Kalman Filter–Based Power Management for Railway Wireless Power Transfer Systems With EDLC Integration

Dynamic wireless power transfer (DWPT) enables power transfer only while the onboard and ground coils are magnetically coupled, necessitating high peak power and a steep power ramp-up. In addition, for several-hundred-kilowatt reception, using a lithium-ion battery (LiB) alone results in an excessively high C-rate and accelerates degradation, whereas implementation constraints in this power range limit the switching frequency of power semiconductors to only a few kilohertz. This study proposes a power management scheme that connects an electric double-layer capacitor (EDLC) in parallel with the LiB and controls the EDLC charging current through feedforward based on transmitted power estimated via a Kalman filter. The proposed scheme suppresses the LiB C-rate while enabling the system to follow steep power variations with a limited number of switching actions. Furthermore, by extracting the high-frequency component of the battery current and using it for damping control, current oscillations during power transients are suppressed. Compared with a conventional disturbance-estimation-plus-feedback method employing a low-pass filter, the proposed method improves command-tracking performance and closed-loop controllability, and its effectiveness in reducing DC–DC converter current ripple is experimentally demonstrated using a 2-kW downscaled setup.