Regenerative Energy Dissipation in Cargo Handling Power Buses
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Solution Overview
Problem
Cargo handling systems for aircraft face challenges in managing regenerative energy dissipation when multiple power drive units share a common power supply, as deceleration of unit load devices can lead to potentially damaging energy feedback to the direct current power bus shared by other units.
Innovation Solution
A cargo handling system that includes a direct current power bus with motor units connected to a unit controller capable of detecting regenerative energy and adjusting the flux reference input to dissipate energy through modified stator voltage adjustments, ensuring safe energy dissipation across motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple power drive units share a common power bus to facilitate cargo transport, then system productivity and ease of operation are improved, but regenerative energy from decelerating units can cause harmful feedback to the power bus, worsening system reliability and causing potential damage
Solution Approach 1:
The patent converts the harmful regenerative energy feedback into a beneficial braking force. When a power drive unit decelerates a unit load device, the motor operates in regenerative mode, generating electrical energy that would normally feedback to the common power bus. Instead, the controller detects this regenerative condition and applies dynamic braking, converting the electrical energy into thermal energy through the motor's internal resistance, thereby eliminating harmful feedback while utilizing the regenerative force for controlled deceleration.
2Use of energy by moving object
If regenerative energy is allowed to feedback to the common power bus, then energy efficiency is improved by回收利用, but the regenerative energy can overload and damage the power bus, worsening system reliability
Solution Approach 1:
The patent introduces an intermediary control mechanism between the regenerative motor and the common power bus. The controller acts as a mediator that detects regenerative conditions through voltage differential sensing and intermediates the energy flow by activating dynamic braking circuits. This prevents direct feedback of regenerative energy to the power bus, converting it into safe thermal dissipation through controlled resistive loading, thereby protecting the power bus from overload while managing the regenerative energy appropriately.
3Reliability
If dynamic braking is applied to dissipate regenerative energy, then power bus protection is improved, but additional control complexity is required to detect and manage regenerative conditions
Solution Approach 1:
The patent implements a feedback-based control system that continuously monitors the electrical conditions on the common power bus. The controller detects regenerative energy feedback by sensing voltage differentials across the power bus connections. When regenerative conditions are detected, the system automatically activates dynamic braking in the affected power drive unit, creating a closed-loop feedback mechanism that protects the power bus without requiring complex external monitoring or manual intervention.
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
Effectively manages regenerative energy dissipation, preventing damage to the power bus and ensuring efficient operation of power drive units by adjusting stator voltages to handle excess energy, thereby maintaining system stability and preventing power bus overload.
Implementation Method 1
deceleration of a ULD when in contact with a PDU can result in a potentially damaging supply of regenerative to a direct current power bus
Implementation Method 2
adjusting a stator voltage across a stator winding of the motor
Data Source
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AI summary
A cargo handling system is disclosed. In various embodiments, the cargo handling system includes a direct current power bus; a motor connected to the direct current power bus and having a flux reference input; a unit controller connected to the motor and configured to detect a level of regenerative energy on the direct current power bus and to alter the flux reference input in response to the level of regenerative energy.