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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 11, Issue 6 - Nov 2011
Volume 11, Issue 5 - Sep 2011
Volume 11, Issue 4 - Jul 2011
Volume 11, Issue 3 - May 2011
Volume 11, Issue 2 - Mar 2011
Volume 11, Issue 1 - Jan 2011
Selecting the target year
Optimal Speed Control of Hybrid Electric Vehicles
Yadav, Anil Kumar ; Gaur, Prerna ; Jha, Shyama Kant ; Gupta, J.R.P. ; Mittal, A.P. ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 393~400
DOI : 10.6113/JPE.2011.11.4.393
The main objective of this paper is to control the speed of Nonlinear Hybrid Electric Vehicle (HEV) by controlling the throttle position. Various control techniques such as well known Proportional-Integral-Derivative (PID) controller in conjunction with state feedback controller (SFC) such as Pole Placement Technique (PPT), Observer Based Controller (OBC) and Linear Quadratic Regulator (LQR) Controller are designed. Some Intelligent control techniques e.g. fuzzy logic PD, Fuzzy logic PI along with Adaptive Controller such as Self Organizing Controller (SOC) is also designed. The design objective in this research paper is to provide smooth throttle movement, zero steady-state speed error, and to maintain a Selected Vehicle (SV) speed. A comparative study is carried out in order to identify the superiority of optimal control technique so as to get improved fuel economy, reduced pollution, improved driving safety and reduced manufacturing costs.
Torque Density Improvement of Five-Phase PMSM Drive for Electric Vehicles Applications
Zhao, Pinzhi ; Yang, Guijie ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 401~407
DOI : 10.6113/JPE.2011.11.4.401
In order to enhance torque density of five-phase permanent magnetic synchronous motor with third harmonic injection for electric vehicles (EVs) applications, optimum seeking method for injection ratio of third harmonic was proposed adopting theoretical derivation and finite element analysis method, under the constraint of same amplitude for current and air-gap flux. By five-dimension space vector decomposition, the mathematic model in two orthogonal space plane,
, was deduced. And the corresponding dual-plane vector control method was accomplished to independently control fundamental and third harmonic currents in each vector plane. A five-phase PMSM prototype with quasi-trapezoidal flux pattern and its fivephase voltage source inverter were designed. Also, the dual-plane vector control was digitized in a single XC3S1200E FPGA. Simulation and experimental results prove that using the proposed optimum seeking method, the torque density of five-phase PMSM is enhanced by 20%, without any increase of power converter capacity, machine size and iron core saturation.
Control and Analysis of an Integrated Bidirectional DC/AC and DC/DC Converters for Plug-In Hybrid Electric Vehicle Applications
Hegazy, Omar ; Van Mierlo, Joeri ; Lataire, Philippe ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 408~417
DOI : 10.6113/JPE.2011.11.4.408
The plug-in hybrid electric vehicles (PHEVs) are specialized hybrid electric vehicles that have the potential to obtain enough energy for average daily commuting from batteries. The PHEV battery would be recharged from the power grid at home or at work and would thus allow for a reduction in the overall fuel consumption. This paper proposes an integrated power electronics interface for PHEVs, which consists of a novel Eight-Switch Inverter (ESI) and an interleaved DC/DC converter, in order to reduce the cost, the mass and the size of the power electronics unit (PEU) with high performance at any operating mode. In the proposed configuration, a novel Eight-Switch Inverter (ESI) is able to function as a bidirectional single-phase AC/DC battery charger/ vehicle to grid (V2G) and to transfer electrical energy between the DC-link (connected to the battery) and the electric traction system as DC/AC inverter. In addition, a bidirectional-interleaved DC/DC converter with dual-loop controller is proposed for interfacing the ESI to a low-voltage battery pack in order to minimize the ripple of the battery current and to improve the efficiency of the DC system with lower inductor size. To validate the performance of the proposed configuration, the indirect field-oriented control (IFOC) based on particle swarm optimization (PSO) is proposed to optimize the efficiency of the AC drive system in PHEVs. The maximum efficiency of the motor is obtained by the evaluation of optimal rotor flux at any operating point, where the PSO is applied to evaluate the optimal flux. Moreover, an improved AC/DC controller based Proportional-Resonant Control (PRC) is proposed in order to reduce the THD of the input current in charger/V2G modes. The proposed configuration is analyzed and its performance is validated using simulated results obtained in MATLAB/ SIMULINK. Furthermore, it is experimentally validated with results obtained from the prototypes that have been developed and built in the laboratory based on TMS320F2808 DSP.
