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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
Selecting the target year
Guest Editorial Special Issue on Multilevel Power Converters for Utility Applications
Peng, Fang Zheng ; Yoo, Dong-Wook ; Sul, Seung-Ki ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1079~1080
DOI : 10.6113/JPE.2014.14.6.1079
Voltage Source Equipment for the Grid Fault Testing and Analysis of Total Harmonic Distortion According to PWM Methods
Gwon, Jin-Su ; Kim, Chun-Sung ; Kang, Dae-Wook ; Park, Jung-Woo ; Kim, Sungshin ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1081~1092
DOI : 10.6113/JPE.2014.14.6.1081
Renewable energy is being spotlighted as the electric power generating source for the next generation. Due to an increase in renewable energy systems in the grid system, their impact on the grid has become non-negligible. Thus, many countries in the world, including Europe, present their own grid codes for grid power conversion devices. In order to experiment with these grid codes, grid fault test equipment is required. This paper proposes both equipment and a control method, which are constructed with a 7-level cascaded H-bridge converter, that are capable of generating various grid faults. In addition, the Pulse Width Modulation (PWM) method for multilevel converters is compared and analyzed. The proposed structure, the control method, and the PWM method are verified through simulation and experimental results.
Multi-Level Operation with Two-Level Converters through a Double-Delta Source Connected Transformer
Park, Yongsoon ; Ohn, Sungjae ; Sul, Seung-Ki ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1093~1099
DOI : 10.6113/JPE.2014.14.6.1093
This paper proposes a power conversion topology involving a multi-winding transformer and converters. The fundamental idea is described with circuit diagrams, and the voltage output of the proposed topology is analyzed mathematically. The effectiveness of the topology is discussed with test results from a small-scale power conversion system. When conventional hardware consisting of two-level converters and a transformer is employed, multi-level voltage outputs can be applied to the transformer windings by the proposed method.
Circulating Current Harmonics Suppression for Modular Multilevel Converters Based on Repetitive Control
Li, Binbin ; Xu, Dandan ; Xu, Dianguo ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1100~1108
DOI : 10.6113/JPE.2014.14.6.1100
Modular multilevel converters (MMCs) have emerged as the most promising topology for high and medium voltage applications for the coming years. However, one particular negative characteristic of MMCs is the existence of circulating current, which contains a dc component and a series of low-frequency even-order ac harmonics. If not suppressed, these ac harmonics will distort the arm currents, increase the power loses, and cause higher current stresses on the semiconductor devices. Repetitive control (RC) is well known due to its distinctive capabilities in tracking periodic signals and eliminating periodic errors. In this paper, a novel circulating current control scheme base on RC is proposed to effectively track the dc component and to restrain the low-frequency ac harmonics. The integrating function is inherently embedded in the RC controller. Therefore, the proposed circulating current control only parallels the RC controller with a proportional controller. Thus, conflicts between the RC controller and the traditional proportional integral (PI) controller can be avoided. The design methodologies of the RC controller and a stability analysis are also introduced. The validity of the proposed circulating current control approach has been verified by simulation and experimental results based on a three-phase MMC downscaled prototype.
A Simple Capacitor Voltage Balancing Method with a Fundamental Sorting Frequency for Modular Multilevel Converters
Peng, Hao ; Wang, Ying ; Wang, Kun ; Deng, Yan ; He, Xiangning ; Zhao, Rongxiang ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1109~1118
DOI : 10.6113/JPE.2014.14.6.1109
A Fundamental Frequency Sorting Algorithm (FFSA) is proposed in this paper to balance the voltages of floating dc capacitors for Modular Multilevel Converters (MMCs). The main idea is to change the sequences of the CPS-PWM carriers according to the capacitor voltage increments during the previous fundamental period. Excessive frequent sorting is avoided and many calculating resources are saved for the controller. As a result, more sub-modules can be dealt with. Furthermore, it does not need to measure the arm currents. Therefore, the communication between the controllers can be simplified and the number of current sensors can be reduced. Moreover, the proposed balancing method guarantees that all of the switching frequencies of the sub-modules are equal to each other. This is quite beneficial for the thermal design of the sub-modules and the lifetime of the power switches. Simulation and experimental results acquired from a 9-level prototype verify the viability of the proposed balancing method.
