PSIM User Manual phần 6 pot

Chapter 3: Control Circuit Components

3-18 PSIM User Manual

Example:

The following circuit performs the function of selecting the maximum value out of two

inputs. When Va is greater than Vb, the comparator output will be 1, and Vo = Va. Other￾wise Vo = Vb.

3.3.10 THD Block

For an ac waveform that contains both the fundamental and harmonic components, the

total harmonic distortion of the waveform is defined as:

where V1 is the fundamental component (rms), Vh is the harmonic rms value, and Vrms is

the overall rms value of the waveform. The THD block is modelled as shown below.

Image:

A second-order band-pass filter is used to extract the fundamental component. The center

frequency and the passing band of the band-pass filter need to be specified.

THD

Vh

V1

----- Vrms

2 V1

2 –

V1

= = ---------------------------

THD Circuit Model of the THD Block

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