Parameter Identification of an Induction Motor Drive with Magnetic Saturation for Electric Vehicle
Jeong, Yu-Seok ; Lee, Jun-Young ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 418~423
DOI : 10.6113/JPE.2011.11.4.418
This paper presents a simulation model and a parameter identification scheme of an induction motor drive for electric vehicle. The induction motor in automotive applications should operate in very high efficiency and achieve the maximum-torque-per-ampere (MTPA) feature even with saturated magnetic flux under very high torque. The indirect vector control which is typically adopted in traction drive system requires precise information of motor parameters, particularly rotor time constants. This work models an induction motor considering magnetic saturation and proposes an empirical identification method using the current controller in the synchronous reference frame. The proposed method is applied to a 22kW-rated induction motor for electric vehicle.
Simulator for Monitoring the Operations of Range Extender Electric Vehicles
Chun, Tae-Won ; Tran, Quang-Vinh ; Lee, Hong-Hee ; Kim, Heung-Geun ; Nho, Eui-Cheol ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 424~429
DOI : 10.6113/JPE.2011.11.4.424
In this paper, the simulator of an on-line monitoring system for the range extender electric vehicle has been developed. The messages from the four control modules, the air pressure and fuel level sensors data, and the on/off switching states of 31 indicator lamps can be received through the control area network (CAN), and displayed on the graphic panel. The simulator was designed using the four DSP boards, variable resistors, and toggle switches instead of the four control modules, sensors, and switching state of indicator lamps on an actual series hybrid electric vehicle (SHEV) bus, respectively. The performance of the monitoring technologies was verified with the simulator at the laboratory, and then it was tested on an actual SHEV bus. The simulator is very useful at the initial development of the monitoring system at the hybrid-type or electrical vehicles.
Robust Nonlinear Control of AC Brushless Motor for Electric Vehicles Application
Langarica-Cordoba, Diego ; Guerrero-Ramirez, Gerardo V. ; Claudio-Sanchez, Abraham ; Duran-Fonseca, Miguel A. ; Adam-Medina, Manuel ; Astorga-Zaragoza, Carlos-Manuel ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 430~438
DOI : 10.6113/JPE.2011.11.4.430
This article proposes a robust nonlinear control based on Lyapunov`s redesign, whose purpose is to deal with parametric uncertainty in the resistance of the motor windings. The robust controller design is based on the passivity properties of the motor, as well as energy shaping and damping injection. The application of this control technique is focused on electric vehicles mainly formed by a battery bank, a power inverter, an AC brushless motor and the mechanical transmission. The sine PWM technique is used to trigger the switching devices of inverter. The results were obtained from simulation, where is shown that robust control makes a proper tracking of electromagnetic torque.
Multi-Domain Model for Electric Traction Drives Using Bond Graphs
Silva, Luis I. ; De La Barrera, Pablo M. ; De Angelo, Cristian H. ; Aguilera, Facundo ; Garcia, Guillermo O. ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 439~448
DOI : 10.6113/JPE.2011.11.4.439
In this work the Multi-Domain model of an electric vehicle is developed. The electric domain model consists on the traction drive and allows including faults associated with stator winding. The thermal model is based on a spatial discretization. It receives the power dissipated in the electric domain, it interacts with the environment and provides the temperature distribution in the induction motor. The mechanical model is a half vehicle model. Given that all models are obtained using the same approach (Bond Graph) their integration becomes straightforward. This complete model allows simulating the whole system dynamics and the analysis of electrical/mechanical/thermal interaction. First, experimental results are aimed to validate the proposed model. Then, simulation results illustrate the interaction between the different domains and highlight the capability of including faults.
