Low-loss DC to AC converter system for stand alone photovoltaic applications

A composite converter with a high-frequency link was investigated for stand alone DC-to-AC-conversion applications such as batteries charged by photovoltaic panels. The secondary converter was a supply-commutated high-frequency bridge, while the primary inverter was investigated further. A center-tap transformer inverter was chosen, and two approaches were used to minimize switching losses. The first approach was to implement regenerative snubbers. The second was a new method that forced zero voltage switching (ZVS). A PSPICE simulation of the second method showed soft switching under no-load conditions, while the experimental setup showed soft switching under both no-load and load conditions up to 2 kVA. This approach offers, in addition to ZVS, features such as greatly reduced losses, a high efficiency, and low implementation cost. It is believed that this approach leads to the optimum configuration for DC-to-220 V-AC-conversion for low-voltage photovoltaic and battery application