No abstract

The paper proposes a methodology for designing a filter for lowering conductive interference level, generated by pulse voltage converters. Not only the proposed method takes into account the requirements of the standard for electromagnetic compatibility, but also the parameters of the LISN node to measure the level of noise, which are given by a converter to a power supply chain. The articles describes the example of the filter design for a lowering DC-DC converter the noise level of which is in accordance with the standard CSPR25. All stages of design are illustrated by models, they are developed in the LTspice program. Models for analyzing the amplitude-frequency response of a interference filter loaded on a LISN are presented. It is shown that when modeling the operation of pulse sources, it is not advisable to use LISNs with the idealized characteristics of elements. The obtained filter calculations’ results confirm the correctness of the proposed method. References 11, figures 9.

A problem of electrical and radioelectronic equipment’s high energy pulse disturbance immunity is considered in the paper, in particular against microsecond high voltage disturbances (MHVD) in the power mains. It is showed causes of MHVD with amplitude up to 4 kV and even higher. A review of various protection methods against MHVD is carried out and it is shown that the use of a two-terminal network (TTN) with a significantly nonlinear current-voltage characteristic: varistors, suppressors and gas arrestors is the most effective. The report analyzes the operation principle of these two-poles and shows that the typical inclusion of such a device directly at the equipment’s input is not effective enough for cases where the high-frequency impedance of the mains is low. An L-circuit for connecting the TTN together with an LR link is proposed, and results of computer simulation with the aid of PSPICE showed that such a scheme reduces the MHVD amplitude on the network input of the equipment by 1.5 times comparing with the typical inclusion of such a device even under a low impedance of the mains Adding the low-pass filter to the L-circuit allows to reduce the MHVD amplitude by 40 and more times comparing with the typical inclusion of the TTN. References 8, figures 6.

The paper considers voltage converters as sources of conductive electromagnetic interference (EMI). Some features of the standard measurement method of converters EMI are considered and it is shown that it measures only the total level of noise, which can be the same at completely different relations between the differential and common components of EMI. This leads to inefficient use of means reducing the total converter noise to the permitted level, because the different ratio between the above components of this noise requires different means to reduce them. The paper proposes to supplement the standard noise measurement method by two additional measurements at frequencies where the total noise exceeds the permitted level, using during the first measurement the additional RFI common mode filter which effectively reduces only the common noise, and the additional RFI differential mode filter which effectively reduces only the differential noise during the second measurement. It is shown that these two additional measurements make it possible to determine the differential and common components of the total noise. This, in turn, makes it possible to reduce the total noise to the permitted level at the minimal cost. References 6.

Розглянуто вплив високочастотних втрат реального накопичувального дроселя (НД) на ємність компенсувального конденсатора (КК) у схемі компенсації паразитної ємності перетворювачів, яка зумовлює проникнення несиметричних кондуктивних завад від перетворювачів в електромережу. Одержано вираз для оптимального значення ємності КК, яке забезпечує мінімізацію напруги несиметричної завади від перетворювача, а також перевірено та підтверджено правильність одержаного виразу. Показано, що оптимальна ємність КК не залежить від високочастотних втрат НД.