Low cost DC to AC converter for photovoltaic power conversion in residential applications

The development and experimental results of a low-cost 500-W DC-AC power converter for photovoltaic power conversion in residential applications are described. The converter uses low-cost technology usually applied in consumer products. The DC-AC converter is specially designed for operation at a wide DC input voltage range (30-170 V) in order to allow optimal power conversion with an arbitrary number of series connected solar arrays. A step-up chopper is used for MPP tracking and provides a constant 200-V DC link for the following push-pull power converter. This galvanic isolating power converter operates at 100 kHz and controls the current in the mains sinusoidally. A thyristor bridge alternates the current after each half line period. The required auxiliary power is kept below 7 W and is taken from the choke of the step-up chopper.>