M. Salehifar

Polytechnic University of Catalonia, Barcino, Catalonia, Spain

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Publications (26)1.56 Total impact

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    ABSTRACT: This study presents a method to improve the output power of five-phase brushless direct current (BLDC) motors under different faulty conditions. Different machine connections are considered while having open-circuit fault in one and two stator phases, and both fundamental and third harmonic component of stator currents are controlled to improve the amplitude and quality of generated torque under faulty conditions. Rated root-mean-square value of stator phase currents is considered as the main limiting factor of generated electrical torque. Genetic algorithm is used in the optimisation procedure of stator reference currents to gain more output power under the fault. Automotive applications are kept in mind, and to verify the theoretical developments, experimental tests are conducted on a five-phase BLDC motor with in-wheel outer-rotor configuration.
    IET Electric Power Applications 08/2014; 8(7):267-277. · 1.56 Impact Factor
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    ABSTRACT: Nowadays, the use of multiphase fault tolerant permanent magnet (PM) machines is a suitable solution for increasing the reliability of high-performance motion control applications. This solution requires fault detection, isolation, and control adaptation. For this reason, a new open switch fault detection scheme in voltage-source inverter supplying a PM motor is presented in this paper. The detection method is based on model identification of the motor phase currents. The detection scheme is fast, robust, general, and capable of detecting multiple faults. The control algorithm, detection method, isolation, and reconfiguration strategies are discussed. After that, the proposed method is implemented in the fault tolerant control of a five-phase brushless direct current (BLDC) motor drive. Simulation results in MATLAB/Simulink are shown to demonstrate the effectiveness of the proposed detection technique. Experimental results on a five-phase fault tolerant BLDC motor validate the theoretical developments.
    Emerging and Selected Topics in Power Electronics, IEEE Journal of. 01/2014; 2(2):212-223.
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    ABSTRACT: This paper deals with fault tolerant model predictive control (MPC) of five-phase brushless direct current (BLDC) motors. The model of machine is used to estimate the stator currents for the next modulation period, and then, the required voltages are calculated to minimize the current errors. Center aligned five-phase space vector modulation (SVM) is used in the inverter section. The proposed controlling strategy is evaluated via simulations in MATLAB environment.
    Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE; 01/2013
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    ABSTRACT: In this paper a five phase fault tolerant converter is proposed for permanent magnet (PM) drives. The proposed configuration is an extension of conventional three phase double switch redundant topologies. In contrast to three phase systems, the proposed configuration has more flexibility and reliability regarding simultaneous faults in more than one phase. Different faulty cases are explained. Optimal reconfiguration strategies are derived under several faulty conditions. Design criteria are defined and a comparative loss analysis is conducted on converter behavior under various conditions. Simulation results are included to validate the theory.
    Applied Power Electronics Conference and Exposition (APEC), 2013 Twenty-Eighth Annual IEEE; 01/2013
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    ABSTRACT: This study is dealt with fault tolerant control of five phase permanent magnet (PM) machines. The main objectives are to increase the output power while eliminating the generated torque ripples. As a new aspect, the effect of available neutral connection is evaluated on the output power and torque ripples.
    Power Electronics and Applications (EPE), 2013 15th European Conference on; 01/2013
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    ABSTRACT: A new open switch fault detection method based on normalized current analysis is proposed for application in multiphase fault tolerant PMSM drives. Performance characteristics of proposed method are single diagnostic variable, ability to detect open phase fault without using auxiliary variable, ability to detect multiple switch fault, simple diagnostic variable, generality, and robustness in case of high unbalanced current waveforms. Theory of diagnostic method with special multiphase drive application is developed; simulation results using Matlab/Simulink and experimental waveforms are shown to validate effectiveness of the presented fault detection method.
    Diagnostics for Electric Machines, Power Electronics and Drives (SDEMPED), 2013 9th IEEE International Symposium on; 01/2013
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    ABSTRACT: This paper deals with model predictive control of five phase permanent magnet motors. Using motor model, the stator currents are estimated for the following modulation period, and the required voltages are applied to minimize the current errors. A comparison between the proposed algorithm and conventional cascade PI configuration is conducted.
