AN1915D Freescale Semiconductor / Motorola, AN1915D Datasheet - Page 13

• Manufacturer Part Number: AN1915D
• Description: 3-Phase BLDC Motor Control with Quadrature Encoder using DSP56F80x
• Manufacturer: Freescale Semiconductor / Motorola

MOTOROLA
e(t), e( )
e(k)
w(k)
m(k)
u(k)
u
u
u
T
T
K
t,
p
p
I
I
I
c
(k)
(k-1)
(k)
The speed controller calculates a Proportional-Integral (PI) algorithm according to equations below:
After transformation to a discrete time domain using an integral approximation by a Backward Euler
method, we get the following equations for the numerical PI controller calculation:
where:
desired
= Controller output in step k
= Integral output portion in step k-1
= Input error in time t,
= Input error in step k
= Desired value in step k
= Measured value in step k
= Proportional output portion in step k
= Integral output portion in step k
= Integral time constant
= Sampling time
= Controller gain
= Time
= Laplace variable
3-Phase BLDC Motor Control with Quadrature Encoder
-
Freescale Semiconductor, Inc.
For More Information On This Product,
actual
Figure 3-14. Speed Controller
error
u
u t
I
k
=
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u k
=
u
K
P
u
Controller
c
I
=
k
Speed
e t
k 1
u
=
–
P
K
+
k
c
---- - e
T
+
1
+
I
e k
K
0
u
c
I
---- - e k
T
T
k
I
PWM Output
Duty Cycle
d
Commutation sector
Commutation
Power Stage
Generator
PWM
Target Motor Theory
(EQ 3-1.)
(EQ 3-2.)
(EQ 3-3.)
(EQ 3-4.)
13