Hybrid Aircraft Propulsor Speed Control Using Electric Machine Torque
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Solution Overview
Problem
Conventional turboprop engine control systems for aircraft rely on propeller blade pitch adjustments to manage propeller speed, which can be inefficient and prone to reliability issues, particularly in hybrid powerplants with both heat engines and electric machines.
Innovation Solution
A control system for hybrid powerplants that adjusts the rotational speed of propulsors using electric machines, independent of blade pitch, by regulating electrical power to the electric machine and controlling torque of the heat engine, allowing for precise speed management and reduced reliance on mechanical pitch adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If propeller blade pitch is adjusted to control propeller speed, then propeller speed can be maintained at desired reference speed, but the control system becomes inefficient and reliability issues arise
Solution Approach 1:
The patent replaces the conventional mechanical blade pitch adjustment system with an electric machine (motor) that directly drives the propeller. This substitution eliminates the need for complex pitch control mechanisms and improves both reliability and efficiency by using electrical control instead of mechanical adjustment.
Solution Approach 2:
The patent introduces a control system with sensors and processors that act as intermediaries between the desired propeller speed and the actual speed. The control system continuously monitors propeller speed and adjusts electrical power to the electric machine, providing precise and reliable speed control without mechanical pitch adjustments.
2Reliability
If hybrid powerplant with electric machine is used to control propulsor speed, then control efficiency improves and reliability increases, but device complexity increases
Solution Approach 1:
The electric machine in the hybrid powerplant serves multiple functions: it acts as a motor to drive the propeller, a generator to recover energy during braking, and a controllable speed regulator. This multi-functionality reduces the need for separate components and justifies the added complexity by providing integrated solutions for propulsion and control.
Solution Approach 2:
The patent implements a feedback control system where sensors monitor propeller speed and feed this information back to the control processor. The processor adjusts electrical power to the electric machine based on the feedback, creating a closed-loop system that automatically maintains desired speed without requiring complex manual intervention or oversized control components.
3Measurement precision
If electrical power is regulated to control propulsor rotational speed, then speed control precision improves, but energy consumption increases
Solution Approach 1:
The control system operates in periodic cycles, continuously monitoring propeller speed and making small adjustments to electrical power only when needed to maintain the desired speed. This periodic control approach, rather than continuous full-power operation, achieves precise speed control while minimizing energy consumption during steady-state operation.
Solution Approach 2:
The patent changes the control parameter from mechanical blade pitch angle to electrical power input to the electric machine. This parameter change enables more precise and energy-efficient control because electrical power can be modulated in fine increments, allowing the propulsor speed to be precisely regulated with minimal energy waste compared to coarse mechanical pitch adjustments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the reliability and efficiency of propulsor speed control, reduces mechanical stress on pitch adjustment systems, and facilitates smoother aircraft operation by maintaining propulsor speed without frequent pitch changes, thereby improving overall aircraft performance and stability.
Implementation Method 1
The electric machine is configured to provide a second portion of the mechanical power
Implementation Method 2
The heat engine is configured to provide a first portion of the mechanical power
Data Source
AI summary
A system is provided for an aircraft. This aircraft system includes a propulsor, a powerplant and a control system. The powerplant is configured to output mechanical power to drive rotation of the propulsor. The powerplant includes a heat engine and an electric machine. The heat engine is configured to provide a first portion of the mechanical power. The electric machine is configured to provide a second portion of the mechanical power. The control system is configured to operate the powerplant to control a rotational speed of the propulsor by adjusting the second portion of the mechanical power.