Novel Five-Level Three-Phase Hybrid-Clamped Converter with Reduced Components
Chen, Bin ; Yao, Wenxi ; Lu, Zhengyu ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1119~1129
DOI : 10.6113/JPE.2014.14.6.1119
This study proposes a novel five-level three-phase hybrid-clamped converter composed of only six switches and one flying capacitor (FC) per phase. The capacitor-voltage-drift phenomenon of the converter under the classical sinusoidal pulse width modulation (SPWM) strategy is comprehensively analyzed. The average current, which flows into the FC, is a function of power factor and modulation index and does not remain at zero. Thus, a specific modulation strategy based on space vector modulation (SVM) is developed to balance the voltage of DC-link and FCs by injecting a common-mode voltage. This strategy applies the five-segment method to synthesize the voltage vector, such that switching losses are reduced while optional vector sequences are increased. The best vector sequence is then selected on the basis of the minimized cost function to suppress the divergence of the capacitor voltage. This study further proposes a startup method that charges the DC-link and FCs without any additional circuits. Simulation and experimental results verify the validity of the proposed converter, modulation strategy, and precharge method.
Efficiency Analysis of a Ladder Multilevel Converter with the Use of the Equivalent Continuous Model
Lopez, Andres ; Patino, Diego ; Diez, Rafael ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1130~1138
DOI : 10.6113/JPE.2014.14.6.1130
This study analyzes a ladder multilevel converter (double ladder topology) with the use of a new averaging modeling technique. This technique introduces an analytical method to compute for the switching losses and is used to conduct an in-depth analysis of the influence of the switching frequency and parasitic resistance of components on converter efficiency. The obtained results enable the selection of switches and switching frequency to minimize losses. Moreover, simulation results and experimental measurements validate the analytical calculations.
Implementation of a No Pulse Competition CPS-SPWM Technique Based on the Concentrated Control for Cascaded Multilevel DSTATCOMs
Wang, Yue ; Yang, Kun ; Chen, Guozhu ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1139~1146
DOI : 10.6113/JPE.2014.14.6.1139
Digital signal processor (DSP) and field programmable gate array (FPGA) based concentrated control systems are designed for implementing CPS-SPWM strategies. The self-defined universal asynchronous receiver/transmitter (UART) protocol is used for communication between a master controller and an individual module controller via high speed links. Aimed at undesired pulse competition, this paper analyzes its generation mechanism and presents a new method for eliminating competition pulses with no time delay. Finally, the proposed concentrated controller is applied to a 10kV/10MVar distribution static synchronous compensator (DSTATCOM) industrial prototype. Experimental results show the accuracy and reliability of the concentrated controller, and verify the superiority of the proposed elimination method for competition pulses.
Quasi-Fixed-Frequency Hysteresis Current Tracking Control Strategy for Modular Multilevel Converters
Mei, Jun ; Ji, Yu ; Du, Xiaozhou ; Ma, Tian ; Huang, Can ; Hu, Qinran ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1147~1156
DOI : 10.6113/JPE.2014.14.6.1147
This study proposes a quasi-fixed-frequency hysteresis current tracking control strategy for modular multilevel converters (MMCs) on the basis of voltage partition principle. First, by monitoring the grid voltage and the deviation between the output and reference currents, the output voltage is determined, thus prompting the output current to quickly and efficiently track the given current. Second, the voltages of the upper/lower capacitor of the arm and the voltages between the upper and lower arms are balanced by combining these arms with virtual loop mapping and arm voltage balance control, respectively. In particular, the proposed method is designed for any level and number of sub-modules. The validity of the proposed method is verified by simulations and experimental results of a five-level MMC prototype.
