ADE7753ARSZ Analog Devices Inc, ADE7753ARSZ Datasheet - Page 33

• Manufacturer Part Number: ADE7753ARSZ
• Description: IC ENERGY METERING 1PHASE 20SSOP
• Manufacturer: Analog Devices Inc

Specifications of ADE7753ARSZ

• Input Impedance: 390 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.8V
• Current - Supply: 3mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP (0.200", 5.30mm Width)
• Meter Type: Single Phase
• Ic Function: Single-Phase Multifunction Metering IC
• Supply Voltage Range: 4.75V To 5.25V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: SSOP
• No. Of Pins: 20
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-ADE7753ZEB - BOARD EVALUATION AD7753
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

REACTIVE POWER CALCULATION
Reactive power is defined as the product of the voltage and
current waveforms when one of these signals is phase-shifted by
90°. The resulting waveform is called the instantaneous reactive
power signal. Equation 25 gives an expression for the instanta-
neous reactive power signal in an ac system when the phase of
the current channel is shifted by +90°.
where:
θ is the phase difference between the voltage and current
channel.
V is the rms voltage.
I is the rms current.
v(t) =
i(t) =
Rp(t) = v(t) × i’(t)
Rp(t) = VI sin ( θ ) + VI sin
i
′
) (
t
=
2
2
2
I
V
I
sin(
sin
CHANNEL 2
sin(
⎛
⎜
⎝
ω
ωt
ω
t
FROM
)
t
ADC
+
+
θ
π
2
)
⎞
⎟
⎠
LPF1
2 (
V
I
ωt
PHASE SHIFT
90 DEGREE
+
MULTIPLIER
θ
)
ZERO-CROSSING
π
2
DETECTION
INSTANTANEOUS REACTIVE
POWER SIGNAL (Rp(t))
Figure 71. Reactive Power Signal Processing
LPF2
LINECYC [15:0]
CALIBRATION
(25)
CONTROL
Rev. A | Page 33 of 60
(23)
(24)
+
+
The average reactive power over an integral number of lines (n)
is given in Equation 26.
where:
T is the line cycle period.
RP is referred to as the reactive power.
Note that the reactive power is equal to the dc component of the
instantaneous reactive power signal Rp(t) in Equation 25. This
is the relationship used to calculate reactive power in the
ADE7753. The instantaneous reactive power signal Rp(t) is
generated by multiplying Channel 1 and Channel 2. In this case,
the phase of Channel 1 is shifted by +90°. The dc component of
the instantaneous reactive power signal is then extracted by a
low-pass filter in order to obtain the reactive power informa-
tion. Figure 71 shows the signal processing in the reactive power
calculation in the ADE7753.
49
23
LVARENERGY [23:0]
RP
=
nT
1
nT
∫
0
Rp
0
(
t
)
dt
ACCUMULATE REACTIVE
ENERGY IN INTERNAL
REGISTER AND UPDATE
THE LVARENERGY REGISTER
AT THE END OF LINECYC HALF
LINE CYCLES
=
VI
sin(
θ
0
)
02875-0-070
ADE7753
(26)