Date of Award


Degree Name

MS in Electrical Engineering


Electrical Engineering





A Flyback Inverter Topology without Electrolytic Input Capacitors as Energy Storage Element

Robert Baake

In today’s PV inverters, the high input capacitance, necessary for the energy storage during the slow 60Hz cycle is provided by bulky electrolytic capacitors. Liquid electrolyte stored in the capacitor is quickly evaporated due to above rating temperatures, leading to a rise in ESR (equivalent series resistance). The resulting elevated heat dissipation reduces efficiency and accelerates degradation, possibly leading to eventual failure of the inverter. The challenge is to replace these electrolytic capacitors with a different energy storage element. This thesis proposes a new inverter using a Flyback transformer to eliminate the use of electrolytic capacitors as energy storage. A 35W inverter prototype was designed and built to demonstrate the operation of the proposed inverter. Results show that the inverter is able to provide a square-wave AC output, without large electrolytic input capacitance, while meeting several design specifications.