Showing 34 results for Synchro
H. Fallah Khoshkar, A. Doroudi, M. Mohebbi,
Volume 10, Issue 4 (12-2014)
Abstract
This paper studies the effects of symmetrical voltage sags on the operational characteristics of a Permanent Magnet Synchronous Motor (PMSM) by Finite Element Method (FEM). Voltage sags may cause high torque pulsations which can damage the shaft or equipment connected to the motor. By recognizing the critical voltage sags, sags that produce hazardous torque variations could be prevented. Simulations results will be provided and the critical voltage sags are recognized. A simple theoretical analysis will also be presented to obtain a qualitative understanding of the phenomena occurring in PMSM during symmetrical voltage sags
A. Darijani, A. Kiyoumarsi, H. A. Lari, B. Mirzaeian Dehkordi, Sh. Bekhrad, S. Rahimi Monjezi,
Volume 11, Issue 1 (3-2015)
Abstract
Permanent-Magnet Synchronous Generators (PMSGs) exhibit high efficiency and power density, and have already been employed in gearless wind turbines. In the gearless wind turbines, due to the removal of the gearbox, the cogging torque is an important issue. Therefore, in this paper, at first, design of a Permanent-Magnet Synchronous Generator for a 2MW gearless horizontal-axis wind turbine, according to torque-speed and capability curves, is presented. For estimation of cogging torque in PMSGs, an analytical method is used. Performance and accuracy of this method is compared with the results of Finite Element Method (FEM). Considering the effect of dominant design parameters, cogging torque is efficiently reduced.
M. Alizadeh Moghadam, R. Noroozian, S. Jalilzadeh,
Volume 11, Issue 3 (9-2015)
Abstract
This paper presents modeling, simulation and control of matrix converter (MC) for variable speed wind turbine (VSWT) system including permanent magnet synchronous generator (PMSG). At a given wind velocity, the power available from a wind turbine is a function of its shaft speed. In order to track maximum power, the MC adjusts the PMSG shaft speed.The proposed control system allowing independent control maximum power point tracking (MPPT) of generator side and regulate reactive power of grid side for the operation of the VSWT system. The MPPT is implemented by a new control system. This control system is based on control of zero d-axis current (ZDC). The ZDC control can be realized by transfer the three-phase stator current in the stationary reference frame into d-and q-axis components in the synchronous reference frame. Also this paper is presented, a novel control strategy to regulate the reactive power supplied by a variable speed wind energy conversion system. This control strategy is based on voltage oriented control (VOC). The simulation results based on Simulink/Matlab software show that the controllers can extract maximum power and regulate reactive power under varying wind velocities.
H. Yaghobi, H. Kafash Haghparast,
Volume 11, Issue 3 (9-2015)
Abstract
Synchronous generators are of two type’s salient pole type and round rotor type. The load angle curve of a cylindrical rotor synchronous machine comprises a single sine term only while in salient pole synchronous generators, power-angle characteristic has two terms. The first term is the fundamental component due to field excitation (the same as the cylindrical rotor) and the second term includes the effect of salient pole. In fact, this term is the second harmonic component due to reluctance torque. This paper presents a study on the new design of cylindrical solid rotor synchronous generator. In this new design, rotor of the machine is designed in such a way that the required inductance values are reached to produce reluctance torque, besides electromagnetic torque due to field excitation. In this contribution, a combination of two different ferromagnetic materials is considered in the design of the rotor. In this theory, the tight connection between the different materials is very important from a mechanical point of view. In other words, this new idea and production principal has potential in some areas after some further research and engineering. But this paper is focused on magnetic flux-carrying materials and presents a study of the new design of cylindrical solid rotor synchronous generator (NCG). Then a comparative analysis was made between this new (NCG) and conventional cylindrical solid rotor synchronous generator (CCG) and the effectiveness of the new cylindrical solid rotor from a magnetic point of view is demonstrated. In this paper, mechanical and thermal aspects of design such as vibration did not analyze.
