مرتب سازی بر اساس: سال انتشار
(نزولی)
IET Electric Power Applications (17518660) 19(1)
PM-assisted synchronous reluctance machines are becoming so attractive for electrical machine designers because of their lower cost due to minor usage of PMs in comparison to IPM and SMPM machines. Besides, they can effectively utilise both the magnetic and reluctance torques, thus, they can play an important role in many industrial applications including electric transportation systems. Up to now, more or less, the conventional distributed-windings are employed in design of the synchronous reluctance machines. However, recent advancements have seen the adoption of fractional-slot concentrated windings (FSCWs) due to their shorter end-winding length, simpler structure, and higher slot fill factor. Although FSCWs offer these advantages, they also suffer from higher magnetomotive force (MMF) space harmonics, which can lead to undesirable effects such as localised iron saturation and increased core losses. The main target of the present research was introducing the winding layouts, which have the benefits of both FSCWs and distributed windings to use in PM-assisted synchronous reluctance machine. To solve the problems related to FSCWs, in this research, the stator slot-shifting has been developed and new types of fractional-slot winding topologies, comprising significantly low MMF harmonics and short-end windings length have been proposed. Based on these proposed winding configurations, a prototype machine was built as case study; and analytical results, finite element analysis, and experimental tests were conducted to validate the machine’s characteristics. Although in the proposed machine the winding is converted to overlapped type and is not concentrated anymore, but the obtained results show significant advantages over the conventional design in terms of air-gap flux density, back electromotive force, torque profile, power factor, power losses, efficiency and flux weakening capability. © 2025 The Author(s). IET Electric Power Applications published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.
IEEE Access (21693536) 12pp. 84374-84386
Maximum power point tracking (MPPT) techniques are regarded as an important component of photovoltaic systems (PVSs) to extract the output power of a photovoltaic array. Algorithms based on perturbation suffer from the tradeoff between steady-state oscillations around (MPP) and the tracking speed. In this article, a fuzzy logic controller (FLC)-based Adaptive P&O MPPT algorithm for PVSs with fast tracking and low oscillations under rapidly irradiance change conditions are developed. When the operation point reaches a steady state, the proposed method can halt any artificial perturbation. Consequently, no oscillations around the MPP, and energy loss is reduced compared with conventional perturbation-based algorithms. The proposed algorithm can detect any change in irradiance without using additional sensors by employing a technique called drift avoidance. In addition, the FLC creates variable step sizes adaptively to accomplish speedy, accurate convergence to the MPP under normal and changeable weather circumstances. In a MATLAB program environment, the suggested method is simulated. DSP TMS320F28335 is used to validate that the proposed algorithm can monitor MPP with a low settling time, low steady-state oscillations, and a high convergence rate at the operational point. © 2013 IEEE.
Farhadian, M. ,
Moallem, M. ,
Fahimi, B. ,
Mirzaeian, B. ,
Sahebzamani, M. IEEE Access (21693536) 12pp. 73-84
Line-start synchronous reluctance motors (LSSynRM) combine the high efficiency of synchronous reluctance Motors (SynRM) with the self-starting capability of induction motors. They operate at synchronous speed in steady state and produce minor rotor losses, thereby providing higher efficiency than induction motors and a higher power density. Despite the simple structure of LSSynRM, its analysis, modeling, and optimal design pose several challenges. In particular, design trends aiming at higher starting capabilities and improved steady-state operation pose significant hurdles. In this study, three synchronous reluctance motors with line-start capability are designed to achieve maximum efficiency at steady-state operation with the optimum amount of copper for starting. The induction cage is constructed using rectangular bars installed in flux barriers to minimize the changes in performance under the steady-state condition. Although different rotor shapes offer similar steady-state performance, they achieve synchronism using different cage bar widths. The rotor with the lowest copper weight is selected for manufacturing. The prototype is constructed based on the optimal design. The experimental results are in good agreement with the simulation results. © 2023 The Authors.
CES Transactions on Electrical Machines and Systems (20963564) 8(3)pp. 264-273
Multi-phase machines are so attractive for electrical machine designers because of their valuable advantages such as high reliability and fault tolerant ability. Meanwhile, fractional slot concentrated windings (FSCW) are well known because of short end winding length, simple structure, field weakening sufficiency, fault tolerant capability and higher slot fill factor. The five-phase machines equipped with FSCW, are very good candidates for the purpose of designing motors for high reliable applications, like electric cars, major transporting buses, high speed trains and massive trucks. But, in comparison to the general distributed windings, the FSCWs contain high magnetomotive force (MMF) space harmonic contents, which cause unwanted effects on the machine ability, such as localized iron saturation and core losses. This manuscript introduces several new five-phase fractional slot winding layouts, by the means of slot shifting concept in order to design the new types of synchronous reluctance motors (SynRels). In order to examine the proposed winding’s performances, three sample machines are designed as case studies, and analytical study and finite element analysis (FEA) is used for validation.①. © 2024 CES.
This paper presents a quadratic high step-up DCDC converter incorporating a coupled inductor (CI), a passive clamp circuit and a voltage multiplier cell (VMC). This converter operates based on parallel charging of capacitors by CI and series discharging of this energy at the output. Moreover, the converter includes a diode-capacitor clamp circuit to decrease the voltage stress on the active switch and the output diode. As a result, this converter has high voltage gain (VG) and low voltage stress on switches, which is appropriate to increase the output voltage in photovoltaic panels. Since the proposed converter reduces voltage stress on the active switch, a switch with low resistance is utilized, which is improving power efficiency. The presented converter is analyzed in continuous conduction mode (CCM), discontinuous conduction mode (DCM) and steady-state. The experimental results relevant to the presented converter is verified with a 300V-90W prototype. © 2024 IEEE.