Tolerance Control for the Inner Open-Switch Faults of a T-Type Three-Level Rectifier
Lee, June-Seok ; Lee, Kyo-Beum ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1157~1165
DOI : 10.6113/JPE.2014.14.6.1157
The T-type topology is a three-level topology that has an advantage in terms of its number of switching device and its efficiency when compared to the neutral-point clamped (NPC)-type topology. With the recent increase in the usage of the T-type topology, the interest in its reliability has also increased. Therefore, a tolerance control for a T-type rectifier is necessary to improve the reliability of applications when an open-switch fault occurs. NPC-type rectifiers cannot eliminate input current distortion completely. However, the T-type rectifier is able to restore distorted current. In this paper, a tolerance control for the
open-switch faults of a T-type rectifier is proposed where it is advantageous in terms of efficiency when compared with other tolerance controls. The performance of the proposed tolerance control is verified through simulation and experimental results.
A Medium-Voltage Matrix Converter Topology for Wind Power Conversion with Medium Frequency Transformers
Gu, Chunyang ; Krishnamoorthy, Harish S. ; Enjeti, Prasad N. ; Zheng, Zedong ; Li, Yongdong ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1166~1177
DOI : 10.6113/JPE.2014.14.6.1166
A new type of topology with medium-frequency-transformer (MFT) isolation for medium voltage wind power generation systems is proposed in this paper. This type of converter is a high density power conversion system, with high performance features suitable for next generation wind power systems in either on-shore or off-shore applications. The proposed topology employs single-phase cascaded multi-level AC-AC converters on the grid side and three phase matrix converters on the generator side, which are interfaced by medium frequency transformers. This avoids DC-Link electrolytic capacitors and/or resonant L-C components in the power flow path thereby improving the power density and system reliability. Several configurations are given to fit different applications. The modulation and control strategy has been detailed. As two important part of the whole system, a novel single phase AC-AC converter topology with its reliable six-step switching technique and a novel symmetrical 11-segment modulation strategy for two stage matrix converter (TSMC) is proposed at the special situation of medium frequency chopping. The validity of the proposed concept has been verified by simulation results and experiment waveforms from a scaled down laboratory prototype.
Finite State Model-based Predictive Current Control with Two-step Horizon for Four-leg NPC Converters
Yaramasu, Venkata ; Rivera, Marco ; Narimani, Mehdi ; Wu, Bin ; Rodriguez, Jose ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1178~1188
DOI : 10.6113/JPE.2014.14.6.1178
This study proposes a finite-state model predictive controller to regulate the load current and balance the DC-link capacitor voltages of a four-leg neutral-point-clamped converter. The discrete-time model of the converter, DC-link, inductive filter, and load is used to predict the future behavior of the load currents and the DC-link capacitor voltages for all possible switching states. The switching state that minimizes the cost function is selected and directly applied to the converter. The cost function is defined to minimize the error between the predicted load currents and their references, as well as to balance the DC-link capacitor voltages. Moreover, the current regulation performance is improved by using a two-step prediction horizon. The feasibility of the proposed predictive control scheme for different references and loads is verified through real-time implementation on the basis of dSPACEDS1103.
Module Multilevel-Clamped Composited Multilevel Converter (M-MC
) with Dual T-Type Modules and One Diode Module
Luo, Haoze ; Dong, Yufei ; Li, Wuhua ; He, Xiangning ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1189~1196
DOI : 10.6113/JPE.2014.14.6.1189
A modular multilevel-clamped composited multilevel converter (
) is proposed.
enables topology reconfiguration, power device reuse, and composited clamping. An advanced five-level converter (
) is derived from the concept of
integrates dual three-level T-type modules and one three-level neutral point clamped module. This converter can also integrate dual three-level T-type modules and one passive diode module by utilizing the device reuse scheme. The operation principle and SPWM modulation are discussed to highlight converter performance. The proposed
is comprehensively compared with state-of-the-art five-level converters. Finally, simulations and experimental results are presented to validate the effectiveness of the main contributions of this study.
