STPMC1 ST Microelectronics, STPMC1 Datasheet - Page 42

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

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Theory of operation
9.16.3
Table 27.
42/76
Mutual current compensation
Mutual current compensation is available only when TCS is clear (Rogowski coil).
When PM is cleared, the CCA and CCB configuration bytes can be used for mutual current
influence compensation according to SYS value.
For monophase systems (SYS > 3) the correction factors,
computed as follows:
Equation 5
Equation 6
An asymmetrical compensation is implemented by multiplying the phase current with
the neutral current with
respectively, as shown below:
Mutual current compensation matrix for single-phase systems (SYS > 3)
i
i
For other values of SYS, the values of CCA and CCB three correction factors, a 7-bit , 6-bit
Equation 7
Equation 8
CS
CT
phase
and 4-bit (gamma) are calculated as follows:
=
=
S
T
i
i
T
S
and these values are subtracted from neutral and phase currents
1
1
1
1
CCA
Doc ID 15728 Rev 1
CCA
CCA
CCA
7
8192
8
8192
8
8192
8
8192
CCB
CCA
CCB
CCA
S
-
7
5
7
7
3 :
0 :
0 :
0 :
(
(
(
(
(alpha) and
3.1 %)
3.1 %)
0.78 %)
0.39 %)
T
-
(beta), are
STPMC1
and