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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 15, Issue 6 - Nov 2015
Volume 15, Issue 5 - Sep 2015
Volume 15, Issue 4 - Jul 2015
Volume 15, Issue 3 - May 2015
Volume 15, Issue 2 - Mar 2015
Volume 15, Issue 1 - Jan 2015
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Four Novel PWM Shoot-Through Control Methods for Impedance Source DC-DC Converters
Vinnikov, Dmitri ; Roasto, Indrek ; Liivik, Liisa ; Blinov, Andrei ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 299~308
DOI : 10.6113/JPE.2015.15.2.299
This study proposes four novel pulse width modulation (PWM) shoot-through control methods for impedance source (IS) galvanically isolated DC-DC converters. These methods are derived from a PWM control method with shifted shoot-through introduced by the authors in 2012. In contrast to the baseline solution, where the shoot-through states are generated by the simultaneous conduction of all transistors in the inverter bridge, our new approach is based on the shoot-through generation by one inverter leg. The idea is to increase the number of soft-switched transients and, therefore, decrease the dynamic losses of the front-end inverter. All the proposed approaches are experimentally verified through an insulated-gate bipolar transistor-based IS DC-DC converter. Conclusions are drawn in accordance with the results of the switching loss analysis.
Dual-Output Single-Stage Bridgeless SEPIC with Power Factor Correction
Shen, Chih-Lung ; Yang, Shih-Hsueh ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 309~318
DOI : 10.6113/JPE.2015.15.2.309
This study proposes a dual-output single-stage bridgeless single-ended primary-inductor converter (DOSSBS) that can completely remove the front-end full-bridge alternating current-direct current rectifier to accomplish power factor correction for universal line input. Without the need for bridge diodes, the proposed converter has the advantages of low component count and simple structure, and can thus significantly reduce power loss. DOSSBS has two uncommon output ports to provide different voltage levels to loads, instead of using two separate power factor correctors or multi-stage configurations in a single stage. Therefore, this proposed converter is cost-effective and compact. A magnetically coupled inductor is introduced in DOSSBS to replace two separate inductors to decrease volume and cost. Energy stored in the leakage inductance of the coupled inductor can be completely recycled. In each line cycle, the two active switches in DOSSBS are operated in either high-frequency pulse-width modulation pattern or low-frequency rectifying mode for switching loss reduction. A prototype for dealing with an
universal line is designed, analyzed, and built. Practical measurements demonstrate the feasibility and functionality of the proposed converter.
Cost-Effective Single Switch Multi-Channel LED Driver
Hwang, Sang-Soo ; Hwang, Won-Sun ; Han, Sang-Kyoo ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 319~326
DOI : 10.6113/JPE.2015.15.2.319
In this paper, a cost-effective single switch multi-channel LED (light emitting diode) driver is proposed. While conventional LED drivers require as many non-isolated DC/DC converters as the number of LED channels, the proposed LED driver needs only one power switch and several balancing capacitors instead of expensive non-isolated DC/DC converters. Therefore, the proposed driver features a simpler structure, with a lower cost and a higher efficiency. Because its power switch can be turned off under the zero current switching condition, it has very desirable advantages such as improved electromagnetic interference characteristics and high efficiency. Moreover, it uses only a small number of DC blocking capacitors with no additional active devices for the current balancing of multi-channel LEDs. As a result, the proposed driver exhibits high reliability and is cost effective. To confirm the validity of the proposed driver, a theoretical analysis is performed, and design considerations and experimental results obtained from a prototype that is applicable to a 46" LED-TV are presented.