A Novel Seamless Direct Torque Control for Electric Drive Vehicles
Ghaderi, Ahmad ; Umeno, Takaji ; Amano, Yasushi ; Masaru, Sugai ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 449~455
DOI : 10.6113/JPE.2011.11.4.449
Electric drive vehicles (EDV) have received much attention recently because of their environmental and energy benefits. In an EDV, the motor drive system directly influences the performance of the propulsion system. However, the available DC voltage is limited, which limits the maximum speed of the motors. At high speeds, the inverter voltage increases if the square wave (SW) voltage (six-step operation) is used. Although conventional direct torque control (DTC) has several advantages, it cannot work in the six-step mode required in high-speed applications. In this paper, a single-mode seamless DTC for AC motors is proposed. In this scheme, the trajectory of the reference flux changes continuously between circular and hexagonal paths. Therefore, the armature voltage changes smoothly from a high-frequency switching pattern to a square wave pattern without torque discontinuity. In addition, because multi-mode controllers are not used, implementation is more straightforward. Simulation results show the voltage pattern changes smoothly when the motor speed changes, and consequently, torque control without torque discontinuity is possible in the field weakening area even with a six-step voltage pattern.
Dual-Loop Power Control for Single-Phase Grid-Connected Converters with LCL Filter
Peng, Shuangjian ; Luo, An ; Chen, Yandong ; Lv, Zhipeng ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 456~463
DOI : 10.6113/JPE.2011.11.4.456
Grid-connected converters have widely adopted LCL filters to acquire high harmonic suppression. However, the LCL filter increases the system order so that the design of the system stability would be complicated. Recently, sole-loop control strategies have been used for grid-connected converters with L or LC filters. But if the sole-loop control is directly transplanted to grid-connected converters with LCL filters, the systems may be unstable. This paper presents a novel dual-loop power control strategy composed of a power outer loop and a current inner loop. The outer loop regulates the grid-connected power. The inner loop improves the system stability margin and suppresses the resonant peak caused by the LCL filter. To obtain the control variables, a single-phase current detection is proposed based on PQ theory. The system transfer function is derived in detail and the influence of control gains on the system stability is analyzed with the root locus. Simulation and experimental results demonstrate the feasibility of the proposed control.
Experimental Evaluation of Position Sensorless Control on Hybrid Electric Vehicle Applications
Choi, Chan-Hee ; Kim, Bum-Sik ; Lee, Young-Kook ; Jung, Jin-Hwan ; Seok, Jul-Ki ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 464~470
DOI : 10.6113/JPE.2011.11.4.464
In this paper, the feasibility of applying a position sensorless control technique to hybrid electric vehicles (HEVs) is practically evaluated. The proposed position estimator has a straightforward structure with properties that combines the model and the saliency tracking-based rotor position estimation for interior permanent magnet synchronous motors (IPMSMs). The proposed method can be used in the event of sensor loss or sensor recovery to sustain continuity of operations. The developed system takes into account the estimated position transition between two distinct sensorless methods. The transition is enhanced by introducing a synchronized transition algorithm based on a single tracking observer. Extensive experimental results are presented to verify the principles and show a reliable estimation performance over the entire speed range including standstill under 150% load conditions.
