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Phase angle Step Response from sawtooth phase signal

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AliBakBak

Electrical
Jul 24, 2007
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I have implemented a phase locked loop (PLL) in SIMULINK. I am just having a few problems in attaining the phase angle step response of the system.

The system takes a power frequency signal (at 50Hz) which has a step change in phase angle at a predefined time (0.1s).

This is done by taking the original input signal (v = Vsin(2*pi*50*t)) and replacing it with a new signal at t = 0.1s (vn = Vsin(2*pi*50*t + (35*(pi/180)))) which is equivalent to a phase angle shift of 35 deg.

The output of the system is a phase signal that resembles a sawtooth waveform (as normal) where a phase angle of zero is noted every zero crossing. How would one obtain a step response of the phase angle tracking. i.e. if a 35 deg. step phase shift occurs at t = 0.1s, how would one plot how the phase angle output of the system tracks the new phase angle?

I have tried to use a reference angle sawtooth waveform (using the repeating sequence block) and subtract it from the output of the system. The problem with this is that there is a gap between the reference angle waveform and the PLL output.

The step response is almost attained using the above methodology but with small gaps in it periodically.

Any help will be greatly appreciated.

Thank you
 
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