagonal onion, horseshoe onion, and vortex states. Reversal from the onion to the vortex state can occur via different routes involving domain wall motion within the rings, and the mechanism depends on the applied field orientation. [ABSTRACT FROM AUTHOR]

This paper presents a methodology for the broken rotor bars fault detection is considered when the rotor speed varies continuously and the induction machine is controlled by Field-Oriented Control (FOC). The rotor fault detection is obtained by analyzing a several mechanical and electrical quantities (i.e., rotor speed, stator phase current and output signal of the speed regulator) by the Discrete Wavelet Transform (DWT) in variable speed drives. The severity of the fault is obtained by stored energy calculation for active power signal. Hence, it can be a useful solution as fault indicator. The FOC is implemented in order to preserve a good performance speed control; to compensate the broken rotor bars effect in the mechanical speed and to ensure the operation continuity and to investigate the fault effect in the variable speed. The effectiveness of the technique is evaluated in simulation and in a real-time implementation by using Matlab/Simulink with the real-time interface (RTI) based on dSpace 1104 board. [ABSTRACT FROM AUTHOR]

This paper studies the modeling and field-oriented control (FOC) for hysteresis motors, with the goal of achieving position control of hysteresis motors for servo applications. Hysteresis motors include a wide range of machines with solid cylindrical or ring-shaped steel rotors, which generate torque primarily via the magnetic hysteresis effect of the rotor material. Previously, hysteresis motors have been mainly used under open-loop operation. However, they are also attractive for position control in some special applications such as in-vacuum operation or when smooth running and high speed is required. In this paper, an equivalent circuit model for hysteresis motors that describes the motor's transient-time dynamics is introduced, and a state-space model for hysteresis motors is developed. This model is used to construct a rotor flux orientation observer for the FOC for hysteresis motors. Three methods for estimating the rotor field angle are introduced. The proposed FOC-based position control method was tested with three hysteresis motors, including two custom-made motors of different rotor materials and one off-the-shelf hysteresis motor. Experimental results show that position control for all three hysteresis motors can reach a bandwidth of 130 Hz with the proposed methods. To the authors’ best knowledge, this is the first experimental study on FOC and position control for hysteresis motors. [ABSTRACT FROM AUTHOR]

The low coupling coefficient between the transmitter and receiver is the major constraint of a wireless power transfer (WPT) system. Although some approaches, such as increasing the quality factor and achieving precise impedance matching, can reduce the adverse impacts of the low coupling coefficient and improve the system performance, high leakage magnetic flux between the transmitter and receiver remains a problem. With the increase in transfer distance and the misalignment between the transmitter and receiver, the increasing leakage magnetic flux of nondirectional fields degrades the WPT system performance. This paper proposes an active field orientation method to shape the magnetic flux so as to minimize the leakage flux. The amplitude and phase angle of the magnetizing current are controlled, and a coil structure for minimizing the coupling among the transmitters and generating a three-dimensional magnetic field is proposed. This method realizes three-dimension full-range field orientation with adjustable magnitude and direction of B-field at an arbitrary point, and as a result the B-field is concentrated with reduced leakage magnetic flux. The proposed field orientation shaping technique is verified by theoretical analysis, simulation, and experimental results. [ABSTRACT FROM PUBLISHER]

The paper proposes an improved low speed performance of classical rotor flux (RF)-based model reference adaptive system (MRAS) for field oriented controlled induction motor (IM) drives. The improved performance of the RF-MRAS estimator is obtained by using voltage reference vector to compute the rotor flux vector in the reference model instead of actual voltage signal vector in the process of speed estimation. The voltage reference vector is estimated by using proportional integral controller over the error signal vectors obtained from the difference between the reference and the measured current vectors. This modification allows satisfactory low or zero speed estimation of IM drive using RF-MRAS-based estimator. The proposed drive's performance is compared with classical RF-MRAS and its performance for the low-speed operation is also authenticated with \vecV^ * \times \vecI based MRAS in MATLAB/ Simulink. Stability and sensitivity studies are further carried out to ensure the robustness of the drive system. Experimental results as obtained by a dSPACE-1104 based IM laboratory prototype are also presented to validate the simulation study. [ABSTRACT FROM PUBLISHER]

