BL0952A BELLING [SHANGHAI BELLING CO., LTD.], BL0952A Datasheet - Page 9

• Manufacturer Part Number: BL0952A
• Description: Three-phase Active Energy Meter
• Manufacturer: BELLING [SHANGHAI BELLING CO., LTD.]

output pulse is given to the counter motor out of the chip, and then the counter value proportional
to the consumed energy is obtained.
and
channel and the current channel, these offsets contribute a dc component for the result of
multiplication. That is, the offsets bring the error of
Additionally, there exists the component of
dc error on the real power will result in measure error, and the component brought to the
frequency of
filter can’t restrain the ac component very completely.
offset on the current channel is removed; the result of multiplication is improved greatly. There is
no dc error, and the additional component at the frequency of
two high-pass filters, the component at the frequency of
of the output signal is advanced. Moreover, in this case, the phases of the voltage channel and the
current channel can be matched completely, and the performance when PF equal 0.5C or 0.5L is
improved. In BL0952A/BL6513/BL6511, this structure is selected. Though it is given in the
system specification that the ripple of the output signal is less than 0.1%, in real measure of
BL0952A/BL6513/BL6511, the calibration output is very stable, and the ripple of the typical
output signal is less than 0.05%.
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Offset Effect
The dc offsets come from the input signals and the forepart analog circuitry.
Assume that the input dc offsets on the voltage channel and the current channel are
As can be seen, for each phase input, if there are simultaneous dc offsets on the voltage
When the offset on the one of the voltage and the current channels is filtered, for instance, the
When the offsets on the voltage channel and the current channel are filtered respectively by
I
p
offset
) (
UI
t
2
, and PF equals 1 (
[
U
I
w
offset
cos(
will also affect the output of the average active power when the next low-pass
U
cos(
Fig.6
t
)
U
t
)
offset
BL0952A/BL6513
BL0952A/BL6513
BL0952A/BL6513
BL0952A/BL6513
Effect of different offset cancellation methods
U
]
0
offset
o
[
).
I
I
cos(
cos(
Total 9 Pages
U
t
- 9 -
t
)
offset
UI
)
U
2
I
offset
cos(
I
offset
w
I
offset
2
]
I
(50Hz) is subdued, and the stability
w
offset
t
)
is also decreased.
U
to the final average real power.
at the frequency of
Three
Three- - - - phase Active
Three
Three
Energy Meter
Energy Meter
Energy Meter
Energy Meter
phase Active
phase Active
phase Active
4/21/2009
w
U
. The
offset