Development of a Unified Research Platform for Plug-In Hybrid Electrical Vehicle Integration Analysis Utilizing the Power Hardware-in-the-Loop Concept
Edrington, Chris S. ; Vodyakho, Oleg ; Hacker, Brian A. ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 471~478
DOI : 10.6113/JPE.2011.11.4.471
This paper addresses the establishment of a kVA-range plug-in hybrid electrical vehicle (PHEV) integration test platform and associated issues. Advancements in battery and power electronic technology, hybrid vehicles are becoming increasingly dependent on the electrical energy provided by the batteries. Minimal or no support by the internal combustion engine may result in the vehicle being occasionally unable to recharge the batteries during highly dynamic driving that occurs in urban areas. The inability to sustain its own energy source creates a situation where the vehicle must connect to the electrical grid in order to recharge its batteries. The effects of a large penetration of electric vehicles connected into the grid are still relatively unknown. This paper presents a novel methodology that will be utilized to study the effects of PHEV charging at the sub-transmission level. The proposed test platform utilizes the power hardware-in-the-loop (PHIL) concept in conjunction with high-fidelity PHEV energy system simulation models. The battery, in particular, is simulated utilizing a real-time digital simulator (
) which generates appropriate control commands to a power electronics-based voltage amplifier that interfaces via a LC-LC-type filter to a power grid. In addition, the PHEV impact is evaluated via another power electronic converter controlled through
, a rapid control systems prototyping software.
Study of Bidirectional DC-DC Converter Interfacing Energy Storage for Vehicle Power Management Using Real Time Digital Simulator (RTDS)
Deng, Yuhang ; Foo, Simon Y. ; Li, Hui ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 479~489
DOI : 10.6113/JPE.2011.11.4.479
The bidirectional dc-dc converter, being the interface between Energy Storage Element (ESE) and DC bus, is an essential component of the power management system for vehicle applications including electric vehicle (EV), hybrid electric vehicle (HEV), and fuel cell vehicle (FCV). In this paper, a novel multiphase bidirectional dc-dc converter interfacing with battery to supply and absorb the electric energy in the FCV system was studied with the help of real time digital simulator (RTDS). The mathematical models of fuel cell, battery and dc-dc converter were derived. A power management strategy was developed and first simulated in RTDS. A Power Hardware-In-the-Loop (PHIL) simulation using RTDS is then presented. The main challenge of this PHIL is the requirement for a highly dynamic bidirectional Simulation-Stimulation (Sim-Stim) interface. This paper describes three different interface algorithms. The closed-loop stability of the resulting PHIL system is analyzed in terms of time delay and sampling rate. A prototype bidirectional Sim-Stim interface is designed to implement the PHIL simulation.
A Three-Phase High Frequency Semi-Controlled Battery Charging Power Converter for Plug-In Hybrid Electric Vehicles
Amin, Mahmoud M. ; Mohammed, Osama A. ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 490~498
DOI : 10.6113/JPE.2011.11.4.490
This paper presents a novel analysis, design, and implementation of a battery charging three-phase high frequency semi-controlled power converter feasible for plug-in hybrid electric vehicles. The main advantages of the proposed topology include high efficiency; due to lower power losses and reduced number of switching elements, high output power density realization, and reduced passive component ratings proportionally to the frequency. Additional advantages also include grid economic utilization by insuring unity power factor operation under different possible conditions and robustness since short-circuit through a leg is not possible. A high but acceptable total harmonic distortion of the generator currents is introduced in the proposed topology which can be viewed as a minor disadvantage when compared to traditional boost rectifiers. A hysteresis control algorithm is proposed to achieve lower current harmonic distortion for the rectifier operation. The rectifier topology concept, the principle of operation, and control scheme are presented. Additionally, a dc-dc converter is also employed in the rectifier-battery connection. Test results on 50-kHz power converter system are presented and discussed to confirm the effectiveness of the proposed topology for PHEV applications.
Analysis, Design and Implementation of a New Chokeless Interleaved ZVS Forward-Flyback Converter
Taheri, Meghdad ; Milimonfared, Jafar ; Namadmalan, Alireza ; Bayat, Hasan ; Bakhshizadeh, Mohammad Kazem ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 499~506
DOI : 10.6113/JPE.2011.11.4.499
This paper presents an interleaved active-clamping zero-voltage-switching (ZVS) forward-flyback converter without an output choke. The presented topology has two active-clamping circuits with two separated transformers. Because of the interleaved operation of the converter, the output current ripple will be reduced. The proposed converter can approximately share the total load current between the two secondaries. Therefore, the transformer copper loss and the rectifier diodes conduction loss can be decreased. The output capacitor is made of two series capacitors which reduces the peak reverse voltage of the rectifier diodes. The circuit has no output inductor and few semiconductor elements, such that the adopted circuit has a simpler structure, a lower cost and is suitable for high power density applications. A detailed analysis and the design of this new converter are described. A prototype converter has been implemented and experimental results have been recorded with an ac input voltage of 85-135Vrms, an output voltage of 12V and an output current of 16A.
