共查询到20条相似文献,搜索用时 15 毫秒
1.
Ortuzar M.E. Carmi R.E. Dixon J.W. Moran L. 《Industrial Electronics, IEEE Transactions on》2006,53(2):477-485
A new topology for active power filters (APF) using an 81-level converter is analyzed. Each phase of the converter is composed of four three-state converters, all of them connected to the same capacitor dc link voltage and their output connected in series through output transformers. The main advantages of this kind of converter are the negligible harmonic distortion obtained and the very low switching frequency operation. The single-phase equivalent circuit is analyzed and their governing equations derived. The dc link voltage control, based on manipulating the converter's voltage phase, is analyzed together with the circuit's characteristics that determine the capability to draw or deliver active and reactive current. Simulation results for this application are compared with conventional pulsewidth-modulated (PWM) converters, showing that this filter can compensate load current harmonics, keeping better-quality sinusoidal currents from the source. The simulated configuration uses a 1-F ultracapacitor in the dc link, making it possible to store energy and deliver it during short voltage dips. This is achieved by applying a modulation control to maintain a stable ac voltage during dc voltage drops. A prototype of the filter was implemented and tested, and the obtained current waveforms showed to be as good as expected. 相似文献
2.
A Modular Strategy for Control and Voltage Balancing of Cascaded H-Bridge Rectifiers 总被引:1,自引:0,他引:1
《Power Electronics, IEEE Transactions on》2008,23(5):2428-2442
3.
Feel-Soon Kang Sung-Jun Park Man Hyung Lee Cheul-U Kim 《Industrial Electronics, IEEE Transactions on》2005,52(6):1600-1606
This paper presents an efficient multilevel-synthesis scheme and its application to a 27-level inverter. In the proposed multilevel scheme, this can be realized by an array of switching devices composing full-bridge inverter modules and proper mixing of each transformer terminal voltage. The most different aspect, compared to the conventional approach, in the synthesis of the multilevel output waveform is the utilization of a combination of transformers rather than the accumulation of capacitor voltage sources. A 27-level inverter consists of three full-bridge modules and their corresponding transformers. Quasi-sinusoidal voltage waves can be generated from a suitable selection of the turns ratio of the transformer. The validity of the proposed system is verified by computer-aided simulation and experimental results using a 500-W prototype, which can generate a 110-V ac output voltage from a 12-V dc input. 相似文献
4.
《Industrial Electronics, IEEE Transactions on》2009,56(7):2513-2521
5.
Rotella M. Penailillo G. Pereda J. Dixon J. 《Industrial Electronics, IEEE Transactions on》2009,56(1):194-201
A nonredundant three-stage 27-level inverter using ldquoHrdquo converters is analyzed for medium- and high-power machine drive applications. The main advantage of this converter is the optimization of levels with a minimum number of semiconductors. However, the system needs six bidirectional and isolated power supplies and three more unidirectional if the machine is not using regenerative braking. In this paper, these nine power supplies are reduced to only four, all of them unidirectional, using three strategies: 1) the utilization of independent and isolated windings for each phase of the motor; 2) the utilization of independent input transformers; and 3) the most important of them, the application of special pulsewidth modulation (PWM) strategies on the 27-level converter, to keep positive average power at the medium power bridges and zero average power at the low-power bridges. The generation of this PWM and control of this multiconverter was implemented using DSP controllers, which give flexibility to the system. 相似文献
6.
Static Var Compensator and Active Power Filter With Power Injection Capability, Using 27-Level Inverters and Photovoltaic Cells 总被引:1,自引:0,他引:1
《Industrial Electronics, IEEE Transactions on》2009,56(1):130-138
An active power filter and static var compensator with active power generation capability has been implemented using a 27-level inverter. Each phase of this inverter is composed of three ldquoHrdquo bridges, all of them connected to the same dc link and their outputs connected through output transformers scaled in the power of three. The filter can compensate load currents with a high harmonic content and a low power factor, resulting in sinusoidal currents from the source. To take advantage of this compensator, the dc link, instead of a capacitor, uses a battery pack, which is charged from a photovoltaic array connected to the batteries through a maximum power point tracker. This combined topology make it possible to produce active power and even to feed the loads during prolonged voltage outages. Simulation results for this application are shown, and some experiments with a 3-kVA device are displayed. 相似文献
7.