Maximum Torque Control (MTC) is a new method applied for control of induction motor drives. The drive is controlled by dc voltage supplying a converter in the range below nominal speed and by a field that weakens for a speed range above the nominal speed. As a consequence, the control is quite similar to the control of a classical separately excited dc motor. This control method could be explained as a kind of simplification of Direct Torque Control (DTC), because the switching scheme is the same as for the DTC, but the variable responsible for a torque control is constantly set for "torque increase". This kind of control of induction motor drive is simpler than DTC because torque values need not be estimated. The proposed control method offers very good performance for 3-phase induction motors and requires smaller switching frequency in comparison to DTC and Field Oriented Control (FOC). The application of the control is widely demonstrated for a 3-phase 315 kW, 6 kV motor drive by use of computer simulation. [ABSTRACT FROM AUTHOR]

In this article, performance of field oriented controlled open-end winding induction motor drive (FOCOEWIMD) using nearest sub-hexagonal centre PWM (NSHCPWM)technique is proposed. In the proposed work, two 2-level inverters are used on either side of OEWIM drive to obtain the three-level output voltage. To generate the control signals for the two inverters, NSHCPWM technique is used. In the proposed method reference vector is realized with two components, based on the tip of the reference vector location nearest sub-hexagonal centre is identified, which is one of the switching vector used to generate the control signals for inverter-I and the other component is realized using inverter-II by mapping into the inner sub-hexagon. So that one inverter is used as switching inverter and the other is as clamping inverter. Ripples in torque and stator current are also reduced in the proposed work over conventional SVPWM techniques. Proposed work is analyzed theoretically and the same can be realized using MATLAB/SIMULINK and the corresponding results are presented for different modulation index. [ABSTRACT FROM AUTHOR]

A fixed switching period sliding mode control (SMC) for permanent-magnet synchronous machines (PMSMs) is presented. The aim of this paper is to design an SMC that improves the traditional PI-based field-oriented control transient response, as well as to reduce the switching frequency variations of the direct torque control. Such SMC requires a decoupling method of the control actions, which also brings constant switching functions slopes. These constant slopes allow to calculate the required hysteresis band value to control the switching frequency. The digital implementation degrades the performance of the hysteresis comparator, and as a consequence, the previously calculated band becomes inaccurate to regulate the switching frequency. In order to recover the analogue hysteresis band comparator performance, a predictive algorithm is proposed. Finally, a set of experimental results with constant switching frequency during a torque reversal and speed control tests are provided. [ABSTRACT FROM PUBLISHER]

This article established with the modeling and the field oriented control of permanent magnet synchronous machines, with a focus on their applications in variable speed domain in photovoltaic source. [ABSTRACT FROM AUTHOR]

This paper presents a two-degrees-of-Freedom (2DOF) and variable structure control (VSC) schemes for induction motor (IM) drives. The designed VSC incorporates independent feedback and feedforward terms as 2DOF control principle. This structure improves the response of the proposed VSC under speed reference tracking and load disturbance changes. Stability of VSC using Lyapunov theory is discussed. Due to the variable nature of the switching function of VSC, two conditions to ensure Lyapunov stability candidate are derived based on the error signal. A design criterion for the parameters of VSC are introduced to guarantee the stability. The complete IM drive system with the proposed VSC controller is built using MATLAB/Simulink. A laboratory prototype is executed experimentally using DSP-DS1104 control board. All controllers are implemented practically. Simulation and experimental results are provided under different working conditions. Performance evaluation of classic control schemes and the proposed VSC approach is presented. The proposed VSC approach gives superior behavior under speed reference variations and torque disturbances. The disturbances using the proposed controller are strongly suppressed compared to classic 2DOF control scheme. [ABSTRACT FROM AUTHOR]