Carrier Phase-Shift PWM to Reduce Common-Mode Voltage for Three-Level T-Type NPC Inverters
Nguyen, Tuyen D. ; Phan, Dzung Quoc ; Dao, Dat Ngoc ; Lee, Hong-Hee ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1197~1207
DOI : 10.6113/JPE.2014.14.6.1197
Common-mode voltage (CMV) causes overvoltage stress to winding insulation and damages AC motors. CMV with high dv/dt causes leakage currents, which create noise problems for equipment installed near the converter. This study proposes a new pulse-width modulation (PWM) strategy for three-level T-type NPC inverters. This strategy substantially eliminates CMV. The principle for selecting suitable triangle carrier signals for the three-level T-type NPC is described. The proposed method can mitigate the peak value of CMV by 50% compared with the phase disposition pulse-width modulation method. Furthermore, the proposed method exhibits better harmonic spectrum and lower root mean square value for the CMV than those of the reduced-CMV method on the basis of the phase opposition disposition PWM scheme with modulation index higher than 0.5. The proposed modulation can easily be implemented using software without any additional hardware modifications. Both simulation and experimental results demonstrate that the proposed carrier phase-shift PWM method has good output waveform performance and reduces CMV.
Stability Analysis and Control of Nonlinear Behavior in V
Switching Buck Converter
Hu, Wei ; Zhang, Fangying ; Long, Xiaoli ; Chen, Xinbing ; Deng, Wenting ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1208~1216
DOI : 10.6113/JPE.2014.14.6.1208
Mismatch between switching frequency and circuit parameters often occurs in industrial applications, which would lead to instability phenomena. The bifurcation behavior of
controlled buck converter is investigated as the pulse width modulation period is varied. Nonlinear behavior is analyzed based on the monodromy matrix of the system. We observed that the stable period-1 orbit was first transformed to the period-2 bifurcation, which subsequently changed to chaos. The mechanism of the series of period-2 bifurcations shows that the characteristic eigenvalue of the monodromy matrix passes through the unit circle along the negative real axis. Resonant parametric perturbation technique has been applied to prevent the onset of instability. Meanwhile, the extended stability region of the converter is obtained. Simulation and experimental prototypes are built, and the corresponding results verify the theoretical analysis.
Half Load-Cycle Worked Dual Input Single Output DC/AC Inverter
Chen, Rong ; Zhang, Jia-Sheng ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1217~1223
DOI : 10.6113/JPE.2014.14.6.1217
A novel half load-cycle worked dual input single output (DISO) DC/AC inverter is presented. The basic circuit consists of a dual buck regulator, which works in continuous current mode. The working principle of DISO DC/AC inverter has been used. The control method applied for half load-cycle worked DISO DC/AC inverter has been studied. The control effects of the open-loop proportional control and closed-loop proportional-integral control are compared by using PSIM software. The parameters are adopted in the realistic simulation and experiment test. Moreover, the waveforms, such as voltage of modulation reference signal and output voltage, were given. The simulation and experiment results proved that the half load-cycle worked DISO DC/AC inverter could achieve good performance, gain a line frequency of 50 Hz, and verify the correctness of theoretical analysis.
Asymmetrical Pulse-Width-Modulated Full-Bridge Secondary Dual Resonance DC-DC Converter
Chen, Zhangyong ; Zhou, Qun ; Xu, Jianping ; Zhou, Xiang ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1224~1232
DOI : 10.6113/JPE.2014.14.6.1224
A full-bridge secondary dual-resonant DC-DC converter using the asymmetrical pulse-width modulated (APWM) strategy is proposed in this paper. The proposed converter achieves zero-voltage switching for the power switches and zero-current switching for the rectifier diodes in the whole load range without the help of any auxiliary circuit. Given the use of the APWM strategy, a circulating current that exists in a traditional phase-shift full-bridge converter is eliminated. The voltage stress of secondary rectifier diodes in the proposed converter is also clamped to the output voltage. Thus, the existing voltage oscillation of diodes in traditional PSFB converters is eliminated. This paper presents the circuit configuration of the proposed converter and analyzes its operating principle. Experimental results of a 1 kW 385 V/48 V prototype are presented to verify the analysis results of the proposed converter.
