Dear all,
My question is regarding the synchronous reference frame phase-locked loop (SRF-PLL), as discussed in the book "Doubly fed induction machines:Modelling and control for wind energy applications". The output of the integrator is taken to be the estimated value of the voltage space vector angle. In simulation, the default value of an integrator is zero; this means that the initial phase angle of the voltage space vector is always estimated to be zero, which may not be true. Does this mean that there is a deficiency with this kind of SRF-PLL? Otherwise, how should the estimator block be modified?
Kind regards
Yes, it is possible to do, but you need to clearly understand dq algebra and trigonometry. For a given initial torque and flux in the machine, you back-calculate what would be the dq set points, by assuming then you find the initial values for sine and cosine, get the trigonometric identity to calculate the initial possible values for the angle. It is algebra + physics + electrical engineering, plus really know what you are doing.
All the propblem is already to estimate frequency and phase. There is a pi controller to produce this phase value. It is impossible to know the current phase.
Larger error in initial phase estimation means a longer transient period to implement phase-locking. You can check if other kind of PLLs have such an issue.
Yes, it is possible to do, but you need to clearly understand dq algebra and trigonometry. For a given initial torque and flux in the machine, you back-calculate what would be the dq set points, by assuming then you find the initial values for sine and cosine, get the trigonometric identity to calculate the initial possible values for the angle. It is algebra + physics + electrical engineering, plus really know what you are doing.
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