Multilane DC Power Bus Switching for Inrush Current Control
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Solution Overview
Problem
Existing multilane power distribution systems in aerospace DC power systems face challenges with unwanted inrush current and current flowing among batteries, which can trigger protection mechanisms, cause thermal runaway, and melt battery cell connections.
Innovation Solution
A multilane power distribution system that incorporates pulse-width modulated switches and contactors to control the connection of DC power sources, limiting inrush current through adjustable duty cycles and ensuring safe voltage alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If batteries are connected in a multilane architecture to allow power sharing and redundancy, then system reliability and power distribution capability are improved, but unwanted inrush current and current flowing among batteries occur causing protection triggers, thermal runaway risk, and battery cell connection damage
Solution Approach 1:
The system performs preliminary voltage matching between batteries before connecting them in parallel. The control unit monitors voltage differences and only enables parallel connection when voltages are within a predetermined threshold, preventing inrush current from damaging battery connections and triggering protection mechanisms
Solution Approach 2:
The control unit continuously monitors voltage differences between batteries and dynamically controls the switching elements. When voltage difference exceeds the threshold, the control unit prevents parallel connection; when voltages are matched, it enables connection. This feedback mechanism prevents inrush current while maintaining power sharing capability
2Adaptability or versatility
If switchable elements are used to connect power buses, then power sharing and redundancy are enabled, but initial current transients trigger battery pack main protection and may cause thermal runaway
Solution Approach 1:
Before enabling power sharing through switchable elements, the system performs preliminary voltage verification. The control unit checks if voltage difference between batteries is within the predetermined threshold, and only then activates the switchable elements to enable parallel operation, preventing protection triggers
Solution Approach 2:
The control unit acts as an intermediary between batteries and switchable elements. It monitors voltage conditions and intelligently controls the switching elements, enabling power sharing only when voltage matching conditions are met, thus preventing harmful current transients
3Adaptability or versatility
If multiple DC power sources are connected to multiple load devices through power buses, then power distribution flexibility and redundancy are improved, but voltage alignment issues cause harmful current flow among power sources
Solution Approach 1:
The system performs preliminary voltage alignment verification before enabling connection between power sources. The control unit monitors voltage differences and only permits connection when voltages are within the predetermined threshold, preventing current from flowing among batteries
Solution Approach 2:
The control unit continuously monitors voltage conditions and provides feedback control for the switchable elements. When voltage difference exceeds the threshold, connection is prevented; when voltages are aligned, connection is enabled. This feedback mechanism eliminates harmful current flow while maintaining distribution flexibility
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 effectively limits inrush current, prevents battery protection triggers, and ensures safe battery connections, thereby enhancing the reliability and safety of aerospace DC power systems.
Implementation Method 1
one of the switchable elements is a pulse-width modulated switch that electrically connects the respective voltage rails in accordance with the pulse-width modulation. The pulse-width modulated switch limits any inrush current when the two DC power sources are connected. The pulse-width modulated switch may control any inrush current through its duty cycle
Implementation Method 2
the other switchable element is a contactor. A contactor is controlled by a circuit that has a much lower power level than the switched circuit. A contactor knows two switching positions and may be monostable, wherein bi-stable contactors may be provided as well in embodiments of the disclosure. In certain examples, a contactor is activated by electromagnets. When a control current flows through a solenoid coil of an electromechanical contactor, the magnetic field pulls the mechanical contacts into the active state
Data Source
AI summary
A multilane power distribution system includes a plurality of DC power sources and a plurality of load devices. Each DC power source powers at least two of the load devices, and each load device is powered by at least two DC power sources. The system further includes a DC connection network including power buses for connecting the DC power sources and the load devices. The power buses having a high side voltage rail for the positive voltage and a low side voltage rail for the negative voltage. At least two power buses are connectable by switchable elements, namely, a first switchable element for the high side voltage rails and a second switchable element for the low side voltage rails. One of the switchable elements is a pulse-width modulated switch that electrically connects the respective voltage rails in accordance with the pulse-width modulation.