Programmable TVS Circuit for Aircraft DC Bus Overvoltage Protection
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Solution Overview
Problem
Controlling DC power buses for overvoltage events is a challenge in power system design, as overvoltages can lead to system failures and damage in aircraft components.
Innovation Solution
A protection system with transient voltage suppressors (TVSs) and switches, controlled by a controller, dynamically adjusts the voltage suppression level across an electrical bus by selectively shunting TVSs to the low side, allowing for programmable overvoltage protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed voltage suppression level is used, then the protection level is simple and reliable, but the system cannot adapt to different operating conditions and may cause unnecessary load shedding or fail to protect against higher voltages
Solution Approach 1:
The voltage suppression protection is divided into multiple discrete levels, each implemented by a separate TVS device with a specific breakdown voltage rating. Each TVS device can be independently selected and activated based on the required protection level, allowing the system to adapt to different operating conditions without requiring a completely different protection architecture.
Solution Approach 2:
The protection system transitions from a static fixed suppression level to a dynamic configurable level by using switches controlled by a controller. The controller can dynamically select which TVS device becomes active based on real-time operating conditions, enabling the suppression level to adapt dynamically while maintaining system reliability.
2Adaptability or versatility
If multiple TVS devices with different voltage ratings are used, then programmable voltage suppression levels are achieved, but the device complexity and control requirements increase
Solution Approach 1:
The switches in the system serve multiple functions: they act as normal circuit switches for power transmission and simultaneously function as selection switches for the TVS protection level. This multi-functionality reduces the need for separate control mechanisms and simplifies the overall operation while achieving programmable voltage suppression.
Solution Approach 2:
The controller automatically determines the appropriate voltage suppression level based on system parameters and control logic, eliminating the need for manual configuration or complex operator intervention. The system self-adjusts the protection level by controlling the switches based on predetermined criteria, making the programmable feature easy to operate.
3Reliability
If TVS devices are shunted to the low side, then the desired voltage suppression level is achieved, but the switch configuration and circuit design become more complex
Solution Approach 1:
The TVS devices are extracted as separate, dedicated protection components rather than being integrated into the main power transmission path. By placing TVS devices in parallel across the bus and using switches to connect/disconnect them to the low side, the protection function is separated from the power transmission function, improving reliability while keeping the circuit configuration manageable.
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 suppresses transient voltages with adjustable thresholds, preventing damage to aircraft components and ensuring safe operation of the DC power bus.
Implementation Method 1
A plurality of transient voltage suppressors (TVSs) that are connected in series across an electrical bus of an aircraft
Data Source
AI summary
An example system includes a plurality of transient voltage suppressors (TVSs) that are connected in series across an electrical bus of an aircraft, the electrical bus having a high side and a low side; a plurality of switches, each switch of the plurality of switches configured to selectively shunt a corresponding TVS of the plurality of TVSs to the low side of the electrical bus; and a controller configured to: determine a desired voltage suppression level; and control operation of the plurality of switches such that the plurality of TVSs provides the desired voltage suppression level.