Comparison of boost and LLC converter and active clamp isolated full-bridge boost converter for photovoltaic DC system

Abstract

DC collection network offers an attractive alternative to AC network for photovoltaic, as it avoids the charging current issues and reduces the size and weight. Variable voltage gain DC/DC converters play an important role in DC collection network. Two topologies suitable for photovoltaic DC collection are studied. Boost and LLC converter and active clamp isolated full-bridge boost converter are two converters with high and variable voltage conversion ratio suitable for the photovoltaic system. This work investigates the two converters comprehensively. The topologies are analysed so as to summarise and compare the characteristic of the converters. Soft switching condition is compared to help extend the zero voltage switching range. Voltage and current stress of the two converters are calculated. Loss comparison is made with the theoretical analysis. Advantages and disadvantages are summarised to get a deep insight into their application field.

Keywords

• DC-DC power convertors
• resonant power convertors
• zero voltage switching
• switching convertors
• active clamp
• full-bridge boost converter
• photovoltaic DC system
• DC collection network
• AC network
• charging current issues
• variable voltage gain DC/DC converters
• topologies
• photovoltaic DC collection
• high voltage conversion ratio
• variable voltage conversion ratio
• photovoltaic system
• zero voltage switching range