Design procedure for computing printed circuit conductors on metal base for AC spacecraft devices


DOI: 10.34759/trd-2020-114-10

Аuthors

Kostin A. V.

Samara National Research University named after Academician S.P. Korolev, 34, Moskovskoye shosse, Samara, 443086, Russia

e-mail: Kostin.AV@samspace.ru

Abstract

The article suggests the technique for the design procedure of printed conductor (PC) width of the printed circuit board, being installed of the metal base, for the onboard spacecraft devices, depending on the flowing sinusoidal current of various frequency. The technique accounts for non-uniform current distribution in the PC volume due to the skin effect. The following problems were solved while this technique developing:

  • Analysis of the PC active resistance dependence on frequency was performed;

  • A refinement, allowing accounting for the skin effect, was developed base on the existing techniques;

  • The analysis of the accepted assumptions impact on the calculations accuracy was performed.

The article presents the dependence of the PC active electrical resistance on frequency. This dependence was obtained under the condition that the PC width is much greater than its thickness. This condition is most often being fulfilled in practice. Such assumption was made with the purpose of simplifying the search for the dependence. As long as active resistance equation turned out to be rather complex even with account for the assumption, the article presents the graph of the reduced active resistance dependence. To obtain the active resistance value, the value of the reduced active resistance should be multiplied by the PC length value and divided by the value of its width. The active resistance value is being determined graphically for the specified AC frequency. It simplifies the PC width calculation while printed circuit boards design.

Analysis of active electrical resistance dependence on the frequency was performed. It was established in the course of the analysis that at the frequencies up to 100 kHz active electrical resistance weakly depended on the frequency. The skin effect can be ignored at these frequencies. At the frequencies above 1 GHz, the active electrical resistance does not depend on the PCB thickness. This allows making a number of simplifications, and calculate the active resistance by the thickness of the skin layer.

The previously developed technique assumes the presence of heat removal only through the printed circuit board on the metal base. The article references the publications recounting its gist.

According to this technique, the thermal resistance of insulation material layers is determined by both the geometry of their part, located under the PC, and thermo-physical properties of the materials themselves. When the current flows through the PC, the dissipated power is determined as the product of the square of current and the PC active resistance. This power will be equal to the thermal flow. Then the overheating will be equal to the product of the thermal flow and the thermal resistance of the insulation material layers. Refinement for the AC consists in the electric resistance dependence on the frequency.

Analysis of temperature distribution in the PCB volume due to the current distribution non-uniformity and heat dissipation from the one side only, was performed analytically by solving thermal conductivity equation. Calculations revealed that the skin effect would not be affecting the temperature distribution in the PCB volume significantly. Analysis of the frequency impact on the temperatures distribution was performed.

It was noted that the temperature distribution law became close to the linear with frequency increasing. This is associated with the fact that the AC is being pushed out to the PC surface, and heat sources inside PCB disappear.

It was noted that other assumptions made while developing the technique for the DC affect the calculation result for the AC as well. It is associated with the fact that the proposed technique is based on the previously developed one. First of all, this concerns the edge thermal fluxes effect to the PC temperature. The article stipulates that the method can be applied even if the PC width is not much great than its thickness. If the condition is met, the current flows along the lateral surfaces can be ignored. Non-fulfillment of this condition will lead to the situation when these currents will significantly affect the result. However, the presence of additional currents means that the larger PCB section will be employed while the current flowing. This will lead to the situation when actual active resistance will be less that the calculated one. Consequently, actual PCB temperature will be less than the calculated one. This will no degrade the PCB reliability, but even increase it.

The actual PC power will be less than the calculated one. And as a result the actual PC temperature will be less than the calculated one. This will not decrease the reliability of the PC and increase it instead.

