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permanent-magnet-synchronous-machine
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Prediction of chaos in non-salient permanent-magnet synchronous machines
, Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 377, Issue 1-2 , December , 2012 , Pages 73-79 ; 03759601 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
2012
Abstract
This Letter tries to find the area in parameter space of a non-salient Permanent-Magnet Synchronous Machine (PMSM) in which chaos can occur. This area is briefly named as chaotic area. The predicted chaotic area is obtained by checking some conditions which are necessary for existence of chaos in a dynamical system. In this Letter, it is assumed that this machine is in the generator mode, and its model is based on direct and quadrature axis of stator voltages and currents. The information of the predicted area is used in non-chaotic maximum power control of torque in the machine
Prediction and Control of Chaos in Permanent Magnet Synchronous Machines
, M.Sc. Thesis Sharif University of Technology ; Tavazoei, Mohammad Saleh (Supervisor)
Abstract
Synchronous machines is one of the most popular machines in industry and in power plants. Because the dynamic of this machine is nonlinear, it can exhibit complex behaviors. In this project we have studied a special case in Permanent Magnet Synchronous Machines. A case in which speed of rotor, frequency, currents amplitude and voltages amplitude change in an irregular manner. This special case is called chaos. Chaos occurs for some specific values of parameters and inputs. In this study in the first step, we have tried to find the chaotic area of parameters of system (Prediction of chaos). Then in the next step, we have designed some controllers which can eliminate chaos in the system. The...
Sensor-Less Control of Permanent Magnet Synchronous Motor Using High Frequency Signal Injection
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
In this thesis one of the sensorless methods which exploits the existing anisotropies of the rotor is utilized to estimate rotor position. In order to implement this method, first a high frequency voltage is injected in a specific, time-varying direction and then the corresponding current response would be observed in order to estimate the rotor saliency position. The estimation of rotor position would be more precise as the magnetic anisotropy due to rotor saliency increases and as a result the effect of noise and different disturbances in estimation of rotor position would be decresed. The effect of stator resistence is one of these disturbances which is usually neglected as a result of...
Speed Control of Permanent Magnet Synchronous Motor with Flexible Coupling Using Load Torque Observer
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
Elastic joints in 2-mass drive systems, because of their limited stiffness, can decrease the performance of the control system and lead to motor and load speed oscillation. Shaft torque ignoring can also stress both mechanical and electrical drive components. Because of low degree of freedom, conventional controllers, such as the PI controllers, cannot improve the performance of the system and keep the system stable at the same time. In this thesis, the dynamic response and stability of the 2-mass systems is improved using state controller. State estimation of 2-mass system is required for state space controller . In the thesis, different state observer is analyzed and compared with each...
Low Cost Sensor-Less Control of Permanent Magnet Synchronous Motor for Home Appliances
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
Proper operation of a permanent magnet synchronous motor (PMSM) requires rotor position information. Commonly a rotor position sensor, such as optical encoder or resolver, is used for this purpose. These sensors add cost, weight and degrade reliability of the drive system. Using position and speed sensors for control of PMSM’s in home appliances is not cost effective. In this thesis, a novel method for predicting position of the rotor and winding inductance of the permanent magnet synchronous machine has been presented. In this method, machine anisotropy is utilized for rotor position estimation purposes like what in the high frequency injection techniques. Each leg of the PWM inverter...
Sensorless control of PMSMs with tolerance for delays and stator resistance uncertainties
, Article IEEE Transactions on Power Electronics ; Volume 28, Issue 3 , 2013 , Pages 1391-1399 ; 08858993 (ISSN) ; Tahami, F ; Sharif University of Technology
2013
Abstract
Position sensorless control of ac machines at zero and low speed is possible using high-frequency carrier injection methods. These methods utilize anisotropic properties of rotor. Therefore, they may lose their efficiency for nonsalient machines or machines with small rotor saliency. In these machines, measurement noise and offset, existing delays, as well as model uncertainties may lead to inaccurate estimation of rotor position. Stator resistance which is usually neglected in these methods may also lead to a considerable error especially in machines with small rotor saliency. In this paper, a new position estimation method is presented, and it is shown that in comparison to conventional...
