Three Phase Inverters for Grid Connected PV Applications
European Photovoltaic Solar Energy Conference, (2001)Abstract
This paper compares single-phase and three-phase inverters for grid-connected
photovoltaic systems. It considers some of the fundamental performance
characteristics, and compares the ratings, size, quantities, and
the relative cost of the major components, as well as some grid-connection
requirements. In terms of power semiconductor ratings, there is an
increased power throughput in a three-phase inverter. Also, magnetic
components like filter inductors and line-frequency transformers
require less material and therefore they can be smaller, lighter,
and cheaper. The DC link capacitor of a three-phase inverter has
significantly less ripple current and can be substantially smaller
without compromising lifetime and reliability. However, the control
requirements and the quantity of auxiliary electronics are generally
greater for a three-phase inverter. The three-phase grid connection
is not always a serious impediment, and the potential to utilise
components commonly found in small three-phase motor drive products
could be a major cost benefit. The advantages of three-phase inverters
described in this paper provide a designer with a number of degrees
of freedom in which they can trade off performance and cost, and
it should be possible to achieve an improvement over single-phase
inverters at lower power levels than have previously been considered
practical