This paper presents the optimization of the wind power in a variable speed Wind Energy Conversion System (WECS) using a sensorless Maximum Power Point Tracking (MPPT) strategy that avoids mechanical measurement of the wind speed. The proposed system consists of a turbine, a direct-drive Permanent Magnet Synchronous Generator (PMSG) controlled by a Field Oriented Control (FOC) through a three phase controlled rectifier connected to a DC load. The choice of the FOC is justified by a power maximization analysis. The generator rotor speed and position required by the FOC and the sensorless MPPT are estimated using a Synchronous Reference Frame Phase Locked Loop (SRF-PLL). The proposed technique is validated using both simulation in Matlab-Simulink and experimental work based on step changes in wind speed. Results are presented at the end of the paper showing that the estimated angle and speed by the SRF-PLL are approximatively the same as the real ones, also figure of the output power shows that it is maximized confirming the effectiveness of the adopted approach. [ABSTRACT FROM AUTHOR]

The paper deals with control of Permanent Magnet Synchronous Motor (PMSM) without a rotor position sensor. In the low and zero speed region, the rotor saliencies are utilized to obtain the information about the rotor position. Self-sensing control techniques employ high frequency (hf) signal injection to excite the saliencies. The proposed algorithm enables tracking the saliency and allows PMSM control at zero and low speed. The theoretical assumptions were experimentally verified including the initial rotor position detection. [ABSTRACT FROM AUTHOR]

A numerical scheme for the effect of flow-field orientation on water management in PEM fuel cell is developed. Since there are limitations on the location of proton exchange membrane fuel cell such as portable applications, different configurations are used for proper water management. Therefore, the best configuration must be chosen for the most efficient and stable operation of the fuel cells. In this research, a 3D numerical model is proposed based on the VOF method in order to simulate the effects of gravity on the gas–liquid two-phase flow in a full-scale single-serpentine flow-field. This model, which is validated by the experimental results, considers the microstructure of the gas diffusion layer by two square pores in every cross section along the channels. The simulations are done for the vertical and horizontal fuel cells. The effects of water coverage ratios and flow regimes on pressure drop and the resulting parasitic power loss are investigated for different configurations. In the vertical orientation, the channels are placed horizontally or vertically in each configuration. The results reveal that in the vertical cells, when the channels are located horizontally and the inlet manifold is embedded on the upper side of the flow-field, the pressure drop is the lowest. The reason is that the film flow is formed in the channels and the gravity assists in the water removal. However, when both the cell and channels are vertical and the cathode inlet manifold is placed on the bottom of the flow-field, the pressure drop and the resulting parasitic power is the highest. This is due to the gravity is against the water purging from the elbows leading to formation of long plugs along the channels. The present numerical model can be used for simulation of two-phase flow in channels of the serpentine flow-field at any cell orientation angle by changing the gravity direction in the model. [ABSTRACT FROM AUTHOR]

This paper addresses the lack of robustness in three phase Induction Motors (I.M) speed control in presence of uncertainty and external unknown disturbance of Model Reference Adaptive Control (MRAC), and present an enhancement of robustness by employing the adaptive law modifications for robustness. Considered modifications were Dead zone modification, Sigma modification, e-modification and projection operator algorithm modification. Speed control of three phase induction motor in this paper was depend on decoupling benefits of rotor flux Indirect Field Orientation (IFO). Simulation results shows improved robustness characteristics and performance. In order to make the case study under consideration more realistic, the work considered the limitation imposed on supplied voltage in real application, where this was the other challenge which has been avoided by many researchers. [ABSTRACT FROM AUTHOR]

This paper presents an investigation of a novel Field-Oriented Control (FOC) performance for star-connected 3-phase induction motor (IM) drives with an open-phase fault. The control system enables to work in healthy and faulty conditions without requiring any modifications to the conventional control structure but with modifications only in the control parameters. This introduced control topology leads to the mitigation of any speed and torque oscillations resulting from the asymmetrical conditions related with this type of fault. A comparative study for vector control strategy using the proposed and conventional methods is experimentally verified. [ABSTRACT FROM AUTHOR]

