Aircraft DC Bus Battery Buffering for Voltage Spike Stability
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Solution Overview
Problem
Existing energy distribution systems in aircraft face instability and potential shutdowns due to voltage spikes in the low voltage DC bus, especially when the high voltage DC bus fails to energize it.
Innovation Solution
An energy distribution system with at least two electrical powertrain units, each equipped with a DC/DC converter arrangement and a DC bus battery, where the DC/DC converters convert the first DC voltage from energy storage units to a lower DC voltage and the DC bus battery provides energy when the storage units fail, stabilizing the low voltage DC bus and enabling emergency power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common high voltage DC bus is used to power propulsion units and a DC/DC converter is provided to create a common low voltage DC bus, then the system structure is simplified and energy distribution is centralized, but the DC voltage on the low voltage DC bus experiences voltage spikes or shut down when the high voltage DC bus fails to energize it
Solution Approach 1:
A DC bus battery is introduced as an intermediary component between the DC/DC converter and the low voltage DC bus. This battery acts as a buffer that absorbs voltage spikes and maintains bus voltage stability during transient conditions or when the high voltage DC bus fails to energize the system, thereby resolving the contradiction between simplified structure and voltage stability.
Solution Approach 2:
The DC bus battery provides beforehand cushioning by being pre-charged and ready to compensate for voltage disturbances before they affect the low voltage DC bus. This protective measure ensures that voltage spikes are mitigated and continuous power supply is maintained, addressing the reliability issue while preserving the simplified centralized structure.
2Reliability
If multiple redundant energy sources are provided for each system to ensure continuous power supply, then the reliability and continuous power supply are improved, but the system complexity and number of components increase
Solution Approach 1:
The DC bus battery serves multiple functions: it acts as an energy storage device, a voltage buffer, and an emergency power source. This multi-functionality provides redundancy and ensures continuous power supply without requiring separate dedicated backup systems for each load, thereby maintaining reliability while minimizing the increase in system complexity.
Solution Approach 2:
The patent merges the functions of voltage regulation, energy storage, and backup power supply into a single DC bus battery component. This consolidation provides the benefits of redundant energy sources for continuous power supply while avoiding the complexity of multiple separate redundant components for each system.
3Reliability
If the DC bus battery is added to stabilize the low voltage DC bus and provide emergency power, then the voltage stability and reliability are improved, but the device complexity and weight increase
Solution Approach 1:
The DC bus battery is integrated directly into the converter unit structure, merging the functions of voltage conversion and voltage stabilization into a single compact assembly. This integration improves voltage stability and provides emergency power capability while minimizing the increase in overall device complexity through unified design.
Solution Approach 2:
The DC bus battery performs multiple functions including voltage spike absorption, bus stabilization, and emergency power provision. This multi-functionality justifies the added complexity by delivering comprehensive reliability improvements through a single component rather than requiring multiple separate devices.
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
The system achieves a more stable low voltage DC bus and ensures continuous energy supply by using the DC bus battery to manage transients and provide emergency power in case of energy storage unit failure.
Implementation Method 1
a DC/DC converter arrangement configured to convert the first DC voltage from each energy storage unit to a second DC voltage on the DC bus
Implementation Method 2
a DC bus battery with a nominal operating DC voltage of the second DC voltage. The DC bus provides energy for charging the DC bus battery when energized from the energy storage units, and the DC bus battery supply energy to the DC bus when the energy storage units fail to energize the DC bus
Data Source
AI summary
The present invention relates to an energy distribution system (20) for an aircraft with at least two electrical powertrain units, each comprising a propulsion unit (1) powered by energy storage units (13) each configured to supply a first direct current, DC, voltage. The energy distribution system (20) comprises at least one converter unit (25) configured to energize a DC bus (16) having a lower DC voltage than the first DC voltage provided from each respective energy storage unit (13), each converter unit (25; 35) comprises a DC/DC converter arrangement (21) configured to convert the first DC voltage from at least one energy storage units (13) to a second DC voltage on the DC bus (16), and a DC bus battery (22) with a nominal operating DC voltage of the second DC voltage. The DC bus (16) provides energy for charging the DC bus battery (22) when energized from the energy storage units (13), and the DC bus battery (22) supply energy to the DC bus (16) when the energy storage units fail to energize the DC bus (16).