STPM01_11 STMICROELECTRONICS [STMicroelectronics], STPM01_11 Datasheet - Page 49

• Manufacturer Part Number: STPM01_11
• Description: Programmable single phase energy metering IC with tamper detection
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STPM01
Equation 21
The RMS voltage value is obtained as:
Equation 22
For the apparent power another value is produced:
Equation 23
Multiplying
Equation 24
Rogowsky coil
In this case we have:
Equation 25
while V
The apparent power is simple calculated multiplying
The DSP then performs the integration of the computed powers into energies. These
integrators are implemented as up/down counters and they can rollover. 20-bit output buses
of the counters are assigned as most significant part of energy data records. It is a
responsibility of an application to read the counters at least every second not to miss any
rollover.
I
I
S
V
RMS
RMS
RMS
T
=
1
T
∫
ω
0
=
=
v
=
⋅
RMS
I
′
2
I
2
2
T
1
(
T
Equation 20:
) t
1
is calculated as in
⋅
T
∫
0
dt
V
∫
i
T
0
′ ′
2
⋅
v
2
(
ω
=
2
) t
) t (
dt
=
V
dt
⋅
VI
2
2
=
ω
=
and
I
2
V
2
Equation 23:
Doc ID 10853 Rev 8
Equation 22:
, the apparent power is produced:
.
Equation 25:
and
Theory of operation
Equation 22:
.
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