共查询到20条相似文献,搜索用时 15 毫秒
1.
Burgos R.P. Wiechmann E.P. Holtz J. 《Industrial Electronics, IEEE Transactions on》2005,52(2):363-377
This paper presents the modeling and control of active front-end (AFE) converters using complex state-space representation, a technique developed and thus far mostly employed for the analysis of ac machines. Particularly, three-phase PWM voltage-source and current-source rectifiers are thoroughly studied using the graphical capabilities of this approach, namely, complex signal flow graphs. These are used to directly and intuitively derive high-performance nonlinear control laws based on input-output feedback linearization. Specifically, a cascaded and a paralleled control scheme are investigated for the voltage-source rectifier, whereas a cascaded scheme is considered for the current-source rectifier. Under these strategies both converters exhibit linear and decoupled d-q axes dynamics, while also attaining a reactive power compensation capacity. Moreover, linearization of their respective dc-link voltage and current loops utterly enforces and ensures their operating stability. All this is achieved without the elaborate mathematical complexity of input-output linearization, effectively shunned out by the proposed complex state-space approach. Finally, experimental results from 5-kVA digital-signal-processor-based laboratory prototypes verify the analysis and downright performance evinced by these AFE converters. 相似文献
2.
3.
Quasi-square-wave converters: topologies and analysis 总被引:2,自引:0,他引:2
A class of converters with zero-voltage or zero-current switching characteristics is analyzed using a method originally developed for quasiresonant and PWM (pulsewidth-modulated) converters. The method relies on identifying simple three-terminal structures, called converter sections, that contain the switches and the resonant tank elements. The various zero-voltage-switched and zero-current-switched converters are obtained by permutation of these converter sections between source and sink. The method unifies the analysis of this class of converters in a single equivalent circuit model. The voltage and current waveforms in these converters are essentially squarelike except during the turn-on and turn-off switching intervals 相似文献
4.
Small-signal analysis and control design of asymmetrical half-bridge DC-DC converters 总被引:1,自引:0,他引:1
Choi B. Lim W. Sanghyun Bang Seungwon Choi 《Industrial Electronics, IEEE Transactions on》2006,53(2):511-520
This paper presents the small-signal modeling, dynamic analysis, and control design of the asymmetrical half-bridge dc-dc converter that employs a clamp capacitor and a magnetizing inductor to accommodate pulsewidth-modulated operation with asymmetrical duty ratios. The circuit averaging technique is applied to extract the small-signal dynamics of the power stage, and a graphical loop-gain method is used to design the feedback compensation and analyze the closed-loop performance of the converter. The distinctive power-stage dynamics of the converter are addressed and design guidelines for voltage feedback compensation are established. The results of the control design and closed-loop analysis are substantiated by experiments using an experimental converter. 相似文献
5.
6.
This paper deals with small-signal analysis of DC-D converters with sliding mode control. A suitable small signal model is developed which allows selection of control coefficients, analysis of parameter variation effects, characterization of the closed loop behavior in terms of audiosusceptibility, output and input impedances, and reference to output transfer function. Unlike previous analyses, the model includes effects of the filters used to evaluate state variable errors. Simulated and experimental results demonstrate model potentialities 相似文献
7.
This paper presents a survey on Nonlinear Analog-to-Digital converters (ADC). This class of converters is extremely relevant in applications where there is a need for non-uniform quantization characteristic, for example, some specific applications in the areas of light detection, hearing aid, nuclear physics, image acquisition, communication systems, etc. This survey outlines the state-of-the-art Nonlinear ADC topologies, such as, floating point, logarithmic, piecewise linear and oversampled nonlinear converters, and discusses their performance and advantages in terms of their applications. 相似文献
8.
Comprehensive analyses for the buck-boost, pulse width modulation DC/DC converters applying peak current current-mode control are given. The analysis provides closed-form solutions for steady-state output, small-signal loop gain, and conducted susceptibility. It also proves that the state-space averaged model developed for converter using a single-loop voltage-mode control is valid for a current-mode-controlled converter. 相似文献
9.