S. Ahmadi, A. Vahedi,
Volume 11, Issue 3 (9-2015)
Abstract
In this paper a multiobjective optimal design method of interior permanent magnet synchronous motor ( IPMSM) for traction applications so as to maximize average torque and to minimize torque ripple has been presented. Based on train motion equations and physical properties of train, desired specifications such as steady state speed, rated output power, acceleration time and rated speed of traction motor are related to each other. By considering the same output power, steady state speed, rated voltage, rated current and different acceleration time for a specified train, multiobjective optimal design has been performed by Broyden–Fletcher–Goldfarb–Shanno (BFGS) method and finite element method (FEM) has been chosen as an analysis tool. BFGS method is one of Quasi Newton methods and is counted in classic approaches. Classic optimization methods are appropriate when FEM is applied as an analysis tool and objective function isn’t expressed in closed form in terms of optimization variables.
M. E. Moazzen, S. A. Gholamian, M. Jafari-Nokandi,
Volume 13, Issue 2 (6-2017)
Abstract
Permanent magnet synchronous generators (PMSG) have a huge potential for direct-drive wind power applications. Therefore, optimal design of these generators is necessary to maximize their efficiency and to reduce their manufacturing cost and total volume. In this paper, an optimal design of a six-phase 3.5 KW direct-drive PMSG to generate electricity for domestic needs is performed. The aim of optimal design is to reduce the manufacturing cost, losses and total volume of PMSG. To find the best design, single/multi-objective design optimization is carried out. Cuckoo optimization algorithm (COA) is adopted to solve the optimization problem. Comparison between the results of the single-objective and multi-objective models shows that simultaneous optimization of manufacturing cost, losses and total volume leads to more suitable design for PMSG. Finally, finite-element method (FEM) is employed to validate the optimal design, which show a good agreement between the theoretical work and simulation results.
S. Heshmatian, D. Arab Khaburi, M. Khosravi, A. Kazemi,
Volume 14, Issue 1 (3-2018)
Abstract
Wind energy is one of the most promising renewable energy resources. Due to instantaneous variations of the wind speed, an appropriate Maximum Power Point Tracking (MPPT) method is necessary for maximizing the captured energy from the wind at different speeds. The most commonly used MPPT algorithms are Tip Speed Ratio (TSR), Power Signal Feedback (PSF), Optimal Torque Control (OTC) and Hill Climbing Search (HCS). Each of these algorithms has some advantages and also some major drawbacks. In this paper, a novel hybrid MPPT algorithm is proposed which modifies the conventional methods in a way that eliminates their drawbacks and yields an improved performance. This proposed algorithm is faster in tracking the maximum power point and provides a more accurate response with lower steady state error. Moreover, it presents a great performance under conditions with intensive wind speed variations. The studied Wind Energy Conversion System (WECS) consists of a Permanent Magnet Synchronous Generator (PMSG) connected to the dc link through a Pulse-Width Modulated (PWM) rectifier. The proposed algorithm and the conventional methods are applied to this WECS and their performances are compared using the simulation results. These results approve the satisfactory performance of the proposed algorithm and its notable advantages over the conventional methods.
A. Younesi, S. Tohidi, M. R. Feyzi,
Volume 14, Issue 3 (9-2018)
Abstract
Model-based predictive control (MPC) is one of the most efficient techniques that is widely used in industrial applications. In such controllers, increasing the prediction horizon results in better selection of the optimal control signal sequence. On the other hand, increasing the prediction horizon increase the computational time of the optimization process which make it impossible to be implemented in real time. In order to solve this problem, this paper presents an improved strategy in the field of nonlinear MPC (NMPC) of the permanent magnet synchronous motor (PMSM). The proposed method applies a sequence of reduction weighting coefficients in the cost function, over the prediction horizon. By using the proposed strategy, NMPC give a more accurate response with less number of prediction horizon. This means the computational time is reduced. It also suggests using an incremental algorithm to reduce the computational time. Performance of the proposed Nonlinear MPC (NMPC) scheme is compared with the previous NMPC methods via simulations performed by MATLAB/Simulink software, in permanent magnet synchronous motor drive system. The results show that the use of proposed structure not only lowers prediction horizon and hence computational time, but also it improves speed tracking performance and reduces electromagnetic torque ripple. In addition, using the incremental algorithm also reduces the computational time which makes it suitable for real-time applications.
