Converting the energy produced by the sun and wind into usable electricity is critical to incorporating large-scale renewable energy systems into our existing grid infrastructure. Enter the grid-tied inverter—an expertly engineered piece of equipment whose primary role is to change the direct current generated by PV panels, wind turbines or batteries into high-voltage, 60-Hz alternating current that can be transmitted on power lines, or sent to a transformer to power loads in a home or business. Although essential; inverters are heavy, often finicky, and use proprietary components and design algorithms, making make them an extremely expensive component of any renewable energy system.
Currently, inverter manufacturers have to build every inverter from scratch. This leads to higher costs for components, design and labor. Finding a smarter, more flexible and cheaper solution to connecting renewable energy resources to the grid is one of the goals of the Electric Infrastructure Systems Research program at the National Renewable Energy Laboratory (NREL).
NREL, with industrial partner Semikron, and with funding from the California Energy Commission, has developed a prototype 50-kilowatt inverter with an integrated modular power block to control the flow of energy from a PV system or wind turbine onto the electric grid. The power block is the size of a microwave, and is considered to be more reliable, more durable, lighter, and significantly cheaper than other power blocks of its size.
The 50-kW power block is designed from off-the-shelf components, meaning it can be incorporated into a variety of inverters. It is also modular and scalable, meaning it can be used for multiple technologies and connected to other power blocks to accommodate larger systems. The power block is currently in its final prototype stage, and will be distributed to industry partners for feedback before being mass-produced.