Razvoj stikalnega pretvornika navzdol za uporabo v avtomobilski industriji

MLAKAR, LUKA (author), Žemva, Andrej (mentor)

Cilj diplomskega dela je bil raziskati možne rešitve za razvoj stikalnega pretvornika navzdol za uporabo v avtomobilski industriji. Stikalni pretvorniki so lahko zelo problematični z vidika elektromagnetnih emisij, saj pri njihovem delovanju prihaja do hitrih sprememb toka in napetosti, kar lahko inducira močna elektromagnetna polja. To je še posebej problematično, saj morajo naprave v tej industriji ustrezati zelo zahtevnim standardom EMC. Te standarde narekujejo tako kupci kot legalne direktive in uredbe. Osnovni standard, ki opisuje zahtevane merilne metode in različne limitne razrede za elektromagnetne emisije za naprave, ki se nahajajo v avtomobilih, ladjah in ostalih vozilih z notranjim izgorevanjem, je CISPR 25, ki ga je razvila mednarodna elektrotehnična komisija. V podjetju smo težave z elektromagnetnimi emisijami reševali z uporabo kovinskih pokrovov, kar pa na veliko novih izdelkih ni več izvedljivo zaradi pomanjkanja prostora. Ena izmed možnih rešitev je bila uporaba stikalnih tuljav s kovinskim ohišjem. V sklopu diplomskega dela sem načrtal tri vezja. Prvo vezje je bilo realizirano na dvoslojni tiskanini, opremljeno pa je bilo s kovinskim ščitom. Ta preverjena rešitev nam bo služila za referenco. Drugo vezje je bilo tudi realizirano na dvoplastni tiskanini, a je namesto kovinskega pokrova bilo opremljeno s tuljavo s kovinskim ščitom. Tretje vezje je bilo podobno kot drugo vezje, le da je bilo realizirano na štiriplastni tiskanini. Načrtovana vezja sem evalviral v internem laboratoriju EMC podjetja Hella Saturnus Slovenija. Pomeril sem sevalne emisije v frekvenčnem območju med 150 kHz in 960 MHz ter prevajalne emisije med 150 kHz in 108 MHz. Najstrožjemu limitnemu razredu, ki ga predpisuje CISPR 25, je v celoti ustrezalo le vezje s kovinskim ščitom. V veliki večini pa je te limite izpolnjevalo tudi štiriplastno vezje s kovinskim ohišjem. Čeprav ta rešitev ni v celoti izpolnila zahtev, se je izkazala za zadostno in bo verjetno uporabljena na prihodnjih projektih.

• Language: Slovenian
• Keywords: EMC, stikalni pretvornik, elektromagnetne emisije.
• Work type: Bachelor thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2023
• PID: 20.500.12556/RUL-147130
• COBISS.SI-ID: 156933123
• Publication date in RUL: 23.06.2023

Secondary language

• Language: English
• Title: Development of a down converter switch for the usage in automotive industry

Abstract

The goal of the thesis was to explore possible solutions for the development of a down converter switch for use in the automotive industry. Switching converters can be very problematic in terms of electromagnetic emissions, as rapid changes in current and voltage during their operation can induce strong electromagnetic fields. This is particularly problematic because devices in this industry must comply with very demanding EMC standards, which are dictated by both customers and legal directives and regulations. The basic standard that describes the required measurement methods and different limit classes for electromagnetic emissions for devices located in automobiles, ships, and other internal combustion engine vehicles is CISPR 25, developed by the International Electrotechnical Commission. In the company, we solved problems with electromagnetic emissions by using metal shields, but this is no longer feasible for many new products due to the lack of space. One possible solution was to use switch inductors with integrated metal shields. During the thesis, I designed three circuits. The first circuit was implemented on a double-layer PCB and was equipped with a metal shield. This proven solution will serve as a reference. The second circuit was also implemented on a double-layer PCB, but instead of a metal shield, it was equipped with a inductor with an integrated shield. The third circuit was similar to the second circuit but was implemented on a 4-layer PCB. I evaluated the designed circuits in the company's internal EMC laboratory. I measured radiation emissions in the frequency range between 150 kHz and 960 MHz and conducted emissions between 150 kHz and 108 MHz. The circuit with the metal cover fully complied with the strictest limit class prescribed by CISPR 25. However, the four-layer circuit with the metal casing mostly complied with these limits as well. Although this solution did not fully meet the requirements, it proved to be sufficient and will likely be used in future projects.

• Keywords: EMC, buck converter, electromagnetic emmisions