Low-voltage, high-efficiency switch-mode high-power inverters for AC link converter applications

A 30 kVA high-frequency link converter, which consists of 6×5 kVA center-tap power block topologies operating in parallel, is considered for battery-fed DC-AC converter applications. Practical solutions for minimizing currents circulating between the different power blocks, avoiding transformer saturation in forced commutated center-tap topologies, and minimizing transistor-on losses are incorporated and illustrated by means of practical measurements and results. A simple single-capacitor snubber network, operating in parallel with a second-stage capacitor snubber, is used for these converter types. Typical applications include mobile and telecommunications uninterruptible power supply systems; high AC-voltage loads fed from photovoltaic or hybrid energy systems; and battery-fed, mobile, variable-speed AC and DC drives