ADE7880 datasheet(37/104 Pages) AD

37 / 104 page

Data Sheet

ADE7880

Rev. A | Page 37 of 104

Figure 63 illustrates how the phase compensation is used to

remove x = −1° phase lead in IA of the current channel from the

external current transducer (equivalent of 55.5 μs for 50 Hz

systems). To cancel the lead (1°) in the current channel of

Phase A, a phase lead must be introduced into the corresponding

voltage channel. Using Equation 8, APHCAL is 57 least

significant bits, rounded up from 56.8. The phase lead is

achieved by introducing a time delay of 55.73 μs into the Phase

A current.

−6.732° to +1.107° and the resolution is 0.0176° (360° × 50 Hz/

1.024 MHz).

Given a phase error of x degrees, measured using the phase

voltage as the reference, the corresponding LSBs are computed

dividing x by the phase resolution (0.0211°/LSB for 60 Hz and

0.0176°/LSB for 50 Hz). Results between −383 and +63 only are

acceptable; numbers outside this range are not accepted. If the

current leads the voltage, the result is negative and the absolute

value is written into the PHCAL registers. If the current lags the

voltage, the result is positive and 512 is added to the result

before writing it into xPHCAL.

APHCAL, BPHCAL, or CPHCAL

⎪

⎭

⎪

⎬

⎫

⎪

⎩

⎪

⎨

⎧

≤

512

resolution

phase

resolution

phase

(9)

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7880 work on 32-, 16-, or 8-bit words. As

shown in Figure 62, APHCAL, BPHCAL, and CPHCAL 10-bit

registers are accessed as 16-bit registers with the six MSBs padded

with 0s.

0000 00

10 9

xPHCAL

Figure 62. xPHCAL Registers Communicated As 16-Bit Registers

PHASE

CALIBRATION

APHCAL = 57

ADC

PGA3

VAP

ADC

PGA1

IAP

IAN

PHASE COMPENSATION

ACHIEVED DELAYING

IA BY 56µs

50Hz

1°

Figure 63. Phase Calibration on Voltage Channels

ADE7880 数据表(PDF) 37 Page - Analog Devices

ADE7880 数据表(HTML) 37 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载