A three-phase ac/dc converter with high-frequency isolation can be realized as a monolithic three-phase or as a phase-modular system by combining three single-phase Power Factor Correction (PFC) rectifier modules with individual isolated dc-dc converters. Advantageously, for a phase-modular system the module configuration can be changed depending on the instantaneous input-output voltage ratio (i.e., a star-(Y)-or a delta-(∆)-arrangement such that wide voltage ranges can be covered without a massive over-dimensioning of the main power components. However, the main disadvantage of a phase-modular converter realization is the fact that the input power of each PFC rectifier module pulsates at twice the mains frequency (which is inherent to single-phase power conversion) such that large dc-link capacitors are required. Recent literature predicts a substantial power pulsation reduction enabled by means of third-(3 rd )harmonic injection modulation which is applicable for the Y-connection (where a common-mode (CM) / zero-sequence (ZS) voltage is injected), and for the ∆-connection of the three single-phase PFC rectifier modules (where a CM / ZS current is injected). This changes the distribution of the power flow in the three-phase system and the power pulsation is shifted to higher frequencies. This paper experimentally verifies and extends the dc-link energy storage requirement reduction of the 3 rd -harmonic injection modulation concept: In a first step, the derivation of the harmonic injection concept is recapitulated and suitable control methods are discussed for both CM voltage (Y-arrangement) and CM current (∆-arrangement) injection. Further, an alternative CM voltage injection strategy with simplified reference generation based only on the instantaneous grid voltage measurements is presented and compared to the pure 3 rd -harmonic injection modulation. Measurement results obtained from a 6 kW prototype reveal a dc-link voltage variation and/or energy buffering reduction by up to 38.6 % enabled by the harmonic injection modulation compared to conventional operation without 3 rd -harmonic injection modulation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.