This paper presents the development, analysis, and performance evaluation of a new topology for an isolated dc power electronic converter (PEC). The proposed topology (called the reverse flyback dc ...PEC ) is developed to process a discontinuous input voltage and produce a continuous output voltage. The reverse flyback dc PEC is operated based on charging the inductive element in the high-frequency transformer, while discharging the energy to the output side through on - off actions of the switching element, which is located on the secondary side of the high-frequency transformer. A prototype for the proposed reverse flyback dc PEC is constructed to evaluate its performance under different operating conditions. Performance results show that the reverse flyback dc PEC is capable of processing discontinuous input voltages with different duty ratios and maintaining continuous output voltages with a minor sensitivity to the load type of ratings.
This paper presents the development, analysis, and performance evaluation of a new topology for an isolated dc power electronic converter (PEC). The proposed topology (called the reverse fly-back dc ...PEC) is developed to process a discontinuous input voltage and produce a continuous output voltage. The reverse fly-back dc PEC is operated based on charging the inductive element in the high-frequency transformer, while discharging the energy to the output side through On-Off actions of the switching element, which is located on the secondary side of the high-frequency transformer. The proposed reverse fly-back dc PEC is tested for its performance under different operating conditions. Performance results show that the reverse fly-back dc PEC is capable of processing discontinuous input voltages with different duty ratios, and maintain continuous output voltages with a minor sensitivity to the load type of ratings.
Methods and a circuit implementation of audible noise reduction (ANR) in switch-mode converters with variable switching frequency are presented. The audible noise caused by magnetic components is ...reduced by controlling the switching frequency so that it remains above the audible range as the load decreases. This is accomplished by decreasing the peak value of the main switch current pulses in discrete steps until the peak value of the main switch current pulses is decreased to a level that is sufficiently low not to produce unacceptable audible noise. At very light loads and at no load, the ANR circuit can be disabled in order to meet various worldwide standards that limit the maximum input power. The performance of the proposed circuit was experimentally verified in a 90-W single-stage power-factor-correction flyback adapter.
In this study, a switched-resonator converter with high efficiency over a wide conversion ratio range is introduced. Inspired by the gyrator resonant switched-capacitor concept, the new topology ...provides high efficiency over wide and continuous range of conversion ratios using a single resonator. This is enabled by new modes of operation (switching sequences) developed and analyzed in this study, that modifies the charge-balance of the flying capacitor. By that, the efficiency characteristics of the converter can be shaped to peak at various conversion ratios. A generalized methodology is presented to describe resonator-type converters with multiple operation-modes as two-ports, which is then used to analyze three showcase operational modes of the presented topology. Experimental results of the three modes validate the developed theoretical model, and demonstrate the superiority of the concept in terms of efficiency (over 10%) and current-sourcing capabilities (over 80%) using a compact 5W prototype.
Uncertainty models for the three basic switch-mode converters: buck, boost, and buck-boost are given in this paper. The resulting models are represented by linear fractional transformations with ...structured dynamic uncertainties. Uncertainties are assumed for the load resistance R=R/sub O/(1+/spl delta//sub R/), inductance L=L/sub O/(1+/spl delta//sub L/), and capacitance C=C/sub O/(1+/spl delta//sub C/). The interest in these models is clearly motivated by the need to have models for switch-mode DC-DC converters that are compatible with robust control analysis, which require a model structure consisting of a nominal model and a norm-bounded modeling uncertainty. Therefore, robust stability analysis can be realized using standard /spl mu/-tools. At the end of the paper, an illustrative example is given which shows the simplicity of the procedure.
Switch mode power converters otter an efficient solution for driving high-brightness LEDs in an enormous range of applications. These driving converters usually rely on analog control techniques to ...ensure the optimal flow of current through the LEDs and provide dimming features. However, due to their inflexibility and non-configurability analog control schemes are not a good option especially in high end applications such as backlighting and automotive lighting. Recently, digital power management of high-brightness LED systems based on microprocessors and digital signal controllers (DSC) has emerged as an alternative to traditional analog control. These control schemes can actually improve overall system performance by adding some extra features like low power consumption, increased system reliability and better design flexibility for a specific application. This paper presents a digital signal controller based control scheme of switching power converter for high-brightness LED applications. A design example based on dc-dc boost topology is presented to provide a useful guide for control design engineers with the perspective of digital power control.
The three basic Switch-Mode PWM converters, buck, boost and buck–boost, have been widely used in computer hardware and industrial applications. There is the need to have models for these converters ...that are compatible with robust control analysis. Uncertainty models for these converters are given in this paper. The resulting models are represented by linear fractional transformations (LFTs) with structured dynamic uncertainties. Therefore, robust stability analysis can be realized using standard
μ-tools. At the end, an illustrative example for a 95 W boost regulator is given which shows the simplicity of the procedure.
In this paper, three modeling techniques that are conventionally used in the derivation of mathematical models for switch-mode DC-DC converters are presented and studied. The state-models obtained by ...applying these general-case approaches are valid under both continuous and discontinuous operating modes. The first two methods use averaging process and allow only a low-frequency representation of the converter, whereas the third one, which is based on the using of the switching function concept, gives a mathematical model that is valid in the entire frequency range and has thus more accuracy in computer implementations. For illustration purpose, and in order to show the extendibility of all three modeling approaches to other families of switch-mode converters, a boost-type single-phase full-bridge rectifier is considered. The most-general switching-function-based model is highly suitable for real-time simulations.
In this paper, new mathematical models of DC-DC switch-mode converters, which are valid under both continuous and discontinuous operating modes, are presented. The modeling technique is based on the ...switching functions concept. The obtained models are represented by time-variant state equations, which offer high simplicity for computer implementation. For illustration purpose, the proposed modeling approach is applied to the conventional buck and Cùk converters. The obtained models are then tested through computer implementation using the Simulink tool of Matlab.
Power Electronic Circuits: An Overview Mohan, N.
Proceedings.14 Annual Conference of Industrial Electronics Society,
1988, Letnik:
3
Conference Proceeding