Compensation of transient error in sensorless alternating carrier injection scheme
, Article IECON Proceedings (Industrial Electronics Conference) ; 2012 , Pages 1702-1706 ; 9781467324212 (ISBN) ; Tahami, F ; Sharif University of Technology
2012
Abstract
High frequency (HF) carrier injection schemes can estimate rotor position in a wide speed range. In these methods, first a HF voltage is injected to stator windings and then the corresponding HF current is exploited to estimate the position of rotor using a closed loop tracking observer. The tracking observer is capable to track rotor saliency with no steady state error. However when the motor starts to move or whenever the rotor speed changes a transient error appears. In this paper a new solution is proposed to compensate the transient error in estimation of rotor position
Transient error compensation in sensorless control of PMSM
, Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 38-43 ; 9781467301114 (ISBN) ; Tahami, F ; Sharif University of Technology
2012
Abstract
Sensorless schemes based on HF carrier injection are capable of estimating rotor position in a wide speed range. In these schemes first an additional HF voltage is injected to stator windings. The corresponding HF current is decoupled from main stator currents and the position of the rotor saliency is estimated based on the decoupled HF current in a closed loop tracking observer. The tracking observer is capable of tracking rotor saliency with no steady state error. Transient error appears when the motor starts to move or whenever the rotor speed changes because of any disturbance or any change in the rotor speed command. In this paper a new solution is proposed in order to compensate for...
Proposal of a Modular Structure and a Load Sharing Strategy among Back to Back Converters for Wind Turbines
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
The utilization of wind power has been increasing in recent years which lead to enhance the the usage of wind power capacity in the range of MegaWatt. However, due to the limitation ofswitching devices capacity, which exists in power electronic converters, improving the capacity of wind power generation is not accessible. Thus, a feasible solution for this problem is paralleling power electronics converters, which increases both the capacity of power generation and the reliability of wind turbine systems. Nevertheless, paralleling converters may cause a circulating-current which brings current discrepancy, current waveform distortion, power losses, increase in THD of currents, and reduction...
Direct Torque Control of Permanent Magnet Synchronous Machine Using Nonlinear Flux Observer
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
Direct Torque Control (DTC) is one of the vector methods to control Permanent Magnet Synchronous Machines (PMSM). In order to achieve an appropriate control in vector control methods, an accurate estimation of flux is indispensable. Flux estimation should be fulfilled in a wide speed range without considerable dependence on motor parameters. Prevalent flux estimation methods are based on integration of stator voltage which is not feasible in low speed, or performed based on assumption of decoupled equations on d and q axis which is not precise for applications with fast dynamic. Different flux estimation methods are investigated in this thesis with the aim of improving the flux estimation in...
Direct Speed Control of Permenant Magnet Synchronous Machine
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
Accurate and fast position controlling is an important issue in today’s industrial needs. Drives used for position control require fast dynamics on speed control. Cascade linear controllers have sluggish response due to bandwidth limitations on speed and current loop. These structures limit the dynamics above all in high power applications where the switching frequency is low. In this thesis, deadbeat direct speed control is proposed, which overcomes limitations by cascade loops resulting in high-speed control dynamics. This approach uses a model of the plant to generate the control signals. According to measured speed and currents, the controller specifies the best voltage vector in order...
Flux estimation by asymmetric carrier injection for sensorless direct torque control of PMSM
, Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 44-50 ; 9781467301114 (ISBN) ; Tahami, F ; Sharif University of Technology
2012
Abstract
The combination of direct torque control and permanent magnet synchronous motors (PMSMs) provides a highly dynamic drive. In this paper direct torque control method of PMSM is merged with a sensorless control algorithm and a robust flux observer is proposed which results in a high performance highly reliable drive. First a high frequency signal injection method within DTC algorithm is introduced to estimate the rotor position of PMSM. Then the method is modified in order to estimate stator dynamic inductances. The stator inductances are then used in a current model flux observer
Design and Optimization of a Flux Reversal Permanent Magnet Generator for Power Density Improvement in Direct Drive wind Turbine Application
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor) ; Nasiri Gheidari, Zahra (Co-Supervisor)
Abstract
Nowadays, due to gearbox drawbacks, the direct-drive wind turbines have received much more attention. Permanent magnet synchronous machines are commonly used for this purpose. The flux reversal machine with a magnetic gearbox and high power density could be an appropriate alternative. Due to placement of permanent magnets on the stator, the machine has a simple and robust structure and provides more reliability. There is limited study on optimization of the flux reversal machine and the existing papers are not complete and many parameters like PM dimension, working temperature, and winding reactance are not considered in the optimization process.Considering the flux reversal machine...
Sensorless control of non-salient PMSM using asymmetric alternating carrier injection
, Article 2011 IEEE Symposium on Industrial Electronics and Applications, ISIEA 2011, 25 September 2011 through 28 September 2011 ; September , 2011 , Pages 7-12 ; 9781457714184 (ISBN) ; Tahami, F ; Sharif University of Technology
Abstract
Sensorless control of permanent magnet synchronous motors allows reducing cost and complexity, and increasing mechanical robustness and noise immunity. Sensorless methods based on high frequency carrier injection have attracted considerable attention in recent years as they can estimate rotor position in a wide speed range. These methods employ anisotropic properties of rotor to estimate rotor position in ac machines. With internal permanent magnet motors, the high frequency signal injection method can deliver precise sensorless control, however in surface-mounted permanent magnet machines, where a small saliency arises from main flux saturation, the estimation of rotor magnet position is...