MODEL OF SWITCH-CONTROLLED PWM STRUCTURE FOR ANALYSIS OF PULSE VOLTAGE CONVERTERS WITH ARBITRARY TOPOLOGY

The article considers the problems of analyzing DC-DC voltage converters and analyzes the advantages, disadvantages, as well as the scope of full switched and averaged continuous models of the converters. The feasibility of using the complex of two models (full switch model and averaged continuous model) for analyzing their operation is proved. The general approach to the construction of continuous models of DC-DC voltage converters based on state-space averaging method is considered. Disadvantages of the averaged models using a classic approach are shown. The relevance of the development of universal continuous models of DC-DC converters is substantiated. The possibility of creating such models using averaged models of PWM switching structure included in the DC-DC voltage converter is shown. Analyzed the typical structure of the switch-mode power supply with feedback. An averaged model of the switching structure is proposed, basing on which continuous models of DC-DC converters with any topology can be built. The processes occurring in this switching structure in the mode of continuous and discontinuous choke current are analyzed. A method for constructing continuous models of the main types of DC-DC voltage converters based on switching structure averaged model is proposed. The adequacy of continuous models obtained by this method has been proven. The results of modeling transients on the continuous and full switch models for inverting voltage regulator are demonstrated. The possibility of accounting in the model of active resistances of switches and cumulative choke is shown. The possibility of using the proposed model to obtain the open loop transfer functions is demonstrated, in particular, the characteristics of the duty factor - output voltage. These transfer functions can be used to synthesize control system compensating circuits of the switch-mode power supply. The possibility of using a single generalized averaged model of the switching structure to build continuous models of converters with complex topology using both the Voltage Mode and Current Mode is shown. This creates prerequisites for developing a universal averaged continuous model for DC-DC converter based on this principle

DIGITAL CONTROL OF A CLOSED LOOP BUCK CONVERTER

The primary focus for the R&D in this area so far has been to figure out the best approach for evaluating and designing the DC-DC converter and perhaps the most appropriate control technique is being applied in different DC-DC converter circuits. Depending on power handling capacity as well as high-frequency switching, certain switching devices are chosen. This paper discusses the deployment of the digital PID controllers in the DC-DC converters. In an attempt to get a quicker response, voltage mode control has been used. Digital controllers started replacing traditional analog controllers more and more. Better immunity to changes in the environment which includes temperature and degradation of components, improved versatility by modifying the software, increasing advanced control methods, and decreased number of the components are the key benefits of the digital control against the analog control. A structured and concise strategy for designing a digitally operated close-loop Dc / Dc buck converter is discussed in this paper beginning with the Buck converter and giving the set of certain performance specification, implementations of the digital Proportional-IntegralDerivative(PID) controller is made. It addresses in depth all the appropriate DSP hardware and/or software methods and approaches needed to implement a controller. In order to illustrate the efficacy of the model, the dynamic response as well as the steady-state performance of controller is provided. The experimental outcomes fit well with the model of simulation. During the implementations of Switch Mode Power Supply (SMPS), application of dsPIC provides new perspectives towards affordable and versatile approaches of digital control.

Comparision of Voltage Stress Across the MOSFET Switch of a Flyback Converter with Various Snubbers

A Flyback converter is a simple switch-mode power supply that can be used to generate a DC output from either an AC or DC input. The converter switch is the most critical part of any converter. The voltage stress across the switch is a major issue as the high voltage spikes occur due to interaction between its output capacitance and the leakage inductance of the transformer. These spikes can be reduced with various snubbers like conventional tertiary winding, Resistor Capacitor and Diode(RCD) snubber, energy regenerative snubber and an active clamp snubber. This paper aims to analyze and compare the voltage stress across the MOSFET switch of Flyback converter with various snubber circuits.

Properties of Fractional-Order Magnetic Coupling

This paper presents the properties of fractional-order magnetic coupling. The difficulties connected with the analysis of two coils in dynamic states, resulting from the classical approach, provided motivation for studying the properties of fractional-order magnetic coupling. These difficulties arise from failure to comply with the commutation laws, i.e., a sudden power disappearance in the primary winding caused by a switch-mode power supply. Theoretically, under ideal conditions, a sudden power disappearance in the coil is, according to the classical method, manifested by a sudden voltage surge in the form of the Dirac delta function. As is well-known, it is difficult to obtain such ideal conditions in practice; the time of current disappearance does not equal zero due to the circuit breaker’s imperfection (even when electronic circuit breakers are used, the time equals several hundred nanoseconds). Furthermore, it is necessary to take into account phenomena occurring in real inductances, such as the skin effect, the influence of the ferromagnetic core and many other factors. It would be very difficult to model all these phenomena using classical differential calculus. The application of fractional-order differential calculus makes it possible to model them in a simple way by appropriate selection of coefficients and fractional-order derivatives. It should be mentioned that the analysis could be used, for example, in the case of high-voltage generation systems, including spark ignition systems of internal combustion engines. The use of fractional-order differential calculus will allow for more accurate modeling of phenomena occurring in such systems.