E. Bounadja, Z. Boudjema, A. Djahbar,
Volume 15, Issue 3 (9-2019)
Abstract
This paper proposes a novel wind energy conversion system based on a Five-phase Permanent Magnetic Synchronous Generator (5-PMSG) and a Five to three Matrix Converter (5-3MC). The low cost and volume and also eliminating grid side converter controller are attractive aspects of the proposed topology compared to the conventional with back-to-back converters. The control of active and reactive power injected to the grid from the proposed system is carried out by a Direct Power Control (DPC) combined with a Space Vector Modulation (SVM). An advantage of this control, compared with the Conventional Direct Power Control (C-DPC) method, is that it eliminates the lookup table and lowers grid powers and currents harmonics through the use of a standard PI controller instead of hysteresis comparators. The efficiency of proposed whole system has been simulated by using MATLAB/Simulink environment.
A. Kumar, P. Kumar,
Volume 15, Issue 4 (12-2019)
Abstract
This paper presents the three topologies of three-phase four-wire DSTATCOM for reduction of harmonics, reactive power compensation, increasing power factor, which occur due to a nonlinear load, environment problem and polluted grid. The performances of the above topologies have been compared for the magnitude of source current, power factor improvement, DC-link voltage regulation, and total harmonic distortion. This paper presents a novel work for the new young scientist /industrialist who working in the improvement of power quality in the grid. This paper helps to provide the application, designing constraints of shunt active filter in many fields. The First topology which is used in this paper is the three-phase four-wire four-pole voltage source converter based DSTATCOM. The second is the three-phase four-wire with three-leg voltage source converter based DSTATCOM with T-connected transformer and the third topology is the three H-bridge voltage source converter based DSTATCOM. The T-connected transformer in the second topology has been used to reduce the rating for voltage source converter. Synchronous reference frame theory based controller has been proposed to the generation of the reference current. Reference current generated from the synchronous frame theory is processed to hysteresis current controller loop which produces switching pulses for VSC based DSTATCOM. All these topologies have been implemented in MATLAB /Simulink platform by using different types of loading conditions such as resistive and power electronics load.
S. R. Hosseini, M. Karrari, H. Askarian Abyaneh,
Volume 15, Issue 4 (12-2019)
Abstract
This paper presents a novel impedance-based approach for out-of-step (OOS) protection of a synchronous generator. The most popular and commonly used approaches for detecting OOS conditions are based on the measurement of positive sequence impedance at relay location. However, FACTS devices change the measured impedance value and thus disrupt the performance of impedance-based relay function. In this paper, the performance of synchronous generator OOS protection function connected to the transmission line in the presence of a static synchronous compensator (STATCOM) is investigated. Moreover, an analytical adaptive approach is used to eliminate the effect of STATCOM. This approach requires only the remote bus voltage and current phasors to be sent to the relay location via a communication channel. Simulation results show that STATCOM changes impedance trajectory and causes the incorrect operation of OOS relay. Furthermore, the proposed approach corrects the relay mal-operation and improves the accuracy of OOS impedance-based function when the STATCOM is used in the system.
S. M. Hoseini, N. Vasegh, A. Zangeneh,
Volume 16, Issue 2 (6-2020)
Abstract
In this paper, a robust local controller has been designed to balance the power for distributed energy resources (DERs) in an islanded microgrid. Three different DER types are considered in this study; photovoltaic systems, battery energy storage systems, and synchronous generators. Since DER dynamics are nonlinear and uncertain, which may destabilize the power system or decrease the performance, distributed robust nonlinear controllers are designed for the DERs. They are based on the Lyapunov stabilization theory and super-twisting integral sliding mode control which guarantees system stability and optimality simultaneously. The reference signals for each DER are generated by a supervisory controller as a power management system. The controllers proposed in this work are robust, have fast response times, and most importantly, the control signals satisfy physical system constraints. The designed controller stability and effectiveness are also verified using numerical simulations.