IEEE Transactions on Industrial Electronics (02780046) 71(12)pp. 15372-15382
This article presents a comprehensive approach to addressing the challenges of unbalanced rotors in permanent magnet (PM) synchronous machines by proposing a load torque (LT) observer for unbalance detection and a current injection technique for minimizing torque oscillations resulting from the unbalanced rotor. The primary objective is to enhance the operational efficiency and performance of electric motors by identifying the effects of the unbalanced rotor on the motor torque. The proposed LT observer utilizes real-time speed measurement to estimate the total LT. To significantly reduce the torque oscillations from the unbalanced rotor, optimum current components are injected with meticulously calculated amplitude and phase. The proposed method operates in synchronization with the rotor position, and the injected currents are extracted via an optimization problem from an adaptive model that is continuously updated through a parameter's identification method. The effectiveness of the proposed approach is demonstrated through experimental evaluations on a representative experimental setup. The results reveal that the LT observer accurately detects rotor unbalance and the current injection technique successfully minimizes motor torque oscillations, resulting in smoother motor operation, reduced noise, and improved overall efficiency. © 1982-2012 IEEE.
International Journal of Energy Research (1099114X) 2023
This paper proposes a perturb and observe (P&O) maximum power point tracking (MPPT) algorithm for photovoltaic (PV) systems. P&O is a simple technique that comes with serious problems, steady-state oscillation, and deviation from the maximum power point (MPP). This algorithm uses variable step size to decrease the convergence time, and it uses the average value of the last three duty cycle to find MPP fast and accurately. In addition, the probability of deviation has been reduced using the direction of the current when the irradiance changes. The irradiance change identifier, steady-state determiner, duty cycle selector, step size alternator, and boundary condition imposer are the extramodules attached to the structure of the original P&O algorithm to change the step size. This algorithm has been tested along with different types of P&O and INC algorithms in MATLAB software and practical experiments using a boost switching converter. The irradiance pattern used in the simulation includes step and slop, increasing and decreasing patterns, and the proposed algorithm obtained an overall efficiency of 98.54%. © 2023 Ali Saberi et al.
One of the most effective winding type for use in electric machines is fractional slot concentrated winding (FSCW). These winding type prepares the shortest end-winding length for electric machines. In addition, they can tolerate the fault condition more in compare to other windings type. Besides, higher copper fill factor, lower cogging torque, simple construction and field weakening capability are another merits of FSCWs. Unfortunately, in compare to conventional distributed-windings, FSCWs have high space Magnetomotive Force harmonics (MMF harmonics). These unwanted harmonics will cause core saturation (localized saturation), mechanical vibration, acoustic noise and iron losses. In order to develop winding benefits, many methods have been introduced. This manuscript introduces some new three-phase windings, by using the stator slot shifting concept. The novelty of this paper is introducing some new winding topologies for the first time. An analytical study and the 2-D FEM are applied to three sample-designed synchronous reluctance machines to evaluate the new winding's characteristics as case studies. © 2023 IEEE.
To eliminate the effect of parameter variation on the sensorless performance of surface-mounted permanent magnet motor (SPMSM) using a flux observer, the parameter sensitivity of the conventional flux observer is assessed in this paper. The simulation results showed that the position estimation error of the flux observer considerably depends on the accuracy of the stator resistance and rotor flux linkage, and they must be updated during motor operation. Therefore, this paper proposes an online parameter identification by recursive least square (RLS) method based on the discrete-time model of SPMSM in the stationary reference frame (RF). The simulation results demonstrated that estimated parameters follow the variation of the actual parameters very well. Furthermore, the performance of three discrete-time speed and position estimation methods in αβ RF, including a sliding mode observer (SMO), a conventional flux observer, and a flux observer improved with the proposed RLS parameter identification, are compared. The simulation results prove that not only is the flux observer improved with the proposed RLS parameter identification as robust as the SMO against parameter uncertainties, but also it has a lower position estimation error at the SPMSM rated speed. © 2023 IEEE.
IET Electric Power Applications (17518660) 17(1)pp. 92-108
Fractional-slot concentrated-windings are appreciated for their simple construction, short end-winding length, high copper fill factor, low cogging torque, good field-weakening capability and fault-tolerant ability. However, in comparison to the conventional distributed windings, the fractional-slot concentrated-windings are characterised with high space magnetomotive force (MMF) harmonics, which results in undesirable effects on the machine performance, such as localised core saturation, eddy current loss in the rotor and noise and vibration. In order to improve winding characteristics, several techniques have been developed recently. This manuscript introduces the 5 new winding topologies by using the general concept of stator slot shifting. It means that, in order to cancel undesirable MMF harmonics, by doubling (or tripling or even multiplying) the slot number and dividing the winding and then relatively shifting the winding by one (or more) slots, the undesirable harmonics have been eliminated effectively. The best choice is chosen according to the lowest amount of the MMF harmonic, highest value of winding factor and torque desirable characteristics. At the end, comprehensive comparisons for the designed synchronous reluctance motor (SynRel) equipped with proposed windings and also distributed winding are presented. The analytical study and 2D FEM analysis results show that it is possible to get an ideal low space-harmonic winding topology, and consequently, a low torque ripple for these motors. © 2022 The Authors. IET Electric Power Applications published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.
