Solid-State Circuit Breaker Layout for Ultrafast DC Fault Isolation
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Solution Overview
Problem
Existing DC power distribution systems in aerospace lack adequate protection devices with fast response times and fail to meet aerospace system requirements, leading to challenges in fault detection and system integrity.
Innovation Solution
A power protection system incorporating a solid state circuit breaker (SSCB) with strategically placed capacitors and inductors near the load or source, enabling ultrafast fault detection and isolation by measuring voltage changes across the inductor to trigger semiconductor switch actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional protection devices are used in aerospace DC power systems, then the system structure is simple, but the fault detection speed and response time are insufficient
Solution Approach 1:
The capacitor and inductor are pre-positioned in close proximity to both the power source and load, ready to immediately respond to faults. When a short circuit occurs, the pre-positioned capacitor can rapidly discharge through the fault path, generating a boosting current that quickly saturates the inductor and triggers the SSCB, achieving ultrafast fault detection without requiring complex detection circuits.
Solution Approach 2:
The capacitor and inductor act as intermediary elements between the power source/load and the SSCB. The capacitor provides a low-impedance path for fault current, while the inductor converts this current into a detectable voltage signal through saturation, mediating the fault detection process and enabling the SSCB to respond extremely quickly to faults.
2Loss of time
If faster fault detection is implemented, then the response time improves, but the system complexity increases
Solution Approach 1:
The capacitor and inductor automatically perform fault detection without requiring external control signals or complex detection circuits. When a short circuit occurs, the capacitor self-discharges through the fault path, the inductor naturally saturates due to the boosting current, and this saturation directly triggers the SSCB gate, creating a self-service fault detection mechanism that achieves ultrafast response with minimal added complexity.
3Measurement precision
If a capacitor is placed close to the power source or load for fast fault detection, then the fault detection quality improves, but the inductor current increases
Solution Approach 1:
The capacitor and inductor are strategically positioned in close proximity to both the power source and load, creating localized fault detection zones. This local placement allows the capacitor to rapidly discharge through nearby faults with minimal resistance, generating sufficient boosting current to saturate the inductor and trigger the SSCB, while limiting the overall inductor current increase to acceptable levels through proper component sizing.
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 provides ultrafast fault detection and isolation, preventing system collapse and reducing weight compared to traditional devices, with decentralized control units allowing independent fault management without communication, and supporting redundancy in multi-SSCB architectures.
Implementation Method 1
the capacitor unloads through the short-circuited load/source and the inductor, thereby causing a boosting current and voltage rise in the inductor
Implementation Method 2
current generated by the first capacitor when unloading in case of a short circuit at the power source or at the load passes the first inductor
Implementation Method 3
the control unit is configured to measure a voltage change over the first inductor and trigger an actuation signal for the first semiconductor switch if a voltage change over the first inductor surpasses a predetermined threshold voltage
Implementation Method 4
SSCBs use semiconductor devices to interrupt DC currents in case of a fault such as a short-circuit
Data Source
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AI summary
A power protection system that comprises: a first DC power source (21), a first load (R01), a first power bus (31, 41) connecting the first power source (21) and the first load (R01), the first power bus (31, 41) comprising a high side voltage rail (31) and a low side voltage rail (41), and a first solid state circuit breaker circuit (51, 52) integrated in the first power bus (31, 41). The first solid state circuit breaker circuit (51, 52) comprises: a first semiconductor switch (S10, S11; S01) controlled by a control unit (71, 72), a first capacitor (C10, C01) arranged between the high side voltage rail (31) and the low side voltage rail (41) closer to the power source (21) or to the load (R01) than the semiconductor switch (S10, S11; S01), wherein a terminal (101) of the first capacitor (C10, C01) is arranged between the first semiconductor switch (S10, S11) and the power source (21) or between the first semiconductor switch (S01) and the load (R01), and a first inductor (L10, L01) located such that current generated by the first capacitor (C10, C01) when unloading in case of a short circuit at the power source (21) or at the load (R01) passes the first inductor (L10, L01). The control unit (71, 72) is configured to measure a voltage change over the first inductor (L10, L01) and trigger an actuation signal for the first semiconductor switch (S10, S11; S01) if a voltage change over the first inductor (L10, L01) surpasses a predetermined threshold voltage.