Note that Google Ventures is an investor in Transphorm, a company that doesn’t make solar inverters but is trying to make gallium nitride more efficient to reduce energy loss in solar inverters, motor drives, power supplies and servers.
Some of the earliest inverters were rotary converters and motor generators. Rotary converters were used in railway electrification and were rather large devices (pictured above). Later, vacuum tubes and gas-filled tubes were used. The thyatron is an example of such a gas-filled tube.
While the progress in technological development may sometimes seem slow, if you compare today’s inverters with technology from previous decades, you can see a lot of progress, though inverters typically don’t get the press other inventions do, such as solar panels and wind turbines.
In fact, the Google Little Box Challenge is likely to be the largest prize ever offered for better solar power inverter design, and so will probably generate some much-needed press for the often less-noticed, but essential devices.