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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Power Electronics
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Journal DOI :
The Korean Institute of Power Electronics
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Volume & Issues
Volume 12, Issue 6 - Nov 2012
Volume 12, Issue 5 - Sep 2012
Volume 12, Issue 4 - Jul 2012
Volume 12, Issue 3 - May 2012
Volume 12, Issue 2 - Mar 2012
Volume 12, Issue 1 - Jan 2012
Selecting the target year
Discharging/Charging Voltage-Temperature Pattern Recognition for Improved SOC/Capacity Estimation and SOH Prediction at Various Temperatures
Kim, Jong-Hoon ; Lee, Seong-Jun ; Cho, Bo-Hyung ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 1~9
DOI : 10.6113/JPE.2012.12.1.1
This study investigates an application of the Hamming network-dual extended Kalman filter (DEKF) based on pattern recognition for high accuracy state-of-charge (SOC)/capacity estimation and state-of-health (SOH) prediction at various temperatures. The averaged nine discharging/charging voltage-temperature (DCVT) patterns for ten fresh Li-Ion cells at experimental temperatures are measured as representative patterns, together with cell model parameters. Through statistical analysis, the Hamming network is applied to identify the representative pattern that matches most closely with the pattern of an arbitrary cell measured at any temperature. Based on temperature-checking process, model parameters for a representative DCVT pattern can then be applied to estimate SOC/capacity and to predict SOH of an arbitrary cell using the DEKF. This avoids the need for repeated parameter measuremet.
Simplified Impedance Modeling and Analysis for Inter-Turn Fault of IPM-type BLDC motor
Kim, Byeong-Woo ; Kim, Kyung-Tae ; Hur, Jin ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 10~18
DOI : 10.6113/JPE.2012.12.1.10
This paper proposes a finite element method (FEM)-based model of an interior permanent magnet (IPM)-type BLDC motor having stator inter-turn faults. We also propose impedance modeling of the magnetic characteristics. By integrating the developed model with a current-controlled voltage source inverter (CCVSI) model, the distributed characteristics of an inter-turn fault operated by a six-switch inverter are investigated considering speed control. Moreover, this paper presents the flux density distribution and torque characteristics for analyzing the inter-turn fault of an IPM-type BLDC motor. Additionally, fault impedance is required to calculate the circulating current that causes magnetic distortion. Thus, this paper proposes a method for estimating the circulating current taking into account the voltage at the shorted turn and the rotating speed. The analysis data were verified experimentally.
Realistic Simulations on Reverse Junction Characteristics of SiC and GaN Power Semiconductor Devices
Wei, Guannan ; Liang, Yung C. ; Samudra, Ganesh S. ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 19~23
DOI : 10.6113/JPE.2012.12.1.19
This paper presents a practical methodology for realistic simulation on reverse characteristics of Wide Bandgap (WBG) SiC and GaN p-n junctions. The adjustment on certain physic-based model parameters, such as the trap density and photo-generation for SiC junction, and impact ionization coefficients and critical field for GaN junction are described. The adjusted parameters were used in Synopsys Medici simulation to obtain a realistic p-n junction avalanche breakdown voltage. The simulation results were verified through benchmarking against independent data reported by others.
Direct Duty-ratio Modulated Fault-tolerant Strategy for Matrix Converter-fed Motor Drives
Li, Yulong ; Choi, Nam-Sup ; Han, Byung-Moon ; Nho, Eui-Cheol ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 24~32
DOI : 10.6113/JPE.2012.12.1.24
Direct duty-ratio PWM schemes for continuous fault tolerant operation of matrix converter-fed motor drives are presented. The proposed method features simple modular modulation structure based on per output phase concept, which requires no additional modification on the normal modulation schemes for fault-tolerant applications. Realizations of fault-tolerant strategy applied to different system configurations are also treated to enhance the system flexibility. The proposed method can be effectively applied to treat the motor open phase fault and converter switching device failure. Simulation and experimental results show the feasibility and validation of the proposed strategies.
