MCP39F511N datasheet(47/61 Pages) MICROCHIP

47 / 61 page

 2015-2018 Microchip Technology Inc.

DS20005473B-page 47

MCP39F511N

9.4

Calibrating the Phase

Compensation Register

Phase compensation is provided to adjust for any

phase delay between the current and voltage paths.

Channel 1 and channel 2 both have independent phase

compensation registers. This procedure requires

sinusoidal current and voltage waveforms with a

significant phase shift between them, and significant

amplitudes. The recommended displacement power

factor for calibration is 0.5. The procedure for

calculating the phase compensation register is as

follows:

Determine what the difference is between the

angle corresponding to the measured power

factor (PFMEAS) and the angle corresponding to

the expected power factor (PFEXP), in degrees.

EQUATION 9-7:

Convert this from degrees to the resolution

provided in Equation 9-8.

There are 56 samples per line cycle. One line cycle is

360 degrees, so for each sample, the angle is 360

degrees/56 samples = 6.4257..degrees/sample.

Since the phase compensation has a bit of sign, the

maximum angle error that can be compensated is only

half, that is +/- 3.21..degrees.

Converting the angle to 8-bit resolution gives 256/6.42

degrees = 39.82..with 40 as an approximation.

EQUATION 9-8:

Combine this additional phase compensation to

whatever value is currently in the phase

compensation and update the register. It is

recommended that Equation 9-9 be computed

in terms of an 8-bit two's complement-signed

value. The 8-bit result is placed in the least

significant

byte

the

16-bit

Phase

Compensation register.

EQUATION 9-9:

Based on Equation 9-9, the maximum angle in degrees

that can be compensated is ±3.2 degrees. If a larger

phase shift is required, contact your local Microchip

sales office.

MEAS

Active Power

Calibration Power Active

-------------------------------------------------------------------

ANGLE

MEA S 



MEAS

 180



---------



acos

ANGLE

EXP 



EXP

 180



---------



acos



ANGLE

MEAS

ANGLE

EXP

–

 40



Phas eCo mpensation

NEW

PhaseCompensation

OLD



MCP39F511N Datasheet(PDF) 47 Page - Microchip Technology

MCP39F511N Datasheet(HTML) 47 Page - Microchip Technology

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

Datasheet Download

Link URL