Hybrid-Electric Propulsor Braking for Aircraft Hotel Mode
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Solution Overview
Problem
Existing aircraft propulsion systems lack efficient and lightweight methods to control propulsor rotation, particularly during grounded operations where electrical power and support functions are required, necessitating complex and weighty hydraulic braking systems.
Innovation Solution
A hybrid-electric propulsion system incorporating an AC electric motor, motor control unit, and electrical distribution system that can switch between normal and hotel modes, using DC power to apply braking forces to the propulsor, allowing control of propulsor rotation through modulation of current and voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic braking systems are used to control propulsor rotation during grounded operations, then propulsor rotation can be controlled, but system weight and complexity increase
Solution Approach 1:
The patent replaces the mechanical hydraulic braking system with an electrical braking system. The motor control unit converts the electric motor into a brake by controlling current flow through the motor windings, creating electromagnetic resistance that opposes propulsor rotation. This substitution eliminates hydraulic components (pumps, valves, fluid lines) and replaces them with electrical control circuitry already present in the hybrid-electric propulsion system.
Solution Approach 2:
The electric motor serves dual functions: it acts as a motor during normal propulsion operations and as a brake during grounded operations when propulsor rotation control is needed. The motor control unit switches between motor mode and brake mode by changing the electrical power conversion (AC to AC for motor operation, AC to DC for braking). This multi-functionality eliminates the need for separate braking components.
2Reliability
If hydraulic braking systems are used to control propulsor rotation, then propulsor rotation can be controlled, but system weight increases
Solution Approach 1:
The patent replaces the mechanical hydraulic braking system with an electrical braking system. The motor control unit converts the electric motor into a brake by controlling current flow through the motor windings, creating electromagnetic resistance that opposes propulsor rotation. This substitution eliminates hydraulic components (pumps, valves, fluid lines) and replaces them with electrical control circuitry already present in the hybrid-electric propulsion system.
Solution Approach 2:
The electric motor serves dual functions: it acts as a motor during normal propulsion operations and as a brake during grounded operations when propulsor rotation control is needed. The motor control unit switches between motor mode and brake mode by changing the electrical power conversion (AC to AC for motor operation, AC to DC for braking). This multi-functionality eliminates the need for separate braking components.
3Reliability
If complex hydraulic braking systems are installed, then propulsor rotation control is achieved, but maintenance requirements increase
Solution Approach 1:
The patent replaces the mechanical hydraulic braking system with an electrical braking system. The motor control unit converts the electric motor into a brake by controlling current flow through the motor windings, creating electromagnetic resistance that opposes propulsor rotation. This substitution eliminates hydraulic components (pumps, valves, fluid lines) and replaces them with electrical control circuitry already present in the hybrid-electric propulsion system.
Solution Approach 2:
The electric motor serves dual functions: it acts as a motor during normal propulsion operations and as a brake during grounded operations when propulsor rotation control is needed. The motor control unit switches between motor mode and brake mode by changing the electrical power conversion (AC to AC for motor operation, AC to DC for braking). This multi-functionality eliminates the need for separate braking components.
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
Enables efficient propulsor braking without additional weight or complexity, utilizing existing electrical components to manage propulsor rotation during non-propulsive operations, enhancing safety and reducing maintenance needs.
Implementation Method 1
The AC electric motor is coupled to the rotational assembly
Implementation Method 2
the motor control unit to convert the electrical power from the electrical distribution system to output DC electrical power and supplying the output DC electrical power to the AC electric motor
Data Source
AI summary
An aircraft propulsion system includes a propulsor, a gas turbine engine, and an electrical assembly. The gas turbine engine includes a bladed turbine rotor connected to the propulsor. The electrical assembly includes an AC electric motor, a motor control unit, and an electrical distribution system. The AC electric motor is coupled to the propulsor. The motor control unit is electrically connected to the AC electric motor and the electrical distribution system. The motor control unit is selectively operable in a normal mode and a hotel mode. The motor control unit is configured to, in the normal mode, convert electrical power from the electrical distribution system to output AC electrical power and supply the output AC electrical power to the electric motor and, in the hotel mode, apply a braking force to the rotational assembly by converting the electrical power from the electrical distribution system to output DC electrical power and supplying the output DC electrical power to the AC electric motor.