Z. Kazemi, A. A. Safavi,
Volume 16, Issue 3 (9-2020)
Abstract
Kalman filtering has been widely considered for dynamic state estimation in smart grids. Despite its unique merits, the Kalman Filter (KF)-based dynamic state estimation can be undesirably influenced by cyber adversarial attacks that can potentially be launched against the communication links in the Cyber-Physical System (CPS). To enhance the security of KF-based state estimation, in this paper, the basic KF-based method is enhanced by incorporating the dynamics of the attack vector into the system state-space model using an observer-based preprocessing stage. The proposed technique not only immunizes the state estimation against cyber-attacks but also effectively handles the issues relevant to the modeling uncertainties and measurement noises/errors. The effectiveness of the proposed approach is demonstrated by detailed mathematical analysis and testing it on two well-known IEEE cyber-physical test systems.
S. Shadpey, M. Sarlak,
Volume 16, Issue 4 (12-2020)
Abstract
This paper presents a pattern recognition-based scheme for detection of islanding conditions in synchronous- based distributed generation (DG) systems. The main idea behind the proposed scheme is the use of spatial features of system parameters such as the frequency, magnitude of positive sequence voltage, etc. In this study, the system parameters sampled at the point of common coupling (PCC) were analyzed using reduced-noise morphological gradient (RNMG) tool, first. Then, the spatial features of the RNMG magnitudes were calculated. Next, to optimize and increase the ability of the proposed scheme for islanding detection, the best features with a much discriminating power were selected based on separability index (SI) calculation. Finally, to distinguish the islanding conditions from the other normal operation conditions, a support vector machine (SVM) classifier was trained based on the selected features. To investigate the power of the proposed scheme for islanding detection, the results of examinations on the various islanding conditions including system loading and grid operating state were presented. These results show that the proposed algorithm reliably detect the islanding condition within 32.7 ms.
S. H. Montazeri, A. Damaki Aliabad, F. Zare, S. Aghaei,
Volume 17, Issue 1 (3-2021)
Abstract
The direct drive permanent magnet synchronous motor (DD-PMSM) is a suitable choice for high-precision position control applications. Among various control methods of this motor, the vector control approaches especially the field oriented control has a high-performance in the industrial drives. In this method, the components of stator current are controlled independently and as a result, the torque and flux are controlled continuously. Since there are some limitations and constraints in the motor, inverter, and control system, a new anti-windup gain scheduling PID controller based on the adaptive control principles is proposed for the position control loop. In the proposed method, different values are assigned to coefficients of the PID controller according to the position error to achieve high precision. Also, a very high-accuracy encoder and an ARM processor are used for measuring the instantaneous position and implementation of the proposed method, respectively. The simulation and experimental results validate the effectiveness, high accuracy, and good dynamic behavior of the proposed control method.
S. R. Hosseini, M. Karrari, H. Askarian Abyaneh,
Volume 17, Issue 1 (3-2021)
Abstract
In this paper, a novel approach based on the Thévenin tracing is presented to modified conventional impedance-based out-of-step (OOS) protection. In conventional approach, the OOS detection is done by measuring positive sequence impedance. However, the measured impedance may be change due to different factors such as capacitor bank switching and reactive power compensators that it can cause the relay to malfunction. In this paper, first, an on-line Thévenin equivalent (TE) approach based on the recursive least square (RLS) is presented. Then, a protection function is developed based on online network Thévenin equivalent parameters to correct the measured impedance path. The main feature of this method is the use of local voltage and current measurements for Thévenin equivalent estimation and OOS protection. The performance of the proposed method is investigated by simulation of synchronous generator OOS protection function in the presence of a static synchronous compensator (STATCOM). The simulation results show that, STATCOM changes the impedance path and can cause the incorrect diagnosis of OOS relay. Furthermore, the proposed method corrects the impedance path and improves the accuracy of OOS impedance-based function when the STATCOM is installed in system.
