Total Harmonic Distortion

R2026b

Total harmonic distortion measurement

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Total Harmonic Distortion block

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Libraries:
Simscape / Electrical / Control / Measurements

Description

The Total Harmonic Distortion block calculates the total harmonic distortion (THD) percentage using these equations:

$$M=\frac{harmonicmagnitude}{\sqrt{2}},$$

and

$\%THD=100\frac{\sqrt{{{\displaystyle \sum }}_{i=2}^n{M}_i{}^2}}{M_1},$

where:

• M_i is the root mean squared (RMS) value of the harmonic magnitude that corresponds to the i^th harmonic order.

• M is V_RMS or I_RMS.

• ${{\displaystyle \sum }}_{i=2}^n{M}_i{}^2$ is the sum of all harmonic components.

Ports

Input

u — Harmonic magnitude

scalar | vector

Harmonic magnitude.

Data Types: single | double

Output

THD (%) — Total harmonic distortion

scalar | vector

Total harmonic distortion as a percentage.

Data Types: single | double

Parameters

Fundamental frequency — Fundamental frequency in Hz

60 Hz (default)

Fundamental frequency, in Hz.

Sample time (-1 for inherited) — Block sample time

-1 (default) | nonnegative scalar

Time between consecutive block executions. During execution, the block produces outputs and, if appropriate, updates its internal state. For more information, see What Is Sample Time? and Specify Sample Time.

For inherited discrete-time operation, specify -1. For discrete-time operation, specify a positive integer. For continuous-time operation, specify 0.

To improve accuracy, set this value at least 10 times smaller than the Time constant parameter.

Note

If this block is in a masked subsystem, or another variant subsystem that allows either continuous or discrete operation, promote the sample time parameter to ensure correct switching between the continuous and discrete implementations of the block. For more information, see Promote Block Parameters to a Mask.

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"ee_sl_lib/Measurements/Total Harmonic Distortion"

Example: add_block("ee_sl_lib/Measurements/Total Harmonic Distortion","myModel/myBlock",MakeNameUnique="on")

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2019b