Synchronous Combined Cuk-SEPIC Converter for Single Phase Transformerless Solar Inverter

In this paper, a bidirectional power electronic converter based on the synchronous combined Cuk-SEPIC converter has been presented for single-phase transformerless solar power generation systems. The proposed topology completely eliminates the common-mode voltage, hence the common-mode current. The proposed converter generates a bipolar output with respect to the common ground; hence a simple half-bridge can be used for grid integration. The proposed synchronous operation allows significant reduction of the DC bus capacitance required for active power decoupling compared to the previously reported asynchronous operation. The converter operation, design, along with the simulation results are presented for a 1 kW prototype at 230 V, 50 Hz. Experimental results of the converter at full load with lagging, leading, and unity power factor conditions are reported as well.