Power-Dense Shipboard-Compatible Low-Horsepower Variable-Frequency Drives

A variable-frequency drive (VFD) having a 440-V front-end current source rectifier (CSR) interface to a voltage source inverter (VSI) feeding a Permanent-Magnet Axial-flux Air Core motor combination is a solution for low-horsepower pump and fan control that is both power dense and compatible with a shipboard environment. This paper describes the control and power platforms for the CSR/VSI and provides experimental results for a 250-V 3.3-kW system. Power density and efficiency comparisons are made between equivalent CSR/VSI- and voltage-source-conversion-based VFDs to demonstrate that the CSR/VSI-based VFD is more power dense.