Q: What safety considerations are critical in motor control system design?
Answer
Motor control safety design: (1) Hardware overcurrent protection: use current shunt amplifier + comparator to generate fast fault signal (<1 us) that disables all MOSFETs immediately. (2) Hardware overvoltage (regeneration): add clamp circuit (TVS or active clamp) to absorb regenerative energy. (3) Undervoltage lockout: prevent motor starting below safe voltage. (4) Overtemperature: thermal shutdown on driver IC + motor thermistor (PTC). (5) Watchdog: MCU must send periodic enable pulse or driver disables PWM. (6) Emergency stop: hardwired ESTOP circuit that cuts motor power regardless of MCU state. (7) Safe torque off (STO): use dual-channel MOSFET disable with cross-check - required for SIL2+ safety systems per IEC 61508. (8) Software: implement fail-safe state (PWM=0 all MOSFETs off) on any detected fault. Use state machine with defined safe states. (9) Redundant limit switches: hardware end-of-travel limits that cut motor power mechanically or via hardwired relay.
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