Mathematical Analysis and Experiment Validation of Modular Multilevel Converters
Zhang, Yushu ; Adam, Grain Philip ; Lim, Tee-Chong ; Finney, Stephen J. ; Williams, Barry W. ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 33~39
DOI : 10.6113/JPE.2012.12.1.33
This paper describes operating and capacitor voltage balancing of the modular multilevel converter. The paper focuses on sizing of the cell capacitor and establishes approximate expressions for the capacitor voltage. Simulations and experiments results obtained from three-level modular converter are used to demonstrate its viability in medium voltage applications. It is shown that the modular converter can operate over the full modulation index linear range independent of load power factor.
LiPB Battery SOC Estimation Using Extended Kalman Filter Improved with Variation of Single Dominant Parameter
Windarko, Novie Ayub ; Choi, Jae-Ho ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 40~48
DOI : 10.6113/JPE.2012.12.1.40
This paper proposes the State-of-charge (SOC) estimator of a LiPB Battery using the Extended Kalman Filter (EKF). EKF can work properly only with an accurate model. Therefore, the high accuracy electrical battery model for EKF state is discussed in this paper, which is focused on high-capacity LiPB batteries. The battery model is extracted from a single cell of LiPB 40Ah, 3.7V. The dynamic behavior of single cell battery is modeled using a bulk capacitance, two series RC networks, and a series resistance. The bulk capacitance voltage represents the Open Circuit Voltage (OCV) of battery and other components represent the transient response of battery voltage. The experimental results show the strong relationship between OCV and SOC without any dependency on the current rates. Therefore, EKF is proposed to work by estimating OCV, and then is converted it to SOC. EKF is tested with the experimental data. To increase the estimation accuracy, EKF is improved with a single dominant varying parameter of bulk capacitance which follows the SOC value. Full region of SOC test is done to verify the effectiveness of EKF algorithm. The test results show the error of estimation can be reduced up to max 5%SOC.
Performance Evaluation of an Integrated Starter-Alternator with an IPM Synchronous Machine under Sensor-less Operation
Xu, Zhuang ; Rahman, M.F. ; Wang, G. ; Xu, Dianguo ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 49~57
DOI : 10.6113/JPE.2012.12.1.49
This paper presents performance evaluation of an Integrated Starter-Alternator (ISA) prototype with an Interior Permanent Magnet (IPM) synchronous machine under sensor-less operation. To attain a high starting torque at zero speed and in subsequent extremely low speed range, a hybrid signal injection method is proposed. At higher speed, an improved stator flux observer is used for the stator flux estimation. This observer is able to produce accurately-estimated stator flux linkage for high performance Direct Torque and Flux Control (DTFC) implementation. The sensor-less DTFC IPM synchronous machine drive takes full advantage of the capacity of the power converter and fulfills the control specifications for the ISA. The trajectory control algorithm responds rapidly and in a well behaved manner over a wide range of operating conditions. The experimental results verify the feasibility and advantages of the system.
A Simple Negative Torque Compensation Scheme for a High Speed Switched Reluctance Motor
Lee, Dong-Hee ; Ahn, So-Yeon ; Ahn, Jin-Woo ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 58~66
DOI : 10.6113/JPE.2012.12.1.58
SRMs(Switched Reluctance Motors) are much interested in high speed applications due to the mechanical robustness, simple structure and high efficiency. In spite of many advantages of SRMs, a higher torque ripple discourages the adoption of SRMs in a high speed application. This paper presents a simple negative torque of tail current compensation scheme using a modified TSF(Torque Sharing Function) for the high speed SRMs. Because of the short commutation in the high speed region, the negative torque from the tail current makes the high torque ripple. In order to reduce and compensate the negative torque from tail current, the proposed control scheme produces an additional compensating torque with a reference torque in the active phase winding. And the compensating value is dependent on the tail current of the inactive phase winding. Furthermore, the switching signals of the outgoing phase are fully turned off to restrict the extended tail current, and the torque error of the outgoing phase is compensated by the incoming phase. The proposed modified TSF control scheme is verified by the computer simulations with 30,000[rpm] high speed 4/2 SRM. The simulation and experimental results show the effectiveness of the proposed control scheme.
