A Novel Isolated Three-Phase Induction Generator with Constant Frequency and Adjustable Output Voltage Using a Three-Phase STATCOM

Jafar Soltani,Yasser Hassani,Navid Reza Abjadi 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents a novel isolated three-phase induction generator with constant frequency and adjustable output voltage using a three-phase STATic COMpensator (STATCOM). The proposed electricity generating system consists of a dual stator-winding and STATCOM. In this generator, there are two sets of windings to be embedded in the stator slots. One, referred to as the 3-phase power winding, supplies power to load and the other, called 3-phase excitation winding is connected to a space vector modulation (SVM) voltage source invertor (VSI). Due to magnetic coupling between stator windings, active power transfer occurs between them. This active power causes serious disturbance in generator performance. A closed-loop controller for STATCOM is used to supply only requested reactive power and prevent active power transfer. In this paper, a hydraulic turbine and its governing system used for controlling requested active power amount by load are modelled. In comparison with other isolated induction generators, important advantages of this one are constant frequency independent from prime mover speed and adjustable output voltage.

THE DYNAMICAL PERFORMANCE OF CONTROLLED FLYWHEELING DUAL CONVERTER-FED DC MOTOR DRIVES WITH SIMULATANEOUS CONTROL AND FUZZY PI CONTROLLER.

Jafar Soltani,Jamshid Sojdei 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

This paper describes the dynamical performance of a four - quadrant criculation current mode control of dc motor drive, using the controlled flywleeling technique, a four - quadrant closed - loop control drive with an inner current control loop and a speed fuzzy PI regulator is designed.<br/> The obtained comouter simulation results of a dc motor drive below and and above the base speed are demonstrated. These result showthat compare to a conventional dual - converter - fed dc motor drive with simultaneous control, the overal system performance has been improved and also, agood stabilty and robstness has been achieved.

DYNAMICAL PERFORMANCE OF A NEW TYPE OF THREE PHASE SYNCHRONOUS MOTOR DRIVESUPPLTED BY SQUARE-WAVE INVERTERS

Jafar Soltani 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

In this paper , a three phase voltage source inverter synchronous motor drive is introduced which is capable of producing an approximate to sine - wave currents in the stator windings . Compare to a conventional current forced ,synchronous machime drive, for the same machine loss , a gain in out put per unit overall volume of 125% at a 5oHz supply frequency has been achieved In addition, the torque pulsation has been drastically reduced<br/> These improvements are achieved by introducing new rotor windings which are capable of controlling the stator current waveforms an approximate to sine - wave A computer program has been developed which can be used to predict the dynamic performance of this drive/system . The paper describes the design of rotor windings for cylindrical rotor motor but the theory is equally applicable to salient - pole designs .

SIMULTANEOUS SPEED AND ROTOR TIME CONSTANT IDENTIFICATION OF AN INDUCTION MOTOR DRIVE BASED ON THE MODEL REFERENCE ADAPTIVE SYSTEM COMBINED WITH A FUZZY RESSITANCE ESTIMATOR

Jafar Soltani,Behzad Mirzaeian 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

In this paper , simultaneous estimation of rotor speed and time constant for a voltage source inverter (VSI) fed induction motor drive are disccussed . The theory is based on the Model Reference Adaptive System (MRAS) . The identifier executes Simultaneous rotor speed and time constant so that vector control of the induction may be achieved in the rotor - flux oriented reference frame . Furthermore , to eliminate the offset error caused by the change in the stator resistance , a fuzzy resistance regulator is also designed which operates in parallel with the rotor speed and time constant identifier.<br/>

Comparative Analysis of Three‑phase and Five‑phase Permanent‑magnet Motor Based on Finite Element Method

Amir Nekoubin,Jafar Soltani,Milad Dowlatshahi 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.4

Permanent-magnet motors are suitable choice for special applications such as aircrafts, marine, and electric vehicles Because of the fault tolerance and high power density capability. In this paper, an analytical design of a fve-phase permanent-magnet motor is done and the advantages of multi phase motor over three phase motor are studied. Next Finite-element method is applied to verify and validate diferent machine designs. Finally thermal analysis of the designed machines is done. The results are shown multi phase motor has lower cogging torque and operation temperature, higher electromagnetic torque and back-emf in comparison with three phase motor.

Sliding Mode Control of a New Wind-Based Isolated Three-Phase Induction Generator System with Constant Frequency and Adjustable Output Voltage

Mohammadreza Moradian,Jafar Soltani 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This paper presents a new stand-alone wind-based induction generator system with constant frequency and adjustable output voltage. The proposed generator consists of a six-phase cage-rotor induction machine with two separate three-phase balanced stator windings and a three-phase space vector pulse width modulation inverter that operates as a static synchronous compensator (STATCOM). The first stator winding is fed by the STATCOM and used to excite the machine while the second stator winding is connected to the generator external load. The main frequency of the STATCOM is determined to be constant and equal to the load-requested frequency. The generator output frequency is independent of the load power demand and its prime mover speed because the frequency of the induced emf in the second stator winding is the same as this constant frequency. A sliding mode control (SMC) is developed to regulate the generator output voltage. A second SMC is used to force the zero active power exchanged between the machine and the STATCOM. Some simulation and experimental results are presented to prove the validity and effectiveness of the proposed generator system.