Keywords:

design procedure, spacecraft onboard electronic equipment, printed circuit board, printed conductor width, alternating current, frequency, skin effect, temperature

References

  1. Belyavskii A.E., Sorokin A.E., Strogonova L.B., Shangin I.A. Trudy MAI, 2018, no. 103. URL: http://trudymai.ru/eng/published.php?ID=100615

  2. Alekseev V.A., Karabin A.E. Trudy MAI, 2011, no. 49. URL: http://trudymai.ru/eng/published.php?ID=28050

  3. Panin Yu.V., Korzhov K.N. Trudy MAI, 2015, no. 80. URL: http://trudymai.ru/eng/published.php?ID=56911

  4. Paleshkin A.V., Mamedova K.I. Trudy MAI, 2016, no. 85. URL: http://trudymai.ru/eng/published.php?ID=67483

  5. Anurov A.E. Trudy MAI, 2011, no. 45. URL: http://trudymai.ru/eng/published.php?ID=25349

  6. Platy pechatnye. Osnovnye parametry konstruktsii. GOST R 53429-2009 (Printed circuit boards. Basic parameters of structure. Russian State Standard 53429-2009), Moscow, Standartinform, 2018, 11 p.

  7. Pechatnye platy. Trebovaniya k konstruktsii. Instruktsiya. RD 50-708-91(Printed circuit boards. Design specifications. Instruction manual. Guidance Document 50-708-91), Moscow, Izd-vo Standarty, 1992, 41 p.

  8. Generic Standard on Printed Board Design. IPC-2221A. 2003, 124 p.

  9. Standard for Determining Current-Carrying Capacity in Printed Board Design. IPC-2152. 2009, 89 p.

  10. Pirogova E.V. Proektirovanie i tekhnologiya pechatnykh plat (Design and technology of printed circuit boards), Moscow, FORUM: INFRA-M, 2005, 250 p.

  11. Belyanin L.N. Konstruirovanie pechatnogo uzla i pechatnoi platy. Raschet nadezhnosti (Design of printed circuit assembly and printed circuit board. Reliability calculation), Tomsk, Izd-vo dom TPU, 2008, 77 p.

  12. Gormakov A.N. Voronina N.A. Konstruirovanie i tekhnologiya elektronnykh ustroistv priborov. Pechatnye platy (Design and technology of electronic devices. Printed circuit boards), Tomsk, Izd-vo TPU, 2006, 164 p.

  13. Murav’ev Yu.V. Proizvodstvo elektroniki: Tekhnologiya, oborudovaniya, materialy, 2010, no. 2, pp. 35 – 38.

  14. Kostin A.V., Shumskikh I.Yu., Bozrikov V.S., Ruzanov A.V., Nikitin D.A. VI Vserossiiskaya nauchno-tekhnicheskoi konferentsii “Aktual’nye problemy raketno-kosmicheskoi tekhniki” (“VI Kozlovskie chteniya”): sbornik materialov, Samara, Samarskii nauchnyi tsentr RAN, 2019, vol. 2, pp. 55 – 62.

  15. Kostin A.V., Shumskikh I.Yu., Ruzanov A.V. XLIV Akademicheskie chteniya po kosmonavtike, posvyashchennye pamyati S.P. Koroleva i drugikh vydayushchikhsya otechestvennykh uchenykh – pionerov osvoeniya kosmicheskogo prostranstva: cbornik tezisov, Moscow, MGTU im. N.E. Baumana, 2020, vol. 2, pp. 264 – 267.

  16. Inkin A.I. Elektromagnitnye polya i parametry elektricheskikh mashin (Electromagnetic fields and parameters of electric motors), Novosibirsk, Izd-vo UKEA, 2002, 464 p.

  17. Nikol’skii V.V. Elektrodinamika i rasprostranenie radiovoln(Electrodynamics and radio wave propagation), Moscow, Nauka, 1978, 544 p.

  18. Dul’nev G.N., Semyashkin E.M. Teploobmen v radioelektronnykh apparatakh (Heat-exhange in radio-electronic devices), Leningrad, Energiya, 1968, 360 p.

  19. Poshekhonov P.V., Sokolovskii E.N. Teplovoi raschet elektronnykh priborov (Thermal calculation of electronic devices), Moscow, Vysshaya shkola, 1977, 156 p.

  20. John H. Lienhard IV, John H. Lienhard V. A heat transfer textbook. Thira edition, Cambridge, MA: Phlogiston Press, 2002, 750 p.


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