    Power Electronics and Applications (EPE), 2013 15th European Conference on; 01/2013
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    ABSTRACT: In this paper, a novel fault detection method based on cost fault evaluation is proposed. The cost function is same as one used in finite control set model predictive control of power converters. Two simple methods are presented to locate the faulty IGBT. Considered methodology is studied for fault detection and fault tolerant operation in a five phase PMSM drive. Theory has been developed and validated by simulation results of a five phase two level converter in Matlab/Simulink.
    Power Electronics and Applications (EPE), 2013 15th European Conference on; 01/2013
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    ABSTRACT: Detection of broken rotor bars has been an important but difficult work in fault diagnosis area of induction motors. The characteristic frequency components of faulted rotor are very close to the power frequency component but by far less in amplitude, which brings about great difficulty for accurate detection. In the present study, a new method is proposed in order to remove the main frequency component, resulting in more efficient detection of the rotor fault characteristics in the frequency spectrum of stator currents. The method is based on Park's transformation in combination with discrete wavelet decomposition to eliminate the effect of main frequency and zoom on the energy of objective fault related frequency components. In addition, the method efficiency is evaluated using Simulations in Matlab.
    Diagnostics for Electric Machines, Power Electronics and Drives (SDEMPED), 2013 9th IEEE International Symposium on; 01/2013
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    ABSTRACT: In this paper, a novel detection algorithm for open switch fault detection is presented; fault signals are utilized to implement fault tolerant control of a five phase PMSM drive. According to the presented method, output currents of the power converter are normalized with a simple method, and then using current average value an appropriate detection index is obtained. The proposed idea is fast, simple, and robust against false alarms. It is also capable of detecting multiple open switch faults. Theory is explained; simulation results are demonstrated for different faulty modes in Matlab. Finally, simulation results of a five phase PMSM drive equipped with fault detection method with closed loop control are presented to show its effectiveness.
    Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE; 01/2013
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    ABSTRACT: In this paper, a new fault detection method based on signal normalization using a simple trigonometric function is presented and applied to a five phase converter for fault tolerant application under nonsinusoidal unbalanced current waveforms. Generality, simplicity, ability to localize faulty switch, multiple switch fault detection and robustness are achieved using this approach. Once theory is explained, simulation results with Matlab/Simulink and experimental waveforms are described to show the effectiveness of the proposed detection method. Experimenal results corroborate these simulation results.
    Diagnostics for Electric Machines, Power Electronics and Drives (SDEMPED), 2013 9th IEEE International Symposium on; 01/2013
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    ABSTRACT: This study deals with the fault tolerant vector control strategies of a five-phase permanent-magnet (PM) machine. The analysis is focused on the effect of accessible neutral point under faulty conditions. Open circuit fault of one and two phases are considered, and proper control strategies are proposed to reduce the amplitude of currents in the remaining healthy phases. Simulations under both healthy and faulty conditions have been undertaken, and the effect of accessible neutral point on current amplitudes and torque ripple is evaluated.
    IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society; 01/2012
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    ABSTRACT: This paper presents a study and analysis of the distorting effects of clamped diodes in multilevel DCI-NPC topology applied to high power and high quality audio-amplifier. The main distorting sources of error are characterized, which are due to the clamped-diodes non-idealities; and they are evaluated for typical commercial diodes values and working conditions. Through this study the distorting contribution of each non-ideality can be quantified, and the influence of the system operating parameters, such as reactive current angle and modulation index, are highlighted. Finally, it is presented the table of optimal parameters that a commercial diode should have to ensure proper operation of the amplifier under rated power and quality specification.
    IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society; 01/2012
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    ABSTRACT: This paper deals with required power electronics interface for a 70 kW microturbine-based distributed Generation system. First, an introduction of microturbine technology and its applications is presented, and then the power electronics interface that is required to transfer microturbine's output power to an islanded local load or an electric power grid is described. Different control strategies for controlling the inverter in stand-alone and grid connected modes and the seamless transfer between two modes are described in this paper. Also, the required power converter protection system is presented. To show effectiveness of the designed inverter and its digital controller the experimental results based on a constructed 70 kW semi-industrial setup has been demonstrated.
