This project aims to develop an early-stage, functional prototype inverter, with appropriate control and modulation schemes to validate performance and eliminate technology risks. The proposed photovoltaic (PV) inverter topology uses a low-cost, reliable, and efficient thyristor, which replaces six active switches, typically insulated-gate bipolar transistors, and eliminates the bulky DC bus capacitor and the output AC line filter. In power semiconductor switches, passive components, and their supporting structures account for a majority of the cost in a typical converter. This topology would allow a significant cost reduction potential.
The research team will focus on proving technical feasibility of thyristors and identifying any technical risks through simulation model and modulation scheme development, as well as prototype testing. The 10 kilowatt functional prototype will be built to demonstrate costs and weight reduction potential. The prototype will also demonstrate high efficiency by reducing power losses in the DC-AC inverter and AC line filter with a target efficiency of more than 98%.
This project will bring thyristors off the shelf to enable a new cost curve for string-level inverters. By avoiding the use of insulated-gate bipolar transistors, an innovative and simple string inverter architecture is possible that could increase string inverter lifetime. The estimated 30% cost reduction and 40% weight reduction potential of this proposal would help to reduce the price of commercial PV inverters from $0.20 per watt to $0.11 per watt.