AC and DC input characteristics of the flyback converter are analysed and investigated via Spice simulations and measurements. The influence of parasitic effects in converter components on input characteristics is studied in continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The results of the calculations based on analytical formulas and averaged models are in a good accordance with Spice simulations and measurements.
In the hybrid multiple H-bridge topology of beam supply, the load change of a DC/DC full-bridge converter can greatly affect the output voltage during onsite operation. An improved sliding mode control (SMC) strategy is thus proposed in this paper, where the rate of switching control is added to the law of system equivalent control to create a law that can realize a complete sliding mode control. Considering the special operating conditions of the load can have an influence on the performance of the controller, the impact of uncertainty existing in onsite conditions is suppressed with the proposed strategy utilized. The validity of the proposed strategy, finally, is verified by simulation, which proves the outperformance of the system in both robustness and dynamics.
In this fast-changing environmental condition, the effect of fossil fuel in vehicle is a significant concern. Many sustainable sources are being studied to replace the exhausting fossil fuel in most of the countries. This paper surveys the types of electric vehicle’s energy sources and current scenario of the onroad electric vehicle and its technical challenges. It summarizes the number of state-of-the-art research progresses in bidirectional dcdc converters and its control strategies reported in last two decades. The performance of the various topologies of bidirectional dc-dc converters is also tabulated along with their references. Hence, this work will present a clear view on the development of state-of-the-art topologies in bidirectional dc-dc converters. This review paper will be a guide for the researchers for selecting suitable bidirectional traction dc-dc converters for electric vehicle and it gives the clear picture of this research field.
The measurement of frequency characteristics, like magnitude and phase, related to a specific transfer function of DC–DC converters, can be a difficult task – especially when the measured signal approaches the boundary of a small-signal model validity (i:e. 1/3 of the switching frequency fS). It is hard to find a paper where authors mention the measurement techniques they use to draw frequency characteristics. Meanwhile the presence of noise in the output signal does not enable to directly measure the gain and the phase shift between the input and output signals. In such situations additional analysis is required in order to achieve a reliable result. This paper contains a description of a few methods that can be used to analyse measured signals in order to determine the gain and the phase shift of a specific transfer function. They enable to verify mathematical models in a wide range of frequencies (up to 1/3 fS). The methods use signals measured in the time domain and can be implemented in mathematical software such as Matlab or Scilab.
The purpose of this paper is to propose a model of a novel quasi-resonant boost converter with a tapped inductor. This converter combines the advantages of zero voltage quasi-resonant techniques and different conduction modes with the possibility of obtaining a high voltage conversion ratio by using a tapped inductor, which results in high converter efficiency and soft switching in the whole output power range. The paper contains an analysis of converter operation, a determination of voltage conversion ratio and the maximum voltage across power semiconductor switches as well as a discussion of control methods in discontinuous, critical, and continuous conduction modes. In order to verify the novelty of the proposed converter, a laboratory prototype of 300 W power was built. The highest efficiency η = 94.7% was measured with the output power Po = 260 W and the input voltage Vin = 50 V. The lowest efficiency of 90.7% was obtained for the input voltage Vin = 30 V and the output power Po = 75 W. The model was tested at input voltages (30–50) V, output voltage 380 V and maximum switching frequency 100 kHz.
Large-signal input characteristics of three DC–DC converter types: buck, boost and flyback working in the discontinuous conduction mode (DCM), obtained by precise large signal PSpice simulations, calculations based on averaged models and measurements are presented. The parasitic resistances of the converter components are included in the simulations. The specific features of the input characteristics in theDCMand the differences between the continuous conduction mode (CCM) and DCM are discussed.
Large-signal input characteristics of three DC–DC converter types: buck, boost and flyback working in the continuous conduction mode (CCM), obtained by simulations and measurements are investigated. The results of investigations are presented in the form of the analytical formulas and the exemplary results of the measurements and two forms of simulations: based on the full description of the converter components and on the averaged models. The parasitic resistances of the converter components are included in the simulations and their influence on the simulation results is discussed.
This paper presents a concept and the results of an investigation of a DC–DC boost converter with high voltage gain and a reduced number of switches. The novel concept assumes that the converter operates in a topology composed of series connection switched- capacitor-based multiplier (SCVM) sections. Furthermore, the structure of the sections has significant impact on parameters of the converter which is discussed in this paper. The paper demonstrates the basic benefit such a multisection SCVM idea in the converter, which is the significant reduction in the number of switches and diodes for high voltage gain in comparison to an SCVM converter. Aside from the number of switches and diodes, such parameters as efficiency and volume of passive components in the multisection converter are analyzed in this paper. In figures, the analysis is demonstrated using the example of 100 kW thyristor-based converters. All the characteristics of the converter are compared between various configurations of switching cells in the particular sections, thus the paper can be useful for a design approach for a high voltage gain multicell converter.
In the description of small-signal transmittances of switch-mode power converters several characteristic frequencies are usually used, corresponding to poles and zeros of transmittances. The knowledge of these frequencies is important in the design of control circuits for converters and usually are assumed to be constant for a given power stage of a converter. The aim of the paper is to evaluate the influence of converter primary parameters and load conductance on characteristic frequencies. Analytical derivations and numerical calculations are performed for an ideal and non-ideal BUCK converter working in continuous or discontinuous conduction mode.
DC-DC converters are popular switch-mode electronic circuits used in power supply systems of many electronic devices. Designing such converters requires reliable computation methods and models of components contained in these converters, allowing for accurate and fast computations of their characteristics. In the paper, a new averaged model of a diodetransistor switch containing an IGBT is proposed. The form of the developed model is presented. Its accuracy is verified by comparing the computed characteristics of the boost converter with the characteristics computed in SPICE using a transient analysis and literature models of a diode and an IGBT. The obtained results of computations proved the usefulness of the proposed model.