STEVAL-IPE012V1 STMicroelectronics, STEVAL-IPE012V1 Datasheet - Page 40

• Manufacturer Part Number: STEVAL-IPE012V1
• Description: EVAL BOARD ENERGY METER
• Manufacturer: STMicroelectronics
• Series: -r

Specifications of STEVAL-IPE012V1

• Design Resources: STEVAL-IPE012V1 Schematic STEVAL-IPE012V1 BOM
• Main Purpose: Power Management, Energy/Power Meter
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: STPM10BTR, STM8L152
• Primary Attributes: Single Phase with 1 Current Transformer & Shunt
• Secondary Attributes: Tamper Detection
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-11462

Theory of operation
7.23.3
40/51
The reactive power, then, presents a ripple at twice the line frequency. Since the average
value of a sinusoid is 0, this ripple does not contribute to the reactive energy calculation over
time. Moreover, in the STPM10 the reactive power is not used for meter calibration or to
generate the stepper pulses, so this ripple does not affect the overall system performance.
Apparent power and RMS values
The RMS values are calculated starting from the following formulas:
Equation 18
Multiplying
Equation 19
The RMS voltage value is obtained by:
Equation 20
For the apparent power, another value is produced:
Equation 21
Multiplying
Equation 22
Q
I
V
RMS
RMS
3
T
T
1
1
(
) t
T
∫
T
∫
0
0
=
I
=
v
2
=
′
(
2
I
2
) t
1
2
(
T
1
dt
) t
Equation 18
Equation 18
⋅
dt
Q
T
∫
0
=
v
1
=
(
2
ω
) t
) t (
V
⋅
⋅
dt
I
ω
⋅
2
ω
2
=
=
by
and
VI
2
V
2
ω
⋅
(
Equation 21
, the I
sin
Doc ID 17728 Rev 3
ϕ
RMS
−
sin(
value is obtained:
, the apparent power is produced:
2
ω
t
+
ϕ
)
)
STPM10