STPMC1 ST Microelectronics, STPMC1 Datasheet - Page 66

• Manufacturer Part Number: STPMC1
• Description: Programmable poly-phase energy calculator IC
• Manufacturer: ST Microelectronics

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Energy calculation algorithm
10.1
66/76
In case of shunt sensor (TCS = 1), an additional stage of internal digital differentiated
produces the value:
Equation 21
v
The shunt preamplifier, AD converter and calibrator produce the value:
Equation 22
vs = i R
The 2
Equation 23
v
Equation 24
v
The frequency compensated values are:
Equation 25
V
Equation 26
v
The 3
Equation 27
v
Equation 28
v
Active energy calculation
The active power is computed as follows.
First, the voltage stream from the 1
16-bit current from the 2
1
filter (
Equation 29
P
Equation 30
P
d
di
si
sic
diic
siic
st
dic
1
2
= dv
= ∫ v
= ∫ v
= v
= v
stage (
=
=
= ∫ v
= ∫ v
Equation 14
nd
rd
u
ui
u
d
S
v
s
stage internal integrations and DC cancellations produce the values:
/dt = A
/ k
v
stage internal integrations produce the values:
dt = A sin ( t) k
/ k
dic
sic
dt = - (C / ) cos ( t + ) k
ii
(A
i
Equation 13
INT
= - ABk
= ABk
INT
dt = - (C / ) sin ( t + ) k
dt = A cos ( t) k
I
/V
v
REF
v
si
di
INT
= - C cos ( t + )
cos ( t) k
= A
) k
INT
or
cos ( t) cos ( t + ) = ABk
I
Equation 23
sin ( t) sin ( t + ) = - ABk
= i k
or
sin ( t) / k
nd
DIF
Equation 22
S
stage (
DIF
= C sin ( t + )
DIF
k
INT
Doc ID 15728 Rev 1
k
INT
= A sin ( t)
), yielding:
Equation 15
INT
st
INT
= A cos ( t)
stage (
INT
) is multiplied to 16-bit voltage from the 2
Equation 12
or
INT
Equation 24
INT
[cos
[cos
or
+ cos (2
Equation 21
- cos (2
) and current stream from the
t + )] / 2
t + )] / 2
) is multiplied to the
nd
stage of
STPMC1