Transformer-Less Single-Phase Four-Level Inverter for PV System Applications
Yousofi-Darmian, Saeed ; Barakati, Seyed Masoud ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1233~1242
DOI : 10.6113/JPE.2014.14.6.1233
A new inverter topology for single-phase photovoltaic (PV) systems is proposed in this study. The proposed inverter offers a four-level voltage in its output terminals. This feature results in easier filtering in comparison with other conventional two-level or three-level inverters. In addition, the proposed four-level inverter (PFLI) has a transformer-less topology, which decreases the size, weight, and cost of the entire system and increases the overall efficiency of the system. Although the inverter is transformer-less, it produces a negligible leakage ground current (LGC), which makes this inverter suitable for PV grid-connected applications. The performance of the proposed inverter is compared with that of a four-level neutral point clamped inverter (FLNPCI). Theoretical analysis and computer simulations verify that the PFLI topology is superior to FLNPCI in terms of efficiency and suitability for use in PV transformer-less systems.
Variable Coefficient Inductance Model-Based Four-Quadrant Sensorless Control of SRM
Kuai, Song-Yan ; Li, Xue-Feng ; Li, Xing-Hong ; Ma, Jinyang ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1243~1253
DOI : 10.6113/JPE.2014.14.6.1243
The phase inductance of a switch reluctance motor (SRM) is significantly nonlinear. With different saturation conditions, the phase inductance shape is clearly changed. This study focuses on the relationship between coefficient and current in an inductance model with ignored harmonics above the order of 3. A position estimation method based on the variable coefficient inductance model is proposed in this paper. A four-quadrant sensorless control system of the SRM drive is constructed based on the relationship between variable coefficient inductance and rotor position. The proposed algorithms are implemented in an experimental SRM test setup. Experimental results show that the proposed method estimates position accurately in operating two/four-quadrants. The entire system also has good static and dynamic performance.
Study on the Temperature Drift Adaptive Compensation Algorithm of a Magneto-Electric Encoder Based on a Simple Neuron
Wang, Lei ; Hao, Shuang-Hui ; Song, Bao-Yu ; Hao, Ming-Hui ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1254~1262
DOI : 10.6113/JPE.2014.14.6.1254
Magneto-electric encoders have been widely used in industry and military applications because of their good shock resistance, small volume, and convenient data processing. However, the characteristics of a magneto-electric encoder`s signal generator and hall sensor changes minimally with temperature variation. These changes cause an angle drift. The main purpose of this study is to construct the compensation system of a neural network and constantly update weight coefficients of temperature correction by finite iteration calculation so that the angle value modified can approach the angle value at the target temperature. This approach is used in adaptive correction of the angle value.
A Novel Hysteresis Control Strategy Based on Ampere-Second Balance of the Modulate Capacitor
Zhao, Jin-Bin ; Dai, Jian-Feng ; Qu, Ke-Qing ; Li, Fen ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1263~1271
DOI : 10.6113/JPE.2014.14.6.1263
A novel hysteresis PWM control strategy for synchronous buck converter is proposed. The proposed control strategy is based on ampere-second balance of the modulate capacitor, which not only offers faster transient response to meet the challenges of the power supply requirements of fast dynamic load changes, but also provides better stability and solves the compensation problem of error amplifier in the conversional voltage PWM control. Finally, the steady-state and dynamic operation of the control method is analyzed and verified by simulation and experimental results.
Detection and Diagnosis Solutions for Fault-Tolerant VSI
Cordeiro, Armando ; Palma, Joao C.P. ; Maia, Jose ; Resende, Maia J. ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1272~1280
DOI : 10.6113/JPE.2014.14.6.1272
This paper presents solutions for fault detection and diagnosis of two-level, three phase voltage-source inverter (VSI) topologies with IGBT devices. The proposed solutions combine redundant standby VSI structures and contactors (or relays) to improve the fault-tolerant capabilities of power electronics in applications with safety requirements. The suitable combination of these elements gives the inverter the ability to maintain energy processing in the occurrence of several failure modes, including short-circuit in IGBT devices, thus extending its reliability and availability. A survey of previously developed fault-tolerant VSI structures and several aspects of failure modes, detection and isolation mechanisms within VSI is first discussed. Hardware solutions for the protection of power semiconductors with fault detection and diagnosis mechanisms are then proposed to provide conditions to isolate and replace damaged power devices (or branches) in real time. Experimental results from a prototype are included to validate the proposed solutions.
