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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 14, Issue 6 - Nov 2014
Volume 14, Issue 5 - Sep 2014
Volume 14, Issue 4 - Jul 2014
Volume 14, Issue 3 - May 2014
Volume 14, Issue 2 - Mar 2014
Volume 14, Issue 1 - Jan 2014
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Improved Bridgeless Interleaved Boost PFC Rectifier with Optimized Magnetic Utilization and Reduced Sensing Noise
Cao, Guoen ; Kim, Hee-Jun ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 815~826
DOI : 10.6113/JPE.2014.14.5.815
An improved bridgeless interleaved boost power factor correction (PFC) rectifier to improve power efficiency and component utilization is proposed in this study. With combined conventional bridgeless PFC circuit and interleaved technology, the proposed rectifier consists of two interleaved and magnetic inter-coupling boost bridgeless converter cells. Each cell operates alternatively in the critical conduction mode, which can achieve the soft-switching characteristics of the switches and increase power capacity. Auxiliary blocking diodes are employed to eliminate undesired circulating loops and reduce current-sensing noise, which are among the serious drawbacks of a dual-boost PFC rectifier. Magnetic component utilization is improved by symmetrically coupling two inductors on a unique core, which can achieve independence from each other based on the auxiliary diodes. Through the interleaved approach, each switch can operate in the whole line cycle. A simple control scheme is employed in the circuit by using a conventional interleaved controller. The operation principle and theoretical analysis of the converter are presented. A 600 W experimental prototype is built to verify the theoretical analysis and feasibility of the proposed rectifier. System efficiency reaches 97.3% with low total harmonic distortion at full load.
Parallel PCS Interconnection Current Surge Elimination Technique Using a Coupled Inductor
Choe, Jung-Muk ; Byen, Byeng-Joo ; Choe, Gyu-Ha ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 827~833
DOI : 10.6113/JPE.2014.14.5.827
This study proposes a coupled inductor method for the parallel operation of a power conditioning system (PCS). When primary and secondary currents flow in the same direction in a coupled inductor, total flux and inductance are cancelled; when currents flow in opposite directions, each flux becomes an individual inductor. These characteristics are applied in the parallel operation of a PCS. To connect at a grid code, abnormal current, which is barred under the grid connection code, is blocked by using a coupled inductor. A design based on the capacity and current duration time of a PCS is verified through hardware implementation. Experiment results show the effectiveness of variance reduction.
Development of Multi-Cell Active Switched- Capacitor and Switched-Inductor Z-Source Inverter Topologies
Ho, Anh-Vu ; Chun, Tae-Won ; Kim, Heung-Geun ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 834~841
DOI : 10.6113/JPE.2014.14.5.834
This paper proposes new active switched-capacitor and switched-inductor Z-source inverter (ASC/SL-ZSI) topologies, which can provide a higher boost ability with a small shoot-through time. The proposed ASC/SL-ZSIs inherit all of the advantages of the classical ZSI, and have a stronger voltage boost inversion ability when compared with the classical ZSI. Thus, the output ac voltage quality is significantly improved. In addition, more cells can be cascaded in the impedance network in order to obtain a very high boost ability. The proposed topologies can be applied to photovoltaic or fuel-cell generation systems with low-voltage renewal sources due to their wide range of obtainable voltages. Both simulations and the experimental results are carried out in order to verify performance of the proposed topologies.
A Review of the Methods for Improving the Efficiency of Drive Motors to Meet IE4 Efficiency Standards
Dorrell, David G. ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 842~851
DOI : 10.6113/JPE.2014.14.5.842
High efficiency standards are slowly being introduced with IE3 efficiency levels shortly becoming compulsory in many countries; IE4 efficiency levels being developed for future implementation. In this paper a review is carried out of the IE 60034-30 standard which covers standard line-start induction motors. Some design techniques that can be used to increase efficiency in order to meet the IE4 standards are discussed. This standard is now being replaced by the IE60034-30-1 standard which extends to other line start motors and also IE 60034-30-2 is being introduced to cover variable speed drives in order to address developing technology. The conclusion is that IE4 standards are obtainable but careful design is needed to reach this. Examples from the literature are given.
