Development of a dc-to-ac inverter based on waveshaping

A new topology for utility interactive dc-ac inverters was explored. The approach is limited to the single phase, 2 to 10 kW power levels typical of residential photovoltaic applications. The approach combines two of the three basic inverter operations, waveshaping and regulation, in a single dc-dc converter stage. The output of this stage is a full wave rectified sine wave. An inversion stage follows, performing the third basic inverter operation. The output is a current sine wave. This approach features unity power factor and less than 2% total current harmonic distortion. A 1 kW prototype was constructed using a buck converter for the dc-dc stage switching at approximately 20 kHz. Efficiency was generally above 90%. A cost breakdown of the prototype indicates that the inverter can be built to meet the cost goals for this class of inverter.