International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This paper describes the design and practical implementation of speed controller for 3-phase induction motor based on ATmega 2560 microcontroller. Based on the theoretical analysis of the induction motor, are defined the requirements that the controller should satisfy them. Then, based on the specificity of the selected controller, the operating mode of the ATmega 2560 controller is designed. The specificity of this solution is that the driver circuit, which is connected between the controller and the motor, is realized with an intelligent power controller. Finally, the results of the practical work of this motor controller are given.

In this paper for full─bridge serial resonant converter, exact general equations for dependencies of phase angle, the maximum voltage of the capacitor and the maximum value of the output current are derived. Mathematical analysis of the this dependence on the resonant circuit dumping frequency when it is excited with pulse voltage with a different frequency than the resonant one is made. This dependences derived in wide a band around the resonant frequency.

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 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.

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.

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.