Performance of cage-less interior PM motor with open-loop inverter drive

The performance of a cage-less 16-kW, 1,500-rpm interior permanent magnet machine developed for a portable generator application is examined when run as a motor under open-loop volts-per-hertz control from an inverter. The analytical and experimental steady-state results show the machine can operate with high power-factor and efficiency. The dynamic results show robust operation in starting and the capability to maintain synchronism even with large step load transients. The motor performance is promising for applications requiring high efficiency, particularly where variable-speed operation is needed or where multiple motors can be run from the same inverter.