Inverter Topologies

[davidbrady]

True, we're still in search of the perfect sinewave inverter technology. Probably, the best we've had so far in terms of waveform is the mechanical rediline used in the older birds! Unfortunately it's shortcomings are many. I think the major advancements in inverter technology over the last 15 years are in the area of configuration, control, and monitoring. The latest inverters sport all the user interface features we've all grown accustomed to in our electronic gadgets: remote access, web browser user interfaces, real data communication protocols to aid in integrating with local and remote management platforms, stackability in 3 phase, or in parallel/series for twice the voltage and/or twice the current. In terms of semiconductor advancements, integrated gate bipolar transistors (IGBTs) are all the rage these days. Typical inverters use banks of MOSFET power transistors. My Trace SW has 54 MOSFETs to provide the 650A of DC current needed for AC surge loads like starting my CruisAir ACs. There are 1200V 1000A IGBTs on the market today that can reduce this number to 2 devices. The trouble is IGBTs are still expensive. They're used in variable frequency motor controls for electric cars and in 3 phase variable speed motor drives for CNC machines but they're still too expensive for 4KW inverters.