The influence of dead-time on AC servo motor’s low-speed operation

PWM technology has been widely used in motor drive systems today. To avoid the short-circuit condition, dead-time must be inserted to the PWM driving pulses. The addition of dead-time increases the harmonic of output voltage, makes the waveform of winding current more badly. The ripple of motor torque and speed is also increased by the addition of dead-time. The influence of dead-time is more remarkable while the motor speed is low, and so, greatly influence the low-speed working ability. This paper analyzes the influence of dead-time for low-speed motor drive in detail. The nonlinear phenomena in the motion of output voltage-vector, which affects the motorpsilas low-speed performance directly, is also indicated.