Mathematical Problems In Engineering (1024123X) 2021
Selective harmonic elimination pulse-width modulation (SHEPWM) is a widely adopted method to eliminate harmonics in multilevel inverters, yet solving harmonic amplitude equations is both time consuming and not accurate. This method is applied here for a 7-level cascaded multilevel inverter (CMLI) with erroneous DC sources. To meet the seven harmonic amplitude equations, two notches are applied with the use of higher switching frequency than nominal. These notches can be placed in six different positions in the voltage wave, and each was assessed in a separate manner. In order to solve the equations, a hybrid algorithm composed of genetic algorithm (GA) and Newton-Raphson (N-R) algorithm is applied to achieve faster convergence and maintain the accuracy of stochastic methods. At each step of the modulation index (M), different positions for the notches are compared based on the distortion factor (DF2%) benchmark, and the position with lowest DF2% is selected to train an artificial neural fuzzy interface system (ANFIS). ANFIS will receive the DC sources' voltages together with required M and will produce one output; thus, eight ANFISs are applied to produce seven firing angles, and the remaining one is to determine which one of the notches' positions should be used. Software simulations and experimental results confirm the validity of this proposed method. The proposed method achieves THD 8.45% when M is equal to 0.8 and is capable of effectively eliminating all harmonics up to the 19th order. © 2021 Seyed Yahya Nikouei et al.
IEEE Transactions on Industrial Electronics (02780046) 68(12)pp. 11783-11793
This article aims to facilitate the practical use of Z-source inverters in motor drive systems due to their outstanding properties. To this end, a robust and fast control scheme with two possible configurations for a permanent magnet synchronous motor (PMSM) drive system using a Z-source inverter is presented. In this article, the proposed control system is applied to the speed and current loops in the motor side as well as the current and voltage loops in the Z-source side. The idea is to combine the features of sliding-mode control as the feedback controller (basic configuration) with a disturbance attenuation technique as a feedforward compensator (enhanced configuration), linking with a newly modified space vector modulator. The disturbances and uncertainties associated with practical PMSM drive systems and Z-source inverters are inherently time varying and introduce high bandwidth characteristics. Hence, the proposed closed-loop control structure provides the following features to the system: 1) high robustness to external disturbances and parameter variations; 2) fast transient response during large and abrupt load changes; and 3) reduced ripple in delivered torque of the motor. In addition, a systematic design procedure for determining the values of the control parameters is presented. The theoretical analyses are validated by experimental tests in a laboratory setup. The results prove the robustness of the enhanced configuration, with a 25% reduction in torque ripple and 60% in settling time. Furthermore, compared to the previous space vector modulation technique, the proposed technique gives a 40% reduction. © 1982-2012 IEEE.
IET Power Electronics (17554543) 14(1)pp. 211-224
The dynamic operation of the conventional boost converters is limited in the continuous conduction mode, due to the presence of at least one right-half plane (RHP) zero in their control transfer function which can limit the open-loop bandwidth of the converter. This problem complicates the control design for the output voltage regulation and conversely influences the closed-loop system stability. To cancel this problem, a new step-up boost converter using the magnetic coupling and the switched capacitor (SC) is presented. In the proposed converter the effect of the RHP zero can be successfully eliminated, the voltage transfer ratio can be enhanced and the circumstances are provided to reach a small operating duty cycle as well as stress reduction of the diodes and power switch. Using the averaging technique, the state-space model of the converter is analytically studied and the essential conditions are given for achieving a minimum-phase structure. Based on the mentioned advantage, a simple classical PI controller for the output voltage regulation is designed. To confirm the theoretical analysis of the proposed converter, simulations and practical results are presented. Also, the performance of the proposed converter is compared with the other boost converters without RHP zero. © 2020 The Authors. IET Power Electronics published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology
International Journal Of Photoenergy (1110662X) 2021
Under partial shading conditions, photovoltaic (PV) arrays are subjected to different irradiance levels caused by nonuniform shading. As a result, a mismatch between the modules, a reduction in the power generated, and the hotspot phenomenon will be observed. One method to reduce mismatch losses is to reconfigure the total-cross-tied (TCT) array in dynamic and static forms, where improved performance can be achieved through more efficient shading distribution thanks to increased dimensions. However, the increase in dimensions leads to the complexity of wiring and installation in static reconfiguration and the large number of switches and sensors required in dynamic reconfiguration. To rectify these problems, a two-step method is proposed in this paper. In the first step, the modules inside the PV array are divided into subarrays with wiring in static reconfiguration, rather than being wired as large-scale PV arrays. In the second step, an algorithm is developed for dynamic reconfiguration. The introduced algorithm searches for all possible connections and finally identifies the most optimal solution. As an advantage, this algorithm employs only the short-circuit current values of the subarray rows, which reduces the number of switches and sensors required in comparison to dynamic reconfiguration. Under 8 different partial shading patterns, simulations are conducted and results confirm that the proposed method outperforms the TCT array and statically modified TCT array in terms of power and mismatch losses. Among these, the highest power improvement is obtained with regard to the TCT array and statically modified TCT array under the fourth and eighth shading patterns, respectively. © 2021 Mohamad Hossien Nahidan et al.