MPPT Control and Architecture for PV Solar Panel with Sub-Module Integrated Converters
Abu Qahouq, Jaber A. ; Jiang, Yuncong ; Orabi, Mohamed ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1281~1292
DOI : 10.6113/JPE.2014.14.6.1281
Photovoltaic (PV) solar systems with series-connected module integrated converters (MICs) are receiving increased attention because of their ability to create high output voltage while performing local maximum power point tracking (MPPT) control for individual solar panels, which is a solution for partial shading effects in PV systems at panel level. To eliminate the partial shading effects in PV system more effectively, sub-MICs are utilized at the cell level or grouped cell level within a PV solar panel. This study presents the results of a series-output-connection MPPT (SOC-MPPT) controller for sub-MIC architecture using a single sensor at the output and a single digital MPPT controller (sub-MIC SOC-MPPT controller and architecture). The sub-MIC SOC-MPPT controller and architecture are investigated based on boost type sub-MICs. Experimental results under steady-state and transient conditions are presented to verify the performance of the controller and the effectiveness of the architecture.
Flyback Inverter Using Voltage Sensorless MPPT for Photovoltaic AC Modules
Ryu, Dong-Kyun ; Choi, Bong-Yeon ; Lee, Soon-Ryung ; Kim, Young-Ho ; Won, Chung-Yuen ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1293~1302
DOI : 10.6113/JPE.2014.14.6.1293
A flyback inverter using voltage sensorless maximum power point tracking (MPPT) for photovoltaic (PV) AC modules is presented. PV AC modules for a power rating from 150 W to 300 W are generally required for their small size and low price because of the installation on the back side of PV modules. In the conventional MPPT technique for PV AC modules, sensors for detecting PV voltage and PV current are required to calculate the PV output power. However, system size and cost increase when the voltage sensor and current sensor are used because of the addition of the auxiliary circuit for the sensors. The proposed method uses only the current sensor to track the MPP point. Therefore, the proposed control method overcomes drawbacks of the conventional control method. Theoretical analysis, simulation, and experiment are performed to verify the proposed control method.
Improvement of Dynamic Behavior of Shunt Active Power Filter Using Fuzzy Instantaneous Power Theory
Eskandarian, Nasser ; Beromi, Yousef Alinejad ; Farhangi, Shahrokh ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1303~1313
DOI : 10.6113/JPE.2014.14.6.1303
Dynamic behavior of the harmonic detection part of an active power filter (APF) has an essential role in filter compensation performances during transient conditions. Instantaneous power (p-q) theory is extensively used to design harmonic detectors for active filters. Large overshoot of p-q theory method deteriorates filter response at a large and rapid load change. In this study the harmonic estimation of an APF during transient conditions for balanced three-phase nonlinear loads is conducted. A novel fuzzy instantaneous power (FIP) theory is proposed to improve conventional p-q theory dynamic performances during transient conditions to adapt automatically to any random and rapid nonlinear load change. Adding fuzzy rules in p-q theory improves the decomposition of the alternating current components of active and reactive power signals and develops correct reference during rapid and random current variation. Modifying p-q theory internal high-pass filter performance using fuzzy rules without any drawback is a prospect. In the simulated system using MATLAB/SIMULINK, the shunt active filter is connected to a rapidly time-varying nonlinear load. The harmonic detection parts of the shunt active filter are developed for FIP theory-based and p-q theory-based algorithms. The harmonic detector hardware is also developed using the TMS320F28335 digital signal processor and connected to a laboratory nonlinear load. The software is developed for FIP theory-based and p-q theory-based algorithms. The simulation and experimental tests results verify the ability of the new technique in harmonic detection of rapid changing nonlinear loads.
