Aircraft Generator Control with CVT Shift Compensation
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Solution Overview
Problem
Large rotational frequency fluctuations in aircraft engine power output lead to unstable electric power generation when using a manual transmission upstream of an electric power generator, as the sudden changes in output rotational frequency exceed the response capability of the downstream continuously variable transmission, causing frequent momentary fluctuations and instability in electric power generation.
Innovation Solution
A controller system that includes a manual transmission control section and a continuously variable transmission control section, which coordinate gear stage switching in the manual transmission and continuously variable transmission to cancel output rotational frequency fluctuations, ensuring stable power input to the electric power generator by anticipating and offsetting changes in the continuously variable transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a manual transmission is provided upstream of the electric power generating apparatus to narrow the rotational frequency fluctuation range, then the rotational frequency range input to the electric power generating apparatus is narrowed, but the output rotational frequency momentarily and suddenly changes at the time of shift-up or shift-down, causing momentary rotational frequency fluctuation of power input to the electric power generator
Solution Approach 1:
The control device predicts the shift timing of the manual transmission in advance and controls the continuously variable transmission to perform speed change operations before the manual transmission shifts. This preliminary action prevents momentary rotational frequency fluctuations by preparing the continuously variable transmission to compensate for upcoming changes in the manual transmission's output rotational frequency.
Solution Approach 2:
The control device applies counter-action in advance by controlling the continuously variable transmission to change speed in opposition to the predicted shift timing of the manual transmission. This preliminary anti-action offsets the momentary rotational frequency changes that would occur during manual transmission shifts, maintaining stable power input to the electric power generator.
2Adaptability or versatility
If the speed change range of the continuously variable transmission is made large to handle large rotational frequency fluctuation, then the continuously variable transmission can adjust rotational frequency to an appropriate range, but the continuously variable transmission increases in diameter and the entire apparatus increases in size
Solution Approach 1:
The speed change function is segmented between two transmissions: the manual transmission handles coarse speed changes across different gear stages, while the continuously variable transmission handles fine speed adjustments. This segmentation allows the continuously variable transmission to have a smaller speed change range, reducing its size while maintaining overall adaptability through the combined system.
Data Source
AI summary
An electric power generation controller for use in an aircraft is a controller of an electric power generating system configured such that: a manual transmission changes speed of rotational power of an aircraft engine; a continuously variable transmission changes the speed of the rotational power which has been changed in speed by the manual transmission; and the continuously variable transmission transmits the rotational power to an electric power generator. The electric power generation controller includes: a manual transmission control section configured to, when a predetermined shift condition is satisfied, control the manual transmission to switch a gear stage of the manual transmission; and a continuously variable transmission control section configured to, when the shift condition is satisfied, control the continuously variable transmission to such a side that fluctuation of an output rotational frequency of the manual transmission by the switching of the gear stage of the manual transmission is canceled.