This paper presents an improved flying restart method for reliable sensorless permanent-magnet synchronous motor (PMSM) drive
system using repetitive zero voltage
vectors. In order to restart the sensorless PMSM drive system, the estimation
method for initial
rotor position and speed is necessary due
to the absence of sensor. The initial rotor position and speed can be estimated
by using
current vector generated after applying
zero voltage vector with the rotating PMSM. However, when the restarting method
is
implemented for the industrial PMSM drive
system, there are many difficulties to measure accurate current vector due to
harmonic
components and electromagnetic
interference (EMI) by switching operation. Therefore, in this paper, the
improved flying restart method
using repetitive zero voltage vectors is
proposed in order to implement a reliable and robust operation of the
sensorless PMSM drive
system by the inverter. The effectiveness of the proposed method is verified by simulation and experimental results.