ABSTRACT
The current loop control of PMSM drive in Figure 2 is based on a vector control approach. That is, if the id is controlled to 0, the PMSM will be decoupled and controlling a PMSM will be similar to controlling a DC motor. Therefore, after decoupling, the torque of PMSM can be written as the following equation,
T P
i K ie f q t q= 3 4
λ Δ (3)
with
K P
t f= 3 4
λ (4)
Te is the motor torque and P is pole pairs. Thus, considering the mechanical load, the overall dynamic equation of linear table system is obtained by
T T J r
d dt
B r
p = +
2 2s2 2
π π (5)
Kt is force constant; Jm is the inertial value; Bm is damping ratio; TL is the external torque; sp represents xp, yp or zp which are the displacement of X-axis, Y-axis and Z-axis table; r is the lead of the ball screw.