In-Dong Kim Eui-Cheol Nho 《Industrial Electronics, IEEE Transactions on》2005,52(1):181-189
Cathodic protection is widely used to prevent corrosion of steel materials buried underground and in seawater. As a rectifier for cathodic protection, the conventional phase-controlled rectifiers with 50- or 60-Hz isolation transformers have been used so far in spite of such shortcomings as large volume, heavy weight, and poor power factor. In order to overcome such disadvantages, this paper proposes a new module-type switching rectifier for cathodic protection, which is composed of two parts, namely, ac/dc converter and module-type dc/dc converter. The ac/dc converter is a single-phase insulated gate bipolar transistor pulsewidth-modulation rectifier, thus resulting in almost unity power factor and controlled dc output voltage. The module-type dc/dc converter operates under zero-voltage switching/zero-current switching condition to permit high-frequency switching operation. It enables the use of a high-frequency transformer for electrical isolation, thus reducing volume and weight of the overall system and improving system efficiency. It is anticipated that the proposed rectifier techniques will apply to the similar technical areas such as multiple-module power supply systems and modular converter-fed dc motor drives. 相似文献
8.
This paper discusses a transformerless hybrid active filter integrated into the 6.6-kV, 1-MW adjustable-speed motor drive having a three-phase diode rectifier at the front end. The hybrid filter consists of an active filter using a three-level diode-clamped pulsewidth modulator converter rated at 60 kVA, and a 250-kVA passive filter tuned to the seventh harmonic frequency. They are directly connected in series without a transformer. This circuit configuration enables one to use 1.2-kV insulated gate bipolar transistors because the dc voltage of the three-level converter is 1.32 kV (20% of 6.6 kV). Voltage balancing control characterized by superimposing a sixth harmonic zero-sequence voltage on the active filter voltage reference in each phase is introduced to the three-level converter with triangle carrier modulation. Experimental waveforms obtained from a 400-V, 15-kW downscaled system verify the viability and effectiveness of the proposed hybrid filter, keeping the two dc capacitor voltages well-balanced. 相似文献
9.
Regenerative medium-voltage AC drive based on a multicell arrangement with reduced energy storage requirements 总被引:1,自引:0,他引:1
Perez M.A. Espinoza J.R. Rodriguez J.R. Lezana P. 《Industrial Electronics, IEEE Transactions on》2005,52(1):171-180
Multicell power circuit topologies have proved to be an effective alternative to medium-voltage ac drives. The main advantage is the improved power quality at both the ac system and the motor sides. However, several drawbacks are present in these configurations, such as a lack of sustained regenerative operating mode, uncontrolled input reactive power, and a large second current harmonic that is injected by the load into the dc link of each cell, which leads to a bulky electrolytic capacitor. This paper proposes to replace the input diode-based front-end rectifier with an active front-end rectifier in all cells of the topology and a novel control strategy in order to overcome the aforementioned drawbacks. In fact, the active front-end rectifier allows the topology to regenerate and the control strategy handles the reactive input power and reduces the large second current harmonic from the dc-link capacitor, thus reducing its size. These features are achieved without any penalties in the quality of both the ac input current and the motor voltage waveforms. Experimental results confirm the theoretical considerations. 相似文献
10.
11.
A simple analog controller is proposed for the single-phase half-bridge pulsewidth modulation rectifier to maintain near unity power factor at the input and balance the voltages across each half of the dc bus. The controller works in the principle of constant-frequency current programmed control. The required gating pulses are generated by comparing the input current with a linear and bipolar carrier without sensing the input voltage. Two voltage controllers and a single reset-integrator are used to generate the carrier. All the necessary control operations are performed without using any phase locked loop, multiplier, and/or divider circuits. Resistor based sensors are used to measure the voltages across two halves of the dc bus and the input current. The controller can be fabricated as a single integrated circuit. The averaged small signal models and all the necessary design equations are provided. The condition of stability against subharmonic oscillation is analyzed. Calculation of switching and conduction losses is presented. The control concept is validated through simulation and also experimentally on an 800-W half-bridge rectifier. Experimental results are presented for ac-dc application, and also for ac-dc-ac application with both linear and nonlinear loads at two different output fundamental frequencies (50 and 60Hz) 相似文献
12.
13.
移相全桥零电压开关变换器是中大功率直直变换场合的理想拓扑之一,但其次级整流二极管反向恢复时,产生严重的寄生振荡,二极管上存在很高的尖峰电压。而文献1中的变换器通过增加一个谐振电感和两个二极管,不仅可以实现软开关,还可以消除次级整流二极管反向恢复引起的电压振荡。基于此变换器的工作原理,文中设计了一台500W移相控制零电压软开关电源,给出了主电路的设计过程和实验波形。 相似文献
14.
