Abstract
Two major challenges in the transformerless photovoltaic (PV) inverters are the presence of common-mode leakage currents, and as in most single-phase converters the need for reliable and compact double-line-frequency power decoupling. In the proposed doubly grounded inverter topology with innovative active-power-decoupling approach, both of these issues are simultaneously addressed. The topology allows the PV negative terminal to be directly connected to the neutral, thereby eliminating the capacitive-coupled common-mode ground currents. The decoupling capacitance requirement is minimized by a dynamically variable dc-link with large voltage swing, allowing an all-film-capacitor implementation. Furthermore, the use of wide bandgap devices enables the converter operation at higher switching frequency, resulting in smaller magnetic components. The topology uses only four switches and potentially enables a high power density solution. The operating principles, design and optimization, and control methods are explained in detail, and compared with other transformer-less, active-decoupling topologies. A 3 kVA, 100/75 kHz single-phase hardware prototype at 400 V dc nominal input and 240 V ac output with a wide range of power factor has been developed using SiC MOSFETs with only 45 μF/1100 V dc-link capacitance. Extensive experimental results from the prototype are presented to validate the concept, design, and superior performance of the proposed topology.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 5188-5201 |
| Number of pages | 14 |
| Journal | IEEE Transactions on Power Electronics |
| Volume | 32 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 1 2017 |
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Keywords
- Active-power decoupling
- common-mode leakage current
- dc-ac converter
- doubly grounded
- high power density
- photovoltaic (PV)
- silicon carbide (SiC) MOSFETs
- single-phase inverter
- transformerless string inverter
- wide bandgap devices
ASJC Scopus subject areas
- Electrical and Electronic Engineering
Cite this
A capacitance-minimized, doubly grounded transformer less photovoltaic inverter with inherent active-power decoupling. / Xia, Yinglai; Roy, Jinia; Ayyanar, Raja.
In: IEEE Transactions on Power Electronics, Vol. 32, No. 7, 01.07.2017, p. 5188-5201.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A capacitance-minimized, doubly grounded transformer less photovoltaic inverter with inherent active-power decoupling
AU - Xia, Yinglai
AU - Roy, Jinia
AU - Ayyanar, Raja
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Two major challenges in the transformerless photovoltaic (PV) inverters are the presence of common-mode leakage currents, and as in most single-phase converters the need for reliable and compact double-line-frequency power decoupling. In the proposed doubly grounded inverter topology with innovative active-power-decoupling approach, both of these issues are simultaneously addressed. The topology allows the PV negative terminal to be directly connected to the neutral, thereby eliminating the capacitive-coupled common-mode ground currents. The decoupling capacitance requirement is minimized by a dynamically variable dc-link with large voltage swing, allowing an all-film-capacitor implementation. Furthermore, the use of wide bandgap devices enables the converter operation at higher switching frequency, resulting in smaller magnetic components. The topology uses only four switches and potentially enables a high power density solution. The operating principles, design and optimization, and control methods are explained in detail, and compared with other transformer-less, active-decoupling topologies. A 3 kVA, 100/75 kHz single-phase hardware prototype at 400 V dc nominal input and 240 V ac output with a wide range of power factor has been developed using SiC MOSFETs with only 45 μF/1100 V dc-link capacitance. Extensive experimental results from the prototype are presented to validate the concept, design, and superior performance of the proposed topology.
AB - Two major challenges in the transformerless photovoltaic (PV) inverters are the presence of common-mode leakage currents, and as in most single-phase converters the need for reliable and compact double-line-frequency power decoupling. In the proposed doubly grounded inverter topology with innovative active-power-decoupling approach, both of these issues are simultaneously addressed. The topology allows the PV negative terminal to be directly connected to the neutral, thereby eliminating the capacitive-coupled common-mode ground currents. The decoupling capacitance requirement is minimized by a dynamically variable dc-link with large voltage swing, allowing an all-film-capacitor implementation. Furthermore, the use of wide bandgap devices enables the converter operation at higher switching frequency, resulting in smaller magnetic components. The topology uses only four switches and potentially enables a high power density solution. The operating principles, design and optimization, and control methods are explained in detail, and compared with other transformer-less, active-decoupling topologies. A 3 kVA, 100/75 kHz single-phase hardware prototype at 400 V dc nominal input and 240 V ac output with a wide range of power factor has been developed using SiC MOSFETs with only 45 μF/1100 V dc-link capacitance. Extensive experimental results from the prototype are presented to validate the concept, design, and superior performance of the proposed topology.
KW - Active-power decoupling
KW - common-mode leakage current
KW - dc-ac converter
KW - doubly grounded
KW - high power density
KW - photovoltaic (PV)
KW - silicon carbide (SiC) MOSFETs
KW - single-phase inverter
KW - transformerless string inverter
KW - wide bandgap devices
UR - http://www.scopus.com/inward/record.url?scp=85027531981&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85027531981&partnerID=8YFLogxK
U2 - 10.1109/TPEL.2016.2606344
DO - 10.1109/TPEL.2016.2606344
M3 - Article
AN - SCOPUS:85027531981
VL - 32
SP - 5188
EP - 5201
JO - IEEE Transactions on Power Electronics
JF - IEEE Transactions on Power Electronics
SN - 0885-8993
IS - 7
ER -