High-Voltage Direct Current (HVDC) systems are increasingly applied to the growing renewable energy segments, with applications in offshore wind energy systems and on-shore bulk power transmission. HVDC transmission is attractive for its efficiency and reduced materials, especially for offshore applications such as wind farms. However, HVDC requires complicated, large, and expensive power electronic converter stations to convert medium voltage alternating current into HVDC and vice versa.
UW-Madison researchers developed an electrostatic generator with integrated passive power electronics that allows machines, such as wind turbines, to produce high-voltage DC directly while eliminating additional conversion stages. Electrostatic generators are an attractive alternative to magnetic synchronous generators for HVCD transmission because they can inherently operate at higher voltages, eliminating the need for a step-up transformer and commutative rectifier such as centralized voltage source converters operating at the transmission voltage level. The innovation uses a set of individual electrostatic generators connected in tandem to a mechanical input and employs floating voltage sources to allow series connection of the individual electrostatic generators without diode ladders or similar components, making it a practical solution.