Characteristics Analysis of a Novel Segmental Rotor Axial Field Switched Reluctance Motor with Single Teeth Winding
Wang, Bo ; Lee, Dong-Hee ; Lee, Chee-Woo ; Ahn, Jin-Woo ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 852~858
DOI : 10.6113/JPE.2014.14.5.852
A novel 12/10 axial field switched reluctance motor (AF-SRM) is proposed for cooling fan applications in this paper. Unlike from conventional structures, the proposed motor uses the axial field instead of the radio field, the rotor is constructed from a series of discrete segments, and the stator poles are constructed from two types of stator poles: exciting and auxiliary poles. This concept improves the torque capability of a previous design by reducing the copper volume, which leads to a higher efficiency. To verify the proposed structure, the finite element method (FEM) and Matlab-Simulink are employed to get characteristics of the proposed SRM. Finally, a prototype of the proposed motor was tested for characteristic comparisons.
Semi-analytical Method for Predicting Shaft Voltage in Field-excited Synchronous Generators
Doorsamy, Wesley ; Cronje, Willem A. ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 859~865
DOI : 10.6113/JPE.2014.14.5.859
This study presents an electromagnetic model for predicting shaft voltages in a 2-pole field-excited synchronous generator. After the first observations on shaft voltages were made more than a century ago, extensive work has been conducted on eliminating, mitigating, and integrating the aforementioned phenomena. Given that emphasis has been placed on modeling shaft- and bearing-induced voltages in AC motors driven by variable frequency drives, similar efforts toward a model that is dedicated to generators are insubstantial. This work endeavors to improve current physical interpretation and prediction methods for shaft-induced voltages in generators through semi-analytical derivation. Aside from the experimental validation of the model, investigations regarding the behavior of shaft voltages under varying machine complexities and operating conditions clarify previous uncertainties regarding these phenomena. The performance of the numerical method is also assessed for application in eccentricity fault diagnosis.
Design and Analysis of a Segmental Rotor Type 12/8 Switched Reluctance Motor
Zhang, Hongtao ; Lee, Dong-Hee ; Lee, Chee-Woo ; Ahn, Jin-Woo ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 866~873
DOI : 10.6113/JPE.2014.14.5.866
In this paper, a novel 12/8 segmental rotor type switched reluctance motor (SRM) is proposed for cooling fan applications. Unlike conventional structures, the rotor of the proposed structure is constructed from a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Moreover, in this structure, short flux paths are taken and no flux reversion exists in the stator. While the auxiliary poles are not wound by the windings, which only provide the flux return path. When compared with the conventional SRM, the proposed structure increases the electrical utilization of the machine and decreases the core losses, which may lead to a higher efficiency. To verify the proposed structure, the finite element method (FEM) and Matlab-Simulink are employed to get the static and dynamic characteristics of the proposed SRM. Finally, a prototype of the proposed motor was tested for characteristic comparisons.
Analysis and Design of a PFC AC-DC Converter with Electrical Isolation
Lin, Chia-Ching ; Yang, Lung-Sheng ; Zheng, Ren-Jun ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 874~881
DOI : 10.6113/JPE.2014.14.5.874
This study presents a single-phase power factor correction AC-DC converter that operates in discontinuous conduction mode. This converter uses the pulse-width modulation technique to achieve almost unity power factor and low total harmonic distortion of input current for universal input voltage
) applications. The converter has a simple structure and electrical isolation. The magnetizing-inductor energy of the transformer can be recycled to the output without an additional third winding. The steady-state analysis of voltage gain and boundary operating conditions are discussed in detail. Finally, experimental results are shown to verify the performance of the proposed converter.