Propulsion system used in applications like electric traction, rolling stock, etc. requires high torque at low speed for starting and climbing and nearly constant power at high speed. Induction machines, which are rugged, reliable, low cost and has less maintenance, satisfy the characteristics of the propulsion and reinstating the traditionally used DC series motor for this purpose. Field oriented control (FOC) of induction machines can decouple its torque control from field control and extended speed range operation with constant power beyond rated speed by field weakening (FW). It is desirable to retain maximum torque capability in the FW region for propulsion applications at high speed. To produce maximum torque that machine could possibly develop at FW region, the maximum inverter voltage and current must be appropriately utilized. This paper proposes an innovative approach to improve the torque capability of induction machine in FW region by modifying the design of induction machine to change the bahaviour of the machine to suit propulsion requirements. Extensive simulation of the design options generated from the design modification has been carried out using MATLAB/Simulink and torque-speed characteristics are compared. [ABSTRACT FROM AUTHOR]

We report on impedance experiments carried out in the reentrant alloys Au -Fe 18 at.% and Au -Fe 21 at.%. A spin-glass system Au -Fe 13.5 at.% was also studied for comparison. Measurements cover an extended temperature interval including the paramagnetic state, the intermediate ferromagnetic-like phase and the low temperature reentrant regime. Several frequencies in the range 0.1–1.8 MHz were applied. Magneto-impedance measurements were also performed in low magnetic fields applied parallel to the current orientation. From the impedance versus temperature data, the real and imaginary components of the circumferential permeability were extracted. A Hopkinson maximum is observed in both permeability components of the reentrant magnets. Also observed in these systems is a downwards inflexion in the permeability versus temperature curves at the canting temperature T K where the reentrant regime sets in. The anisotropy field H K was obtained from the magneto-impedance measurements in several temperatures spanning the ferromagnetic and reentrant states. A marked increase of the H K magnitude occurs in temperatures below T K , indicating the stabilization of the reentrant phase by the anisotropic Dzyaloshisnskii–Moriya coupling. These results are in agreement with predictions of the mean-field theory that explains canting and the reentrant state with basis on the freezing of the spin components which are transverse to the field orientation. [ABSTRACT FROM AUTHOR]

This paper introduces new schemes for detection, isolation, and compensation of speed and current sensor (CS) faults in field oriented induction motor (IM) drives. These schemes do not use any kind of machine model and motor parameters. This is a prominent feature of the proposed approaches, which only rely on main concepts of field-oriented control (FOC)-based IM drives. Moreover, the proposed fault detection and isolation (FDI) schemes can take partial sensor failures into account. These kinds of faults that might be caused by mechanical or electrical failures, or intentional sensor tampering, are difficult to be dealt with since embedded speed and current control loops react swiftly, and inherently try to camouflage partial sensor failures. CS faults result in imbalance current flow in the motor stator phases, and speed sensor fault repudiates the orthogonally alignment of field and torque current components in field oriented IM drives. These features are cornerstones of introduced FDI methodology. Furthermore, model and parameter free compensators are proposed to recover normal operation of the machine before fault incident. After in-depth analysis, extensive simulation and experimental tests validate the proposed schemes. [ABSTRACT FROM AUTHOR]

Electromagnetic torque and stator flux of a permanent magnet synchronous motor (PMSM) can be controlled indirectly with model predictive current control (MPCC). In MPCC, a predefined cost function is minimised by selecting and applying appropriate voltage vectors to stator terminals. Since MPCC employs machine model to predict stator currents, it requires accurate knowledge of its parameters. Furthermore, MPCC results in high torque and current ripples at normal sampling rates. In this study, torque and current ripples of a surface-mounted PMSM are effectively reduced by incorporating the concept of duty cycle and applying two voltage vectors, instead of one voltage vector as in conventional MPCC, during a control period. A fuzzy logic modulator is designed and utilised to determine the duty cycles of voltage vectors. Furthermore, sensitivity of the proposed control strategy against parameter variations is alleviated by employing a full-order Luenberger observer. Various case studies are carried out on a hardware-in-the-loop setup and performance of the proposed method is compared with conventional and a recently introduced duty cycle-based predictive control. The obtained results verify the superiority of the proposed MPCC and its effectiveness in reducing the PMSM torque and current ripples with accurate and erroneous knowledge of motor parameters. [ABSTRACT FROM AUTHOR]