IET Power Electronics (17554543) 13(16)pp. 3590-3600
In this study, an advanced predictive control system is proposed which consists of two cascade predictive controllers; the first one minimises the power losses while the second one minimises the torque ripple. In the first controller, motor losses are formulated as a function of stator-flux linkage components. Then, the optimal stator-flux linkage vector which causes the minimum losses is found by adopting fast-iterative shrinkage thresholding algorithm (FISTA). The second controller is a predictive direct torque controller adopted to control the stator-flux linkage and torque directly. In this controller, torque ripple is formulated as a function of the stator-voltage vector. Then, the optimal voltage vector which causes the minimum torque ripple is found by adopting FISTA. In the second controller, deadbeat control of the stator-flux linkage is considered as a constraint in minimisation of torque ripple. To assess the effectiveness of the proposed control system, performance of the motor is assessed through various experimental tests, where the results confirm that the proposed control system minimises the power losses and torque ripple, simultaneously. The comparative assessment with the recent predictive controllers indicates that the proposed control system has higher efficiency as well as lower torque ripples in all operating points. © 2020 Institution of Engineering and Technology. All rights reserved.
IET Electric Power Applications (17518660) 13(3)pp. 385-401
So far, various categorisations have been proposed for segregating predictive controllers (PCs). However, these categorisations have some shortcomings which lead to improper segregation of PCs. In this study, a new categorisation is proposed for more precise segregation of PCs applied to AC motor drives. In this categorisation, PCs are categorised based on existence or the absence of a cost function, number of voltage vectors applied to motor in each control cycle, and prediction horizon. Basic concepts, operating principles, and important characteristics of each category are explained in depth. Moreover, the advantages and disadvantages of each category are identified by conducting various experimental tests. © The Institution of Engineering and Technology 2018.
IEEE Transactions on Industrial Electronics (02780046) 66(10)pp. 7672-7682
In photovoltaic (PV) strings based on series-connected PV modules, mismatches among the modules due to partial shading will cause power loss either due to series connection constraint or bypass diodes. This paper proposes a new distributed maximum power point tracking (DMPPT) scheme using multiwinding forward-based converter, which acts as a current balancing differential power processing converter. The converter is configured in the way that each converter port is connected in parallel with individual PV module to enable module-level maximum power extraction. The proposed architecture operates in two modes: local maximum power point tracking (MPPT) mode and current balancing mode. The new maximum power points (MPPs) at module levels are tracked in a local MPPT mode and then dispatched to start current balancing mode of operation. In the current balancing mode, this paper proposes a simple control approach to maximize the output power from partially shaded PV string by maintaining an effective MPPT at module levels and directly transferring the compensation currents toward the shaded modules from modules under normal conditions without any intermediary. The proposed DMPPT scheme is validated by the simulation and experimental results. The results show that using the proposed scheme, the system efficiency is significantly improved compared to other existing topologies. © 1982-2012 IEEE.
International Journal of Circuit Theory and Applications (1097007X) 46(6)pp. 1228-1248
Multiple-output flyback converters are widely used in switching power supplies due to their low component count and cost-effective structure. The main problem of this structure is how to balance output voltages in different load conditions. This paper proposes a new approach for single-input multiple-output flyback converters operating in DCM and CCM by a small-signal averaged model. The averaged model is derived by presenting the piecewise-linear waveform for the inductor currents inside the converter. In DCM, the magnetizing current and currents through the output windings reach zero when the switch is turned off. In CCM, the magnetizing current of the converter is continuous over a switching interval and this possibility exists that only some of the output diodes completely conduct when the switch is off. The proposed model of the converter can be used in a wide range of operations within identical and non-identical loading conditions. Using a laboratory prototype, several case studies and input-to-output transfer functions are considered to verify the proposed model. The controller design is performed for the both CCM and DCM, and then dynamic characteristics of the overall system are evaluated. Copyright © 2018 John Wiley & Sons, Ltd.
IEEE Transactions on Power Electronics (08858993) 32(12)pp. 9117-9130
In this paper, an overall power control strategy is proposed for control of a fixed-pitch small-scale wind energy conversion system operating at both underrated and overrated wind speeds. At underrated wind speeds, the dynamical behavior of the rotor is considered, and the optimal reference torque is generated without the need of wind speed sensors through a robust variable structure observer with the aim of maximum power point tracking. At overrated wind speed, the flux-weakening strategy is invoked to let the machine exploit maximum electrical torque under given current and voltage constraints. As a new approach, the optimal reference flux magnitude together with a reference torque angle is provided by online numerically solving an optimization problem in the whole wind speed range. Moreover, a space-vector-modulation -based direct torque control (SVM-DTC) is used to track the provided references for flux magnitude and torque angle. In particular, the SVM-DTC is composed of a reference voltage vector calculator providing a desired voltage vector. The effectiveness of the proposed overall power control strategy is verified not only by applying the strategy to a commercial 10-kW wind turbine simulated in MATLAB/Simulink, but also by experimental results derived from a developed laboratory setup. © 1986-2012 IEEE.