Single-Switch Buck Converter with a Ripple-Free Inductor Current
Do, Hyun-Lark ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 507~511
DOI : 10.6113/JPE.2011.11.4.507
This paper presents a single-switch buck converter with a ripple-free inductor current. In the proposed converter, the filter inductor current ripple is completely removed by utilizing an auxiliary circuit consisting of an additional winding of the filter inductor, an auxiliary inductor, and an auxiliary capacitor. Moreover, the ripple-free current characteristic is maintained under both light load and full load conditions. The theoretical analysis and performance of the proposed converter were verified with a 110W experimental prototype operating at a 107 kHz switching frequency.
Flying Capacitor DTC Drive with Reductions in Common Mode Voltage and Stator Overvoltage
Rahmati, Abdolreza ; Arasteh, Mohammad ; Farhangi, Shahrokh ; Abrishamifar, Adib ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 512~519
DOI : 10.6113/JPE.2011.11.4.512
This paper gives a detailed analysis of the direct torque control (DTC) strategy in a five-level drive and proposes a 24-sector switching table. The known problems in low-voltage drives such as bearings currents and an overvoltage phenomenon which leads to premature failure are reviewed and the occurrence of these problems in medium voltage drives has been investigated. Then a solutions to these problems is presented and the switching table to deal with these problems is modified. Simulation and experimental results on a 3kVA prototype confirm the proposed solution. In implementing the above strategy a TMS320F2812 is used.
Current Control Scheme of High Speed SRM Using Low Resolution Encoder
Khoi, Huynh Khac Minh ; Ahn, Jin-Woo ; Lee, Dong-Hee ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 520~526
DOI : 10.6113/JPE.2011.11.4.520
This paper presents a balanced soft-chopping circuit and a modified PI controller for a high speed 4/2 Switched Reluctance Motor (SRM) with a 16 pulse per revolution encoder. The proposed balanced soft-chopping circuit can supply double the switching frequency in the fixed switching frequency of power devices to reduce current ripple. The modified PI controller uses maximum voltage, back-emf voltage and PI control modes to overcome the over-shoot current due to the time delay effect of current sensing. The maximum voltage mode can supply a fast excitation current with consideration of the hardware time delay. Then the back-emf voltage mode can suppress the current over-shoot with consideration of the feedback signal delay. Finally, the PI control mode can adjust the phase current to a desired value with a fast switching frequency due to the proposed balanced soft-chopping technology.
Design Considerations for Low Voltage Claw Pole Type Integrated Starter Generator (ISG) Systems
Lee, Geun-Ho ; Choi, Geo-Seung ; Choi, Woong-Chul ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 527~532
DOI : 10.6113/JPE.2011.11.4.527
Due to the need for improved fuel consumption and the trend towards increasing the electrical content in automobiles, integrated starter generator (ISG) systems are being considered by the automotive industry. In this paper, in order to change the conventional generator of a vehicle, a belt driven integrated starter generator is considered. The overall ISG system, the design considerations for the claw pole type AC electric machine and a low voltage very high current power stage implementation are discussed. Test data on the low voltage claw pole type machine is presented, and a large current voltage source DC/AC inverter suitable for low voltage integrated starter generator operation is also presented. A metal based PCB (Printed Circuit Board) power unit to attach the 4-parallel MOS-FETs is used to achieve extremely high current capability. Furthermore, issues related to the torque assistance during vehicle acceleration and the generation/regeneration characteristics are discussed. A prototype with the capability of up to 1000 A and 27 V is designed and built to validate the kilo-amp inverter.