Two cascaded two-level inverters can synthesise three-level voltage space vector. For the cascaded three-level inverter controlled induction motor, this study proposes a five-level torque controller (FLTC)-based direct torque control (DTC) method especially for improving steady-state motor torque performance and retaining the high dynamic performance. The proposed FLTC method employs hysteresis controllers, uses look-up tables and ends up with variable switching frequency of the cascaded three-level inverter. Computationally, the envisaged FLTC method is quite comparable to that of the basic DTC method. The FLTC method ensures reduced switching commutations in the inverter switching devices during low speeds of operation and simultaneously achieves reduced dv/dt switching stresses. An inherent drawback of FLTC method at higher speeds of operation is identified, theoretically analysed and a pseudo error-based correction is also suggested in this study to overcome the drawback. The steady-state and transient motor torque performance of the induction motor with the use of the envisaged FLTC-based DTC method is thoroughly analysed, simulated using Matlab/Simulink and then experimentally validated on a laboratory prototype for starting, speed reversal and load change conditions with the use of the cascaded three-level inverter. [ABSTRACT FROM AUTHOR]

This paper investigates the development of a simplified speed control of induction motor based on indirect field oriented control (FOC). An original PI-P controller is designed to obtain good performances for speed tracking. Controller coefficients are carried out with analytic approach. The algorithm is implemented using a low cost Field Programmable Gate Array (FPGA). The implementation is followed by an efficient design methodology that offers considerable design advantages. The main advantage is the design of reusable and reconfigurable hardware modules for the control of electrical systems. Experimental results carried on a prototyping platform are given to illustrate the efficiency and the benefits of the proposed approach. [ABSTRACT FROM AUTHOR]

A comparative study between Integral and Classical Backstepping IFOC structures of induction motor is proposed in this work. The Integral one is based mainly on a suitable combination of a nonlinear integral backstepping approach and an indirect field orientation control (IFOC). The first part ensures a global system stability using recursive Lyapounov design and increases robustness despite disturbances and model uncertainties. The second part will guarantee flux orientation, decoupling, and current regulation. The effectiveness of the proposed control structure is validated by simulation as well as by experiment under critical disturbance conditions. Obtained results show a fast dynamic response, better load disturbance rejection capability, less parameters sensitivity and better tracking performance. [ABSTRACT FROM AUTHOR]

A synchronous current controller for field-oriented control is a popular control scheme that is used in industry to separately control the synchronous current of an induction motor in steady state. However, in some transient states such as during start-up and variation of the mechanical load, the synchronous current along the d -axis remains coupled to the q-axis current. Conventional decoupling current control considers only the model of an induction motor to compensate these coupling terms, but the motor is often powered by an inverter, which also influences the current, voltage, and torque behavior. Thus, a novel decoupling current control method is proposed to consider the coupling terms of both the motor and power converter in a synchronous current controller. Existing approaches assume that the motor is directly connected to the power supply, so a model is also suggested for a pulse width modulation (PWM) inverter. Analytical equations with simulation and experimental results prove that the coupling terms are still present when not considering the PWM inverter in the decoupling network. The proposed method shows good performance, and the d-axis current is always separated from the q-axis current during variation of the mechanical load. [ABSTRACT FROM PUBLISHER]

Compared to the widespread modulation-based control strategies such as field oriented control (FOC), MPC eliminates the use of internal current control loops and modulation block, hence featuring very quick dynamic response. Furthermore, MPC well respects the discrete nature of power converters by evaluating the influence of each voltage vector on the concerned control variables, which are usually combined into a cost function, hence featuring simple concept. In spite of the merits of quick response and conceptual simplicity, it seems that MPC may be inferior to FOC in terms of steady-state performance, especially in the low speed range, which is usually a drawback of MPCbranched methods. This study proposes an improved two-vectors-based MPC (MPC2) and compares it to the wellestablished FOC. A detailed experimental study of both methods is presented, including steady-state performance, dynamic response, low speed operation and control complexity. Very promising results are obtained in MPC2 by providing better steady-state performance and much quicker response than FOC under the condition of similar average switching frequency. The results prove that MPC2 is a powerful alternative to FOC and may find wide applications in the near future. [ABSTRACT FROM AUTHOR]

