Digitalno krmiljen dvosmerni stikalni pretvornik za monitoring PV modulov v mobilnih aplikacijah

MEH PEER, JAŠA VID (author), Jankovec, Marko (mentor)

Fotovoltaika je v zadnjih nekaj desetletjih doživela izjemen razvoj. Za doseganje takšnega razvoja so ključnega pomena kvalitetno testiranje in natančne meritve. Zaradi vse večje razširjenosti fotovoltaike in novih trendov v avtomobilski industriji se fotovoltaika postopoma integrira tudi v vozila. Takšna vozila imenujemo vozila z integriranimi PV moduli (angl. Vehicle Integrated PV, VIPV). Ker so VIPV sistemi izpostavljeni zelo dinamičnim razmeram, se izkaže, da standardna merilna oprema ni primerna za opravljanje meritev v realnih pogojih delovanja. Potrebna je posebna merilna oprema, ki omogoča meritve pri hitro spreminjajočih se pogojih. V tem delu smo identificirali tipične pogoje, katerim so izpostavljeni VIPV sistemi in določili zahteve in funkcionalnost merilnega sistema, ki bi omogočal izvajanje kakovostnih meritev med tipičnim delovanjem VIPV sistemov. Osredotočili smo se na zasnovo in razvoj močnostnega dela sistema, ki omogoča dvosmerno pretvorbo energije med PV modulom in baterijo ter kompenzacijo padcev napetosti na priključnih vodnikih. Za zagotavljanje visoke prilagodljivosti sta bila implementirana digitalno krmiljena stikalna pretvornika (navzdol in navzdol-navzgor) z uporabo naprednih perifernih enot mikrokrmilnika, ki poleg krmiljenja tranzistorjev ter merjenja vhodnih in izhodnih veličin tudi izvaja algoritem za sledenje točki maksimalne moči. Rezultati testiranj so pokazali, da oba načrtovana pretvornika delujeta učinkovito in izpolnjujeta zastavljene cilje. Pretvornik navzdol se je izkazal kot primeren za kompenzacijo padcev napetosti, saj valovitost izhodne napetosti pri največji obremenitvi ne presega 36 mVrms in tako v sistem ne vnaša dodatnega šuma. Pretvornik navzdol-navzgor dosega izkoristek pretvorbe nad 90 % v celotnem območju delovanja in v najoptimalnejših pogojih doseže maksimalen izkoristek 98,4 %. Implementiran algoritem sledenja točke pri maksimalni moči po metodi spremeni in odčitaj (P&O) dosega izkoristek sledenja nad 99 % pri frekvenci sledenja 100 Hz, kar je tudi zahteva za mobilne VIPV sisteme in ga uvršča daleč nad konkurenčne rešitve na trgu.

• Language: Slovenian
• Keywords: fotovoltaika, VIPV, stikalni pretvornik, dvosmerni prenos energije, sledenje točki maksimalne moči
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2024
• PID: 20.500.12556/RUL-161055
• Publication date in RUL: 06.09.2024

Secondary language

• Language: English
• Title: Digitally Controlled Bidirectional Switch Mode Power Converter for Monitoring PV Modules in Mobile Applications

Abstract

Photovoltaics have experienced remarkable development over the past few decades. Key to achieving this progress are high-quality testing and precise measurements. With the increasing prevalence of photovoltaics and new trends in the automotive industry, photovoltaics are gradually being integrated into vehicles, known as Vehicle Integrated Photovoltaics (VIPV). Since VIPV systems are exposed to highly dynamic conditions, standard measurement equipment has proven inadequate for conducting measurements under real operating conditions. Therefore, specialized measurement equipment that can operate under rapidly changing conditions is necessary. In this thesis, we identified the typical conditions to which VIPV systems are exposed and determined the requirements and functionalities of a measurement system capable of performing quality measurements during typical VIPV system operations. We focused on the design and development of the power section of the system, which enables bidirectional energy conversion between the PV module and the battery and compensates for voltage drops on the connecting conductors. To ensure high adaptability, digitally controlled switching converters (buck and buck-boost) were implemented using advanced microcontroller peripheral units. These not only control the transistors and measure input and output quantities but also execute the Maximum Power Point Tracking (MPPT) algorithm. Test results demonstrated that both designed converters operate efficiently and meet the set objectives. The buck converter proved to be suitable for voltage drop compensation, with output voltage ripple at maximum load not exceeding 36 mVrms, thereby introducing no additional noise into the system. The buck-boost converter achieves a conversion efficiency above 90 % across the entire operating range, reaching a maximum efficiency of 98,4 % under optimal conditions. The implemented MPPT algorithm, based on the perturb and observe (P&O) method, achieves a tracking efficiency of over 99 % at a tracking frequency of 100 Hz, which is a requirement for mobile VIPV systems and places it well above competing solutions on the market.

• Keywords: photovoltaics, Vehicle Integrated Photovoltaics (VIPV), switching converter, bidirectional energy transfer, Maximum Power Point Tracking (MPPT)