Noise Lowering for a Large Variable Speed Range Use Permanent Magnet Motor by Frequence Shift and Structural Response Evaluation of Electromagnetic Forces
Arata, Masanori ; Takahashi, Norio ; Fujita, Masafumi ; Mochizuki, Motoyasu ; Araki, Takashi ; Hanai, Takashi ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 67~74
DOI : 10.6113/JPE.2012.12.1.67
According to electrical output up rating of a permanent magnet motor and request to operate for a large variable speed range, resonance between structural natural vibration and electromagnetic force inside the motor can take place and make noise. This paper describes the mechanism of a resonance between them and noise lowering procedure by frequency shift when they are applied to the reluctance torque largely employed new motor named Permanent magnet Reluctance Motor (PRM).
Low-Cost Position Sensorless Switched Relutance Motor Drive Using a Single-Controllable Switch Converter
Yang, Hyong-Yeol ; Kim, Jae-Hyuck ; Krishnan, R. ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 75~82
DOI : 10.6113/JPE.2012.12.1.75
Elimination of rotor position sensors mechanically coupled with the rotor shaft is attractive to variable speed drives primarily due to increased system reliability and cost reduction. In this regard, search for a simple and robust position sensorless control has been intensified in past few years specifically for low-cost, high-volume applications such as home appliances. This paper describes a new parameter insensitive position sensorless control for switched reluctance motor (SRM) drives satisfying such a need in this market segment. Two consecutive switch-on times of the controllable switch in hysteresis current control are compared to estimate the rotor position and speed. The proposed sensorless control algorithm is very simple to implement since it does not depend on extensive computation or any additional hardware. In addition, the proposed method is robust in that its dynamic performance is least affected by system parameter variations. The proposed approach is demonstrated on a single-controllable-switch-converter-driven SRM with two-phases that lends itself to a system with low cost and compact packaging which comes close to the intended applications. Analysis and simulation results followed by experimental verification are presented to demonstrate the feasibility of the proposed sensorless control method.
Input Voltage Sharing Control for Input-Series-Output-Parallel DC-DC Converters without Input Voltage Sensors
Guo, Zhiqiang ; Sha, Deshang ; Liao, Xiaozhong ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 83~87
DOI : 10.6113/JPE.2012.12.1.83
Input-series-output-parallel (ISOP) modular converters consisting of multiple modular DC/DC converters can enable low voltage rating switches for use in high voltage input applications. In this paper, an input voltage sharing control strategy for input-series-output-parallel (ISOP) full-bridge (FB) DC/DC converters is proposed. By sensing the difference in the input current of two modules, the system can achieve input voltage sharing for DC-DC modules. The effectiveness of the proposed control strategy is verified by simulation and experimental results obtained with a 200w-50kHz prototype.
Digital Control of an AC/DC Converter using the Power Balance Control Technique with Average Output Voltage Measurement
Wisutmetheekorn, Pisit ; Chunkag, Viboon ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 88~97
DOI : 10.6113/JPE.2012.12.1.88
This paper presents a method for the digital control of a high power factor AC/DC converter employing the power balance control technique to achieve a fast response of the output voltage control. To avoid the effects of an output voltage ripple in the voltage control loop, the average output voltage is sampled and used as a feedback signal for the output voltage controller. The proposed control technique was verified by simulations using MATLAB/Simulink and its implementation was realized by a dsPIC30F4011 digital signal processor to control a CUK topology AC/DC converter with a 48V output voltage and a 250 W output power. The experimental results agree with the simulation results. The proposed control technique achieves a fast transient response with a lower line current distortion than is achieved when using a conventional proportional-integral controller and the power balance control technique with the conventional sampling method.