Design of Parallel-Operated SEPIC Converters Using Coupled Inductor for Load-Sharing
Subramanian, Venkatanarayanan ; Manimaran, Saravanan ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 327~337
DOI : 10.6113/JPE.2015.15.2.327
This study discusses the design of a parallel-operated DC-DC single-ended primary-inductor converter (SEPIC) for low-voltage application and current sharing with a constant output voltage. A coupled inductor is used for parallel-connected SEPIC topology. Generally, two separate inductors require different ripple currents, but a coupled inductor has the advantage of using the same ripple current. Furthermore, tightly coupled inductors require only half of the ripple current that separate inductors use. In this proposed work, tightly coupled inductors are used. These produce an output that is more efficient than that from separate inductors. Two SEPICs are also connected in parallel using the coupled inductors with a single common controller. An analog control circuit is designed to generate pulse width modulation (PWM) signals and to fulfill the closed-loop control function. A stable output current-sharing strategy is proposed in this system. An experimental setup is developed for a 18.5 V, 60 W parallel SEPIC (PSEPIC) converter, and the results are verified. Results indicate that the PSEPIC provides good response for the variation of input voltage and sudden change in load.
Tradeoff between the Output Voltage Deviation and Recovery Time of Boost Converters
Ge, Junjie ; Yuan, Liqiang ; Zhao, Zhengming ; Lu, Ting ; He, Fanbo ; Feng, Gaohui ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 338~345
DOI : 10.6113/JPE.2015.15.2.338
The time-optimal control for boost converters can achieve the minimum recovery time. However, their output voltage deviation is quite large. Since the minimum output voltage deviation and minimum recovery time cannot be obtained at the same time, a novel energy control is proposed to achieve a superior tradeoff between them in this paper. The peak value of the inductor current can be decreased as well. Its control parameter is easy to choose. When compared with the conventional control methods, the proposed control shows a better dynamic performance. Experimental results, which are in agreement with the theoretical analysis, are provided to verify the proposed control method.
An FPGA-Based Modified Adaptive PID Controller for DC/DC Buck Converters
Lv, Ling ; Chang, Changyuan ; Zhou, Zhiqi ; Yuan, Yubo ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 346~355
DOI : 10.6113/JPE.2015.15.2.346
On the basis of the conventional PID control algorithm, a modified adaptive PID (MA-PID) control algorithm is presented to improve the steady-state and dynamic performance of closed-loop systems. The proposed method has a straightforward structure without excessively increasing the complexity and cost. It can adaptively adjust the values of the control parameters (
) by following a new control law. Simulation results show that the line transient response of the MA-PID is better than that of the adaptive digital PID because the differential coefficient
is introduced to changes. In addition, experimental results based on a FPGA indicate that the MA-PID control algorithm reduces the recovery time by 62.5% in response to a 1V line transient, 50% in response to a 500mA load transient, and 23.6% in response to a steady-state deviation, when compared with the conventional PID control algorithm.
Single-Phase Bridgeless Zeta PFC Converter with Reduced Conduction Losses
Khan, Shakil Ahamed ; Rahim, Nasrudin Abd. ; Bakar, Ab Halim Abu ; Kwang, Tan Chia ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 356~365
DOI : 10.6113/JPE.2015.15.2.356
This paper presents a new single phase front-end ac-dc bridgeless power factor correction (PFC) rectifier topology. The proposed converter achieves a high efficiency over a wide range of input and output voltages, a high power factor, low line current harmonics and both step up and step down voltage conversions. This topology is based on a non-inverting buck-boost (Zeta) converter. In this approach, the input diode bridge is removed and a maximum of one diode conducts in a complete switching period. This reduces the conduction losses and the thermal stresses on the switches when compare to existing PFC topologies. Inherent power factor correction is achieved by operating the converter in the discontinuous conduction mode (DCM) which leads to a simplified control circuit. The characteristics of the proposed design, principles of operation, steady state operation analysis, and control structure are described in this paper. An experimental prototype has been built to demonstrate the feasibility of the new converter. Simulation and experimental results are provided to verify the improved power quality at the AC mains and the lower conduction losses of the converter.