Mitigation of Voltage Sag and Swell Using Direct Converters with Minimum Switch Count
Abuthahir, Abdul Rahman Syed ; Periasamy, Somasundaram ; Arumugam, Janakiraman Panapakkam ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1314~1321
DOI : 10.6113/JPE.2014.14.6.1314
A new simplified topology for a dynamic voltage restorer (DVR) based on direct converter with a reduced number of switches is presented. The direct converter is fabricated using only three bi-directional controlled switches. The direct converter is connected between the grid and center-tapped series transformer. The center-tapped series transformer is used to inject the compensating voltage synthesized by the direct converter. The DVR can properly compensate for long-duration, balanced, and unbalanced voltage sag and swell by taking power from the grid. The switches are driven by ordinary pulse width modulation signals. Simulation and hardware results validate the idea that the proposed topology can mitigate sag of 50% and swell of unlimited quantity.
Simplified Controller Design Method for Digitally Controlled LCL-Type PWM Converter with Multi-resonant Quasi-PR Controller and Capacitor-Current-Feedback Active Damping
Lyu, Yongcan ; Lin, Hua ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1322~1333
DOI : 10.6113/JPE.2014.14.6.1322
To track the sinusoidal current under stationary frame and suppress the effects of low-order grid harmonics, the multi-resonant quasi-proportional plus resonant (PR) controller has been extensively used for digitally controlled LCL-type pulse-width modulation (PWM) converters with capacitor-current-feedback active damping. However, designing the controller is difficult because of its high order and large number of parameters. Moreover, the computation and PWM delays of the digitally controlled system significantly affect damping performance. In this study, the delay effect is analyzed by using the Nyquist diagrams and the system stability constraint condition can be obtained based on the Nyquist stability criterion. Moreover, impact analysis of the control parameters on the current loop performance, that is, steady-state error and stability margin, identifies that different control parameters play different decisive roles in current loop performance. Based on the analysis, a simplified controller design method based on the system specifications is proposed. Following the method, two design examples are given, and the experimental results verify the practicability and feasibility of the proposed design method.
A Novel Single Phase Synchronous Reference Frame Phase-Locked Loop with a Constant Zero Orthogonal Component
Li, Ming ; Wang, Yue ; Fang, Xiong ; Gao, Yuan ; Wang, Zhaoan ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1334~1344
DOI : 10.6113/JPE.2014.14.6.1334
A novel single phase Phase-Locked Loop (PLL) is proposed in this paper to accurately and rapidly estimate the instantaneous phase angle of a grid. A conjugate rotating vector pair is proposed and defined to synthesize the single phase signal in the stationary reference frame. With this concept, the proposed PLL innovatively sets one phase input of the PARK transformation to a constant zero. By means of a proper cancellation, a zero steady state phase angle estimation error can be achieved, even under magnitude and frequency variations. The proposed PLL structure is presented together with guidelines for parameters adjustment. The performance of the proposed PLL is verified by comprehensive experiments. Satisfactory phase angle estimation can be achieved within one input signal cycle, and the estimation error can be totally eliminated in four input cycles for the most severe conditions.
Experimental Investigations for Thermal Mutual Evaluation in Multi-Chip Modules
Ayadi, Moez ; Bouguezzi, Sihem ; Ghariani, Moez ; Neji, Rafik ;
Journal of Power Electronics, volume 14, issue 6, 2014, Pages 1345~1356
DOI : 10.6113/JPE.2014.14.6.1345
The thermal behavior of power modules is an important criterion for the design of cooling systems and optimum thermal structure of these modules. An important consideration for high power and high frequency design is the spacing between semiconductor devices, substrate structure and influence of the boundary condition in the case. This study focuses on the thermal behavior of hybrid power modules to establish a simplified method that allows temperature estimation in different module components without decapsulation. This study resulted in a correction of the junction temperature values estimated from the transient thermal impedance of each component operating alone. The corrections depend on mutual thermal coupling between different chips of the hybrid structure. A new experimental technique for thermal mutual evaluation is presented. Notably, the classic analysis of thermal phenomena in these structures, which was independent of dissipated power magnitude and boundary conditions in the case, is incorrect.