I have attached inductor current waveform of PFC boost converter. After the particular current level, an undesired peak is coming. I have done some study and thinking it might be because of inductor saturation but not sure.
I observed same behaviour in interleaved PFC controlled by MCU. At higher load same peaks at coils currents affect the line current. Higher Proportional value of current loop controller help slightly together with some feedforward shape which help current controllers performance. Some people have similar problem with TI pfc IC, but there was the problem with some clamping of internal structure - the solution was to decrease shunt value.
(Image source: TI E2E forum topic: UCC28180: UCC28180 PFC : distorsion of the PFC coil current [sic])
But in my case the shunt voltage after amplification with OPAMP is far from ADC max 3.3V. My current scale is 8Amps and issue is at 3-4Amp
In general: A boost converter is a kind of switching regulator, where a current flowing through a coil is switched on and off. This switching action causes very abrupt current change which results in very high coil voltage (V=L*dI/dt).