UM-YROTATE-IT-RX62T Datasheet, PDF (20/54 Pages) Renesas Technology Corp – Low Cost Motor Control Kit based on RX62T

RX62T
YROTATE-IT-RX62T Motor Control Kit
The reference frame transformations from the (α,β) system to the (d, q) system depends on the instantaneous
position angle ϑ
So we obtain two inter-dependant equations in the (d, q) system:
v_d
=
R_S i_d
+ L ^did
dt
− ωLi_q
v_q
=
R_S i_q
+
L
di_q
dt
+ ωLi_d
+ ωΛ_m
These two equations represent the mathematical motor model.
Vd
+
+
Id
1/(R+sL)
Vq
+^-
-
Iq
1/(R+sL)
Λωe
pΛ
Lωe
pL
(3/2)pΛ
τload
τ ^+-
1/(B+sJ)
ωmec
A control algorithm which wants to produce determined currents in the (d, q) system must impose voltages given
from the formulas above.
This is ensured by closed loop PI control on both axis “d” & “q” (Proportional Integral).
Since there is a mutual influence between the two axes, decoupling terms can be used.
In the block scheme the mechanic part is included, where “p” is the number of pole pairs, while “B” represents
friction, “J” the inertia, “τ_load“ the load torque and “τ” the motor torque.
τ = ³Ã— p×Λ
2
The angular speed ω is represented in the scheme as ω_e to distinguish the electrical speed from the mechanical one.
Let’s now consider the equations we have seen in (α,β) system:
UM-YROTATE-IT-RX62T Rev.1.00
Jan 15, 2014
Page 20 of 51