IEEE Transactions on Power Electronics (08858993) 32(4)pp. 2964-2975
In this paper, a new advanced deadbeat direct torque and flux control (A-DB-DTFC) system is proposed that improves the steady-state and transient-state performances of the permanent-magnet synchronous motor by adopting two improved deadbeat methods. Whenever the error between the torque and its reference value is low, an improved deadbeat method is adopted by the A-DB-DTFC system, in which the phase and time duration of the voltage vector applied to the motor are adjusted in a manner that the stator flux and torque reach their reference values after just one control cycle. Whenever the torque error is high, another deadbeat method is adopted by the A-DB-DTFC system, where the voltage vector phase is adjusted such that the fastest torque response is achieved. In order to assess the effectiveness of the proposed A-DB-DTFC system, the steady-state and transient-state performances of the motor are tested in MATLAB software and in practice, where the simulation and experimental results confirm that the proposed control system reduces the torque and stator flux ripples and achieves the fastest dynamic response. The comparative assessment with the recent DB-DTFC method indicates that the proposed A-DB-DTFC system yields lower torque and flux ripples and a faster dynamic response with the advantage of a lower computation complexity. © 1986-2012 IEEE.
2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025 pp. 484-489
In this paper, a sliding surface is defined based on the inductor current to construct a robust controller for Maximum Power Point Tracking (MPPT) in the photovoltaic (PV) systems. An adaptive incremental conductance algorithm has been used to obtain the set point of the controller. An improvement is achieved by this combination, especially in fast irradiance variations. The robust stability of the method is proved using the Lyapunov stability theorem. A comparative study is also made to highlight the benefits of the proposed algorithm. The features of this controller, in terms of robustness against the irradiance variations, are demonstrated by theoretical analysis, simulations and an experimental study. The results demonstrate that the proposed controller can be implemented effectively and economically with high MPPT efficiency. © 2016 IEEE.
IEEE Transactions on Industrial Electronics (02780046) 63(6)pp. 3876-3888
In this paper, a new predictive direct torque control (DTC) method is proposed, which improves the dynamic response of the conventional DTC in the transient state and yields the minimum torque and flux ripples in the steady state through an optimal voltage vector. At the steady state, the magnitude, phase, and time duration of the voltage vector are adjusted in a manner where the minimum torque and flux ripples are obtained; whereas in the transient state, the voltage vector parameters are adjusted in a manner where the fastest dynamic response is achieved. The space-vector modulation is used in synthesizing the selected voltage vector where a fixed switching frequency is achieved. In order to improve the control system efficiency, the principle of maximum torque per ampere is adopted in obtaining the commanding stator flux magnitude. To investigate the effectiveness of the proposed method, the steady-state and transient-state performances are tested in MATLAB software and in practice. The simulation and experimental results confirm that the proposed method yields the minimum torque and flux ripples while improving the dynamic response of the conventional DTC. The comparative investigation with an existing predictive DTC method indicates that the proposed method has a better performance in both the steady state and transient state. © 2015 IEEE.
IET Renewable Power Generation (17521416) 10(9)pp. 1264-1277
This study presents an overall power control strategy for control of fixed-pitch small-scale wind energy conversion system (WECS). The overall power control strategy is designed in such a way that the WECS efficiently operates for both underrated and overrated wind speeds. At underrated wind speeds, maximum power point tracking is achieved through a proportional-integral (PI) mechanical torque controller while no wind speed sensor is required. The PI mechanical torque controller together with a high-gain observer, estimating mechanical torque, generates the reference electrical torque. At overrated wind speed, the control strategy limits the generated power to rated power of generator via an anti-windup algorithm. In this case, the flux weakening strategy then is invoked. The optimal (reference) flux magnitude is provided by off-line numerically solving an optimisation problem. An space-vector modulation (SVM)-based direct-torque control (DTC) is used to track the electrical torque and flux references. In particular, the SVM-DTC is composed of a reference voltage vector calculator providing a desired voltage vector. The effectiveness of the proposed overall power control strategy is verified by applying the strategy to a commercial 10 kW wind turbine simulated in MATLAB/Simulink. © 2016 The Institution of Engineering and Technology.
Electric Power Components and Systems (15325016) 44(19)pp. 2212-2223
The main aim of this work is to present the results of the shape design optimization process of an interior permanent-magnet synchronous motor. The shape design optimization process is accomplished based on the variations of the rotor structure using the Taguchi method. The time-stepping finite-element method is used for analysis of the motor. It is found that the optimal two-layer Machaon design has the lowest torque pulsation compared with the other structures. Finally, the optimized Machaon and preliminary one-layer interior permanent-magnet synchronous motors, which are amended from industrial three-phase induction motors, are manufactured. The results of numerical, analytical, and practical tests are in good agreement. © 2016, Copyright © Taylor & Francis Group, LLC.
Journal of Magnetism and Magnetic Materials (03048853)
In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. © Elsevier B.V. All rights reserved.
Mirzaeian, B. ,
Moallem, M. ,
Rezazadeh S.J. ,
Amanifar O. ,
Keivanfard M.
This paper presents a new approach in order to determine the optimal placement and size of capacitors in TABRIZ radial distribution system to minimize investment cost, energy loss reduction, improvement of voltage profile. Capacitor optimal placement & sizing are done by determination of loss sensitivity factors and PSO. Loss sensitivity factors can be introduced as an important parameter for sequencing of effective nodes in loss reduction. In this paper, combination of this method with PSO algorithm is used as a novel approach for optimal capacitor placement. This method is tested on a 10 buses distribution system and applied on the all feeders of ROSHANAEI and GOLESTAN regions of TABRIZ Distribution Company. The findings clearly demonstrate the advantage of proposed method comparing with fuzzy-reasoning. Finally, investment return time, loss reduction percentage and capacity release of feeders have economically justified the practical usage of this method. © 2012 Iranian Association of Elect.
