Papers by Ljupco Karadzinov
IEEE Transactions on Power Electronics, 2000
Diode reverse recovery can cause anomalies in highfrequency rectifier operation, including self-s... more Diode reverse recovery can cause anomalies in highfrequency rectifier operation, including self-sustaining quasiperiodic oscillations. The output voltage can increase considerably beyond that predicted by the usual analysis. This nonlinear effect is analyzed using a recently developed piecewise-linear diode model. The theoretical results agree with experimental measurements. Design guidelines are presented to avoid overvoltage and instability in practical converters.
In the paper are presented the features of the control signals that affect on the work of the pow... more In the paper are presented the features of the control signals that affect on the work of the power bridge converter. The main purpose of the paper is to be done analysis on the features of the electronic switches and the circuits in a power converter and also to defines the requirements for their proper operation. These requirements must be satisfied by the electronic circuits for management of the power converter. In the paper is analyzed the operation of the power full bridge converter applied in mode of induction heating of metals. The researches in the paper are implementated in practical produced induction furnace. In the paper the simulation program PowerSim is used
Serial resonant bridge converter commonly used in process of induction heating on metal materials... more Serial resonant bridge converter commonly used in process of induction heating on metal materials. In these applications during the heating process, the converter load equivalent electrical parameters are changed. This contributes to the transferred power from the converter to the induction device to change. In this paper with mathematical analysis are determined the quantities from which depends the active power of the resonant converter. Derived is an equation that gives the dependence of the active power from the phase angle between the voltage and current the converter as and from the duty cycle. This equation can be used in control methods to maintain maximum convertor power transfer
This paper describes the design and practical implementation of AC/DC/DC converter in mode of arc... more This paper describes the design and practical implementation of AC/DC/DC converter in mode of arc welding. An analysis of the operation of AC/DC/DC converter and its input/output characteristics are determined with computer simulations. The practical part is consisted of AC/DC/DC converter prototype for arc welding with output power of 3 kW and switching frequency of 64 kHz. The operation of AC/DC/DC converter is validated with experimental measurements.
Proceedings of 14th International Power Electronics and Motion Control Conference EPE-PEMC 2010, 2010
This paper presents a design procedure for a full-bridge converter with IGBT transistors loaded w... more This paper presents a design procedure for a full-bridge converter with IGBT transistors loaded with serial resonant circuit. The main concern was the reduction of the switching losses in order to increase converter efficiency and power density. One of the basic applications of this topology with serial resonant load is with the induction heating converters. Theoretical analysis of the switching
IEEE EUROCON 2017 -17th International Conference on Smart Technologies, Jul 1, 2017
Direct phase or indirect frequency control methods are used in series-resonant bridge power inver... more Direct phase or indirect frequency control methods are used in series-resonant bridge power inverters for induction heating to maintain maximum power transfer as the load equivalent electrical parameters change during the heating process. In these applications, to control the power level it is common to use the above resonance operating frequency, where only measurement of the deviation of the phase angle from its reference value is used to calculate the new bridge switching frequency. Below resonance is not used since its control is non-linear, has high level of harmonics and is considered unstable, so no detailed analysis have been carried out. The paper present mathematical analysis of the output power, voltage and current phase angle dependence on the resonant circuit damping frequency when it is excited with pulse voltage with a different frequency than the resonant one, in both above and below resonance regions. Based on this analysis, possibilities of below resonance power control are investigated and new insight in circuit behavior is presented based on variation in resonant tank parameter values.
IEEE EUROCON 2015 - International Conference on Computer as a Tool (EUROCON), 2015
The 33rd International Convention Mipro, 2010
The 33rd International Convention Mipro, 2010
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Papers by Ljupco Karadzinov