| 摘要 |
A low voltage battery provides the power source for energizing an aircraft generator to operate it as a motor during a starting operation. The battery is coupled to an input to an inverter whose a.c. output is controlled by a pulse width modulator. By controlling the switching points of the output, the generator is so energized that it operates as a brushless d.c. motor. At a point where the available voltage to the generator is insufficient to further accelerate the turbine, even with field weakening and an increased commutation angle, an autotransformer is switched into the system to step up the output voltage from the invertor. Throughout the starting operation the commutation angle is controlled so that current drain on battery is such that the battery terminal voltage at one half its no load terminal voltage, thus providing maximum power transfer from the battery.
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