Positive-Sequence (PLL-Driven)

Block Positive-Sequence (PLL-Driven) calculates the component (amplitude and phase) of the direct sequence of the input three-phase signal abc during one cycle of the fundamental frequency specified by the input signal Freq. The angle of the reference frame required for calculations is set by the input signal wt.

A component of the direct sequence of a three-phase signal (voltage or current ) is calculated as follows:

Where

First, Fourier analysis is applied to the three input signals using a sliding window usage covering one cycle of the fundamental frequency (input Freq). The unit calculates the values of the voltage vectors at the fundamental frequency. Then the transformation is applied to obtain a direct sequence.

Since the unit uses a moving average window to perform Fourier analysis, it is necessary to complete one simulation cycle before the output values correspond to the correct amplitude and phase values. For example, the reaction of the block to an abrupt change in the vector It is a single-stroke linearly varying signal. During the first simulation cycle, the output values are kept constant and correspond to the values set by the initial input parameters.