IEEE Transactions on Instrumentation and Measurement (00189456) (12)
In this paper, a new method based on adaptive neuro fuzzy inference system (ANFIS) and fuzzy logic is presented to determine the slag quality in electric arc furnace using power quality indices. To train ANFIS, all electrical power quality parameters are measured for 13 meltings using a power quality analyzer. Twelve different sets of power quality parameters are examined to predict the slag quality. Finally, one parameter set consisting of total current harmonic distortion, seventh current harmonic, and three phase current unbalance is selected, which shows the best prediction accuracy. Although the trained ANFIS can accurately predict the slag quality, it is not a robust predictor. If the power quality analyzer model or furnace capacity is changed, then the predictor accuracy will be decreased. To overcome this problem, the fuzzy method is used to predict the slag quality using selected power quality parameters. The predictor reports the slag quality every 1 min in experimental test. The designed fuzzy slag quality predictor can also be used in an automatic slag control process. © 2011 IEEE.
A velocity controller for a permanent magnet linear synchronous motor (PMLSM) is designed using a brain emotional learning based intelligent control (BELBIC). This is performed for a comprehensive nonlinear model of PMLSM including non-idealities such as detent force, parameter uncertainty, unpredicted disturbance, and nonlinear friction. As an evaluation criterion of the performance of the proposed method, a proportional-integral (PI) controller is designed whose parameters are optimally tuned by the particle Swarm Optimization (PSO) algorithm for better comparison. © 2011 IEEE.
International Review of Electrical Engineering (18276660) (1)
Restructuring and deregulation in power system market result in growing attention to power quality (PQ) issues. Along with the increment of disturbing loads in the power system, the effect on network that is brought by the power quality problems, become increasingly serious. Existing PQ indices are usually isolated and lack the cost impact of bad power quality. This paper presents a method based on mathematical statistics and fuzzy logic to obtain a quantitative global index for PQ evaluation and pricing in competitive electricity market. Taking into account the cost of PQ phenomena with their relative weights in this index, it can be used as a PQ measure in electricity tariffs by utility companies. The method provides some basis for contract's subscribing in the future. Advantage of the method is its consistency which gives a useful and unique measure of quality of electricity for both supply side and customer side. The proposed algorithm has been implemented on real measured data of a distribution network. Results show the capability of this method to obtain an accurate measure for PQ evaluation and pricing. © 2010 Praise Worthy Prize S.r.l. - All rights reserved.
IET Generation, Transmission and Distribution (17518687) (7)
A problem of concern in the deregulated electricity market is to obtain a global power quality (PQ) index for the supply and load side to estimate the cost of PQ in order to include it in the contracts between customers and utility companies. Existing PQ indices are usually isolated and lack the cost impact of bad PQ. This study presents an intelligent method based on artificial neural network (ANN) and fuzzy logic to obtain a quantitative global index for PQ evaluation and pricing in competitive electricity market. Taking into account the cost of PQ phenomena with their relative weights in this index, it can be used as a PQ measure in electricity tariffs by utility companies. Although individual cost assignments used in this study are subject to approximation, once the assignments are made, the calculation is consistent and gives a useful and unique measure of quality of electricity for both supply side and customer side. The proposed algorithm has been implemented on real measured data of a distribution network. The results show the capability of this method to obtain an accurate measure for PQ evaluation and pricing. © 2010 The Institution of Engineering and Technology.
Parsapoor, A. ,
Mirzaeian Dehkordi B. ,
Moallem, M. ,
Parsapoor, A. ,
Mirzaeian, B. ,
Moallem, M. 2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025 pp. 861-866
Foaming slag quality is an important parameter that can be used to improve the efficiency and quality of electric arc furnace process. However due to its fast and unpredictable changes, its quality is difficult to control. In this paper, an Adaptive Neuro Fuzzy Inference System (ANFIS) is used to determine slag quality based on power quality indices in electric arc furnaces. In order to train the intelligent system, a power quality analyzer is installed on an electric arc furnace feeder to record its power quality parameters. All electrical power quality parameters have been measured for 13 melting. Twelve groups of power quality parameters are examined for prediction slag quality and finally one group including total current harmonic distortion, seventh current harmonic, and three phase current unbalance are selected which shows the best prediction accuracy. The intelligent system trained by six melting data and tested experimentally by connecting power quality analyzer to furnace feeder to predict the slag quality every minute. Experimental results show the accuracy of prediction is about 95%. The designed intelligent system can also be used in slag control process. ©2010 IEEE.
Journal of Power Electronics (15982092) (3)
In this paper, a nonlinear controller is proposed for Doubly-Fed Induction Machine (DFIM) drives. The nonlinear controller is designed based on an adaptive backstepping control technique, using a fifth order model of an induction machine in the synchronous d and q axis rotating reference frame, whose d axis coincides with the space voltage vector of the main AC supply, and using the rotor current and stator flux components as state variables. The nonlinear controller can perfectly track the torque reference signal measured in the stator terminals under the condition of unity power factor regulation, in spite of the stator and rotor resistance variations. In order to make the drive system capable of operating in the motoring and generating modes below and above the synchronous speed, two level Space-Vector PWM (SV-PWM) back-to-back voltage source inverters are employed in the rotor circuit. It is confirmed through computer simulation results that the proposed control approach is effective and valid.