Modified Digital Pulse Width Modulator for Power Converters with a Reduced Modulation Delay
Qahouq, Jaber Abu ; Arikatla, Varaprasad ; Arunachalam, Thanukamalam ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 98~103
DOI : 10.6113/JPE.2012.12.1.98
This paper presents a digital pulse width modulator (DPWM) with a reduced digital modulation delay (a transport delay of the modulator) during the transient response of power converters. During the transient response operation of a power converter, as a result of dynamic variations such as load step-up or step-down, the closed loop controller will continuously adjust the duty cycle in order to regulate the output voltage. The larger the modulation delays, the larger the undesired output voltage deviation from the reference point. The three conventional DPWM techniques exhibit significant leading-edge and/or trailing-edge modulation delays. The DPWM technique proposed in this paper, which results in modulation delay reductions, is discussed, experimentally tested and compared with conventional modulation techniques.
Optimal Controller Design for Single-Phase PFC Rectifiers Using SPEA Multi-Objective Optimization
Amirahmadi, Ahmadreza ; Dastfan, Ali ; Rafiei, Mohammadreza ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 104~112
DOI : 10.6113/JPE.2012.12.1.104
In this paper a new method for the design of a simple PI controller is presented and it has been applied in the control of a Boost based PFC rectifier. The Strength Pareto evolutionary algorithm, which is based on the Pareto Optimality concept, used in Game theory literature is implemented as a multi-objective optimization approach to gain a good transient response and a high quality input current. In the proposed method, the input current harmonics and the dynamic response have been assumed as objective functions, while the PI controller`s gains of the PFC rectifier (Kpi, Tpi) are design variables. The proposed algorithm generates a set of optimal gains called a Pareto Set corresponding to a Pareto Front, which is a set of optimal results for the objective functions. All of the Pareto Front points are optimum, but according to the design priority objective function, each one can be selected. Simulation and experimental results are presented to prove the superiority of the proposed design methodology over other methods.
Design and Control of the Phase Shift Full Bridge Converter for the On-board Battery Charger of Electric Forklifts
Kim, Tae-Hoon ; Lee, Seung-Jun ; Choi, Woo-Jin ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 113~119
DOI : 10.6113/JPE.2012.12.1.113
This paper describes the design and control of a phase shift full bridge converter with a current doubler, which can be used for the on-board charger for the lead-acid battery of electric forklifts. Unlike the common resistance load, the battery has a large capacitance element and it absorbs the entire converter output ripple current, thereby shortening the battery life and degrading the system efficiency. In this paper a phase shift full bridge converter with a current doubler has been adopted to decrease the output ripple current and the transformer rating of the charger. The charge controller is designed by using the small signal model of the converter, taking into consideration the internal impedance of the battery. The stability and performance of the battery charger is then verified by constant current (CC) and constant voltage (CV) charge experiments using a lead-acid battery bank for an electric forklift.
Diagnosis Methods for IGBT Open Switch Fault Applied to 3-Phase AC/DC PWM Converter
Im, Won-Sang ; Kim, Jang-Sik ; Kim, Jang-Mok ; Lee, Dong-Choon ; Lee, Kyo-Beum ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 120~127
DOI : 10.6113/JPE.2012.12.1.120
Fault diagnosis technique of electrical drives is becoming more and more important, since voltage fed converter system has become industrial standard in many applications. Many studies have been conducted an inverter fault diagnosis for induction motors. However, there are few researches about fault diagnosis of 3-phase ac/dc PWM (Pulse Width Modulation) converter compared to the dc/ ac inverter. The ac/dc converter is the opposite of dc/ac inverter at current flow. Also, inverter and converter have different current patterns under the same condition of IGBT (Insulated gate bipolar transistor) open switch fault. Therefore, it is difficult to apply intact diagnosis methods of inverter to the converter. This paper proposes modified fault detection methods for IGBT open switch fault in 3-phase ac/dc PWM converter by modifying established fault diagnostic methods for dc/ac inverters.