Half-Bridge Zero Voltage Switching Converter with Three Resonant Tanks
Lin, Bor-Ren ; Lin, Wei-Jie ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 882~889
DOI : 10.6113/JPE.2014.14.5.882
This paper presents a zero voltage switching (ZVS) converter with three resonant tanks. The main advantages of the proposed converter are its ability to reduce the switching losses on the power semiconductors, decrease the current stress of the passive components at the primary side, and reduce the transformer secondary windings. Three resonant converters with the same power switches are adopted at the low voltage side to reduce the current rating on the transformer windings. Using a series-connection of the transformer secondary windings, the primary side currents of the three resonant circuits are balanced to share the load power. As a result, the size of both the transformer core and the bobbin are reduced. Based on the circuit characteristics of the resonant converter, the power switches are turned on at ZVS. The rectifier diodes can be turned off at zero current switching (ZCS) if the switching frequency is less than the series resonant frequency. Therefore, the reverse recovery losses on the rectifier diodes are overcome. Experiments with a 1.6kW prototype are presented to verify the effectiveness of the proposed converter.
Enhanced Variable On-time Control of Critical Conduction Mode Boost Power Factor Correction Converters
Kim, Jung-Won ; Yi, Je-Hyun ; Cho, Bo-Hyung ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 890~898
DOI : 10.6113/JPE.2014.14.5.890
Critical conduction mode boost power factor correction converters operating at the boundary of continuous conduction mode and discontinuous conduction mode have been widely used for power applications lower than 300W. This paper proposes an enhanced variable on-time control method for the critical conduction mode boost PFC converter to improve the total harmonic distortion characteristic. The inductor current, which varies according to the input voltage, is analyzed in detail and the optimal on-time is obtained to minimize the total harmonic distortion with a digital controller using a TMS320F28335. The switch on-time varies according to the input voltage based on the computed optimal on-time. The performance of the proposed control method is verified by a 100W PFC converter. It is shown that the optimized on-time reduces the total harmonic distortion about 52% (from 10.48% to 5.5%) at 220V when compared to the variable on-time control method.
A High-Efficiency Bidirectional AC/DC Topology for V2G Applications
Su, Mei ; Li, Hua ; Sun, Yao ; Xiong, Wenjing ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 899~907
DOI : 10.6113/JPE.2014.14.5.899
This paper proposes a single-phase bidirectional AC/DC converter topology applied in V2G systems, which consists of an inverter and a bidirectional non-inverting buck-boost converter. This topology can operate in four modes: buck charging, boost charging, buck discharging and boost discharging with high input current quality and unity input power factor. The inverter switches at line frequency, which is different from conventional voltage source inverters. A bidirectional buck-boost converter is utilized to adapt to a wider charging voltage range. The modulation and control strategy is introduced in detail, and the switching patterns are optimized to reduce the current ripple. In addition, the semiconductor losses are analyzed. Simulation and experimental results demonstrate the validity and effectiveness of the proposed topology.
Output Voltage Ripple Analysis and Design Considerations of Intrinsic Safety Flyback Converter Based on Energy Transmission Modes
Hu, Wei ; Zhang, Fangying ; Xu, Yawu ; Chen, Xinbing ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 908~917
DOI : 10.6113/JPE.2014.14.5.908
For the purpose of designing an intrinsic safety Flyback converter with minimal output voltage ripple based on a specified output current, this paper first classified the energy transmission modes of the system into three sorts, namely, the Complete Inductor Supply Mode-CCM (CISM-CCM), the Incomplete Inductor Supply Mode-CCM (IISM-CCM) and the Incomplete Inductor Supply Mode-DCM (IISM-DCM). Then, the critical secondary self-inductance assorting the three modes are deduced and expressions of the output voltage ripples (OVR) are presented. For a Flyback converter with constant loads and switching frequency, it is shown that the output voltage ripple in the CISM-CCM is the smallest and that it has no relationship with the secondary self-inductance. Otherwise, the OVR of the other two modes are bigger than the previously mentioned one. It is concluded that the critical inductance between the CISM-CCM and the IISM-CCM is the minimal secondary self-inductance to ensure the smallest output voltage ripple. At last, a design method to guarantee the minimum OVR within the scales of the input voltage and load are analyzed, and the minimum secondary self-inductance is proposed to minimize the OVR. Simulations and experiments are given to verify the results.
