Design and analysis of quasi-resonant high-gain impedance source DC–DC converter for DC microgrid

ABSTRACT

This paper presents a quasi-resonant, isolated, high-gain, Y-source, DC/DC converter for a DC microgrid. Here, quasi-resonance is obtained by the LC tank during the shoot through period, resulting in natural commutation at the turn-off instant of the MOSFETs. The LC tank is formed by an additional parallel capacitor $(C_p)$ and transformer leakage inductance. The high voltage gain is obtained by including an isolation transformer with lower turns ratio, coupled inductor and voltage doubler. Here, frequency is modulated to regulate the output voltage with ON period $(T_{on})$ constant. This converter’s zero current switching feature allows it to operate at a higher switching frequency and thus enhances the power density and efficiency. This converter’s continuous input current feature is an added advantage. The proposed converter inherits all the benefits of traditional impedance source converters. Finally, a 250 W hardware prototype is developed, and its performance is tested in the laboratory.

KEYWORDS:

• DC microgrid
• high-gain DC/DC converters
• impedance source converter (ISC)
• zero current switching (ZCS)

Abbreviations

$A_p$	=	Area product
AC	=	Alternating current
CIC	=	Continuous input current
DC	=	Direct current
DG	=	Distributed generation
DIC	=	Discontinuous input current
$d_{ST}$	=	Shoot-through duty
HFT	=	High-frequency transformer
ISC	=	Impedance source converter
LED	=	Light-emitting diodes
PV	=	Photovoltaic
RCD	=	Resistor-capacitor-diode
RES	=	Renewable energy sources
ZCS	=	Zero current switching

Disclosure statement

No potential conflict of interest was reported by the author(s).