## DEPENDENCE OF THE ACTIVE POWER OF THE SERIAL RESONANT BRIDGE CONVERTER FROM THE PHASE DIFFERENCE AND THE DUTY CYCLE

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.

## FEM 2D AND 3D DESIGN OF TRANSFORMER FOR CORE LOSSES COMPUTATION

Machines. Technologies. Materials., Vol. 11 (2017), Issue 6, pg(s) 301-304

Accurate simulation and prediction of losses in power transformer is important during transformer lifetime but also during the design stage. Paper presents the simulation model of transformer based of Finite Element Method that allows calculation of core losses and magnetic flux density in transformer cross-section. Two different models are constructed for 2D and 3D simulation. Obtained results are compared with experiments. Finally, flux density in both models is calculated and obtained results are presented for different time steps.

## DETERMINATION OF INPUT/OUTPUT CHARACTERISTICS OF FULL-BRIDGE AC/DC/DC CONVERTER FOR ARC WELDING

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 con- sisted 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.

• ## ANALYSIS AND PERFORMANCE OF TWO PV CELLS UNDER VARIOUS WEATHER CONDITIONS

This paper presents performances of two different types of PV cells under various temperature clime of Stip, R. Macedonia.
Stip with geographical position 41 .742N, 22.1 94E has 2260 sun hours yearly with average temperature 25 °C during spring.
The types of cells examined in this study are: crystalline silicone (c-Si) and polycrystalline silicon (p-Si). The calculations are made for various operating conditions and a comparation of I-V and P-V characteristics are represented here. Also, the efficiency and fill factor for photovoltaic (PV) cells is calculated based on simulation results.

• ## ANALYSIS OF PARALLEL RESONAT CONVERTERS WITH COMPUTER SIMULATIONS

In this paper analysis of power converters with parallel resonant circuit by using of computer simulations is made. The full bridge IGBT power converter is analyzing. The simulations are made in PowerSim simulation program. Calculation is the efficiency of the converter and is made harmonic analysis of the output voltage and current. Also, is made and compare on the obtained results of the parallel resonant converter with the results of the serial resonant converter in applications with variable RL-load.

• ## APPLICATION OF NUMERICAL METHODS IN CALCULATION OF ELECTROMAGNETIC FIELDS IN ELECTRICAL MACHINES

Finite Element Method has been proved as valuable tool for solving different electromagnetic problems inside electrical machines. Calculation of magnetic flux density and its distribution in machine cross-section is difficult to be calculated by analytical methods. Therefore Finite Element Method is implemented for solving set off Maxwell equation which enables precise calculation of electromagnetic field and magnetic flux density in three different electrical machines: three phase squirrel cage motor type 5AZ801-4 prodct of company Rade Koncar, three phase distribution transformer type product of company EMO, and single phase capacitor motor FMR-35/6 product of company MikronTech. Distribution of magnetic flux density in all three machines is calculated for different operating regimes.

• ## APPLICATION OF NUMERICAL METHODS IN CALCULATION OF ELECTROMAGNETIC FIELDS IN ELECTRICAL MACHINES

Finite Element Method has been proved as valuable tool for solving different electromagnetic problems inside electrical machines. Calculation of magnetic flux density and its distribution in machine cross-section is difficult to be calculated by analytical methods. Therefore Finite Element Method is implemented for solving set off Maxwell equation which enables precise calculation of electromagnetic field and magnetic flux density in three different electrical machines: three phase squirrel cage motor type 5AZ801-4 prodct of company Rade Koncar, three phase distribution transformer type product of company EMO, and single phase capacitor motor FMR-35/6 product of company MikronTech. Distribution of magnetic flux density in all three machines is calculated for different operating regimes.

• ## COMPLEX ANALYSIS OF PERGORMANCE CHARACTERISTICS OF SINGLE PHASE SHADED POLE MOTOR

Development of automatic, robotic and computer science has lead to development of wide range special motors (micro motors) which have large application and are interesting for research purposes. One of them is single phase shaded pole motor having a wide application in large number of household devices. Motor performance characteristics are analyzed using method of symmetrical components. For research purposes motor mathematical model is developed enabling prediction of motor operational characteristics. Obtained results are compared with experimental ones. Motor dynamic characteristics are obtained by building the simulation model in MATLAB/SIMULINK. Adequate conclusion regarding accuracy of developed motor models is derived.

## FEM 2D AND 3D DESIGN OF TRANSFORMER FOR CORE LOSSES COMPUTATION

Industry 4.0, Vol. 2 (2017), Issue 3, pg(s) 119-122

Accurate simulation and prediction of losses in power transformer is important during transformer lifetime but also during the design stage. Paper presents the simulation model of transformer based of Finite Element Method that allows calculation of core losses and magnetic flux density in transformer cross-section. Two different models are constructed for 2D and 3D simulation. Obtained results are compared with experiments. Finally, flux density in both models is calculated and obtained results are presented for different time steps.