排序方式: 共有51条查询结果,搜索用时 15 毫秒
1.
A new hybrid active power filter (APF) topology 总被引:12,自引:0,他引:12
In this paper, a new hybrid active power filter topology is presented. A higher-voltage, low-switching frequency insulated gate bipolar transistor (IGBT) inverter and a lower-voltage high-switching frequency metal oxide semiconductor field effect transistor (MOSFET) inverter are used in combination to achieve harmonic current compensation. The function of the IGBT inverter is to support utility fundamental voltage and to compensate for the fundamental reactive power. The MOSFET inverter fulfills the function of harmonic current compensation. To further reduce cost and to simplify control, the IGBT and MOSFET inverters share the same DC-link via a split capacitor bank. With this approach harmonics can be cancelled over a wide frequency range. Compared to the conventional APF topology, the proposed approach employs lower dc-link voltage and generates less noise. Simulation and experimental results show that the proposed active power filter topology is capable of compensating for the load harmonics 相似文献
2.
W. Choi P. N. Enjeti J. W. Howze G. Joung 《Journal of Materials Engineering and Performance》2004,13(3):257-264
In this article, an impedance model of the proton exchange membrane fuel cell stack (PEMFCS) is proposed. The proposed study
employs an equivalent circuit of the PEMFCS derived by the frequency response analysis technique. An equivalent circuit for
the PEMFCS is developed to evaluate the effects of ripple currents generated by the power-conditioning unit. The calculated
results are then verified by means of experiments using a commercially available PEMFCS. The relationship between ripple current
and fuel cell performance, such as power loss and fuel consumption, is investigated. Experimental results show that the ripple
current can contribute up to a 6% reduction in the available output power.
This paper was presented at the Fuel Cells: Materials, Processing, and Manufacturing Technologies Symposium sponsored by the
Energy/Utilities Industrial Sector & Ground Transportation Industrial Sector and the Specialty Materials Critical Technologies
Sector at the ASM International Materials Solutions Conference, October 13–15, 2003, in Pittsburgh, PA. The symposium was
organized by P. Singh, Pacific Northwest National Laboratory, S.C. Deevi, Philip Morris USA, T. Armstrong, Oak Ridge National
Laboratory, and T. Dubois, U.S. Army CECOM. 相似文献
3.
In this paper, a new three-phase power-factor correction (PFC) scheme is proposed using two single-phase PFC modules. In this approach, the "three" phase input is first transformed to "two" phase by means of a 0.14-pu-rated autotransformer. Two standard single-phase PFC modules are then employed to process the "two" phase power to DC output. Split inductors and diodes are employed to limit interaction between the two PFC stages. Due to cascade operation of two PFC stages, low-frequency (120 Hz) ripple in the DC-link capacitor is cancelled. Detailed analysis and simulation results are presented. A 220-V 1.5-kVA design example along with experimental results is shown 相似文献
4.
Duran-Gomez J.L. Enjeti P.N. von Jouanne A. 《Industry Applications, IEEE Transactions on》2002,38(2):514-522
Adjustable-speed drives under short-term power interruptions can interrupt a critical process. In this paper, an approach to provide ride-through with flyback converter modules powered by super capacitors is explored. The proposed approach is modular and facilitates additional modules to be added to suit higher voltage/power ratings. Both unidirectional and bidirectional flyback DC/DC converter topologies are examined. Simulation and experimental results are presented 相似文献
5.
von Jouanne A. Rendusara D.A. Enjeti P.N. Gray J.W. 《Industry Applications, IEEE Transactions on》1996,32(4):919-926
In this paper, filtering techniques are investigated to reduce the motor terminal overvoltage, ringing, and dv/dt in inverter-fed AC motor drive systems where long leads are required. Analysis is presented to show that the distributed LC of a cable and the pulse-width modulated (PWM) inverter switching action lead to motor terminal voltage reflections and ringing that stress the turn insulation and contribute to bearing currents. First- and second-order shunt filter designs are analyzed and compared. Detailed design equations to match the filter impedance to the cable surge impedance and to determine the filter component values are presented. It is demonstrated that a first-order shunt filter connected at the motor terminals significantly reduces the overvoltage stress and ringing, and also lowers the dv/dt of the PWM switching pulse. Simulation and experimental results are presented to verify the proposed filter designs for 50-ft and 100-ft cable lengths for 460-V PWM insulated gate bipolar transistor (IGBT) AC motor drive systems 相似文献
6.
