ADE5166 datasheet(66/156 Pages) AD

66 / 156 page

ADE5166/ADE5169/ADE5566/ADE5569

Rev. B | Page 66 of 156

REACTIVE ENERGY CALCULATION

(ADE5169/ADE5569 ONLY)

As for active energy, the ADE5169/ADE5569 achieve the integra-

tion of the reactive power signal by continuously accumulating

the reactive power signal in an internal, nonreadable, 49-bit energy

represents the upper 24 bits of this internal register. The VARHR

The discrete time sample period (T) for the accumulation register

in the ADE5169/ADE5569 is 1.22 μs (5/MCLK). As well as

calculating the energy, this integration removes any sinusoidal

components that may be in the active power signal. Figure 72

shows this discrete time integration or accumulation. The

reactive power signal in the waveform register is continuously

added to the internal reactive energy register.

The reactive energy accumulation depends on the setting of

SAVARM (Bit 2) and ABSVARM (Bit 3) in the ACCMODE

is signed and, therefore, negative energy is subtracted from the

reactive energy contents. When both bits are set, the ADE5169/

ADE5569 are set to the more restrictive mode, which is the

absolute accumulation mode.

When the SAVARM bit (Bit 2) in the ACCMODE register

(Address 0x0F) is set, the reactive power is accumulated

depending on the sign of the active power. When active power

is positive, the reactive power is added as it is to the reactive energy

subtracted from the reactive energy accumulator (see the Var

Antitamper Accumulation Mode section).

When the ABSVARM bit (Bit 3) in the ACCMODE register

(Address 0x0F) is set, the absolute reactive power is used for the

reactive energy accumulation (see the Var Absolute Accumulation

Mode section).

The output of the multiplier is divided by VARDIV. If the value

in the VARDIV register (Address 0x25) is equal to 0, the internal

reactive energy register is divided by 1. VARDIV is an 8-bit,

unsigned register. After dividing by VARDIV, the reactive energy is

accumulated in a 49-bit internal energy accumulation register.

The upper 24 bits of this register are accessible through a read to

the reactive energy register (VARHR, Address 0x04[23:0]). A read

to the RVARHR register (Address 0x05) returns the contents of

the VARHR register, and the upper 24 bits of the internal register

are cleared.

As shown in Figure 72, the reactive power signal is accumulated in

an internal 49-bit, signed register. The reactive power signal can be

read from the waveform register by setting the WAVMODE reg-

ister (Address 0x0D) and setting the WFSM bit (Bit 5) in the Inter-

rupt Enable 3 SFR (MIRQENH, Address 0xDB). Like the current

and voltage channel waveform sampling modes, the waveform data

is available at sample rates of 25.6 kSPS, 12.8 kSPS, 6.4 kSPS, and

3.2 kSPS.

Figure 67 shows this energy accumulation for full-scale signals

(sinusoidal) on the analog inputs. These curves also apply to the

reactive energy accumulation.

Note that the energy register contents roll over to full-scale

negative (0x800000) and continue to increase in value when

the power or energy flow is positive. Conversely, if the power is

negative, the energy register underflows to full-scale positive

(0x7FFFFF) and continues to decrease in value.

Using the Interrupt Enable 2 SFR (MIRQENM, Address 0xDA),

the ADE5169/ADE5569 can be configured to issue an ADE

interrupt to the 8052 core when the reactive energy register is

half full (positive or negative) or when an overflow or under-

flow occurs.

VARGAIN[11:0]

VARDIV[7:0]

LPF2

CURRENT

CHANNEL

VOLTAGE

CHANNEL

TIME (nT)

MCLK

REACTIVE POWER

SIGNAL

VARHR[23:0]

UPPER 24 BITS ARE

ACCESSIBLE THROUGH

VARHR[23:0] REGISTER

WAVEFORM

VALUES

VAROS[15:0]

sgn

2–6 2–7 2–8

FOR WAVEFORM

SAMPLING

HPF

PHCAL[7:0]

90° PHASE

SHIFTING FILTER

OUTPUTS FROM THE LPF2 ARE

ACCUMULATED (INTEGRATED) IN

THE INTERNAL REACTIVE ENERGY

DIGITAL-TO-FREQUENCY

CONVERTER

Figure 72. Reactive Energy Calculation

ADE5166 数据表(PDF) 66 Page - Analog Devices

ADE5166 数据表(HTML) 66 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