Extended Boost Single-phase qZ-Source Inverter for Photovoltaic Systems
Shin, Hyun-Hak ; Cha, Honnyong ; Kim, Hongjoon ; Kim, Heung-Geun ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 918~925
DOI : 10.6113/JPE.2014.14.5.918
This study presents an extended boost single-phase qZ-source DC-AC inverter for a single-phase photovoltaic system. Unlike the previously proposed single-phase qZ-source and semi-qZ-source inverters that achieve the same output voltage as that of the traditional voltage-fed full-bridge inverter, the proposed inverter can obtain higher output than input voltage. The proposed inverter also shares a common ground between DC input voltage and AC output voltage. Thus, possible ground leakage current problem in non-isolated grid-tied inverters can be eliminated with the proposed inverter. A 120 W prototype inverter is built and tested to verify the performance of the proposed inverter.
Simplified SVPWM that Integrates Overmodulation and Neutral Point Potential Control
Zhu, Rong-Wu ; Wu, Xiao-Jie ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 926~936
DOI : 10.6113/JPE.2014.14.5.926
A simplified and effective space vector pulse-width modulation (SVPWM) algorithm with two and three levels for three-phase voltage-source converters is proposed in this study. The proposed SVPWM algorithm only uses several linear calculations on three-phase modulated voltages without any complicated trigonometric calculations adopted by conventional SVPWM. This simplified SVPWM also avoids choosing the vector sector required by conventional SVPWM. A two-level overmodulation scheme is integrated into the proposed two-level SVPMW to generate the output voltage that increases from a linear region to a six-step state with a smoothly linear transition characteristic and a simple overmodulation process without a lookup table and complicated nonlinear functions. The three-level SVPWM with a proportional-integral controller effectively balances the neutral point potential of the neutral point clamped converter. Results from the simulation in MATLAB/Simulink and the experiment based on a digital signal processor are provided to clearly demonstrate the validity and effectiveness of the proposed strategies.
Optimized Space Vector Pulse-width Modulation Technique for a Five-level Cascaded H-Bridge Inverter
Matsa, Amarendra ; Ahmed, Irfan ; Chaudhari, Madhuri A. ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 937~945
DOI : 10.6113/JPE.2014.14.5.937
This paper presents an optimized space vector pulse-width modulation (OSVPWM) technique for a five-level cascaded H-bridge (CHB) inverter. The space vector diagram of the five-level CHB inverter is optimized by resolving it into inner and outer two-level space vector hexagons. Unlike conventional space vector topology, the proposed technique significantly reduces the involved computational time and efforts without compromising the performance of the five-level CHB inverter. A further optimized (FOSVPWM) technique is also presented in this paper, which significantly reduces the complexity and computational efforts. The developed techniques are verified through MATLAB/SIMULINK. Results are compared with sinusoidal pulse-width modulation (SPWM) to prove the validity of the proposed technique. The proposed simulation system is realized by using an XC3S400 field-programmable gate array from Xilinx, Inc. The experiment results are then presented for verification.
Fault-Tolerant Control of Cascaded H-Bridge Converters Using Double Zero-Sequence Voltage Injection and DC Voltage Optimization
Ji, Zhendong ; Zhao, Jianfeng ; Sun, Yichao ; Yao, Xiaojun ; Zhu, Zean ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 946~956
DOI : 10.6113/JPE.2014.14.5.946
Cascaded H-Bridge (CHB) converters can be directly connected to medium-voltage grids without using transformers and they possess the advantages of large capacity and low harmonics. They are significant tools for providing grid connections in large-capacity renewable energy systems. However, the reliability of a grid-connected CHB converter can be seriously influenced by the number of power switching devices that exist in the structure. This paper proposes a fault-tolerant control strategy based on double zero-sequence voltage injection and DC voltage optimization to improve the reliability of star-connected CHB converters after one or more power units have been bypassed. By injecting double zero-sequence voltages into each phase cluster, the DC voltages of the healthy units can be rapidly balanced after the faulty units are bypassed. In addition, optimizing the DC voltage increases the number of faulty units that can be tolerated and improves the reliability of the converter. Simulations and experimental results are shown for a seven-level three-phase CHB converter to validate the efficiency and feasibility of this strategy.
