Circuits and Control for High-Performance Grid-tied Ac-Dc Conversion Systems

Zitao Liao, Robert Pilawa-Podgurski, Seth R. Sanders, Duncan Callaway and Minjie Chen

EECS Department
University of California, Berkeley
Technical Report No. UCB/EECS-2022-22
May 1, 2022

http://www2.eecs.berkeley.edu/Pubs/TechRpts/2022/EECS-2022-22.pdf

Ac-dc (and dc-ac) power converters are the interfaces between the electrical grid and the systems for emerging applications such as electric vehicle (EV) charging, renewable energy source integration, data center power delivery, consumer electronics and numerous other applications. In this dissertation, new circuit topologies and control techniques to improve the performance for both single-phase and three-phase grid-tied converters are explored for three major conversion scenarios: high power bidirectional single-phase ac-dc converters for EV charging and data center applications, low power single-phase ac-dc converters for consumer electronics, and high power three-phase ac-dc converters. For single-phase conversion, the challenge of twice-line frequency energy bu ering is addressed with active bu ering techniques that can signi cantly reduce the required capacitor size compared to conventional solutions. Through the development of active bu ers with systematic multi-objective optimization methods and associated advanced digital control, the energy utilization ratios of the passive components are much improved, and the system losses are optimized. For threephase conversion, control and modulation techniques to reduce computational complexity and inductor current ripple are proposed and validated. The proposed circuit topologies and control techniques for both single-phase and three-phase are all validated with high performance hardware demonstrations. Some of the highlighted ones in this dissertation are: a 6 kW, 400 Vdc single-phase liquid-cooled EV charger with optimized series-stacked buffer, achieving record power density; a 6 kW 400 Vdc three-phase multilevel recti er with advanced digital control techniques; an active single-phase buffer with the smallest reported capacitor size for 2 kW, 400 Vdc inverters; a compact active buffer for 65 W USB-C charger.

Advisor: Robert Pilawa-Podgurski


BibTeX citation:

@phdthesis{Liao:EECS-2022-22,
    Author = {Liao, Zitao and Pilawa-Podgurski, Robert and Sanders, Seth R. and Callaway, Duncan and Chen, Minjie},
    Title = {Circuits and Control for High-Performance Grid-tied Ac-Dc Conversion Systems},
    School = {EECS Department, University of California, Berkeley},
    Year = {2022},
    Month = {May},
    URL = {http://www2.eecs.berkeley.edu/Pubs/TechRpts/2022/EECS-2022-22.html},
    Number = {UCB/EECS-2022-22},
    Abstract = {Ac-dc (and dc-ac) power converters are the interfaces between the electrical grid and the
systems for emerging applications such as electric vehicle (EV) charging, renewable energy
source integration, data center power delivery, consumer electronics and numerous other applications.
In this dissertation, new circuit topologies and control techniques to improve the
performance for both single-phase and three-phase grid-tied converters are explored for three
major conversion scenarios: high power bidirectional single-phase ac-dc converters for EV
charging and data center applications, low power single-phase ac-dc converters for consumer
electronics, and high power three-phase ac-dc converters. For single-phase conversion, the
challenge of twice-line frequency energy buering is addressed with active buering techniques
that can signicantly reduce the required capacitor size compared to conventional
solutions. Through the development of active buers with systematic multi-objective optimization
methods and associated advanced digital control, the energy utilization ratios of
the passive components are much improved, and the system losses are optimized. For threephase
conversion, control and modulation techniques to reduce computational complexity
and inductor current ripple are proposed and validated. The proposed circuit topologies
and control techniques for both single-phase and three-phase are all validated with high
performance hardware demonstrations. Some of the highlighted ones in this dissertation
are: a 6 kW, 400 Vdc single-phase liquid-cooled EV charger with optimized series-stacked
buffer, achieving record power density; a 6 kW 400 Vdc three-phase multilevel rectier with
advanced digital control techniques; an active single-phase buffer with the smallest reported
capacitor size for 2 kW, 400 Vdc inverters; a compact active buffer for 65 W USB-C charger.}
}

EndNote citation:

%0 Thesis
%A Liao, Zitao
%A Pilawa-Podgurski, Robert
%A Sanders, Seth R.
%A Callaway, Duncan
%A Chen, Minjie
%T Circuits and Control for High-Performance Grid-tied Ac-Dc Conversion Systems
%I EECS Department, University of California, Berkeley
%D 2022
%8 May 1
%@ UCB/EECS-2022-22
%U http://www2.eecs.berkeley.edu/Pubs/TechRpts/2022/EECS-2022-22.html
%F Liao:EECS-2022-22