Immunity Testing

Immunity testing verifies that equipment continues to operate correctly — or fails safely — when exposed to external electromagnetic disturbances representative of industrial environments. SiCore wireless charging docks and receivers undergo EN 61000-4-x immunity suites aligned with EN 61000-6-2 (residential/commercial/light industrial) or EN 61000-6-4 (industrial) depending on declared environment. Failures during immunity stress manifest as CAN dropouts, false safety interlock trips, charge session aborts, or in worst cases uncontrolled power output — unacceptable outcomes requiring hardware or firmware hardening.

AGV factory floors expose equipment to ESD from operator contact and vehicle triboelectric charging, EFT from contactor switching on shared mains, surge from lightning-induced transients on facility power, and radiated RF from nearby transmitters, VFDs, and mobile radios. Immunity levels selected for SiCore industrial SKUs exceed consumer product baselines.

01Core immunity test methods

• IEC 61000-4-2 ESD: contact and air discharge to enclosure, connectors, and user-accessible surfaces — ±8 kV contact typical industrial criterion.
• IEC 61000-4-4 EFT/Burst: fast transients on AC mains, DC ports, and signal cables — 2 kV on power ports common industrial level.
• IEC 61000-4-5 Surge: 1.2/50 µs voltage wave on AC mains — combination wave coupling through dock PFC front-end.
• IEC 61000-4-6 Conducted RF: 150 kHz–80 MHz injected on cables — validates CAN and mains immunity simultaneously.
• IEC 61000-4-3 Radiated RF: 80 MHz–6 GHz field in semi-anechoic chamber — operational monitoring during charge at rated power.

02Performance criteria during WPT operation

SiCore defines immunity performance criteria per IEC 61000 series: Criterion A — normal operation within specification during test; Criterion B — temporary degradation with self-recovery; Criterion C — loss of function requiring operator intervention. Dock transmitters at rated charge power during radiated RF immunity must maintain power control within ±10% and must not exceed thermal or field-strength safety limits — Criterion A on safety functions, Criterion B acceptable on non-critical telemetry with logged recovery.

ESD to CAN connectors must not corrupt safety interlock state — firmware validates CRC and redundant GPIO reads after ESD events. Surge immunity coordinates with MOV and gas discharge tube placement on AC inlet — failed surge test indicates inadequate coordination with PFC inrush, not merely missing TVS on signal lines.

03Design for immunity and retest triggers

Immunity margin is designed into PCB partitioning: isolated transceivers, TVS and CM filter networks on external ports, watchdog and safe-state defaults on MCU reset, and hardware interlocks independent of software RF susceptibility. Cable shield termination, enclosure bonding, and filter BOM match immunity-validated configuration — field substitution of comm cables voids immunity claims.

Retest triggers include MCU family change, new wireless comms module, AC front-end topology revision, and customer OEM spec updates. SiCore maintains immunity test correlation across product generations to avoid regression when cost-reducing filter components.