Wound field synchronous machine with resonant field exciter

摘要

A brushless field exciter for wound synchronous machines that uses the resonance of the leakage inductance and a capacitor in a resonant field exciter to transfer energy to the rotating field winding. By resonating at frequencies greater than 50 kHz, this exciter reduces the overall size and weight of synchronous wound field motors at all power levels and extends the practical and economic power limits of synchronous wound field machines down to low integral and fractional HP applications, eliminating the permanent magnets now used in high efficiency motors and generators in that power range.

主权项

1. An apparatus, comprising,
a wound field synchronous machine having a rotor winding and having no rotor magnets for torque production; at least one square wave AC voltage generator having a voltage and driving frequency; at least one resonant field exciter in communication with the square wave AC generator, the resonant field exciter having a rotary reference frame, a static reference frame, and a resonant circuit comprising in series a resonant capacitor and a rotary transformer with a variable leakage inductance, and the resonant field exciter is configured to operate in a resonant mode at a resonant frequency of at least 50 kHz; a controller device in communication with the square wave AC generator and the resonant field exciter and configured to measure the voltage and current into the resonant field exciter, track the resonance frequency, and adjust the driving frequency to substantially match the resonance frequency to maximize AC current transfer; and a rectifier in communication with the resonant field exciter and the wound field synchronous machine and configured to convert the AC current to DC current before it goes into the rotor winding of the wound field synchronous machine.