Comparison of Efficiency for Different Switching Tables in Six-Phase Induction Motor DTC Drive
Taheri, Asghar ; Rahmati, Abdolreza ; Kaboli, Shahriyar ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 128~135
DOI : 10.6113/JPE.2012.12.1.128
In this paper, different switching tables proposed for the Direct Torque Controlled (DTC) of a six-phase induction machine are simulated and implemented. A six-phase induction motor has 64 space voltage vectors which result in increased complexity in the selecting of inverters switching. The unsuitable selection of a switching table leads to large harmonics especially at low speed and it also reduces drive efficiency. A six-phase induction machine has large zero sequence harmonic currents of the order
. These harmonic currents are varied in various techniques. Decreasing this loss is essential in a six-phase induction machine. The main purpose of this paper is to improve the ST-DTC of six-phase induction machines to reduce the voltage and current harmonics and the torque pulsation. Selecting a suitable method for minimizing these harmonics is very important.
Simulation Study of a New Approach for Field Weakening Control of PMSM
Elsayed, Mohamed Taha ; Mahgoub, Osama Ahmed ; Zaid, Sherif Ahmed ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 136~144
DOI : 10.6113/JPE.2012.12.1.136
In this paper, the different techniques for the field weakening, also known as constant power speed range (CPSR) operation, for permanent magnet synchronous motor (PMSM) will be introduced and analysed. Field weakening of PMSM, can be done using either vector control (VC) or conventional phase in advance (CPA). Implementation of these techniques depending on some features and constrains. Most of these features and constrains came from the motor parameters. One of these constrains is the motor inductance which determining whether the motor can be driven in the CPSR or not. A new approach for the field weakening will be discussed and to be verified to overcome this constrain. The new approach will be verified through both techniques VC and CPA.
Improving the Dynamic Performance of Distribution Electronic Power Transformers Using Sliding Mode Control
Hooshmand, Rahmat-Allah ; Ataei, Mohammad ; Rezaei, Mohammad Hosein ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 145~156
DOI : 10.6113/JPE.2012.12.1.145
These days, the application of electronic power transformers (EPTs) is expanding in place of ordinary power transformers. These transformers can transmit power via three or four wire converters. Their dynamic performance is extremely important, due to their complex structure. In this paper, a new method is proposed for improving the dynamic performance of distribution electronic power transformers (DEPT) by using sliding mode control (SMC). Hence, to express the dynamic characteristics of a system, different factors such as the voltage unbalance, voltage sag, voltage harmonics and voltage flicker in the system primary side are considered. The four controlling aims of the improvement in dynamic performance include: 1) maintaining the input currents so that they are in sinusoidal form and in phase with the input voltages so they have a unity power factor, 2) keeping the dc-link voltage within the reference amount, 3) keeping the output voltages at a fixed amount and 4) keeping the output voltages in sinusoidal and symmetrical forms. Simulation results indicate the potential and capability of the proposed method in improving DEPT behavior.
Comparative Study on 220V AC Feed System and 300V DC Feed System for Internet Data Centers
Kim, Hyo-Sung ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 157~163
DOI : 10.6113/JPE.2012.12.1.157
Internet Data Centers (IDCs), which are essential facilities in the modern IT industry, typically have scores of MW of concentrated electric loads. The provision of an Uninterruptible Power Supply (UPS) is necessary for the power feed system of IDCs owing to the need for stable power. Thus, conventional IDC AC power feed systems have three cascaded power conversion stages, (AC-DC), (DC-AC), and (AC-DC), resulting in a very low conversion efficiency. In comparison, DC power feed systems require only a single power conversion stage (AC-DC) to supply AC main power to DC server loads, resulting in comparatively high conversion efficiency and reliability [4-11]. This paper compares the efficiencies of a 220V AC power feed system with those of a 300V DC power feed system under equal load conditions, as established by the Mok-Dong IDC of Korea Telecom Co. Ltd. (KT). Experimental results show that the total operation efficiency of the 300V DC power feed system is approximately 15% higher than that of the 220V AC power feed system.
