Multi-Propulsor Power Scaling Under Battery Depletion
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Solution Overview
Problem
Electric multi-propulsion systems, such as eVTOL aircraft, face challenges in maintaining attitude control when energy storage systems are depleted, leading to asymmetrical propulsor responses and unsafe landing conditions due to the collapsing energy storage system potential.
Innovation Solution
A system comprising multiple propulsors with a vehicle controller that calculates and adjusts power levels based on the energy source's capability, reducing power consumption proportionally to maintain attitude control by directing each propulsor to consume electrical power at a reduced level when the energy source's output is insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the energy storage system operates at low state of charge, then the usable range is extended, but the attitude control becomes difficult due to asymmetrical propulsor response
Solution Approach 1:
The system dynamically changes the operational parameters of propulsors by adjusting power distribution based on real-time energy storage state. When energy storage potential collapses, the controller modifies power commands to each propulsor to maintain symmetrical response characteristics, thereby preserving attitude control reliability even at low state of charge
Solution Approach 2:
The system implements feedback control by continuously monitoring the energy storage system's terminal voltage and power output capability. This feedback loop allows the controller to detect when the energy storage is approaching depletion and adjust propulsor power commands accordingly, preventing the asymmetrical response that would otherwise occur
2Reliability
If the safe operating range is reduced to ensure energy storage never limits propulsor power, then attitude control reliability is maintained, but the usable range is restricted and oversized batteries are required
Solution Approach 1:
The system transitions from a static safe operating range definition to a dynamic approach where the allowable operating envelope is continuously adjusted based on real-time energy storage state. The controller adapts power distribution strategies according to the current state of charge and power capability, enabling full utilization of the energy storage system without compromising attitude control
Solution Approach 2:
The system changes the operational parameters of the energy management strategy by allowing the energy storage system to operate across its full range rather than restricting it to a conservative window. The controller dynamically adjusts propulsor power commands to match the actual power delivery capability of the energy storage system at each moment
3Reliability
If propulsors with highest power commands are used to correct aircraft attitude, then attitude control authority is improved, but these propulsors are most affected by collapsing energy storage potential causing asymmetrical response
Solution Approach 1:
The system dynamically changes the power distribution parameters to each propulsor based on real-time energy storage capability. When energy storage potential collapses, the controller adjusts the power commands to maintain symmetrical propulsor response, preventing the asymmetry that would otherwise occur when high-power propulsors are most affected by the depletion
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
This approach ensures more controllable behavior of the electric multi-propulsion system, allowing for safe emergency procedures like landings by maintaining the relative thrust magnitude between propulsors, thereby minimizing the risk of losing attitude control.
Implementation Method 1
at least an energy source providing electrical power to the plurality of propulsors
Data Source
AI summary
A system for maintaining attitude control under degraded or depleted energy source conditions using multiple electric propulsors includes a plurality of propulsors, at least an energy source providing electric power to the plurality of propulsors and a vehicle controller communicatively coupled to each propulsor and configured to calculate initial power levels for the plurality of propulsors, the initial power levels including an initial power level for each propulsor, determine an energy output capacity of the least an energy source under load, calculate, by the vehicle controller, an aggregate potential demand of the plurality of propulsors as a function of the initial power levels, determine that electric potential is insufficient to match the aggregate potential demand, and for each initial power level generate a reduced power level, the reduced power level less than the initial power level and direct a corresponding propulsor to consume electrical power at the reduced power level.