A Complete Harmonic Elimination Approach to DC Link Voltage Balancing for a Cascaded Multilevel Rectifier 总被引:1,自引:0,他引:1
Watson A.J. Wheeler P.W. Clare J.C. 《Industrial Electronics, IEEE Transactions on》2007,54(6):2946-2953
This paper presents a complete method that is used to balance dc link voltages in a cascaded H-Bridge (CHB) multilevel rectifier. Recently, such converters have been the subject of extensive research due to their suitability for high-power applications. One requirement in using a multilevel active rectifier at high levels of power is to limit the switching losses by reducing the switching frequency to a minimum. Another requirement for these converters is to ensure that individual dc link capacitor voltages for each cell of the converter are always balanced to ensure controllability and to limit stress on the converter cells. This paper presents a complete method in solving both of these problems using a selective-harmonic-elimination pulsewidth-modulation scheme. The scheme utilizes a simple controller to track each cell dc link capacitor voltage magnitude and accordingly biases the power flowing into each cell to ensure that the voltages across each cell capacitor converge. This is the case even when the loads attached to the individual cells are not balanced. The theory is supported by both simulated results from Saber and by experimental results from a seven-level CHB single-phase multilevel rectifier. 相似文献
15.
This paper describes the conception and analysis of a unidirectional hybrid three-phase rectifier suitable for medium- and high-power applications. The rectifier is composed of a single-switch diode bridge boost-type rectifier in parallel with a pulsewidth modulation (PWM) three-phase unidirectional boost rectifier. The objective is to obtain a structure capable of providing sinusoidal input currents with low harmonic distortion and dc output voltage regulation. The diode rectifier operates at low frequency and has a higher output power rating. Therefore, the PWM unidirectional rectifier is designed to operate with a small power rating and at a high switching frequency. The total harmonic distortion of the proposed structure varies between 0% and 32%, depending only on the amount of power processed by the PWM three-phase unidirectional rectifier. The rectifier topology conception, principle of operation, control scheme, and simulation and experimental results of a 20-kW laboratory prototype are also presented in this paper. 相似文献
16.
A Three-Phase Current-Fed DC/DC Converter With Active Clamp for Low-DC Renewable Energy Sources 总被引:1,自引:0,他引:1
《Power Electronics, IEEE Transactions on》2008,23(6):2784-2793
17.
Daniel Flores Cortez Marcello C. Maccarini Samir A. Mussa Ivo Barbi 《International Journal of Electronics》2013,100(5):821-839
In this paper, a single-phase unity power factor rectifier, based on a hybrid boost converter, resulting from the integration of a conventional dc–dc boost converter and a switched-capacitor voltage doubler is proposed, analysed, designed and tested. The high-power rectifier is controlled by two feedback loops with the same control strategy employed in the conventional boost-based rectifier. The main feature of the proposed rectifier is its ability to output a dc voltage larger than the double of the peak value of the input line voltage, while subjecting the power switches to half of the dc-link voltage, which contributes to reducing the cost and increasing the efficiency. Experimental data were obtained from a laboratory prototype with an input voltage of 220 Vrms, line frequency of 60 Hz, output voltage of 800 Vdc, load power of 1000 W and switching frequency of 50 kHz. The efficiency of the prototype, measured in the laboratory, was 96.5% for full load and 97% for half load. 相似文献
18.
《Industrial Electronics, IEEE Transactions on》2009,56(6):2005-2014
19.
Feed-Forward Space Vector Modulation for Single-Phase Multilevel Cascaded Converters With Any DC Voltage Ratio 总被引:1,自引:0,他引:1
《Industrial Electronics, IEEE Transactions on》2009,56(2):315-325
20.
《Power Electronics, IEEE Transactions on》2006,21(5):1243-1252
This paper presents a zero-voltage switching (ZVS) two-transformer full-bridge (TTFB) pulsewidth modulation (PWM) converter with lossless diode-clamp rectifier for a plasma display panel sustaining power module (PSPM). The TTFB converter has series-connected two transformers which act as an output inductor as well as a main transformer. Although the naturally doubled leakage inductor due to the series-connected two transformers contributes to achieve the ZVS of the lagging leg, it creates a serious voltage ringing across the output rectifier diodes. This results in the heavy voltage stresses across the rectifier diodes. Thus the dissipative snubber circuits are required in spite of the severe power dissipation. To overcome these problems, a new lossless diode-clamp rectifier (LDCR) is employed as the output rectifier, which helps the voltage across rectifier diodes to be clamped at one half the output voltage ($V_o/$ 2) or a full output voltage$(V_o)$ . Therefore, no dissipative snubber circuits for the rectifier diodes are needed and a high efficiency as well as a low noise output voltage can be realized. In addition, the clamping capacitors of the LDCR can help considerably to reduce the primary circulating current. The operations, analysis, and design consideration of proposed converter are presented. Also, a 425-W, 385-$V_ dc$ input, 170-$V_ dc$ output prototype is constructed and experimental results show the validity of the proposed converter. 相似文献