MCP3909-I/SS Microchip Technology, MCP3909-I/SS Datasheet - Page 94

• Manufacturer Part Number: MCP3909-I/SS
• Description: IC POWER METERING-1 PHASE 24SSOP
• Manufacturer: Microchip Technology

Specifications of MCP3909-I/SS

• Package / Case: 24-SSOP (0.200", 5.30mm Width)
• Input Impedance: 390 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.85V
• Current - Supply: 2.3mA
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Meter Type: Single Phase
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Supply Voltage Range: 4.5V To 5.5V
• Digital Ic Case Style: SSOP
• No. Of Pins: 24
• Interface Type: Serial, SPI
• Supply Voltage Max: 5.5V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MCP3909EV-MCU16 - EVALUATION BOARD FOR MCP3909MCP3909RD-3PH1 - REF DESIGN MCP3909 3PH ENGY MTR
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design
C.12 HARMONIC COMPONENTS OF CURRENT, VOLTAGE AND TOTAL
DS51723A-page 94
HARMONIC DISTORTION
In Section C.3 “The Harmonic Analysis Algorithm Of Quasi-synchronous Sam-
pling”, we discussed the measuring of current and voltage signals for each order of
harmonics. 3 parameters are used to show to what extent a distorted wave deviates
from a sine wave. They are: harmonic content, total distortion and harmonic ratio of the
k-th harmonic. The term harmonic content means the root of square of effective values
for all harmonics, which is defined as:
EQUATION C-60:
The total voltage distortion ratio of harmonics is the ratio of harmonic content to the
fundamental in percentage, which is defined as:
EQUATION C-61:
The k-th harmonic ratio for voltage is the ratio of the k-th harmonic to the fundamental
in percentage, defined as:
EQUATION C-62:
Similarly, harmonics of each order for the current and total distortion ratio can be sorted
out.
THD
U
=
THD
U
-------
U
U
H
H
I
Uk
×
=
100%
=
k
U
------
U
∑
N
=
1
k
2
×
k
U
∑
100%
N
=
k
2
2
(
THD
Uk
)
© 2009 Microchip Technology Inc.
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