Sinewave Notch During AC Coupling – Choke Saturation?

Author	Message
jony787 Newbie Joined: 07/01/2025 Location: Puerto Rico Posts: 7	Posted: 11:42pm 18 Jun 2025         analog8484 said   Off-grid profiles still have active anti-islanding just more tolerance for frequency, voltage and rate of impedance changes.  Since you are already using an off-grid profile I suggest you find one with anti-islanding disabled completely.  IIRC, such profiles have "AI" in the name somewhere. Your chokes appear to be using common green ferrite cores so it's likely they are saturated at 5500W (> 100A to battery).  You'll need to use sendust or similar cores to avoid saturation (see KeepIS threads for more detail).  Having said that, I doubt core saturation is the main reason for the distortions you are seeing. It would help determine the main distortion cause if you could capture the current waveform from the iQ7's.  Anti-islanding disturbances are pretty obvious in the current waveform. I need to get a current probe for my oscilloscope.... I made some research regarding the anti-islanding and found the following. I could be wrong but it doesn't seem like the IQ7+ are pushing any distortion. I will contact Enphase since I'm still intrigued by this but most likely, IQ7+ are on Group 1. Edited 2025-06-19 09:53 by jony787