Input-Output Feedback Linearization of Sensorless IM Drives with Stator and Rotor Resistances Estimation

Hajian, Masood,Soltani, Jafar,Markadeh, Gholamreza Arab,Hosseinnia, Saeed The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

Direct torque control (DTC) of induction machines (IM) is a well-known strategy of these drives control which has a fast dynamic and a good tracking response. In this paper a nonlinear DTC of speed sensorless IM drives is presented which is based on input-output feedback linearization control theory. The IM model includes iron losses using a speed dependent shunt resistance which is determined through some effective experiments. A stator flux vector is estimated through a simple integrator based on stator voltage equations in the stationary frame. A novel method is introduced for DC offset compensation which is a major problem of AC machines, especially at low speeds. Rotor speed is also determined using a rotor flux sliding-mode (SM) observer which is capable of rotor flux space vector and rotor speed simultaneous estimation. In addition, stator and rotor resistances are estimated using a simple but effective recursive least squares (RLS) method combined with the so-called SM observer. The proposed control idea is experimentally implemented in real time using a FPGA board synchronized with a personal computer (PC). Simulation and experimental results are presented to show the capability and validity of the proposed control method.

Sliding Mode Control of a New Wind-Based Isolated Three-Phase Induction Generator System with Constant Frequency and Adjustable Output Voltage

Moradian, Mohammadreza,Soltani, Jafar The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This paper presents a new stand-alone wind-based induction generator system with constant frequency and adjustable output voltage. The proposed generator consists of a six-phase cage-rotor induction machine with two separate three-phase balanced stator windings and a three-phase space vector pulse width modulation inverter that operates as a static synchronous compensator (STATCOM). The first stator winding is fed by the STATCOM and used to excite the machine while the second stator winding is connected to the generator external load. The main frequency of the STATCOM is determined to be constant and equal to the load-requested frequency. The generator output frequency is independent of the load power demand and its prime mover speed because the frequency of the induced emf in the second stator winding is the same as this constant frequency. A sliding mode control (SMC) is developed to regulate the generator output voltage. A second SMC is used to force the zero active power exchanged between the machine and the STATCOM. Some simulation and experimental results are presented to prove the validity and effectiveness of the proposed generator system.

Input-Output Feedback Linearization of Sensorless IM Drives with Stator and Rotor Resistances Estimation

Masood Hajian,Jafar Soltani,Gholamreza Arab Markadeh,Saeed Hosseinnia 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

Direct torque control (DTC) of induction machines (IM) is a well-known strategy of these drives control which has a fast dynamic and a good tracking response. In this paper a nonlinear DTC of speed sensorless IM drives is presented which is based on input-output feedback linearization control theory. The IM model includes iron losses using a speed dependent shunt resistance which is determined through some effective experiments. A stator flux vector is estimated through a simple integrator based on stator voltage equations in the stationary frame. A novel method is introduced for DC offset compensation which is a major problem of AC machines, especially at low speeds. Rotor speed is also determined using a rotor flux sliding-mode (SM) observer which is capable of rotor flux space vector and rotor speed simultaneous estimation. In addition, stator and rotor resistances are estimated using a simple but effective recursive least squares (RLS) method combined with the so-called SM observer. The proposed control idea is experimentally implemented in real time using a FPGA board synchronized with a personal computer (PC). Simulation and experimental results are presented to show the capability and validity of the proposed control method.

Analysis of survival data in thalassemia patients in Shiraz, Iran

Abdolreza Rajaeefard,Mahmoud Hajipour,Hamid Reza Tabatabaee,Jafar Hassanzadeh,Shahab Rezaeian,Zahra Moradi,Mehdi Sharafi,Mohsen Shafiee,Ali Semati,Sanaz Safaei,Maryam Soltani 한국역학회 2015 Epidemiology and Health Vol.37 No.-

OBJECTIVES: The survival rate of thalassemia patients has not been conclusively established, and the factors associated with survival remain unclear. This study aimed to determine the survival rate of thalassemia among patients in southern Iran and to identify the factors associated with mortality from thalassemia. METHODS: This retrospective cohort study was conducted based on a retrospective review of the medical records of 911 beta-thalassemia patients in 2014. Data analysis was conducted using the Kaplan-Meier method and Cox regression analysis. RESULTS: Overall, 212 patients (23.3%) died, and 26.8% had thalassemia intermedia. The 20-year, 40-year, and 60-year survival rates were 85%, 63%, and 54%, respectively. Both crude and adjusted analyses found that education, marital status, ferritin levels, and comorbidities were related to mortality. CONCLUSIONS: Sociodemographic and hematological factors were found to be significantly associated with the survival rate of thalassemia. Addressing these factors may help healthcare providers and physicians to provide the best possible care and to improve the survival rate.