Scaling Factor Design Based Variable Step Size Incremental Resistance Maximum Power Point Tracking for PV Systems
Ahmed, Emad M. ; Shoyama, Masahito ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 164~171
DOI : 10.6113/JPE.2012.12.1.164
Variable step size maximum power point trackers (MPPTs) are widely used in photovoltaic (PV) systems to extract the peak array power which depends on solar irradiation and array temperature. One essential factor which judges system dynamics and steady state performances is the scaling factor (N), which is used to update the controlling equation in the tracking algorithm to determine a new duty cycle. This paper proposes a novel stability study of variable step size incremental resistance maximum power point tracking (INR MPPT). The main contribution of this analysis appears when developing the overall small signal model of the PV system. Therefore, by using linear control theory, the boundary value of the scaling factor can be determined. The theoretical analysis and the design principle of the proposed stability analysis have been validated using MATLAB simulations, and experimentally using a fixed point digital signal processor (TMS320F2808).
Unified MPPT Control Strategy for Z-Source Inverter Based Photovoltaic Power Conversion Systems
Thangaprakash, Sengodan ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 172~180
DOI : 10.6113/JPE.2012.12.1.172
Z-source inverters (ZSI) are used to realize both DC voltage boost and DC-AC inversion in single stage with a reduced number of power switching devices. A traditional MPPT control algorithm provides a shoot-through interval which should be inserted in the switching waveforms of the inverter to output the maximum power to the Z-network. At this instant, the voltage across the Z-source capacitor is equal to the output voltage of a PV array at the maximum power point (MPP). The control of the Z-source capacitor voltage beyond the MPP voltage of a PV array is not facilitated in traditional MPPT algorithms. This paper presents a unified MPPT control algorithm to simultaneously achieve MPPT as well as Z-source capacitor voltage control. Development and implementation of the proposed algorithm and a comparison with traditional results are discussed. The effectiveness of the proposed unified MPPT control strategy is implemented in Matlab/Simulink software and verified by experimental results.
A Review of Power Electronics Based Microgrids
Wang, Xiongfei ; Guerrero, Josep M. ; Blaabjerg, Frede ; Chen, Zhe ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 181~192
DOI : 10.6113/JPE.2012.12.1.181
The increased penetration of Distributed Energy Resources (DER) is challenging the entire architecture of conventional electrical power system. Microgrid paradigm, featuring higher flexibility and reliability, becomes an attractive candidate for the future power grid. In this paper, an overview of microgrid configurations is given. Then, possible structure options and control methods of DER units are presented, which is followed by the descriptions of system controls and power management strategies for AC microgrids. Finally, future trends of microgrids are discussed pointing out how this concept can be a key to achieve a more intelligent and flexible power system.
Analysis and Design of the Interface Inductor and the DC Side Capacitor in a STATCOM with Phase and Amplitude Control Considering the Stability of the System
Zhao, Guopeng ; Han, Minxiao ; Liu, Jinjun ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 193~200
DOI : 10.6113/JPE.2012.12.1.193
Previous publications regarding the design and specifications of the interface inductor and the DC side capacitor for a STATCOM usually deal with the interface inductor and the DC side capacitor only. They seldom pay attention to the influences of the interface inductor and capacitor on the performance of a STATCOM system. In this paper a detailed analysis of influence of the interface inductor and the DC side capacitor on a STATCOM system and the corresponding design considerations is presented. Phase and amplitude control is considered as the control strategy for the STATCOM. First, a model of a STATCOM system is carried out. Second, through frequency domain methods, such as transfer functions and Bode plots, the influence of the interface inductor and the DC side capacitor on the stability and filtering characteristics of the STATCOM are extensively investigated. Third, according to this analysis, the design considerations based on the phase margin for the interface inductor and the DC side capacitor are discussed, which leads to parameters that are different from those of the traditional design.