Pulse Counting Sensorless Detection of the Shaft Speed and Position of DC Motor Based Electromechanical Actuators
Testa, Antonio ; De Caro, Salvatore ; Scimone, Tommaso ; Letor, Romeo ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 957~966
DOI : 10.6113/JPE.2014.14.5.957
Some of DC actuators used in home automation, office automation, medical equipment and automotive systems require a position sensor. In low power applications, the introduction of such a transducer remarkably increases the whole system cost, which justifies the development of sensorless position estimation techniques. The well-known AC motor drive sensorless techniques exploiting the fundamental component of the back electromotive force cannot be used on DC motor drives. In addition, the sophisticated approaches based on current or voltage signal injection cannot be used. Therefore, an effective and inexpensive sensorless position estimation technique suitable for DC motors is presented in this paper. This technique exploits the periodic pulses of the armature current caused by commutation. It is based on a simple pulse counting algorithm, suitable for coping with the rather large variability of the pulse frequency and it leads to the realization of a sensorless position control system for low cost, medium performance systems, like those in the field of automotive applications.
Speed and Current Sensor Fault Detection and Isolation Based on Adaptive Observers for IM Drives
Yu, Yong ; Wang, Ziyuan ; Xu, Dianguo ; Zhou, Tao ; Xu, Rong ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 967~979
DOI : 10.6113/JPE.2014.14.5.967
This paper focuses on speed and current sensor fault detection and isolation (FDI) for induction motor (IM) drives. A new, accurate and high-efficiency FDI approach is proposed so that a system can continue operating with good performance even in the presence of speed sensor faults, current sensor faults or both. The proposed three paralleled adaptive observers are capable of current sensor fault detection and localization. By using observers, the rotor flux and rotor speed can be estimated which allows the system to run under the speed sensorless vector control mode when a speed sensor fault occurs. In order to detect speed sensor faults, a threshold-based scheme is proposed. To verify the feasibility and effectiveness of the proposed FDI strategy, experiments are carried out under different conditions based on a dSPACE DS1104 induction motor drive platform.
Sliding Mode Control of SPMSM Drivers: An Online Gain Tuning Approach with Unknown System Parameters
Jung, Jin-Woo ; Leu, Viet Quoc ; Dang, Dong Quang ; Choi, Han Ho ; Kim, Tae Heoung ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 980~988
DOI : 10.6113/JPE.2014.14.5.980
This paper proposes an online gain tuning algorithm for a robust sliding mode speed controller of surface-mounted permanent magnet synchronous motor (SPMSM) drives. The proposed controller is constructed by a fuzzy neural network control (FNNC) term and a sliding mode control (SMC) term. Based on a fuzzy neural network, the first term is designed to approximate the nonlinear factors while the second term is used to stabilize the system dynamics by employing an online tuning rule. Therefore, unlike conventional speed controllers, the proposed control scheme does not require any knowledge of the system parameters. As a result, it is very robust to system parameter variations. The stability evaluation of the proposed control system is fully described based on the Lyapunov theory and related lemmas. For comparison purposes, a conventional sliding mode control (SMC) scheme is also tested under the same conditions as the proposed control method. It can be seen from the experimental results that the proposed SMC scheme exhibits better control performance (i.e., faster and more robust dynamic behavior, and a smaller steady-state error) than the conventional SMC method.
Dynamic Performance Analysis for Different Vector-Controlled CSI- Fed Induction Motor Drives
Mark, Arul Prasanna ; Irudayaraj, Gerald Christopher Raj ; Vairamani, Rajasekaran ; Mylsamy, Kaliamoorthy ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 989~999
DOI : 10.6113/JPE.2014.14.5.989
High-performance Current Source Inverter (CSI)-fed, variable speed alternating current drives are prepared for various industrial applications. CSI-fed Induction Motor (IM) drives are managed by using different control methods. Noteworthy methods include scalar Control (V/f), Input-Output Linearization (IOL) control, Field-Oriented Control (FOC), and Direct Torque Control (DTC). The objective of this work is to compare the dynamic performance of the aforementioned drive control methods for CSI-fed IM drives. The dynamic performance results of the proposed drives are individually analyzed through sensitivity tests. The tests selected for the comparison are step changes in the reference speed and torque of the motor drive. The operation and performance of different vector control methods are verified through simulations with MATLAB/Simulink and experimental results.
