skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Generalized Architecture of a GaN-Based Modular Multiport Multilevel Flying Capacitor Converter
This paper proposes a generalized Gallium Nitride (GaN) based modular multiport multilevel flying capacitor architecture. In other words, the attractive flying capacitor multilevel (FCML) design and the full-bridge unfolding circuit are employed to develop a multiport multilevel converter architecture that fits various applications. Each module can be designed to contain any combination of AC and DC ports connected through DC-to-DC and DC-to-AC power conversion paths. These conversion paths are FCML topologies that can be designed with any number of levels; the DC-to-AC paths incorporate the full-bridge unfolding circuit. Two example prototypes with open-loop control, three-port and four-port, have verified this generalized architecture. A single module 3 kW three-port four-level prototype with two DC ports and an AC port has achieved a compact size of 11.6 in 3 (4.8 in ×4.3 in × 0.56 in) and a high power density of 258.6 W/in 3 . The three ports are connected through DC-to-AC and DC-to-DC paths that have achieved peak efficiencies of 98.2% and 99.43%, respectively. The total harmonic distortion (THD) of the AC port's voltage and current are 1.26% and 1.23%, respectively. It operates at a high switching frequency of 120 kHz because of the GaN switches and has an actual frequency (inductor's ripple frequency) of 360 kHz thanks to the frequency multiplication effect of the FCML. The four-port prototype contains three DC ports and an AC port and achieved similar high figures of merit. These experimental results of the two prototypes of high efficiency, power density, and compact size are presented in this article and highlight this architecture's promising potential. The choice of the number of modules, ports, and levels depends on the application and its specification; therefore, this proposed generalized structure may serve as a reference design approach for various applications of interest.  more » « less
Award ID(s):
2103442
PAR ID:
10412579
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
IEEE Transactions on Power Electronics
ISSN:
0885-8993
Page Range / eLocation ID:
1 to 21
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; (, 2022 IEEE Energy Conversion Congress and Exposition (ECCE))
    Electric Vehicles (EV s) that are wholly charged from renewable energy resources to avoid indirect emissions are the most effective solution for climate change and energy insecurity. This paper proposes a four-port isolated PV -based EV charging architecture that contains an LLC input stage to harvest solar energy with high efficiency because of its dual PV input ports with independent MPPT capabilities that share a common resonant tank. This architecture also includes a GaN -based flying capacitor multilevel (FCML) output stage with two GaN-based FCML converter paths, DC and AC paths. These two paths transfer power with high efficiency to two output ports, a DC port for direct DC charging and an AC port for level-2 AC charging. The system has been verified by building a 2 kW prototype module, and experimental results are presented. 
    more » « less
  2. ; (, IECON 2021 – 47th Annual Conference of the IEEE Industrial Electronics Society)
    A three-port multilevel inverter with two DC ports and an AC port using Flying Capacitor Multilevel (FCML) design based on Gallium Nitride (GaN) switches is proposed in this paper. Recently, FCML inverter has shown a superior ability for power conversion with high power density, improved Total Harmonic Distortion (THD), and efficiency. The presented three-port multilevel inverter fits various applications such as battery and photovoltaic (PV) grid integration and standalone AC load. The proposed inverter is experimentally verified by building a 3-kW prototype using GaN switches which include two 4-level FCML converter paths, each share the same bus capacitor (C bus ), which links them together. One FCML path is 1 kW that incorporates an unfolder for the DC-to-AC conversion and has achieved a peak efficiency of 98.2% with AC voltage and current THDs of 1.26% and 1.23%, respectively. While the second FCML converter path is 2 kW used for the DC-to-DC conversion and has achieved a 99.43% peak efficiency. 
    more » « less
  3. ; (, IEEE Open Journal of Power Electronics)
    In this article, a high-efficiency and high-density 2.5 kW four-level interleaved flying capacitor multilevel (FCML) totem-pole bridgeless power-factor-correction (PFC) rectifier with 200 V GaN devices is analyzed, designed, and tested. This 2.5 kW four-level continuous conduction mode (CCM) GaN totem pole PFC operates with three times inductor current ripple frequency than that of the switching frequency which significantly reduces the size of the inductors while also supporting switching loss reduction. This article compares the loss of the two-level CCM GaN totem-pole PFC, four-level non-interleaved FCML PFC and interleaved four-level FCML PFC with the same ripple frequency (300 kHz) and shows that the interleaved four-level CCM GaN PFC has much less device loss. In addition, this article discusses the detailed EMI spectrum analysis and derivation of the mathematical model for determining the attenuation requirement of the four-level interleaved FCML PFC converter followed by volumetric co-optimization of AC-side passives i.e., the boost inductor and differential mode (DM) EMI filter. A 2.5 kW four-level interleaved FCML GaN totem-pole PFC prototype with an optimized 94 kHz switching frequency is developed and tested in this article. The converter exhibits a peak efficiency of 99.14% with system power density reaching 89.47 W/inch3. 
    more » « less
  4. ; (, 2022 IEEE 7th Southern Power Electronics Conference (SPEC))
    The size, weight, power density, cost, and efficiency are crucial factors that should be considered when designing or employing power electronics converters for a specific application. Therefore, comparing different converters to investigate which converter provides better figures of merit at the same application and operating condition is essential. This paper uses theoretical, simulation and experimental comparisons between the two-level and multilevel converters. The DC-DC two-level buck and the flying capacitor multilevel (FCML) buck converters are chosen to carry out the theoretical, simulation and experimental prototypes when both employ Gallium Nitride (GaN) power semiconductor switches. It was found that the FCML converter inherently provides superior performance and figures of merit over both the two-level and multilevel converters. Simulation and experimental results that validate each other are provided in this paper. 
    more » « less
  5. ; ; (, 2019 20th Workshop on Control and Modeling for Power Electronics (COMPEL))
    This work explores the mechanisms and limitations of natural voltage balancing in flying capacitor multilevel (FCML) DC-DC converters. A simple discrete-time state space model is used to explore the fundamental conditions that will lead to (or prevent) natural balance of flying capacitor voltages, along with the balancing dynamics. The treatment is used to highlight straightforward ways to alleviate problems with natural imbalance by adjusting the switching scheme. The model is compared against circuit simulations and the proposed switching scheme is verified in a hardware prototype. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email