Fundamental (PLL-Driven)

Block Fundamental (PLL-Driven) calculates the amplitude and phase of the fundamental harmonic of the input signal In during a sliding window equal to one cycle of the fundamental frequency set by the input signal Freq. The coordinate system required for calculations is set by the input signal of the angle of the reference frame wt.

Based on the Fourier analysis of a periodic signal, the magnitude of the fundamental harmonic of the signal can be expressed as

,

,

,

, where — main frequency,

.

The amplitude and phase of the fundamental harmonic are calculated as follows:

,

.

To solve these equations, the block uses the value on the input port Freq for and the value on the input port wt for . These two input signals are usually connected to the outputs of the PLL unit.

Since this block uses a moving average window, one simulation cycle must be completed before the output values match the correct amplitude and phase values. For the first simulation cycle, the output values correspond to the parameter in which the initial values are set.