Passive Lossless Snubbers Using the Coupled Inductor Method for the Soft Switching Capability of Boost PFC Rectifiers
Kim, Ho-Sung ; Baek, Ju-Won ; Ryu, Myung-Hyo ; Kim, Jong-Hyun ; Jung, Jee-Hoon ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 366~377
DOI : 10.6113/JPE.2015.15.2.366
In order to minimize switching losses for high power applications, a boost PFC rectifier with a novel passive lossless snubber circuit is proposed. The proposed lossless snubber is composed of coupled inductors merged into a boost inductor. This method compared with conventional methods does not need additional inductor cores and it reduces extra costs to implement a soft switching circuit. Especially, the proposed circuit can reduce the reverse recovery current of output diode rectifiers due to the coupling effect of the inductor. During turn-on and turn-off operating modes, the proposed PFC converter operates under soft switching conditions with high power conversion efficiency. In addition, the performance improvement and analysis of the operating effects of the coupled inductors were also presented and verified with a 3.3 kW prototype rectifier.
PWM-Based Sliding Mode Controller for Three-Level Full-Bridge DC-DC Converter that Eliminates Static Output Voltage Error
Liu, Jilong ; Xiao, Fei ; Ma, Weiming ; Fan, Xuexin ; Chen, Wei ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 378~388
DOI : 10.6113/JPE.2015.15.2.378
This paper proposes a pulse width modulation (PWM)-based sliding mode controller (SMC) for a full-bridge DC-DC converter that can eliminate static output voltage error. Hysteretic SMC in DC-DC converter does not have a fixed switching frequency, and applying hysteretic SMC to full-bridge converters is difficult. Fixed-frequency SMC, which is also called PWM-based SMC, based on equivalent control overcomes these shortcomings. However, the controller order reduction in equivalent control in PWM-based SMC causes static output voltage error. To resolve this issue, an integral item is added to the PWM-based SMC. Sliding mode coefficients are designed by applying a standard second-order system to the sliding mode surface. The effect of adding an integral item on the controller is analyzed, and an integral coefficient design method is proposed. Experiment results on a three-level full-bridge DC-DC converter verify the control scheme and design method proposed in this paper.
Medium Voltage Resonant Converter with Balanced Input Capacitor Voltages and Output Diode Currents
Lin, Bor-Ren ; Du, Yan-Kang ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 389~398
DOI : 10.6113/JPE.2015.15.2.389
This paper presents a 1.92 kW resonant converter for medium voltage applications that uses low voltage stress MOSFETs (500V) to achieve zero voltage switching (ZVS) turn-on. In the proposed converter, four MOSFETs are connected in series to limit the voltage stress of the power switches at half of the input voltage. In addition, three resonant circuits are adopted to share the load current and to reduce the current stress of the passive components. Furthermore, the transformer primary and secondary windings are connected in series to balance the output diode currents for medium power applications. Split capacitors are adopted in each resonant circuit to reduce the current stress of the resonant capacitors. Two balance capacitors are also used to automatically balance the input capacitor voltage in every switching cycle. Based on the circuit characteristics of the resonant converter, the MOSFETs are turned on under ZVS. If the switching frequency is less than the series resonant frequency, the rectifier diodes can be turned off under zero current switching (ZCS). Experimental results from a prototype with a 750-800 V input and a 48V/40A output are provided to verify the theoretical analysis and the effectiveness of the proposed converter.
The Development of High-Current Power Supply System for Electrolytic Copper Foil
Luo, An ; Ma, Fujun ; Xiong, Qiaopo ; He, Zhixing ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 399~410
DOI : 10.6113/JPE.2015.15.2.399
A 6.5 V/50 kA high-frequency switching power supply (HSPS) system composed of 10 power modules is developed to meet the requirements of copper-foil electrolysis. The power module is composed of a two-leg pulse width modulation (PWM) rectifier and a DC/DC converter. The DC/DC converter adopts two full-wave rectifiers in parallel to enhance the output. For the two-leg PWM rectifier, the ripple of the DC-link voltage is derived. A composite control method with a ripple filter is then proposed to effectively improve the performance of the rectifier. To meet the process demand of copper-foil electrolysis, the virtual impedance-based current-sharing control method with load current full feedforward is proposed for n-parallel DC/DC converters. The roles of load current feedforward and virtual impedance are analyzed, and the current-sharing control model of the HSPS system is derived. Virtual impedance is used to adjust the current-sharing impedance without changing the equivalent output impedance, which can effectively reduce current-sharing errors. Finally, simulation and experimental results verify the structure and control method.
