DEC Fault Isolation and Ride-Through

The burner's direct energy conversion couples the plasma to an electrical load; the reflex tier isolates load-side faults before they perturb the plasma.

Two systems that must not drag each other down

The burner uses direct energy conversion (DEC) to turn escaping charged-particle energy into electricity, coupling plasma physics to a power-electronics load. That coupling is a fault path in both directions: a load-side fault (a short, a grid disturbance) could perturb the plasma, and a plasma-side transient could stress the converter. The reflex tier isolates the two so a fault on one side is contained, not transmitted.

def dec_action(load_fault, dv_dt, plasma_ok, limits):
    # isolate first, ask questions later
    if load_fault or abs(dv_dt) > limits['dv_dt']:
        return 'ISOLATE load -> ride-through on plasma side'
    if not plasma_ok:
        return 'DECOUPLE DEC -> controlled ride-down'
    return 'run'

Ride-through, then decide

• Load-side fault: disconnect the load fast, hold the plasma on a controlled setpoint, then resynchronize or shut down deliberately.
• Plasma-side fault: decouple the DEC collector so a plasma transient does not appear as a converter fault.
• Both: the isolation action is a reflex; the recovery decision is supervisory.

The dv/dt limit is the fast trigger: a rapid collector-voltage swing is the earliest sign of trouble on either side, and the reflex trips on it before slower protections would react. This is the same fast-slow split used across the reflex tier — act on the fastest robust indicator, defer the reasoning to the supervisory layer.

DEC fault isolation is part of the burner safe-state definition: a safe burner is one where the DEC has ridden down in a controlled way and the plasma is on a benign holding path. It does not touch the confinement gates, but it must never be the thing that trips the plasma — hence the isolation-first design. Grid-side behavior and availability are discussed under the honest availability gate.