Switching power converters operating in a multistate switching mode (more than two states) feature multidimensional control over their state variables. In this paper, a large-signal multistate modeling method is developed based on the switching flow-graph method to study the steady-state and dynamic properties of pulse-width-modulated (PWM) multistate-switching power converters for the continuous conduction mode. This modeling method translates a switching power converter directly to its graphic dynamic model and uses graphical representation to reveal the cause and effect relationship of the dynamics within a multidimensional power converter. A three-state buck-boost circuit is conceived with two duty ratios controlling two outputs as an example to test this modeling method. Experimental results confirm the theoretical prediction. This multistate-switching flow-graph modeling method is very general, easy to use and accurate, and it provides deep physical insight for engineering design 相似文献
10.
Constant-frequency control of quasi-resonant converters 总被引:1,自引:0,他引:1
An additional independent control needed to eliminate the undesirable variable switching frequency of quasi-resonant (QR) converters is obtained by replacing the output rectifier by an active switch. The concept is applicable to all classes of converters. Compared to QR converters with conventional switch realization, constant-frequency quasi-resonant (CF-QR) converters exhibit the same type of switching transitions and similar switch voltage and current stresses. Advantages of CF-QR converters are not restricted to the constant-frequency control. In all classes, operation at zero load is possible, so that the available load range is unlimited. The range of attainable, conversion ratios is significantly extended in the classes of zero-voltage quasi-square-wave (CF-ZV-QSW) and zero-voltage multiresonant (CF-ZV-MR) topologies. A practical design example of a 25 W CF-ZV-MR buck converter is constructed and evaluated. The converter operates at 2 MHz from zero load to full load, with a full-load efficiency of 83%. Simple duty ratio control is used to maintain the output voltage constant for all loads. The circuit is inherently immune to the short-circuit condition at the output. Disadvantages of CF-QR converters are the increased gate-drive losses and increased complexity of the power stage and the control circuitry 相似文献
11.
Multi-loop control for quasi-resonant converters 总被引:2,自引:0,他引:2
Ridley R.B. Tabisz W.A. Lee F.C.Y. Vorperian V. 《Power Electronics, IEEE Transactions on》1991,6(1):28-38
A multiloop control scheme for quasi-resonant converters (QRCs) is described. Like current-mode control for pulse width modulation (PWM) converters, this control offers excellent transient response and replaces the voltage-controlled oscillator (VCO) with a simple comparator. In this method, referred to as current-sense frequency modulation (CSFM), a signal proportional to the output-inductor current is compared with an error voltage signal to modulate the switching frequency. The control can be applied to either zero-voltage-switched (ZVS) or zero-current-switched (ZCS) QRCs. Computer simulation is method applied to a ZCS buck QRC. A circuit implementation is presented that allows multiloop control to be used on circuits switching up to 10 MHz. This circuit requires few components and produces clean control waveforms. Experimental results are presented for zero-current flyback and zero-voltage buck QRCs, operating at up to 7 MHz. Good small-signal characteristics have been obtained 相似文献
12.
One-cycle control of switching converters 总被引:25,自引:0,他引:25
A new large-signal nonlinear control technique is proposed to control the duty-ratio d of a switch such that in each cycle the average value of a switched variable of the switching converter is exactly equal to or proportional to the control reference in the steady-state or in a transient. One-cycle control rejects power source perturbations in one switching cycle; the average value of the switched variable follows the dynamic reference in one switching cycle; and the controller corrects switching errors in one switching cycle. There is no steady-state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with a constant frequency buck converter have demonstrated the robustness of the control method and verified the theoretical predictions. This new control method is very general and applicable to all types of pulse-width-modulated, resonant-based, or soft-switched switching converters for either voltage or current control in continuous or discontinuous conduction mode. Furthermore, it can be used to control any physical variable or abstract signal that is in the form of a switched variable or can be converted to the form of a switched variable 相似文献
13.