Robust On-line Rotor Time Constant Estimation for Induction Machines
Yoo, Anno ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 1000~1007
DOI : 10.6113/JPE.2014.14.5.1000
This paper proposes an on-line rotor time constant estimation strategy for indirect field oriented induction machines. The performance of the indirect field oriented control is dependent especially on the rotor time constant whose value varies according to the temperature. The proposed method calculates the difference between the nominal rotor time constant and the real value from the d- and q-axis integration terms of a proportional integral (PI) current regulator and the demanded voltages of the induction machine to regulate the current in the steady state. Because the proposed strategy has a simple structure and is available in wide speed and torque ranges, the proposed method can be easily used in the industrial field. The effectiveness of proposed strategy is verified with simulations and a 7.5kW experimental setup.
A PMSM Driven Electric Scooter System with a V-Belt Continuously Variable Transmission Using a Novel Hybrid Modified Recurrent Legendre Neural Network Control
Lin, Chih-Hong ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 1008~1027
DOI : 10.6113/JPE.2014.14.5.1008
An electric scooter with a V-belt continuously variable transmission (CVT) driven by a permanent magnet synchronous motor (PMSM) has a lot of nonlinear and time-varying characteristics, and accurate dynamic models are difficult to establish for linear controller designs. A PMSM servo-drive electric scooter controlled by a novel hybrid modified recurrent Legendre neural network (NN) control system is proposed to solve difficulties of linear controllers under the occurrence of nonlinear load disturbances and parameters variations. Firstly, the system structure of a V-belt CVT driven electric scooter using a PMSM servo drive is established. Secondly, the novel hybrid modified recurrent Legendre NN control system, which consists of an inspector control, a modified recurrent Legendre NN control with an adaptation law, and a recouped control with an estimation law, is proposed to improve its performance. Moreover, the on-line parameter tuning method of the modified recurrent Legendre NN is derived according to the Lyapunov stability theorem and the gradient descent method. Furthermore, two optimal learning rates for the modified recurrent Legendre NN are derived to speed up the parameter convergence. Finally, comparative studies are carried out to show the effectiveness of the proposed control scheme through experimental results.
Sliding Mode Control of Three-Phase Four-Leg Inverters via State Feedback
Yang, Long-Yue ; Liu, Jian-Hua ; Wang, Chong-Lin ; Du, Gui-Fu ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 1028~1037
DOI : 10.6113/JPE.2014.14.5.1028
To optimize controller design and improve static and dynamic performances of three-phase four-leg inverter systems, a compound control method that combines state feedback and quasi-sliding mode variable structure control is proposed. The linear coordinate change matrix and the state variable feedback equations are derived based on the mathematical model of three-phase four-leg inverters. Based on system relative degrees, sliding surfaces and quasi-sliding mode controllers are designed for converted linear systems. This control method exhibits the advantages of both state feedback and sliding mode control. The proposed controllers provide flexible dynamic control response and excellent stable control performance with chattering suppression. The feasibility of the proposed strategy is verified by conducting simulations and experiments.
State-of-charge Estimation for Lithium-ion Batteries Using a Multi-state Closed-loop Observer
Zhao, Yulan ; Yun, Haitao ; Liu, Shude ; Jiao, Huirong ; Wang, Chengzhen ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 1038~1046
DOI : 10.6113/JPE.2014.14.5.1038
Lithium-ion batteries are widely used in hybrid and pure electric vehicles. State-of-charge (SOC) estimation is a fundamental issue in vehicle power train control and battery management systems. This study proposes a novel model-based SOC estimation method that applies closed-loop state observer theory and a comprehensive battery model. The state-space model of lithium-ion battery is developed based on a three-order resistor-capacitor equivalent circuit model. The least square algorithm is used to identify model parameters. A multi-state closed-loop state observer is designed to predict the open-circuit voltage (OCV) of a battery based on the battery state-space model. Battery SOC can then be estimated based on the corresponding relationship between battery OCV and SOC. Finally, practical driving tests that use two types of typical driving cycle are performed to verify the proposed SOC estimation method. Test results prove that the proposed estimation method is reasonably accurate and exhibits accuracy in estimating SOC within 2% under different driving cycles.
