I have simulated a model in Simulink of a three-phase three-level Active NPC (ANPC) inverter connected to a grid via an RL filter. I have to implement a full feedback control for voltage and current with a phase locked loop (PLL). The output of the controller are voltages in d-q system which are converted to abc-system and used as reference signals to generate sine-PWM for the inverter. Both PLL and voltage and current controllers are based on PI controllers.
Initially, I'm trying to only run the current controller without voltage control. The three phase voltage output of the controller waveforms are satisfactory. But the three-phase grid currents (which are converted to d-q and used as actuating signals for current controller) has a lot of oscillations. Also, the frequency output from PLL is oscillating +-0.2 about 50 Hz.
After checking and checking the model and all its parameters, I think the PI controllers are not properly tuned. I have used the Kp and Ki values given in the book by Remus Teodorescu.
If anyone has worked on the same, please help.
Thank you.
Hi Mohd Umar,
As I understand, your question has basically two parts below.
My Answers:
[1] Yazdani A, Iravani R. "Voltage-sourced converters in power systems: modeling, control, and applications." John Wiley & Sons; 2010 Mar 25.
All the best,
Babak
Babak Abdolmaleki Thanks for the informative reply. I haven't been active here, so I didn't see your suggestion. In the meantime, I found some literature on Internal Model Control method, and fortunately that worked for me. Thanks anyways, I'm sure your insight will help me in future.
Regards
Umar
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