Estimation of ESR in the DC-Link Capacitors of AC Motor Drive Systems with a Front-End Diode Rectifier
Nguyen, Thanh Hai ; Le, Quoc Anh ; Lee, Dong-Choon ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 411~418
DOI : 10.6113/JPE.2015.15.2.411
In this paper, a new method for the online estimation of equivalent series resistances (ESR) of the DC-link capacitors in induction machine (IM) drive systems with a front-end diode rectifier is proposed, where the ESR estimation is conducted during the regenerative operating mode of the induction machine. In the first place, a regulated AC current component is injected into the q-axis current component of the induction machine, which induces the current and voltage ripple components in the DC-link. By processing these AC signals through digital filters, the ESR can be estimated by a recursive least squares (RLS) algorithm. To acquire the AC voltage across the ESR, the DC-link voltage needs to be measured at a double sampling frequency. In addition, the ESR current is simply reconstructed from the stator currents and switching states of the inverter. Experimental results have shown that the estimation error of the ESR is about 1.2%, which is quite acceptable for condition monitoring of the capacitor.
An Improved Flux Estimator for Gap Flux Orientation Control of DC-Excited Synchronous Machines
Xu, Yajun ; Jiang, Jianguo ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 419~430
DOI : 10.6113/JPE.2015.15.2.419
Flux estimation is a significant foundation of high-performance control for DC-excited synchronous motor. For almost all flux estimators, such as the flux estimator based on phase locked loop (PLL), DC drift causes fluctuations in flux magnitude. Furthermore, significant dynamic error may be introduced at transient conditions. To overcome these problems, this paper proposes an improved flux estimator for the PLL-based algorithm. Filters based on the generalized integrator are used to avoid flux fluctuation problems caused by the DC drift at the back electromotive force. Programmable low-pass filters are employed to improve the dynamic performance of the flux estimator, and the cutoff frequency of the filter is determined by the dynamic factor. The algorithm is verified by a 960V/1.6MW industrial prototype. Simulation and experimental results show that the proposed estimator can estimate the flux more accurately than the PLL-based algorithm in a cycloconverter-fed DC-excited synchronous machine vector control system.
Analysis and Compensation Control of Dead-Time Effect on Space Vector PWM
Shi, Jie ; Li, Shihua ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 431~442
DOI : 10.6113/JPE.2015.15.2.431
Dead-time element must be set into space vector pulsed width modulation signals to avoid short circuits of the inverter. However, the dead-time element distorts the output voltage vector, which deteriorates the performance of electrical machine drive system. In this paper, dead-time effect and its compensation control strategy are analyzed. Based on the analysis, the voltage distortion caused by dead-time is regarded as two disturbances imposed on dq axes in the rotor reference frame, which degenerates the current tracking performance. To inhibit the adverse effect caused by the dead-time, a control scheme using two linear extended state observers is proposed. This method provides a strong ability to suppress dead-time effects. Simulations and experiments are conducted on a permanent magnet synchronous motor drive system to demonstrate the effectiveness of the proposed method.
A Load Compensator Based on One-Cycle Control with Plug-In Repetitive Control
Hu, Jian ; Sun, Zhaohui ; Ma, Hao ; Chen, Guozhu ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 443~454
DOI : 10.6113/JPE.2015.15.2.443
This study proposes a novel one-cycle control scheme with a plug-in repetitive controller for load compensator. The novelty of this scheme lies in the combination of high dynamics and the simplicity of a one-cycle controller and good steady-state harmonic suppression ability of the repetitive controller. In addition, the proposed scheme can reduce the effect of the harmonics in phase voltage for the existence of the repetitive controller. Finally, experimental results on a three-phase, four-wire, three-level load compensator are reported to validate the effectiveness of the proposed control scheme.
