Aircraft Electric Propulsion Control Using Look-Up Tables
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Solution Overview
Problem
Existing aircraft electric propulsion systems face inefficiencies and operational limitations in optimizing thrust and energy usage, particularly in adapting to varying flight conditions and safety constraints, which affect overall propulsion system efficiency.
Innovation Solution
A control system for an aircraft electric propulsion system that uses a look-up table or online model to correlate airspeed and desired thrust with optimal motor and propeller configurations, considering component efficiencies and safety limitations, to achieve maximum propulsion system efficiency by adjusting motor speed, torque, and propeller pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If existing aircraft electric propulsion systems operate with conventional control methods, then the system structure remains simple, but propulsion system efficiency is suboptimal and energy usage is not optimized
Solution Approach 1:
The patent pre-calculates and stores optimal motor speed and torque combinations in a look-up table before operation. During flight, the controller simply queries this pre-computed table based on desired thrust and airspeed, avoiding real-time complex optimization calculations. This preliminary action enables efficient energy usage without requiring complex real-time control algorithms.
Solution Approach 2:
The patent creates a simplified digital model (look-up table) that represents the complex relationship between motor parameters, propeller characteristics, and flight conditions. This copied representation allows the controller to efficiently determine optimal operating points without directly solving complex physical equations during operation, thus improving energy efficiency while keeping the control system relatively simple.
2Adaptability or versatility
If the propulsion system adapts to varying flight conditions with optimized control, then energy efficiency improves, but the control system becomes more complex
Solution Approach 1:
The patent implements a dynamic control system that continuously adapts motor speed and torque based on real-time flight conditions (airspeed, desired thrust). The controller queries the look-up table with current flight parameters and adjusts motor operating points dynamically, enabling the system to maintain optimal efficiency across varying flight conditions without requiring complex adaptive algorithms.
Solution Approach 2:
The patent changes the control parameters from direct propeller pitch control to motor speed and torque control. By controlling the electric motor's rotational speed and torque output, the system indirectly optimizes propeller performance across different flight conditions. This parameter transformation simplifies the control approach while maintaining adaptability to varying flight regimes.
3Use of energy by moving object
If new propulsion control methods are implemented to improve efficiency, then energy usage optimizes, but certification difficulty increases
Solution Approach 1:
The patent utilizes a universal control approach that works with existing propeller designs and pitch control mechanisms. The look-up table method can be applied to various propeller types and motor configurations without requiring fundamental changes to the propulsion system hardware. This universality facilitates certification by demonstrating compatibility with established components and procedures.
Solution Approach 2:
The patent replaces complex mechanical propeller pitch control systems with an electrically-controlled motor speed and torque system. By using the electric motor's control capabilities to achieve propeller optimization instead of mechanical pitch adjustment mechanisms, the system simplifies the overall control architecture while maintaining energy efficiency benefits, making certification more straightforward.
Data Source
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AI summary
A method of controlling an electric propulsion system (5) of an aircraft (1). The propulsion system comprising an electric motor (10) configured to drive a variable pitch propulsor (12). The method comprises determining a commanded thrust setting; determining one or more flight parameters; determining either a corresponding rotor governor speed and motor torque set-point, or a corresponding motor speed and rotor pitch angle set point, which provides the commanded thrust setting at the determined flight parameter having a maximum propulsion system efficiency; and controlling the rotor governor and electric motor in accordance with the determined respective set-points.