Ablative Plasma Gun for Low-Energy Arc Triggering
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Solution Overview
Problem
Conventional spark gap triggering methods for electric arc devices are costly due to high trigger voltage requirements, with conventional trigger sources and electronics being several times more expensive than the main spark gap, especially in high-voltage systems like 600V systems where a 250 kV trigger pulse is needed.
Innovation Solution
A plasma gun with diagonally opposed electrodes in an open-ended chamber of ablative material is used to generate and control ablative plasma, which is then used to trigger main arc devices like arc crowbars or high power switches with reduced energy and cost, utilizing a divergent nozzle to eject plasma at supersonic speeds and control initial arc properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spark gap triggering is used with high bias voltage, then the trigger voltage requirement increases to at least 250 KV for a 20 mm gap, but the cost of trigger source and electronics becomes several times higher than the main spark gap itself
Solution Approach 1:
The patent employs a disposable ablative material insert that is consumed during each triggering event. This low-cost consumable component replaces expensive, complex trigger electronics by using a simple ablative polymer that vaporizes to create the plasma channel, eliminating the need for high-voltage trigger sources and associated electronics.
Solution Approach 2:
The patent substitutes the conventional electrical/mechanical trigger system with a chemical-thermal-plasma mechanism. Instead of using high-voltage electrical pulses to ionize the gas, the system uses thermal ablation of polymer material to generate plasma, replacing complex electrical triggering mechanisms with a simpler thermal-chemical process.
2Reliability
If conventional trigger pulse is applied, then the trigger voltage must be at least 250 KV for a 20 mm gap in a 600V system, but the energy consumption and circuit requirements increase significantly
Solution Approach 1:
The patent changes the physical state and parameters of the ablative material through controlled heating. The polymer undergoes thermal decomposition at specific temperature thresholds, transforming from solid to vapor to plasma, thereby initiating the arc at much lower energy levels than conventional electrical triggering methods.
Solution Approach 2:
The ablative material undergoes phase transitions from solid polymer to vapor gas to plasma during the triggering process. This phase transition sequence allows the material to absorb energy gradually and release it in a controlled manner, creating an effective plasma channel with significantly lower energy input than conventional methods.
3Speed
If high voltage pulses are used for triggering, then the trigger source cost increases, but the triggering speed and arc control precision remain limited
Solution Approach 1:
The patent employs periodic pulsed heating of the ablative material to achieve controlled plasma generation. The periodic application of energy allows precise timing control of the plasma formation, enabling fast and repeatable triggering without requiring complex high-voltage pulse generation circuits.
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 ablative plasma gun provides a faster and more energy-efficient triggering mechanism, reducing the cost of trigger sources and circuitry while enabling precise control over the triggered arc in main arc devices, as demonstrated in tests where a 150V bias voltage was effectively triggered with a significantly lower 20 kV pulse, compared to conventional methods.
Implementation Method 1
A pulse of electrical potential applied between the electrodes creates an arc that heats and ablates some of the cup material to create a highly conductive plasma
Implementation Method 2
A pulse of electrical potential applied between the electrodes creates an arc that heats and ablates some of the cup material
Implementation Method 3
The plasma exits the nozzle in a spreading pattern at supersonic speed
Data Source
AI summary
A plasma gun with two gap electrodes on opposite ends of a chamber of ablative material such as an ablative polymer. The gun ejects an ablative plasma at supersonic speed. A divergent nozzle spreads the plasma jet to fill a gap between electrodes of a main arc device, such as an arc crowbar or a high voltage power switch. The plasma triggers the main arc device by lowering the impedance of the main arc gap via the ablative plasma to provide a conductive path between the main electrodes. This provides faster triggering and requires less trigger energy than previous arc triggers. It also provides a more conductive initial main arc than previously possible. The initial properties of the main arc are controllable by the plasma properties, which are in turn controllable by design parameters of the ablative plasma gun.