B. Mamipour Matanag, N. Rostami, S. Tohidi,
Volume 17, Issue 2 (6-2021)
Abstract
This paper proposes a new method for direct control of active power and stator flux of permanent magnet synchronous generator (PMSG) used in the wind power generation system. Active power and stator flux are controlled by the proposed discrete time algorithm. Despite the commonly used vector control methods, there is no need for inner current control loops. To decrease the errors between reference and measured values of active power and stator flux, the space vector modulation (SVM) is used, which results in a constant switching frequency. Compared to vector control, the proposed direct control method has advantages such as higher dynamic response due to elimination of inner current control loops and no need to coordinate system transformation blocks as well as the PI controllers and their adjustment. Moreover, permanent magnet flux vector and several machine parameters such as stator inductances are not required which can improve the robustness of the control system. The proposed method can be used in both types of surface-mounted and interior PMSGs. The effectiveness of the proposed method in comparison to the vector control method with optimized PI coefficients by the particle swarm algorithm is evaluated. Simulation results performed in MATLAB/Simulink software show that higher dynamic response with lower active power and the stator flux ripple are achieved with the proposed method.
Z. Najafniya, Gh. Karimi, Mahnaz Ranjbar,
Volume 17, Issue 3 (9-2021)
Abstract
Neural synchronization is considered as a key role in several neurological diseases, such as Parkinson’s and Epilepsy’s disease. During these diseases, there is increased synchronization of massive numbers of neurons. In addition, evidences show that astrocytes modulate the synaptic interactions of the neuronal population. The Astrocyte is an important part of a neural network that can be involved in the desynchronization of the neuronal population. In this paper, we design a new analog neuromorphic circuit to implement the effect of astrocyte in the desynchronization of neural networks. The simulation results demonstrate that the astrocyte circuit as a feedback path can be desynchronized to a synchronized neural population. In this circuit, as a first step, the population of twenty neurons is synchronized with the same input currents. Next, by involving an astrocyte feedback circuit, the synchronization of the neural network is disturbed. Then, the neuronal population will be desynchronized. The proposed circuit is designed and simulated using HSPICE simulator in 0.35 μm standard CMOS technology.
Nabiollah Ramezani, Mohsen Shahnazdoost Kilvaei,
Volume 21, Issue 1 (3-2025)
Abstract
In this paper, a novel method is presented that can accurately estimate the Thevenin equivalent circuit parameters of an external power system by RTUs. The presented method is based on the simultaneous measurements of the desired points in the boundary system, which includes the bus voltage amplitude, the current amplitude of the boundary transmission lines, as well as active and reactive power, and is continuously active until the Thevenin equivalent circuit model would be available online. The practical application of the proposed method is related to online monitoring and control of wide-area power systems as well as their development design. Also, the innovation of the method is the accurate estimation of the Thevenin equivalent circuit model from part of the power network where information is not available. In the proposed method, an additional measurement and the least squares method are used to eliminate measurement errors in order to accurately estimate the parameters of the equivalent circuit model. In order to avoid providing the wrong equivalent circuit model due to external system changes, a method is presented that can track the correct system changes to continuously monitor the disturbances. The proposed method performance has been implemented and validated by DigSILENT software.
Mohammad Reza Eesazadeh, Zahra Nasiri-Gheidari,
Volume 21, Issue 4 (11-2025)
Abstract
This research focuses on electromagnetic position sensors, particularly synchros, which play a crucial role in the closed-loop control systems of permanent magnet synchronous machines (PMSMs). Compared to two-phase resolvers, three-phase synchros provide enhanced reliability by ensuring continued operation even in the event of an open-circuit fault. One of the key challenges in designing such sensors lies in selecting optimal windings and configurations while also developing efficient modeling techniques to minimize computational complexity. To address this issue, the study introduces a matrix-based method for designing wound rotor (WR) synchros. This approach allows for flexible configurations depending on the number of pole pairs and stator tooth counts. The proposed design methodology ensures adaptability and precision, making it a valuable tool for engineers working on electromagnetic sensor development. To validate the effectiveness of the proposed method, the Field Reconstruction Method (FRM) is employed, providing a fast and accurate modeling technique that can be implemented using MATLAB. Additionally, a comparative analysis is conducted with finite element analysis (FEA) to confirm the accuracy and reliability of the approach. Results demonstrate that the matrix-based method is an efficient and effective solution for optimizing WR synchro designs, significantly improving performance and computational efficiency.