《Circuits and Devices Magazine, IEEE》1993,9(2):36-37
An improved design for a switched-capacitor pulsewidth modulated (PWM) DC-DC converter with adjustable conversion ratios is presented. The converter provides a nominal power of 40 W and nominal voltage conversion ratio of 12/5. The same structure can provide other conversion ratios, as required. Such low power supplies use relatively small, low-value capacitors, and could conceivably be realized with IC technology 相似文献
14.
Performance analysis of variable optical delay circuit using highly nonlinear fiber parametric wavelength converters 总被引:1,自引:0,他引:1
Sakamoto T. Okada A. Moriwaki O. Matsuoka M. Kikuchi K. 《Lightwave Technology, Journal of》2004,22(3):874-881
The performance of a variable optical delay circuit that employs a fiber loop with highly nonlinear fiber parametric wavelength converters is discussed using both experiments and simulations. In our optical delay circuit, the delay time is determined from the number of circulations, which is controlled by the initially selected wavelength of the optical signal. We discuss the factors that limit the number of circulations described in our previous paper, derive the parameters that provide good performance levels, and confirm the performance by simulation. The simulated results indicate that 100 wavelength conversions can be achieved, namely, 100 different delay times can be given to optical packets. 相似文献
15.
Gateau G. Fadel M. Maussion P. Bensaid R. Meynard T.A. 《Industrial Electronics, IEEE Transactions on》2002,49(5):998-1008
The multicell converters introduced more than ten years ago make it possible to distribute the voltage constraints among series-connected switches and to improve the output waveforms (increased number of levels and apparent frequency). The balance of the constraints requires an appropriate distribution of the flying voltages. This paper presents some solutions for the active control of the voltages across the flying capacitors in the presence of rapid variation of the input voltage. The latter part of this paper is dedicated to the observation of these voltages using an original modeling of the converter. 相似文献
16.
Quasi-linear modeling and control of DC-DC converters 总被引:2,自引:0,他引:2
A quasi-linear approach is proposed for modeling and control of DC-DC power converters. The method presented is derived by perturbing an approximate large signal equation around a varying operating point in a reduced variable space. This differs from the usual practice of applying the perturbation technique around a fixed operating condition. In the proposed algorithm, the control equation and the control parameter are constantly adjusted according to environmental changes to meet the specified dynamical requirement 相似文献
17.
Jong-Lick Lin Chun-Hsiao Hsia 《IEEE transactions on circuits and systems. I, Regular papers》2005,52(9):1919-1927
In this paper, the small-signal mathematical model of a zero-current-zero-voltage-transition (ZCZVT) soft-switching boost power converter is proposed. It shows that the ZCZVT boost converter exhibits better dynamic behavior than the conventional pulsewidth modulated boost converter. The input-to-output voltage conversion ratio of the ZCZVT soft-switching converters lies in a range which is related to the load. Based on the derived model, a classical controller and a modified integral variable structure controller are designed to achieve output voltage regulation and line voltage disturbance rejection. The experimental results regarding converters performances for two controllers are compared by experimental results. 相似文献
18.
19.
This paper deals with control and design of quasi-direct converters, i.e. AC/AC converters including a forced-commutated rectifier, an inverter, and a small filter in the DC link. Converter performance can be optimized by means of a predictive digital control strategy, which ensures instantaneous input-output power balance, fast response, and high power factor. After a discussion of the control strategy, the paper gives design criteria of both power and control sections. Experimental results of a 2.5-kVA prototype are reported 相似文献
20.
Modeling of chaotic DC-DC converters by iterated nonlinear mappings 总被引:22,自引:0,他引:22
In parameter ranges where conventional methods break down, DC-DC converters may be described by iterated mappings, a nonlinear discrete modeling technique. The underlying principles are explained and are applied to the example of a PWM-controlled buck converter. Stable behavior and bifurcations to chaos are predicted by numerical evaluation of the governing mapping and are confirmed by experiment 相似文献