Abstract
LVDC networks offer improved conductor utilisation on existing infrastructure and reduced conversion stages, which can lead to a simpler and more efficient distribution network. However, LVDC networks must continue to support AC loads, requiring efficient, low distortion DC-AC converters. In addition, there are increasing numbers of DC loads on the LVAC network requiring controlled, low distortion, unity power factor AC-DC converters with increasing capacity, and bi-directional capability. An efficient AC-DC/DC-AC converter design is therefore proposed in this paper to minimise conversion loss and maximise power quality. A comparative analysis is carried out for a conventional IGBT 2-level converter, a SiC MOSFET 2-level converter, a Si MOSFET MMC and a GaN HEMT MMC, in terms of power loss, reliability, fault tolerance, converter cost, and heatsink size. The analysis indicates that the 5-level MMC with parallel-connected Si MOSFETs is an efficient, cost effective converter for LV converter applications. MMC converters suffer negligible switching loss, which enables reduced device switching without loss penalty from increased harmonics and filtering. Optimal extent of parallel connection for MOSFETs in an MMC is investigated. Experimental results are presented for current sharing in parallel-connected MOSFETs, showing reduction in device stress and EMI generating transients through the use of reduced switching.
Highlights
There have been reported cases of distribution networks operating close to their capacity limits [1]
Reports state that low-voltage direct-current (LVDC) technology could provide large power capacities without replacing the existing cables [2,3,4]
LVDC networks present the additional benefit of no reactive power flow and allow reduction in the number of conversion stages [5,6,7]
Summary
There have been reported cases of distribution networks operating close to their capacity limits [1]. Reports state that low-voltage direct-current (LVDC) technology could provide large power capacities without replacing the existing cables [2,3,4]. LVDC networks present the additional benefit of no reactive power flow and allow reduction in the number of conversion stages [5,6,7]. These systems will retain the need to supply local AC loads which must be provided by DC–AC converters meeting the same stringent performance criteria outlined above for AC–DC converters supplying DC loads such as electric vehicles (EVs). Issues of power quality affect LVDC networks and are complicated by the need to supress DC harmonics associated with single-phase loads and to have resilience to DC network faults
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