A general analysis procedure for a static power converter using the transfer function approach is presented. This method provides for closed-form expressions for all harmonics under balanced and unbalanced operating conditions. Unbalance in voltage magnitude and phase angle and errors in switching angles can be easily incorporated into the analysis. An example illustrating the effectiveness of this approach is given 相似文献
7.
Fuel cell stacks produce a dc output with a 2:1 voltage variation from no load to full load. It is customary for a utility-scale fuel cell stack to consist of several hundreds of series-connected cells, each producing 0.6 V at full load. A power conditioner consisting of dc-dc and dc-ac converters is required for utility interface, which are operated in high frequency, employing pulsewidth-modulation control for voltage and current regulation. Due to their switch-mode nature, a common-mode voltage with respect to ground is generated. The common-mode voltage, in turn, contributes to the circulating ground current, which can interfere with the ground fault protection system. In addition, it also contributes to the neutral shift and electromagnetic interference. Moreover, the electrostatic potential to ground within the fuel cell stack needs to be limited for safe operation. This paper presents an analysis of common-mode voltage in several fuel-cell-powered converter topologies connected to the electric utility and discusses several mitigation methods suitable for utility-scale generation. 相似文献
8.
A transformer performs many functions such as voltage transformation, isolation and noise decoupling, and it is an indispensable component in electric power distribution systems. However, at low frequencies (60/50 Hz), it is a bulky and expensive component. In this paper, the concept of electronic transformers is further extended and explored for its suitability in power distribution systems. It should be noted that from the input/output behavior, the electronic transformer and the conventional transformer are identical. Possible topologies employing static converters connected on the primary and secondary sides are explored to realize high-frequency operation of the magnetic core. To assist the commutation process, a four-step switching has been developed which does not require the use of snubbers. Reduced size, losses, higher efficiency, and better voltage regulation are some of the advantages of this approach. A 10 kVA design example along with experiment results are discussed. It is shown that a transformer designed with a conventional grain-oriented silicon-steel core can process three times the power at 1 kHz operating frequency as compared to 60 Hz. The proposed method is scalable in voltage/current with the currently available insulated gate bipolar transistor (IGBT) devices connected in series without special snubbers 相似文献
9.
von Jouanne A. Enjeti P.N. Banerjee B. 《Industry Applications, IEEE Transactions on》1999,35(4):908-916
Adjustable-speed drive (ASD) ride-through issues have caused increased concerns due to the susceptibility of ASDs to power disturbances, and the costly results of process disruptions. These losses can be avoided for critical production processes by using ASDs with ride-through capabilities. This paper assesses industrial ride-through requirements through power quality surveys and the results of an ASD ride-through questionnaire conducted by the authors. ASD ride-through alternatives are evaluated based on design, implementation and cost considerations, in order to determine the most suitable solutions for various kilovoltampere ratings and time duration requirements 相似文献
10.
A three-phase current-fed dc/dc converter with a three-leg high frequency transformer for fuel cells
In this paper, a three-phase current-fed dc/dc converter with an active clamp is introduced, and a new three-phase three-leg high frequency transformer is proposed for the converter. The three-phase dc/dc converter transfers power through transformer leakage inductances in the discontinuous current mode; a single common active clamp branch is employed for zero-voltage switching (ZVS) in all active switches. Further, the converter's three-phase power configuration increases power transfer, and it reduces the rms current per phase, thus reduces conduction losses. Moreover, a delta–delta connection on the three-phase transformer provides parallel current paths and reduces conduction losses in the transformer windings. A three-phase transformer can be constructed by connecting three discrete single-phase transformers, but this process results in a higher volume and higher material costs. Therefore, a new three-phase three-leg high frequency transformer is designed with three discrete cores integrated into a single transformer core. The proposed transformer is analyzed according to the several operating modes of the converter, and its design rules are determined. Experimental results are obtained on a 500-W prototype unit; the design is fully verified and analyzed. 相似文献