Redundant Operation of a Parallel AC to DC Converter via a Serial Communication Bus
Kanthaphayao, Yutthana ; Kamnarn, Uthen ; Chunkag, Viboon ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 533~541
DOI : 10.6113/JPE.2011.11.4.533
The redundant operation of a parallel AC to DC converter via a serial communication bus is presented. The proposed system consists of three isolated CUK power factor correction modules. The controller for each converter is a dsPIC30F6010 microcontroller while a RS485 communication bus and the clock signal are used for synchronizing the data communication. The control strategy of the redundant operation relies on the communication of information among each of the modules, which communicate via a RS485 serial bus. This information is received from the communication checks of the converter module connected to the system to share the load current. Performance evaluations were conducted through experimentation on a three-module parallel-connected prototype, with a 578W load and a -48V dc output voltage. The proposed system has achieved the following: the current sharing is quite good, both the transient response and the steady state. The converter modules can perform the current sharing immediately, when a fault is found in another converter module. In addition, the transient response occurs in the system, and the output voltages are at their minimum overshoot and undershoot. Finally, the proposed system has a relatively simple implementation for the redundant operation.
Design and Implementation of a Single Input Fuzzy Logic Controller for Boost Converters
Salam, Zainal ; Taeed, Fazel ; Ayob, Shahrin Md. ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 542~550
DOI : 10.6113/JPE.2011.11.4.542
This paper describes the design and hardware implementation of a Single Input Fuzzy Logic Controller (SIFLC) to regulate the output voltage of a boost power converter. The proposed controller is derived from the signed distance method, which reduces a multi-input conventional Fuzzy Logic Controller (CFLC) to a single input FLC. This allows the rule table to be approximated to a one-dimensional piecewise linear control surface. A MATLAB simulation demonstrated that the performance of a boost converter is identical when subjected to the SIFLC or a CFLC. However, the SIFLC requires nearly an order of magnitude less time to execute its algorithm. Therefore the former can replace the latter with no significant degradation in performance. To validate the feasibility of the SIFLC, a 50W boost converter prototype is built. The SIFLC algorithm is implemented using an Altera FPGA. It was found that the SIFLC with asymmetrical membership functions exhibits an excellent response to load and input reference changes.
High-Efficiency Grid-Tied Power Conditioning System for Fuel Cell Power Generation
Jeong, Jong-Kyou ; Han, Byung-Moon ; Lee, Jun-Young ; Choi, Nam-Sup ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 551~560
DOI : 10.6113/JPE.2011.11.4.551
This paper proposes a grid-tied power conditioning system for the fuel cell power generation, which consists of a 2-stage DC-DC converter and a 3-phase PWM inverter. The 2-stage DC-DC converter boosts the fuel cell stack voltage of 26-48V up to 400V, using a hard-switching boost converter and a high-frequency unregulated LLC resonant converter. The operation of the proposed power conditioning system was verified through simulations with PSCAD/EMTDC software. Based on the simulation results, a laboratory experimental set-up was built with a 1.2kW PEM fuel-cell stack to verify the feasibility of hardware implementation. The developed power conditioning system shows a high efficiency of 91%, which is a very positive result for the commercialization.
High-Efficiency Power Conditioning System for Grid-Connected Photovoltaic Modules
Choi, Woo-Young ; Choi, Jae-Yeon ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 561~567
DOI : 10.6113/JPE.2011.11.4.561
This paper presents a high-efficiency power conditioning system (PCS) for grid-connected photovoltaic (PV) modules. The proposed PCS consists of a step-up DC-DC converter and a single-phase DC-AC inverter for the grid-connected PV modules. A soft-switching step-up DC-DC converter is proposed to generate a high DC-link voltage from the low PV module voltage with a high-efficiency. A DC-link voltage controller is presented for constant DC-link voltage regulation. A half-bridge inverter is used for the single-phase DC-AC inverter for grid connection. A grid current controller is suggested to supply PV electrical power to the power grid with a unity power factor. Experimental results are obtained from a 180 W grid-connected PV module system using the proposed PCS. The proposed PCS achieves a high power efficiency of 93.0 % with an unity power factor for a 60 Hz / 120 Vrms AC power grid.