A new four quadrant Field Orientation-Controlled (FOC) three-phase induction motor drive based on Hysteresis Current Comparison (HCC) has been developed. The direct relationship between current and torque in the Direct-Quadrature (dq) reference frames has been exploited to develop an HCC scheme that offers accurate tracking of current and torque based on the pulse width modulation technique. The parameters of the inner HCC and the outer Proportional-Integral (PI) speed controllers have been optimised to obtain effective current and torque tracking. The complete closed loop system being speed-controlled, four quadrant operation has been obtained using step speed input while the suitability of the developed model has been tested under full load stress during steady state. The results obtained satisfy the four quadrant operation requirements of advanced drives where controlled starts and stops are essential in both forward and reverse directions. This is evident in the effectiveness of current and torque tracking and ease of speed transition from motoring to regeneration and vice versa. The developed model finds applications in advanced industrial drives as an energy-efficient and cost-effective alternative to eliminate the effects of supply voltage drops and mechanical load variations. [ABSTRACT FROM AUTHOR]

In the future a significant shift in focus will occur towards electric vehicles as fossils decrease and fuel prices become extremely high. Also use of renewable energy sources will be required in electric vehicles, so as not to depend on thermal or nuclear power indirectly. Characteristic of a IC engine (Internal Combustion Engine) such as higher torque on demand, rapid acceleration and row power are often a hindrance in acceptance of Electric vehicles by mass public. This Research work emphasis's on a design of a grid solar hybrid electric vehicle Which addresses the above issues effectively and efficiently. The proposed system uses a higher power 3 q induction motor with FOC (Field Oriented control) or vector control to deliver IC Engine vehicles like performance in terms of row power, acceleration, torque etc. with highest energy efficiency achievable. Also the system comprises of an intelligent electronic PWM switching system which facilitates use of Root solar energy in priority and energy deficit to be derived from battery when the vehicle is running. The switching system also provides for priority to on board Root top solar panels for vehicle battery charging and tabs deficit power from grid. [ABSTRACT FROM AUTHOR]

The Field Oriented Control algorithm needs accurate estimation of motor state variables in order to ensure full torque performances and good efficiency. On electric vehicle traction drives, Induction motor Field Oriented Control is widely adopted. Good control results are strongly related to parameter values used by observers or estimators, which vary according to machine working conditions and temperature. The most important parameter is the rotor resistance. The paper shows and compares two different MRAS rotor resistance estimators, based on reactive power and motor torque, studied by means of a sensitivity analysis for different load and speed operating conditions. A nonlinear correction algorithm has been proposed in order to assure a good rotor resistance estimation convergence also under dynamic conditions. Sensitivity analysis, simulation and experimental results are reported for the proposed methods. The estimation algorithm has been also experimentally tested on a prototypal electric vehicle to demonstrate its validity under dynamic condition during a real driving cycle. [ABSTRACT FROM AUTHOR]

This paper presents a robust sensorless vector control of Double Star Induction Motor (DSIM) using Extended Kalman filter (EKF). At First stage, presenting Park model of the DSIM, we used the field oriented control (FOC) to decoupling the flux and the electromagnetic torque to control the speed of the machine which is fed by a cascade of two voltage inverters on three levels. Secondly, the same control structure of the indirect vector control is used, but, we introduced extended Kalman filter (EKF) to estimate the rotor flux, the rotor speed and both stator and rotor resistance of the machine for speed sensorless control purposes. Finally the robustness of the EKF against the injection of noise in the stator phase flux, parametric variations and changes in covariance of measurement noise and state is tested and discussed. [ABSTRACT FROM AUTHOR]