    Power Electronics, Drive Systems and Technologies Conference (PEDSTC), 2011 2nd; 03/2011
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    ABSTRACT: Grid interaction of DG units with a novel hybrid flying capacitor multicell converter which is suitable for hybrid systems, is presented in this paper. Multicell inverters have important advantages which make them a flexible solution for medium voltage/high power applications such as: lower rating of switches and lower output voltage THD. Proposed configuration of multicell inverter requires less number of switches in comparison with typical flying capacitor multicell inverters. Simulation results using MATLAB software are demonstrated to confirm theory.
    Power Electronics, Drive Systems and Technologies Conference (PEDSTC), 2011 2nd; 03/2011
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    ABSTRACT: Multicell multilevel converters are very interesting alternatives for high power applications. A modified mixed cascade flying capacitor multicell inverter is proposed in this paper which leads to reduction in the number of switches. The proposed configuration is used for compensation of voltage sag/swell and voltage unbalance. Simulation results by MATLAB simulink confirm the effectiveness of this configuration.
    Power Quality Conference (PQC), 2010 First; 10/2010
  • A. Moghadasi, S.M. Torabi, M. Salehifar
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    ABSTRACT: This paper evaluates combined operation of the unified power quality conditioner (UPQC) with superconducting fault current limiter (SFCL) and superconducting magnetic energy storage (SMES). The proposed scheme can compensate both voltage sag and current harmonics at the point of common coupling (PCC) on power distribution systems. The results show that the SFCL can reduce the Volt-Ampere rating of the UPQC by limiting the excessive current in the event of a fault. Due to the limited fault current with SFCL, less energy is released from SMES. The combination of electrical and thermal model of a resistive type high temperature superconducting (HTS)-FCL is explained. SMES is a good source due to the high response time of charge and discharge. The operation of the proposed system is verified through simulations with PSCAD/EMTDC.
    Power Quality Conference (PQC), 2010 First; 10/2010
  • A. Moghadasi, S.M. Torabi, M. Salehifar
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    ABSTRACT: A Unified Power Quality Conditioner (UPQC), which integrates shunt and series active filters, is a powerful tool to settle the power quality problems. In this paper analysis results of a combination the UPQC with the superconducting magnetic energy storage (SMES) are presented. The proposed scheme can compensate voltage sag, voltage interruption and harmonics at the point of common coupling (PCC) on power distribution systems. Through the results of several analyses and simulations carried out by PSCAD/EMTDC, this demonstrates the signification effect of the control by SMES on improvement of power system performance.
    Power Quality Conference (PQC), 2010 First; 10/2010
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    ABSTRACT: The paper deals with an optimized Unified Power Quality Conditioner (UPQC), which aims at the integration of series and shunt active power filters with minimum rating of the UPQC. In this paper analysis results of a combination the UPQC with a superconducting fault current limiter (SFCL) are presented. SFCL aids on reduction in VA rating of the UPQC with limiting the excessive current in the event of fault. The combination of electrical and thermal model of a designed resistive type SFCL is defined as a component in PSCAD/EMTDC simulations. The proposed scheme can compensate voltage sag and current harmonics at the point of common coupling (PCC) on power distribution systems. Through the results of several analyses and simulations carried out by PSCAD/EMTDC, this demonstrates the signification effect of the control by SFCL on rating reduction of the UPQC.
    Power Electronic & Drive Systems & Technologies Conference (PEDSTC), 2010 1st; 03/2010
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    ABSTRACT: In this paper, a fully-digital-controlled hybrid series active filter (HSAF) for harmonic elimination and reactive power compensation in single phase systems is presented. The HSAF is composed of two single tuned LC filters and a small-rated active filter. Discrete Fourier transformation is used as the control method. Simulation results using MATLAB program shows the effectiveness of the control method. A hybrid series active filter is implemented verifying the accuracy of the control method.
    Power Electronic & Drive Systems & Technologies Conference (PEDSTC), 2010 1st; 01/2010