Inverters are considered key components to enable the integration of renewable energy sources into the grid. These power processing circuits convert dc voltage into ac, and are needed in numerous applications, including residential photovoltaic (PV) systems. The state of the art inverters have several shortcomings such as limited voltage gain, low power density, high failure rates, and low efficiency.
This thesis proposes a new inverter topology that can overcome the problems associated with most conventional inverters. The proposed inverter is a single stage configuration, and employs five semiconductor switches, in which one is operating at a high frequency and the rest are operating at the fundamental frequency of the load. The proposed inverter is capable of both stepping up and stepping down the voltage. This is a unique advantage over most state of the art single-stage inverters, which can either step up or step down the voltage. In the proposed inverter, a small capacitor transfers power from the input towards the output. The inverter is designed and controlled such that the required link capacitance is very low; therefore, film capacitors that have longer lifetime compared to electrolytic capacitors can be used. Unlike most conventional isolated inverters that use low frequency transformer (LFT), in the proposed inverter a high frequency transformer (HFT) can be used for providing galvanic isolation. This feature decreases the total size of the system.
The proposed inverter can be modified slightly to offer soft-switching, which significantly increases the efficiency.
In this thesis, the principles of the operation of the proposed inverter is studied, and its performance is evaluated through simulation and experiment.
Advisor: Professor Mahshid Amirabadi
Professor Mahshid Amirabadi
Professor Ali Abur
Professor Bradley Lehman