Field-Oriented-Control (FOC) Motor Datapath

What it is

foc_motor is a Field-Oriented-Control (FOC) motor-control datapath for BLDC/PMSM machines (drone propulsion + industrial servo), delivered as synthesizable SystemVerilog soft-IP with an APB4-lite control interface and built-in ISO 26262 (ASIL-B) safety instrumentation.

Key Features

• Full fixed-point FOC inner loop in one hardware tick: Clarke, Park, two independent current-regulator PIs (per-axis Kp/Ki, Q4.12), inverse Park, and SVPWM (inverse-Clarke + zero-sequence centering) -> duty_a/b/c
• On-chip signed Q1.15 sin/cos LUT (SIN_N entries/revolution) indexed by the rotor electrical-angle phase index — no external trig required
• APB4-lite sidecar config plane, separate from the real-time torque-loop wires: per-axis Kp/Ki, current envelope (ILIM), duty envelope (DUTYLIM), Id/Iq torque setpoints, pole pairs, sticky STATUS + duty/current readback
• Current/duty plausibility + over-current envelope check drives a structural zero-duty safe-state (all phases to mid-rail, integrators frozen) independent of software -> err_code 3
• Control-loop watchdog: a tick must arrive within LOOP_TIMEOUT clocks or the loop is declared hung -> err_code 4, sized to the drive’s FTTI
• KEEP_ATTR complementary-DMR on the FOC control FSM and both PI integrators catches a state-holding-element upset -> err_code 9; even-parity config registers catch an SEU in gains/limits/setpoints -> err_code 1
• fi_* DFT fault-inject ports exercise every mechanism for a fault-injection campaign; catalog FMEDA: SPFM 91.60%, LFM 88.41%, PMHF 3.43×10⁻⁹/h — PASS vs ASIL-B

Standards & Compliance

Field-Oriented-Control (Clarke/Park/SVPWM) current-loop algorithm; APB4-lite config interface; ISO 26262 ASIL-B SEooC (SPFM 91.60%, LFM 88.41%, PMHF 3.43×10⁻⁹/h)

Functional Safety

ASIL-B target (SEooC) · SPFM 91.60% · LFM 88.41% · Informational — not gated

Informational FMEDA — this IP is reported but NOT gated. The SPFM/LFM figures above are engineering estimates from a model that is not held to the ASIL metric gates (QM, safety-by-composition, a vendor-core overlay, or a pre-sign-off Technology Preview, depending on the IP). They are not a certification claim and must not be relied on as one. See the safety manual for this IP’s exact status, assumptions of use, and any open items.

ISO 26262:2018 · FMEDA available · Safety Manual included

Register Map

…4 more registers — see datasheet for the full table.

Getting Started

// Minimal instantiation
foc_motor #(
 .ADDR_W(6)
) u_foc_motor (
 .clk (clk),
 .rst_n (rst_n),
 // APB4
 .p_paddr (paddr),
 .p_psel (psel),
 .p_penable (penable),
 .p_pwrite (pwrite),
 .p_pwdata (pwdata),
 .p_prdata (prdata),
 .p_pready (pready),
 // Safety
 .err_clear (1'b0),
 .err_valid (err_valid),
 .err_code (err_code)
);

Configure via the CTRL register after reset to enable the IP and set operating parameters. Monitor err_valid / err_code for any safety faults reported by the built-in safety monitor.