Co-design of the LCL Filter and Control for Grid-Connected Inverters
Zhang, Yu ; Xue, Mingyu ; Li, Minying ; Kang, Yong ; Guerrero, Josep M. ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 1047~1056
DOI : 10.6113/JPE.2014.14.5.1047
In most grid-connected inverters (GCI) with an LCL filter, since the design of both the LCL filter and the controller is done separately, considerable tuning efforts have to be exerted when compared to inverters using an L filter. Consequently, an integrated co-design of the filter and the controller for an LCL-type GCI is proposed in this paper. The control strategy includes only a PI current controller and a proportional grid voltage feed-forward controller. The capacitor is removed from the LCL filer and the design procedure starts from an L-type GCI with a PI current controller. After the PI controller has been settled, the capacitor is added back to the filter. Hence, it introduces a resonance frequency, which is identified based on the crossover frequencies to accommodate the preset PI controller. Using the proposed co-design method, harmonic standards are satisfied and other practical constraints are met. Furthermore, the grid voltage feed-forward control can bring an inherent damping characteristic. In such a way, the good control performance offered by the original L-type GCI and the sharp harmonic attenuation offered by the latter designed LCL filter can be well integrated. Moreover, only the grid current and grid voltage are sensed. Simulation and experimental results verify the feasibility of the proposed design methodology.
A Canonical Small-Signal Linearized Model and a Performance Evaluation of the SRF-PLL in Three Phase Grid Inverter System
Mao, Peng ; Zhang, Mao ; Zhang, Weiping ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 1057~1068
DOI : 10.6113/JPE.2014.14.5.1057
Phase-locked loops (PLL) based on the synchronous reference frame (SRF-PLL) have recently become the most widely-used for grid synchronization in three phase grid-connected inverters. However, it is difficult to study their performance since they are nonlinear systems. To estimate the performances of a SRF-PLL, a canonical small-signal linearized model has been developed in this paper. Based on the proposed model, several significant specifications of a SRF-PLL, such as the capture time, capture rang, bandwidth, the product of capture time and bandwidth, and steady-state error have been investigated. Finally, a noise model of a SRF-PLL has been put forward to analyze the noise rejection ability by computing the SNR (signal-to-noise ratio) of a SRF-PLL. Several simulation and experimental results have been provided to verify and validate the obtained conclusions. Although the proposed model and analysis method are based on a SRF-PLL, they are also suitable for analyzing other types of PLLs.
LabVIEW-based Remote Laboratory Experiments for a Multi-mode Single-leg Converter
Bayhan, Sertac ;
Journal of Power Electronics, volume 14, issue 5, 2014, Pages 1069~1078
DOI : 10.6113/JPE.2014.14.5.1069
This study presents the design and implementation of a web-based remote laboratory for a multi-mode single-leg power converter, which is a topic in advanced power electronics course. The proposed laboratory includes an experimental test rig with a multi-mode single-leg power converter and its driver circuits, a measurement board, a control platform, and a LabVIEW-based user interface program that is operated in the server computer. Given that the proposed web-based remote laboratory is based on client/server architecture, the experimental test rig can be controlled by a client computer with Internet connection and a standard web browser. Although the multi-mode single-leg power converter can work at four different modes (main boost, buck-boost, boost-boost, and battery boost modes), only the buck-boost mode is used in the experiment because of page limit. Users can choose the control structure, control parameters, and reference values, as well as obtain graphical results from the user interface software. Consequently, the feedbacks received from students who conducted remote laboratory studies indicate that the proposed laboratory is a useful tool for both remote and traditional education.