Explore the vast range of titles available.

Goal. To analyze the efficiency and EMI of a half-bridge converter built on GaN transistors at different switching frequencies and to issue recommendations for its application. Methodology. An EPC9035 development board from Efficient Power Conversion was selected for research. This board is a half-bridge converter built on the EPC2022 eGaN[R] transistors and contains a driver for controlling these transistors. To simplify the assessment of the conversion efficiency, it is suggested to use a computer model of the development board and LISN, which simulates the active load with the LC filter. Results. Simulation results of the converter efficiency with the nominal values of the elements according to the EPC9035 manual showed significant deviations from the calculated values at frequencies above 50 kHz. This is explained by the presence of inrush current through transistors. The inrush current depends on the <> between the intervals when the transistors are open and the delays specified in the SPICE model of LM5113 driver. To reduce the amplitude of inrush current and, accordingly, to increase the duration of the <> interval, it is proposed to double the capacitors responsible for the formation of this interval. Simulation of the converter efficiency with the doubled values of the circuit elements showed that the results almost coincide with the calculated values of the efficiency in the range from 0.05 MHz to 5 MHz. The converter on the EPC2022 transistors has the highest efficiency at 50 kHz which decreases by 0.03-0.04 at 500 kHz. Therefore, it is recommended that the operating frequency should be set close to 500 kHz. Simulation of EMI levels resulted that the difference in the duration of the <> does not have a significant effect on the levels of simulated EMI. The largest difference between the simulation results and the experiment is observed at frequencies about 30 MHz and is 3-6 dB. Originality. For the first time, the computer model was used to calculate the efficiency of a half-bridge converter on GaN transistors at different frequencies. Practical significance. Considering the high output current, high operating voltage and short switching times, GaN transistors are promising for use in pulse generators, power supplies with operating frequencies exceeding 500 kHz, and in powerful Class D hi-fi amplifiers with small dimensions, such as automotive ones. References 10, tables 3, figures 5.

The influence of magnetic coupling between the parasitic inductances of Y capacitors of an RFI filter on the level of the filter insertion loss was studied. It is shown that the magnetic coupling mentioned above significantly worsens the attenuation introduced by the filter at frequencies from 150 kHz to 30 MHz. Mutually perpendicular, parallel, and end-to-end arrangement of capacitors relative to each other was analyzed as one of the methods of reducing the magnetic coupling between parasitic inductances of Y capacitors. It is shown that an increase in the distance between the said capacitors increases the attenuation introduced by the filter into common mode noise in the frequency range of 150 kHz to 30 MHz by 10 to 15 dB. References 27, Figures 9.

An overview of the main structures of uninterruptible power systems is provided. The impact on internal-system and external-system electromagnetic compatibility of these devices is determined. Contemporary standards and requirements for ensuring electromagnetic compatibility of uninterruptible power systems are analyzed. Features of the structures of uninterrupted power systems such as online, offline and line interactive by the conductive path of propagation of interference are given. The main advantages of eco uninterrupted power supply are summarized. A generalized approach is proposed for the application of radiofrequency interference filters depending on the electromagnetic environment and features of uninterruptible power systems. Refined limitations on the possibilities of adjusting the basic and influence parasitic parameters of the filter links by symmetric and asymmetric propagation of conductive disturbances. The possibility of using remote control of the effectiveness of means of reducing conductive disturbances was assessed. The expediency of localization of control parameters of smart radiofrequency interference filters with the use of artificial intelligence is determined. References 10, figures 6, tables 2.