Journal of Power Electronics (15982092) (3)
In this paper an optimal damped input filter is designed based on a Genetic Algorithm (GA) for an electrolytic capacitor-less AC-AC converter. Sufficient passive damping and minimum losses in passive damping elements, minimization of the filter output impedance at the filter cut-off frequency, minimization of the DC-link voltage and input current fluctuations, and minimization of the filter costs are the main objectives in the multi-objective optimization of the input filter. The proposed filter has been validated experimentally using an induction motor drive system employing an electrolytic capacitor-less AC-AC converter.
In this paper, the effect of rotor time constant variation on the dynamic performance of rotor flux in the speed sensorless indirect Field Oriented Control (FOC) method of induction motor is considered, then a novel method for adaptation of rotor time constant based on Model Reference Adaptive System (MRAS) is presented. The computer simulations have shown the validity and the feasibility of the proposed method that possesses the advantages of MRAS implementation; the high speed of processing. In addition this method is more adapted for practical implementation because it uses the stator voltages and currents in the estimation of the rotor time constant and speed. Also, the method is suitable for implementation with conventional sensorless FOC drives. © 2007 IEEE.
Payam A.F. ,
Mirzaeian Dehkordi B. ,
Moallem, M. ,
Payam A.F. ,
Mirzaeian, B. ,
Moallem, M. 2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025 pp. 830-835
In this paper a nonlinear controller is presented for Doubly-Fed Induction Machine (DFIM) drives. The nonlinear controller is designed based on adaptive input-output feedback linearization control technique, using the fifth order model of induction machine in fixed stator d, q axis reference frames with stator currents and rotor flux components as state variables. The nonlinear controller can perfectly track the torque and flux reference signals inspite of stator and rotor resistance variations. Two level SVM-PWM back-to-back voltage source inverters are employed in the rotor circuit, in order to make the drive system capable of operating in the motoring and generating modes below and above synchronous speed. Computer simulation results obtained, confirm the effectiveness and validity of the proposed control approach. © 2007 IEEE.
In this paper a new energy method for determination of flicker source in power system is proposed. This method is based on the energy of flicker signal; therefore, an expression for flicker energy signals is defined, which can be successfully utilized for detection of the flicker source. The main advantage of this method is its simplicity which can be implemented in time domain and no transformation to frequency domain is required. There are good agreements between simulation and test results.
2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025 pp. 267-272
In this paper two different Decision Tree learning systems for modeling of a switched reluctance motor have been developed. The design vector consists of the design parameters in the first one whereas in the second one, it is a combination of hysteresis current band in the current limiter and the switching angles. The output performance variables are efficiency and torque ripple in both systems. An accurate analysis program based on Improved Magnetic Equivalent Circuit (IMEC) method has been used to generate the input-output data. These input-output data is used to produce the Decision Trees for predicting the performance of Switched Reluctance Motor (SRM). The performance prediction results for a 6/8, 4kw, SR motor show good agreement with the results obtained from IMEC method or Finite Element (FE) analysis. The developed Decision Tree systems can be used for fast prediction of motor performance in the optimal design process or on-line control schemes of SR motor. ©2007 IEEE.
WSEAS Transactions on Circuits and Systems (11092734) (8)
Nowadays nonlinear functions play a significant role in some fields like communication and signal processing. One of important problems that can be solved with them is designing nonlinear functions that are applicable in nonlinear control and effective control. Using discrete time nonlinear controllers cause some problems like instability that can be eliminated using continuous time nonlinear controllers. The most essential block for creating nonlinear functions is a precision multiplier. In this article redesigning and simulating a precision multiplier block using BJT Gilbert cell to creating nonlinear functions like a sinusoidal function block is desirable.
In this paper using Adaptive Backstepping approach an adaptive rotor flux observer which provides stator and rotor resistances estimation simultaneously for induction motor used in series hybrid electric vehicle is proposed. The controller of induction motor (IM) is designed based on input-output feedback linearization technique. Combining this controller with adaptive backstepping observer the system is robust against rotor and stator resistances uncertainties. In additional, mechanical components of a hybrid electric vehicle are called from the Advanced Vehicle Simulator Software Library and then linked with the electric motor. Finally, a typical series hybrid electric vehicle is modeled and investigated. Various tests, such as acceleration traversing ramp, maximum speed, fuel consumption and emission are performed on the proposed model of a series hybrid vehicle. Computer simulation results obtained, confirm the validity and performance of the proposed IM control approach using for series hybrid electric vehicle. © 2006 IEEE.
In this paper, the robust nonlinear sliding-mode speed sensorless speed controller for a dc servo motor is proposed. Based on state-space model representing the speed and current dynamics, the nonlinear sliding mode control is designed to track a linear reference model. An observer based on adaptive backstepping approach is used to estimate speed and uncertain parameters. With the proposed speed controller, the controlled dc servo motor possesses the advantages of good transient performance and robustness for parameters deviations, and transient dynamics of dc servo motor can be regulated through the design of a linear reference model which has the desired dynamic behaviors for the drive system. Finally, simulation results are demonstrated to validate the proposed controller. © 2006 IEEE.
In this paper, a novel multi-objective optimization method based on Genetic Algorithm (MGA) is proposed. MGA is applied to optimize the three objective functions. The objective functions are designed for reactive power optimization control, such as, loss and/or invest cost minimization. The simulation results of the new method for IEEE-30 bus system are compared with the results obtained by the single weighted objective method, which shows better performance. © 2006 IEEE.
