The U.S. Department of Energy's National Renewable Energy Laboratory (NREL), along with industrial partner Semikron and with funding from the California Energy Commission (CEC), has developed a prototype of a 50 kW inverter that converts distributed renewable energy, such as wind or solar power, into grid-compatible alternating-current (AC) power.
The 50 kW modular power block is the size of a microwave oven, and it can be included with a photovoltaic array, small wind turbine, battery charger, fuel cell or flywheel to control the flow of energy into the electric grid, according to NREL, adding that when the power block is produced in volume, the price is expected to be one-third of the cost of other integrated power electronics of the same rating.
Because the power block is modular, it can be used for multiple technologies. It is also scalable, so two or more can be connected to create a larger power converter without having to redesign a system, according to NREL.
The power block includes electronic switches, sensors, direct-current (DC) bus filtering, a heat sink, a driver and a controller board. It will be packaged inside a 6-foot by 2.5-foot inverter, which also will contain inductors, capacitors, sensors, contactors, pilot relays and a DC power supply, along with protective devices to suppress surges, protect against ground faults and ensure emergency shutoff.
‘After one more redesign, we'll get a dozen or so of these into the hands of industry across different disciplines to get their feedback,’ says NREL's Bill Kramer, the principal investigator for the project.
NREL's Cooperative Research and Development Agreement with the CEC is being used to develop the power block.