ADE7769ARZ datasheet(10/20 Pages) AD

Part #	ADE7769ARZ

Description	Energy Metering IC with Integrated Oscillator and No-Load Indication

Download	20 Pages

Scroll/Zoom	100%

Manufacturer	AD [Analog Devices]

Direct Link	http://www.analog.com

Logo

10 / 20 page

ADE7769

Rev. A | Page 10 of 20

FUNCTIONAL DESCRIPTION

THEORY OF OPERATION

The two ADCs in the ADE7769 digitize the voltage signals from

the current and voltage sensors. These ADCs are 16-bit Σ-Δs

with an oversampling rate of 450 kHz. This analog input

structure greatly simplifies sensor interfacing by providing a

wide dynamic range for direct connection to the sensor and by

simplifying the antialiasing filter design. A high-pass filter in

the current channel removes any dc component from the

current signal. This eliminates any inaccuracies in the real

power calculation due to offsets in the voltage or current

signals.

The real power calculation is derived from the instantaneous

power signal. The instantaneous power signal is generated by

a direct multiplication of the current and voltage signals. To

extract the real power component (the dc component), the

instantaneous power signal is low-pass filtered. Figure 15

illustrates the instantaneous real power signal and shows how

the real power information can be extracted by low-pass

filtering the instantaneous power signal. This scheme correctly

calculates real power for sinusoidal current and voltage

waveforms at all power factors. All signal processing is carried

out in the digital domain for superior stability over temperature

and time.

TIME

ADC

CH1

CH2

MULTIPLIER

F1

F2

DIGITAL-TO-

FREQUENCY

CF

DIGITAL-TO-

FREQUENCY

INSTANTANEOUS REAL

POWER SIGNAL

INSTANTANEOUS

POWER SIGNAL – p(t)

LPF

HPF

Figure 15. Signal Processing Block Diagram

The low frequency outputs (F1 and F2) are generated by

accumulating this real power information. This low frequency

inherently means a long accumulation time between output

pulses. Consequently, the resulting output frequency is propor-

tional to the average real power. This average real power

information is then accumulated (by a counter) to generate real

energy information. Conversely, due to its high output frequen-

cy and shorter integration time, the CF output frequency is

proportional to the instantaneous real power. This is useful for

system calibration, which can be done faster under steady load

conditions.

Power Factor Considerations

The method used to extract the real power information from

the instantaneous power signal, that is, by low-pass filtering, is

still valid even when the voltage and current signals are not in

phase. Figure 16 shows the unity power factor condition and a

displacement power factor (DPF) = 0.5, that is, current signal

lagging the voltage by 60°. Assuming that the voltage and

current waveforms are sinusoidal, the real power component of

the instantaneous power signal (that is, the dc term) is given by

( °

×

⎟

⎠

⎞

⎜

⎝

⎛ ×

60

cos

2

I

V

)

(1)

This is the correct real power calculation.

V

× I

2

0V

POWER

CURRENT

VOLTAGE

POWER

TIME

VOLTAGE

CURRENT

V

× I

2

COS (60

°)

0V

INSTANTANEOUS

POWER SIGNAL

INSTANTANEOUS REAL

POWER SIGNAL

INSTANTANEOUS

POWER SIGNAL

INSTANTANEOUS REAL

POWER SIGNAL

60

°

Figure 16. DC Component of Instantaneous Power Signal Conveys

Real Power Information, PF < 1

Nonsinusoidal Voltage and Current

The real power calculation method also holds true for

nonsinusoidal current and voltage waveforms. All voltage

and current waveforms in practical applications have some

harmonic content. Using the Fourier transform, instantaneous

voltage and current waveforms can be expressed in terms of

their harmonic content.

(

h

0

h

0

α

t

hω

V

t

v

+

×

+

=

∑

∞

≠

sin

2

)

(

)

(2)

where:

v(t) is the instantaneous voltage.

V0 is the average value.

Vh is the rms value of voltage harmonic h.

αh is the phase angle of the voltage harmonic.

Similar Part No. - ADE7769ARZ

Manufacturer	Part #	Datasheet	Description
Analog Devices	ADE7769	385Kb / 20P	Energy Metering IC with Integrated Oscillator and No-Load Indication REV. A

More results

Similar Description - ADE7769ARZ

Manufacturer	Part #	Datasheet	Description
Analog Devices	ADE7769	385Kb / 20P	Energy Metering IC with Integrated Oscillator and No-Load Indication REV. A
	AD71056	412Kb / 20P	Energy Metering IC with Integrated Oscillator and Reverse Polarity Indication REV. A
	AD71056	413Kb / 20P	Energy Metering IC with Integrated Oscillator and Reverse Polarity Indication REV. A
	ADE7757	534Kb / 14P	Energy Metering IC with Integrated Oscillator REV. PrC.
	ADE7757	218Kb / 16P	Energy Metering IC with Integrated Oscillator REV. A
	ADE7762	424Kb / 28P	Polyphase Energy Metering IC with Phase Drop Indication REV. 0
	ADE7768	405Kb / 20P	Energy Metering IC with Integrated Oscillator and Positive Power Accumulation REV. A
	ADE7762	856Kb / 28P	Polyphase Energy Metering IC with Phase Drop Indication Rev. PrB
	ADE7768	404Kb / 20P	Energy Metering IC with Integrated Oscillator and Positive Power Accumulation REV. A
	ADE9153B	68Kb / 2P	Energy Metering IC

More results

ADE7769ARZ Datasheet(PDF) 10 Page - Analog Devices

ADE7769ARZ Datasheet(HTML) 10 Page - Analog Devices

Similar Part No. - ADE7769ARZ

Similar Description - ADE7769ARZ

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Datasheet Download

Link URL