Project Name: M4 Inverter: Modular, Multifunction, Multiport, and Medium-Voltage Utility-Scale Silicon Carbide PV Inverter
Funding Opportunity: Advanced Power Electronics Designs for Solar Applications
SETO Subprogram: Systems Integration
Location: Austin, TX
SETO Award Amount: $3 million
Awardee Cost Share: $840,000

This project team will develop and test a next-generation utility-scale photovoltaic (PV) inverter called the M4 inverter. The four Ms stand for modular, multifunction, multiport, and medium-voltage. The M4 will save costs by directly converting direct-current solar electricity to medium-voltage alternating current, eliminating the need for a bulky, low-frequency transformer. It will have three ports, one of which will be a direct-current port to connect with an energy storage device, providing functionalities that go beyond traditional solar generation.


The project team will conduct a comprehensive cost-benefit analysis and system operation optimization for the M4 inverter to quantify the potential reduction of the levelized cost of energy (LCOE). The team will develop 1 megavolt-ampere hardware using silicon carbide (SiC) power metal-oxide-semiconductor field-effect transistor (MOSFET) modules, and design a converter that minimizes power loss. The M4 will be capable of interfacing with 1,500-volt PV panels and high-voltage battery storage units with high charge and discharge rates. The team will use hardware-in-the-loop simulation—a testing technique that incorporates the complexity of a power plant—to verify the control before implementation.


The SiC power MOSFET inverter will have a novel soft-switching design to filter high-frequency electric current oscillations in the device and achieve high-energy efficiency. The M4’s modular configuration will reduce the manufacturing cost and improve reliability. The multiport inverter will enable battery energy storage co-located with solar arrays to be directly connected to the medium-voltage power grid to provide additional functionalities, including reactive power support, fast frequency regulation, solar power curtailment, and various grid support services. These advances will enable the drastic reduction of the LCOE.