Implementation and Applications of Grid-Forming Inverter with SiC for Power Grid Conditioning

Sustainable energy technologies have become promising solutions to global warming and climate change. Operation of the electric power grid has been dominated in the past by synchronous generation, wherein conventional sustainable energy inverters are designed simply to feed maximum real power into the grid. With the increasing penetration of renewable energy, it is undergoing a rapid shift toward the power generation of inverter-based resources (IBRs). As a result, transitioning to a power grid with more IBRs requires introducing advanced inverter technology that can respond to various disturbances in frequency and voltage occurring on the grid. The grid-forming (GFM) inverter equipped with an energy storage system featuring frequency and voltage support functionalities is vital for the stability of the micro power grid system. The GFM inverter also offers PV output smoothing, low voltage ride through, and low frequency ride through. In addition, the GFM inverter functions as a voltage source inverter to supply energy under off-grid state when the main grid is in fault conditions. A SiC-based 30 kVA GFM inverter is presented with a 3-phase 3-level neutral-point-clamped (NPC) topology for high-frequency operation to achieve high efficiency and power density. Design challenges in gate driver design, PCB layout, and thermal consideration are addressed. The performances of the designated GFM inverter are measured and tested under on-grid and off-grid operations to verify the functionalities of the advanced inverter, as well.