Analysis of Multi-Agent-Based Adaptive Droop-Controlled AC Microgrids with PSCAD: Modeling and Simulation
Li, Zhongwen ; Zang, Chuanzhi ; Zeng, Peng ; Yu, Haibin ; Li, Hepeng ; Li, Shuhui ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 455~468
DOI : 10.6113/JPE.2015.15.2.455
A microgrid (MG) with integrated renewable energy resources can benefit both utility companies and customers. As a result, they are attracting a great deal of attention. The control of a MG is very important for the stable operation of a MG. The droop-control method is popular since it avoids circulating currents among the converters without using any critical communication between them. Traditional droop control methods have the drawback of an inherent trade-off between power sharing and voltage and frequency regulation. An adaptive droop control method is proposed, which can operate in both the island mode and the grid-connected mode. It can also ensure smooth switching between these two modes. Furthermore, the voltage and frequency of a MG can be restored by using the proposed droop controller. Meanwhile, the active power can be dispatched appropriately in both operating modes based on the capacity or running cost of the Distributed Generators (DGs). The global information (such as the average voltage and output active power of the MG and so on) required by the proposed droop control method to restore the voltage and frequency deviations can be acquired distributedly based on the Multi Agent System (MAS). Simulation studies in PSCAD demonstrate the effectiveness of the proposed control method.
Braking Torque Closed-Loop Control of Switched Reluctance Machines for Electric Vehicles
Cheng, He ; Chen, Hao ; Yang, Zhou ; Huang, Weilong ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 469~478
DOI : 10.6113/JPE.2015.15.2.469
In order to promote the application of switched reluctance machines (SRM) in electric vehicles (EVs), the braking torque closed-loop control of a SRM is proposed. A hysteresis current regulator with the soft chopping mode is employed to reduce the switching frequency and switching loss. A torque estimator is designed to estimate the braking torque online and to achieve braking torque feedback. A feed-forward plus saturation compensation torque regulator is designed to decrease the dynamic response time and to improve the steady-state accuracy of the braking torque. The turn-on and turn-off angles are optimized by a genetic algorithm (GA) to reduce the braking torque ripple and to improve the braking energy feedback efficiency. Finally, a simulation model and an experimental platform are built. The simulation and experimental results demonstrate the correctness of the proposed control strategy.
Study on the Parameter Optimization of Soft-switching DC/DC Converters with the Response Surface Methodology, a SPICE Model, and a Genetic Algorithm
Liu, Shuai ; Wei, Li ; Zhang, Yicheng ; Yao, Yongtao ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 479~486
DOI : 10.6113/JPE.2015.15.2.479
The application of soft-switching techniques is increasing in the DC/DC converter area. It is important to design soft-switching parameters to ensure the converter operates properly and efficiently. An optimized design method is presented in this paper. The objective function is the total power loss of a converter, while the variables are soft-switching parameters and the constraints are the electrical requirements for soft-switching. Firstly, a response surface methodology (RSM) model with a high precision is built, and the rough optimized parameters can be obtained with the help of a genetic algorithm (GA) in the solution space determined by the constraints. Secondly, a re-optimization is conducted with a SPICE model and a GA, and accurate optimized parameters can be obtained. Simulation and experiment results show that the proposed method performs well in terms of a wide adaptability, efficiency, and global optimization.
An Improved Variable Step Size MPPT Algorithm Based on INC
Xu, Zhi-Rong ; Yang, Ping ; Zhou, Dong-Bao ; Li, Peng ; Lei, Jin-Yong ; Chen, Yuan-Rui ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 487~496
DOI : 10.6113/JPE.2015.15.2.487
In order to ensure that photovoltaic (PV) systems work at the maximum power point (MPP) and maximize the economic benefits, maximum power point tracking (MPPT) techniques are normally applied to these systems. One of the most widely applied MPPT methods is the incremental conductance (INC) method. However, the choice of the step size still remains controversial. This paper presents an improved variable step size INC MPPT algorithm that uses four different step sizes. This method has the advantages of INC but with the ability to validly adjust the step size to adapt to changes of the PV's power curve. The presented algorithm also simultaneously achieves increased rapidity and accuracy when compared with the conventional fixed step size INC MPPT algorithm. In addition, the theoretical derivation and specific applications of the proposed algorithm are presented here. This method is validated by simulation and experimental results.