Improved LVRT Capability and Power Smoothening of DFIG Wind Turbine Systems
Nguyen, Thanh Hai ; Lee, Dong-Choon ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 568~575
DOI : 10.6113/JPE.2011.11.4.568
This paper proposes an application of energy storage devices (ESD) for low-voltage ride-through (LVRT) capability enhancement and power smoothening of doubly-fed induction generator (DFIG) wind turbine systems. A grid-side converter (GSC) is used to maintain the DC-link voltage. Meanwhile, a machine-side converter (MSC) is used to control the active and reactive powers independently. For grid disturbances, the generator output power can be reduced by increasing the generator speed, resulting in an increased inertial energy of the rotational body. Design and control techniques for the energy storage devices are introduced, which consist of current and power control loops. Also, the output power fluctuation of the generator due to wind speed variations can be smoothened by controlling the ESD. The validity of the proposed method has been verified by PSCAD/EMTDC simulation results for a 2 MW DFIG wind turbine system and by experimental results for a small-scale wind turbine simulator.
Control Strategy for Selective Compensation of Power Quality Problems through Three-Phase Four-Wire UPQC
Pal, Yash ; Swarup, A. ; Singh, Bhim ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 576~582
DOI : 10.6113/JPE.2011.11.4.576
This paper presents a novel control strategy for selective compensation of power quality (PQ) problems, depending upon the limited rating of voltage source inverters (VSIs), through a unified power quality conditioner (UPQC) in a three-phase four-wire distribution system. The UPQC is realized by the integration of series and shunt active power filters (APFs) sharing a common dc bus capacitor. The shunt APF is realized using a three-phase, four-leg voltage source inverter (VSI), while a three-leg VSI is employed for the series APF of the three-phase four-wire UPQC. The proposed control scheme for the shunt APF, decomposes the load current into harmonic components generated by consumer and distorted utility. In addition to this, the positive and negative sequence fundamental frequency active components, the reactive components and harmonic components of load currents are decomposed in synchronous reference frame (SRF). The control scheme of the shunt APF performs with priority based schemes, which respects the limited rating of the VSI. For voltage harmonic mitigation, a control scheme based on SRF theory is employed for the series APF of the UPQC. The performance of the proposed control scheme of the UPQC is validated through simulations using MATLAB software with its Simulink and Power System Block set toolboxes.
Deadbeat Control with a Repetitive Predictor for Three-Level Active Power Filters
He, Yingjie ; Liu, Jinjun ; Tang, Jian ; Wang, Zhaoan ; Zou, Yunping ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 583~590
DOI : 10.6113/JPE.2011.11.4.583
Three-level NPC inverters have been put into practical use for years especially in high voltage high power grids. This paper researches three-level active power filters (APFs). In this paper a mathematical model in the d-q coordinates is presented for 3-phase 3-wire NPC APFs. The deadbeat control scheme is obtained by using state equations. Canceling the delay of one sampling period and providing the predictive value of the harmonic current is a key problem of the deadbeat control. Based on this deadbeat control, the predictive output current value is obtained by the state observer. The delay of one sampling period is remedied in this digital control system by the state observer. The predictive harmonic command current value is obtained by the repetitive predictor synchronously. The repetitive predictor can achieve a better prediction of the harmonic current with the same sampling frequency, thus improving the overall performance of the system. The experiment results indicate that the steady-state accuracy and the dynamic response are both satisfying when the proposed control scheme is implemented.