Teaching Magnetic Component Design in Power Electronics Course using Project Based Learning Approach
Hren, Alenka ; Milanovic, Miro ; Mihalic, Franc ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 201~207
DOI : 10.6113/JPE.2012.12.1.201
This paper presents the results and gained experiences from the Project Based Learning (PBL) of magnetic component design within a Power Electronics Course. PBL was applied during the laboratory exercises through a design-project task based on a boost converter test board. The students were asked to calculate the main boost converter`s circuit parameters` capacitor C and inductor L, and then additionally required to design and build-up the inductor L, in order to meet the project`s goals. The whole PBL process relied on ideas from the CDIO (Conceive, Design, Implement, Operate), where the students are encouraged to consider the whole system`s process, in order to obtain hands-on experience. PBL is known to be a motivating and problem-centered teaching method that gives students the ability to transfer their acquired scientific knowledge into industrial practice. It has the potential to help students cope with demanding complexities in the field, and those problems they will face in their future careers.
Wing Technique: A Novel Approach for the Detection of Stator Winding Inter-Turn Short Circuit and Open Circuit Faults in Three Phase Induction Motors
Ballal, Makarand Sudhakar ; Ballal, Deepali Makarand ; Suryawanshi, Hiralal M. ; Mishra, Mahesh Kumar ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 208~214
DOI : 10.6113/JPE.2012.12.1.208
This paper presents a novel approach based on the loci of instantaneous symmetrical components called "Wing Shape" which requires the measurement of three input stator currents and voltages to diagnose interturn insulation faults in three phase induction motors operating under different loading conditions. In this methodology, the effect of unbalanced supply conditions, constructional imbalances and measurement errors are also investigated. The sizes of the wings determine the loading on the motor and the travel of the wings while their areas determine the degree of severity of the faults. This approach is also applied to detect open circuit faults or single phasing conditions in induction motors. In order to validate this method, experimental results are presented for a 5 hp squirrel cage induction motor. The proposed technique helps improve the reliability, efficiency, and safety of the motor system and industrial plant. It also allows maintenance to be performed in a more efficient manner, since the course of action can be determined based on the type and severity of the fault.
A Cost Effective Energy Saving of Fluorescent Lighting in Commercial Buildings
Lee, Seong-Ryong ; Nayar, Chemmangot V. ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 215~222
DOI : 10.6113/JPE.2012.12.1.215
Lighting represents a significant component of commercial buildings, particularly office buildings. Fluorescent lighting is invariably used in all commercial, industrial and residential areas. A significant amount of lighting energy is wasted every day by leaving the lights on and not utilizing daylight energy. However, if daylight illuminance can be harnessed, this will reduce the electricity consumption of fluorescent lamps and save energy. This paper explains possible significant savings in lighting energy consumption and hence in costs, without reducing the performance and visual satisfaction in office or industrial buildings. It is proposed to obtain energy saving by reducing the supply voltage without degradation in lighting performance. Experimental results confirm that as much as 20% of electrical energy can be saved by reducing about 9% of the supply voltage, without noticeably affecting light output while complying with lighting standard limits.
Selection Criteria for Supercapacitors Based on Performance Evaluations
Kim, Sang-Hyun ; Choi, Woo-Jin ;
Journal of Power Electronics, volume 12, issue 1, 2012, Pages 223~231
DOI : 10.6113/JPE.2012.12.1.223
In this paper, criteria for better selection of a supercapacitor through EIS (Electrochemical Impedance Spectroscopy) experiments are presented. The performance characteristics of a supercapacitor are thoroughly analyzed in terms of losses and available energy to select the optimal product. The validity of the proposed criteria is demonstrated through the computer simulations and experiments on a fuel cell vehicle using a supercapacitor module with the FTP-72 urban dynamometer driving schedule.