Improved Control Strategy Based on Space Vectors for Suppressing Grid-Side Current Harmonics in Three-Phase Current Source Rectifiers with a Hybrid Switch
Xu, Yan ; Lu, Guang-Xiang ; Jiang, Li-Jie ; Yi, Gui-Ping ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 497~503
DOI : 10.6113/JPE.2015.15.2.497
This paper analyses the harmonic pollution to power grids caused by several high-power rectifiers, summarizes the requirements for rectifiers in suppressing grid-side current harmonics and optimizes a new-type of current source PWM rectifier with a hybrid switch. The rectifier with a hybrid switch boasts significant current characteristics and cost advantages in the high-power area. To further enhance the working frequency of the current source rectifier with a hybrid switch for suppressing grid-side harmonics and reducing the inductance size, this paper proposes an optimal control strategy based on space vector. It also verifies that the optimal control strategy based on space vector can reduce the total harmonic distortion of the grid-side current of the rectifier with a hybrid switch via circuit simulation and experimental results.
Switching Voltage Modeling and PWM Control in Multilevel Neutral-Point-Clamped Inverter under DC Voltage Imbalance
Nguyen, Nho-Van ; Nguyen, Tam-Khanh Tu ; Lee, Hong-Hee ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 504~517
DOI : 10.6113/JPE.2015.15.2.504
This paper presents a novel switching voltage model and an offset-based pulse width modulation (PWM) scheme for multilevel inverters with unbalanced DC sources. The switching voltage model under a DC voltage imbalance will be formulated in general form for multilevel neutral-point-clamped topologies. Analysis of the reference switching voltages from active and non-active switching voltage components in abc coordinates can enable voltage implementation for an unbalanced DC-source condition. Offset voltage is introduced as an indispensable variable in the switching voltage model for multilevel voltage-source inverters. The PWM performance is controlled through the design of two offset components in a subsequence. One main offset may refer to the common mode voltage, and the other offset restricts its effect on the quality of PWM control in related DC levels. The PWM quality can be improved as the switching loss is reduced in a discontinuous PWM mode by setting the local offset, which is related to the load currents. The validity of the proposed algorithm is verified by experimental results.
Control of Grid-Connected Inverters Using Adaptive Repetitive and Proportional Resonant Schemes
Abusara, Mohammad A. ; Sharkh, Suleiman M. ; Zanchetta, Pericle ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 518~529
DOI : 10.6113/JPE.2015.15.2.518
Repetitive and proportional-resonant controllers can effectively reject grid harmonics in grid-connected inverters because of their high gains at the fundamental frequency and the corresponding harmonics. However, the performances of these controllers can seriously deteriorate if the grid frequency deviates from its nominal value. Non-ideal proportional-resonant controllers provide better immunity to variations in grid frequency by widening resonant peaks at the expense of reducing the gains of the peaks, which reduces the effectiveness of the controller. This paper proposes a repetitive control scheme for grid-connected inverters that can track changes in grid frequencies and keep resonant peaks lined up with grid frequency harmonics. The proposed controller is implemented using a digital signal processor. Simulation and practical results are presented to demonstrate the controller capabilities. Results show that the performance of the proposed controller is superior to that of a proportional-resonant controller.
Loss Analysis and Air-Cooled Design for a Cascaded Electrical Source Transmitter
Xue, Kai-Chang ; Wang, Shuang ; Lin, Jun ; Li, Gang ; Zhou, Feng-Dao ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 530~543
DOI : 10.6113/JPE.2015.15.2.530
Air-cooling method is adopted on the basis of the requirements for the thermal stability and convenient field use of an electrical source transmitter. The power losses of the transmitter are determined after calculating the losses of the alternating current (AC)-direct current (DC) power supply, the constant-current circuit, and the output circuit. According to the analysis of the characteristics of a heat sink with striped fins and a fan, the engineering calculation expression of the Nusselt number and the design process for air-cooled dissipation are proposed. Experimental results verify that the error between calculated and measured values of the transmitter losses is 12.2%, which meets the error design requirements of less than 25%. Steady-state average temperature rise of the heat sink of the AC-DC power supply is
, which meets the design requirements of a temperature rise between
. The transmitter has favorable thermal stability with 40 kW output power.