Medium Voltage Power Supply with Enhanced Ignition Characteristics for Plasma Torches
Jung, Kyung-Sub ; Suh, Yong-Sug ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 591~598
DOI : 10.6113/JPE.2011.11.4.591
This paper investigates a power supply of medium voltage with enhanced ignition characteristics for plasma torches. A series resonant half-bridge topology is presented as a suitable ignition circuitry. The ignition circuitry is integrated into the main power conversion system of a multi-phase staggered three-level dc-dc converter with a diode front-end rectifier. A plasma torch rated at 3MW, 2kA and having a physical size of 1m is selected to be the high enthalpy source for a waste disposal system. The steady-state and transient operations of a plasma torch are simulated. The parameters of a Cassie-Mary arc model are calculated based on 3D magneto-hydrodynamic simulations. The circuit simulation waveform shows that the ripple of the arc current can be maintained within
of its rated value under the presence of a load disturbance. This power conversion configuration provides a high enough ignition voltage, around 5KA, during the ignition phase and high arc stability under the existence of arc disturbance noise resulting in a high-performance plasma torch system.
Stability Improvement of Distributed Power Generation Systems with an LCL-Filter Using Gain Scheduling Based on Grid Impedance Estimations
Choi, Dae-Keun ; Lee, Kyo-Beum ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 599~605
DOI : 10.6113/JPE.2011.11.4.599
This paper proposes a gain scheduling method that improves the stability of grid-connected systems employing an LCL-filter. The method adjusts the current controller gain through an estimation of the grid impedance in order to reduce the resonance that occurs when using an LCL-filter to reduce switching harmonics. An LCL-filter typically has a frequency spectrum with a resonance peak. A change of the grid-impedance results in a change to the resonant frequency. Therefore an LCL-filter needs a damping method that is applicable when changing the grid impedance for stable system control. The proposed method instantaneously estimates the grid impedance and observes the resonant frequency at the same time. Consequently, the proposed method adjusts the current controller gain using a gain scheduling method in order to guarantee current controller stability when a change in the resonant frequency occurs. The effectiveness of the proposed method has been verified by simulations and experimental results.
Z-Source Inverter with SiC Power Semiconductor Devices for Fuel Cell Vehicle Applications
Aghdam, M. Ghasem Hosseini ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 606~611
DOI : 10.6113/JPE.2011.11.4.606
Power electronics is a key technology for electric, hybrid, plug-in hybrid, and fuel cell vehicles. Typical power electronics converters used in electric drive vehicles include dc/dc converters, inverters, and battery chargers. New semiconductor materials such as silicon carbide (SiC) and novel topologies such as the Z-source inverter (ZSI) have a great deal of potential to improve the overall performance of these vehicles. In this paper, a Z-source inverter for fuel cell vehicle application is examined under three different scenarios. 1. a ZSI with Si IGBT modules, 2. a ZSI with hybrid modules, Si IGBTs/SiC Schottky diodes, and 3. a ZSI with SiC MOSFETs/SiC Schottky diodes. Then, a comparison of the three scenarios is conducted. Conduction loss, switching loss, reverse recovery loss, and efficiency are considered for comparison. A conclusion is drawn that the SiC devices can improve the inverter and inverter-motor efficiency, and reduce the system size and cost due to the low loss properties of SiC devices. A comparison between a ZSI and traditional PWM inverters with SiC devices is also presented in this paper. Based on this comparison, the Z-source inverter produces the highest efficiency.
Pulsed-Power System for Leachate Treatment Applications
Jang, Sung-Roc ; Ryoo, Hong-Je ; Ok, Seung-Bok ;
Journal of Power Electronics, volume 11, issue 4, 2011, Pages 612~619
DOI : 10.6113/JPE.2011.11.4.612
This paper presents a water treatment system for leachate from sewage-filled ground that uses a pulsed-power modulator developed based on semiconductor switches in order to realize a long life, a high repetition rate, and a fast rising time. The specifications of the developed pulsed-power modulator are the pulsed output voltage, the output current, the pulse repetition rate (PRR), the pulse width, and an average output power of
, and 15 kW, respectively. The pulsed-power water treatment system was introduced and analyzed using an equivalent electrical circuit model to optimize the output voltage waveform. The experimental results verify that the proposed water treatment system can be effectively used for industrial applications.