Split-phase switched-capacitor ac-ac converter

This study proposes an ac-ac direct static power converter based on the switched-capacitor (SC) principle, aimed at supplying a split-phase system from an ac single-phase voltage source. The main advantages of the proposed split-phase SC converter are (i) the provision of three output voltages, two being equal to the input voltage and one being twice the input voltage, (ii) balanced output voltages even under unbalanced loads, (iii) the absence of magnetic elements in the power circuit, (iv) the stress voltages in all components being equal to the input voltage, (v) the ability to be bidirectional, (vi) high efficiency and (vii) high power density. These characteristics make the proposed converter suitable for modern applications where a split-phase system needs to be generated from a renewable energy source, distributed generation system, uninterruptible power supply (UPS), battery bank, electric/hybrid vehicle, smart grid or even the electrical grid itself. To verify the performance of the proposed converter, a 1 kW prototype was built and tested with standard voltages, such as 110 V input voltage and 110 V/110 V/220 V output voltages. The efficiency, output voltage regulation, tests with input voltages of 16.6, 60 and 400 Hz and other experimental results are reported herein.