Q: What are the causes of motor vibration and how to diagnose them using current signature analysis? Answer Motor vibration diagnosis via motor current signature analysis (MCSA): motor current spectrum reveals mechanical faults without speed sensors. Common fault signatures: (1)…
Q: How to implement soft starters and variable frequency drives (VFDs) for AC motors? Answer Soft starter: limits inrush current and torque during AC motor startup. Methods: (1) Voltage ramp: start at reduced voltage (e.g. 30% for 3 seconds then…
Q: How to design a 3-phase inverter for motor drive applications? Answer 3-phase inverter design: (6 MOSFETs or IGBTs in H-bridge configuration). Top: 3 high-side MOSFETs (VM supply). Bottom: 3 low-side MOSFETs (ground). Gate drives: use 3-phase gate driver IC…
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 (
Q: How to implement PID control for DC motor speed regulation? Answer DC motor PID speed control: (1) Measure speed with encoder or tachogenerator. (2) Calculate speed error: e = desired_speed – measured_speed. (3) PID output: u = Kp*e +…
Q: What thermal management strategies are needed for motor drive electronics? Answer Motor driver thermal design: (1) Calculate power dissipation: P_loss = P_conduction + P_switching. Conduction loss = I_RMS^2 x Rds_on x 2 (half-bridge). Switching loss = 0.5 x V…
Q: How to implement position control for servo motors in robotics and CNC applications? Answer Servo position control architecture: trajectory generator -> position PID -> velocity PID -> current PI -> PWM. Trajectory generation: S-curve or trapezoidal velocity profile to…
Q: How to implement stepper motor closed-loop control to prevent missed steps? Answer Closed-loop stepper (also called servo stepper or hybrid servo): combines stepper simplicity with encoder feedback. Implementation: (1) Add rotary encoder to stepper motor shaft (1000-4000 CPR). (2)…
Q: What are the motor control algorithms for AC induction motors (V/Hz and vector control)? Answer AC Induction Motor (ACIM) control methods: (1) V/Hz (scalar control): simplest method – keep voltage/frequency ratio constant to maintain constant flux. Program the V/Hz…
Q: How to design the power stage for a BLDC motor driver (MOSFET selection and gate drive)? Answer MOSFET selection for BLDC driver: (1) VDS: 2x supply voltage (e.g. 50V for 24V system). (2) Rds_on: Motor -> GND) as small…