Voltage-controlled DC link for variable frequency generator excitation

摘要

Apparatus for controlling the excitation current of a variable frequency generator (VFG) including means to create a voltage-regulated DC link using PMG power and frequency information, the latter being the image of the VFG mechanical input speed. A step-down voltage-controlled chopper is inserted between the passive rectifier stage and the excitation current control chopper. The control law of this voltage-controlled source is such that when the mechanical input speed of the VFG increases, its output (controlled DC-link voltage) decreases non-linearly, leading to DC link voltage varying from V (engine at idle) to V/2 (engine at take-off speed). The DC voltage becomes inverse-proportional to input mechanical speed.

主权项

1. An apparatus for controlling the excitation current of a variable frequency generator driven by a rotator shaft, comprising:
a step-down chopper configured to output a voltage-regulated DC link voltage that is inversely proportional to a rotational speed of the rotator shaft; and a chopper current source configured to derive, from the voltage-regulated DC link voltage, a controlled current for injection into the variable frequency generator using the voltage-regulated DC link voltage.