STPM01_11 STMICROELECTRONICS [STMicroelectronics], STPM01_11 Datasheet - Page 45

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

STPM01
8.24.1
Figure 28. Active energy computation diagram
Equation 3
i(t) = I • sin (
where I is the peak current,
between voltage and current.
Active power
In the STPM01, after the pre-conditioning and the A/D conversion, the digital voltage signal
(which is dynamically more stable with respect to the current signal) is processed by a
differentiated stage which transforms:
Equation 4
v(t) → v’(t) = dv/dt = V
The resulted signal, together with the pre-processed and digitalized current signal:
Equation 5
i(t) = I
are then available for the calculation process. These digital signals are also provided into
two additional stages which perform the integration of themselves, obtaining:
⋅
sin(
ω
ω
t +
t +
ϕ
ϕ
); [see
);
⋅ ω ⋅
Figure 28
cos
ω
Doc ID 10853 Rev 8
is related to the line frequency and
ω
t − [see
- 6]
Figure 28
- 5]
ϕ
is the phase difference
Theory of operation
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