This paper presents a new method for coefficient determination of feedback linearization control method for position control of switched reluctance motors. Feed back linearization method is unstable against uncertainties of rotor inertia and stator resistance, this disadvantage makes us to design a method that is robust against those mentioned uncertainties, in this paper by adding a torque term to the motor dynamical equation, we have made the controlling method, robust against uncertainties of rotor inertia and stator resistance. The main problem in adaptive feed back linearization method is determination of its feed back coefficients, multi-objective optimization based on genetic algorithm is proposed as an stochastic method to determine the coefficients. The major gain of our proposed method compared to those reported so far, is that, it needs less time to converge and also less speed rise time. Because of the significance of determining the coefficients precisely, the proposed method can be used in these applications, the simulation results have been compared with trial and error method and show the benefits of the proposed method. © 2005 IEEE.
Antilock braking systems (ABS) have been developed to reduce tendency of wheel lock and to improve vehicle control during sudden braking especially on slippery road surfaces. The objective of such control is to increase wheel tractive force in the desired direction while maintaining adequate vehicle stability and steerability and also reducing the vehicle stopping distance. In this paper, an optimized hybrid controller using a fuzzy system is proposed for antilock braking systems. Hie objective function is defined to maintain wheel slip to a desired level so that maximum wheel tractive force and maximum vehicle deceleration are obtained. An components of fuzzy system are optimized using a genetic algorithm and error based optimization technique. The error based global optimization approach is used for fast convergence near optimum point Simulation results show fast convergence and good performance of the controller for different road conditions. ©2005 IEEE.
IEEE Transactions on Magnetics (00189464) (3)
In this paper, a novel multiobjective optimization method based on a genetic-fuzzy algorithm (GFA) is proposed. The new GFA method is used for optimal design of a switched reluctance motor (SRM) with two objective functions: high efficiency and low torque ripple. The results of the optimal design for an 8/6, four-phase, 4 kW, 250 V, 1500 rpm SRM show improvement in both efficiency and torque ripple of the motor.
IEEE Transactions on Magnetics (00189464) (5 I)
In this paper, a novel multi-objective optimization method based on Genetic-Fuzzy Algorithm (GFA) is proposed. GFA is applied to optimize the five PI controller gains in the Indirect Field Oriented Control (IFOC) of an induction motor drive. The PI controller gains are designed to optimize the step response of the system. Rise-time, maximum over-shoot, settling time and steady state error are the objective functions. In this drive system, the simultaneous estimation of the rotor speed and time constant for a voltage source inverter-fed induction motor is discussed. The theory is based on the parallel Model Reference Adaptive Control System (MRAC). The vector control of the induction motor may be achieved in the rotor-flux-oriented frame. Furthermore, to eliminate the offset error caused by the change in the stator resistance, a fuzzy resistance is also designed. The simulation results of the new method for induction motor speed control is compared with the results obtained by the conventional method, which shows better performance.
Mirzaei, A. ,
Mirzaei A. ,
Moallem, M. ,
Moallem, M. ,
Mirzaeian, B. ,
Mirzaeian, B. ,
Fahimi, B. ,
Fahimi, B. IEEE Transactions on Vehicular Technology (00189545) 55pp. 1725-1730
Antilock braking systems (ABS) have been developed to improve vehicle control during sudden braking especially on slippery road surfaces. The objective of such control is to increase wheel tractive force in the desired direction while maintaining adequate vehicle stability and steerability and also reducing the vehicle stopping distance. In this paper, an optimized Fuzzy controller is proposed for antilock braking systems. The objective function is defined to maintain wheel slip to a desired level so that maximum wheel tractive force and maximum vehicle deceleration are obtained. All components of fuzzy system are optimized using genetic algorithms. The error based global optimization approach is used for fast convergence near optimum point. Simulation results show fast convergence and good performance of the controller for different road conditions. ©2005 IEEE.
Anti-lock braking systems (ABS) have been developed to reduce tendency for wheel lock and improve vehicle control during sudden braking especially on slippery road surfaces. The objective of such control is to increase wheel tractive force in the desired direction while maintaining adequate vehicle stability and steerability and also reducing the vehicle stopping distance. In this paper, a genetic-fuzzy ABS controller is designed. The objective function is defined to maintain wheel slip to a desired level so that maximum wheel tractive force and maximum vehicle deceleration are obtained. All components of the fuzzy system that is Takagi-Sugeno-Kang (TSK) type are obtained using a genetic algorithm. Simulation results show very good performance of the controller for different road conditions. © 2005 IEEE.
This paper presents an analysis on electrolytic capacitor-less inverter and proposes a strategy for resonance suppression control for a DC-link voltage and input current in electrolytic capacitor-less inverter. The proposed electrolytic capacitor-less inverter can operate both in the motoring mode and regenerating mode owing to its inherent bidirectional power flow capability of the active front-end rectifier whose switching frequency is equal to the input line frequency. However, in the electrolytic capacitor-less inverter, the DC-link voltage is fluctuating with six times of the frequency of input three phase source due to its small DC link capacitance. Also, an input filter should be employed to remove the high frequency component generated by PWM inverter. By the input filter, the DC-link voltage can be resonant, and a specific resonance suppression control is required when the input line-to-line voltage is low and the demanded power is large. In this paper, a novel resonance suppression strategy is proposed for a stable operation of the electrolytic capacitor-less inverter. The experimental results show the effectiveness of proposed strategy. ©2009 IEEE.
