The separation of variables approach to formulate the averaged models of DC-DC switch-mode power converters is presented in the paper. The proposed method is applied to basic converters such as BUCK, BOOST and BUCK-BOOST. The ideal converters or converters with parasitic resistances, working in CCM and in DCM mode are considered. The models are presented in the form of equation systems for large signal, steady-state and small-signal case. It is shown, that the models obtained by separation of variables approach differ in some situations from standard models based on switch averaging method.
The averaged models of switch-mode DC-DC power converters are discussed. Two methods of averaged model derivation are considered - the first, based on statespace averaging and the second, on the switch averaging approach. The simplest converters: BUCK, BOOST and BUCK-BOOST working in CCM (continuous conduction mode) or DCM are taken as examples in detailed considerations. Apart from the ideal converters, the more realistic case of converters with parasitic resistances is analyzed. The switch averaging approach is used more frequently than the other and is believed to be more convenient in practical applications. It is shown however, that in the deriving the averaged models based on the switch-averaging approach, some informalities have been made, which may be the source of errors in the case of converters with parasitic resistances, or working in DCM mode.
In the constant pursue of the sustainability of socio-industrial systems, the definition of useful, reliable and informative, and at the same time simple and transparent, indicators is an important step for the evaluation of the circularity of the assessed systems. In the circular economy (CE) context, scientific literature has already identified the lack of overarching indicators (social, urban, prevention-oriented, etc.), pointing out that mono-dimensional indicators are not able to grasp the complexity of the systemic, closed-loop, feedback features of CE. In this respect, Emergy accounting is one of the approaches that have been identified as holding the potential to capture both resource generation and product delivery dimensions and therefore to provide an enhanced systems’ evaluation in a CE perspective.
Because of Emergy’s intrinsic definition and its calculation structure, Emergy-based indicators conceptually lend themselves very well to the evaluation and monitoring of circular processes. Additionally, Emergy has the unique feature of enabling the evaluation of systems that are not necessarily only technosphere systems, but also of technological systems which embed nature (techno-ecological systems).
The present paper gives a perspective on a set of Emergy-based indicators that we have identified as suitable to evaluate circular systems, and outlines the different perspective compared to the circularity indicators defined in the “Circularity Indicators Project” launched by the Ellen MacArthur Foundation.
The paper presents new ensemble solutions, which can forecast the average level of particulate matters PM10 and PM2.5 with increased accuracy. The proposed network is composed of weak predictors integrated into a final expert system. The members of the ensemble are built based on deep multilayer perceptron and decision tree and use bagging and boosting principle in elaborating common decisions. The numerical experiments have been carried out for prediction of daily average pollution of PM10 and PM2.5 for the next day. The results of experiments have shown, that bagging and boosting ensembles employing these weak predictors improve greatly the quality of results. The mean absolute errors have been reduced by more than 30% in the case of PM10 and 20% in the case of PM2.5 in comparison to individually acting predictors.
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.
A novel circuit topology of modified switched boost high frequency hybrid resonant inverter fitted induction heating equipment is presented in this paper for efficient induction heating. Recently, induction heating technique is becoming very popular for both domestic and industrial purposes because of its high energy efficiency and controllability. Generally in induction heating, a high frequency alternating magnetic field is required to induce the eddy currents in the work piece. High frequency resonant inverters are incorporated in induction heating equipment which produce a high frequency alternating magnetic field surrounding the coil. Previously this high frequency alternating magnetic field was produced by voltage source inverters. But VSIs have several demerits. So, in this paper, a new scheme of modified switched boost high frequency hybrid resonant inverter fitted induction heating equipment has been depicted which enhances the energy efficiency and controllability and the same is validated by PSIM.
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.
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