Steady-State Analysis of ZVS and NON-ZVS Full-Bridge Inverters with Asymmetrical Control for Induction Heating Applications
Yachiangkam, Samart ; Sangswang, Anawach ; Naetiladdanon, Sumate ; Koompai, Chayant ; Chudjuarjeen, Saichol ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 544~554
DOI : 10.6113/JPE.2015.15.2.544
This paper presents a steady-state operation analysis of full-bridge series-resonant inverters focusing on the distorted load current due to low-quality-factor resonant circuits in induction heating and other applications. The regions of operation based on the zero-voltage switching (ZVS) and non-zero-voltage switching (NON-ZVS) operations of the asymmetrical voltage-cancellation control technique are identified. The effects of a distorted load current under a wide range of output powers are also analyzed for achieving a precise ZVS operating region. An experimental study is performed with a 1kW prototype. Simulation and experimental studies have confirmed the validity of the proposed method. An efficiency comparison between the variable frequency method and the conventional fixed-frequency method is provided.
LED Driver with TRIAC Dimming Control by Variable Switched Capacitance for Power Regulation
Lee, Eun-Soo ; Sohn, Yeung-Hoon ; Nguyen, Duy Tan ; Cheon, Jun-Pil ; Rim, Chun-Taek ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 555~566
DOI : 10.6113/JPE.2015.15.2.555
A TRIAC dimming LED driver that can control the brightness of LED arrays for a wide range of source voltage variations is proposed in this paper. Unlike conventional PWM LED drivers, the proposed LED driver adopts a TRIAC switch, which inherently guarantees zero current switching and has been proven to be quite reliable over its long lifetime. Unlike previous TRIAC type LED drivers, the proposed LED driver is composed of an LC input filter and a variable switched capacitance, which is modulated by the TRIAC turn-on timing. Thus, the LED power regulation and dimming control, which are done by a volume resistor in the same way as the conventional TRIAC dimmers, can be simultaneously performed by the TRIAC control circuit. Because the proposed LED driver has high efficiency and a long lifetime with a high power factor (PF) and low total harmonic distortion (THD) characteristics, it is quite adequate for industrial lighting applications such as streets, factories, parking garages, and emergency stairs. A simple step-down capacitive power supply circuit composed of passive components only is also proposed, which is quite useful for providing DC power from an AC source without a bulky and heavy transformer. A prototype 60 W LED driver was implemented by the proposed design procedure and verified by simulation and experimental results, where the efficiency, PF, and THD are 92%, 0.94, and 6.3%, respectively. The LED power variation is well mitigated to below
for 190 V <
< 250 V by using the proposed simple control circuit.
An Improved Topology for the Current Fed Parallel Resonant Half Bridge Circuits Used in Fluorescent Lamp Electronic Ballasts
Wang, Qingsong ; Cheng, Ming ; Zhang, Bing ;
Journal of Power Electronics, volume 15, issue 2, 2015, Pages 567~575
DOI : 10.6113/JPE.2015.15.2.567
An improvement in the current fed parallel resonant half bridge (CFPRHB) circuits used in fluorescent lamp electronic ballasts is provided in this paper. The CFPRHB belongs to the self-oscillating family which includes the current fed push-pull and series resonant inverters, most of which are used in instant-start applications. However, many failure modes are related to the bypass capacitor according to an analysis of failed samples. In this paper, the operating functions of the existing topology in the steady state are analyzed and the main root cause of failure modes has been found. Comparisons between the two topologies are conducted in terms of the voltage stress of the bypass capacitor as well as the thermal and performance of the ballasts to verify the advantages of the proposed topology. It is found that the improved topology is capable of enhancing the reliability and reducing the cost of products without having a negative influence on the system performance.