| Abstract |
Macro scale electrostatic machines have promising characteristics for low speed direct drive applications. However, their medium voltage (7kV) and low current (inf.1A) characteristics provide a unique challenge for power electronics. Models for the semiconductors, electrostatic machine, and magnetic components were combined to perform a simulation-based comparison between the standard two-level voltage and current source inverter topologies. A low current 10 kV JFET super-cascode was modelled based off static and dynamic characterizations for the switch. Inductors were designed for the CSI dc-link and the VSI output filters and the improved generalized steinmetz equation algorithm modeled magnetic core loss. System losses and harmonic content, combined with implementation considerations, form a basis to compare the two inverter topologies. The comparison shows that the current source inverter is a better choice for a variable-speed drive with a wide operating range, especially at higher speeds. The voltage source inverter topology is speed limited due to the resonance between the inductive output-filter and capacitive machine. However, at low speeds, the VSI can provide high efficiency (~90\%) over a wide operating range, suitable for "position and hold" applications. |
