A Multi-Load Capacitive Power Transfer System With Load-Independent Characteristic for Reefer Container Application

In order to supply power wirelessly to reefer containers without constructing an extra power tower, this article proposed a novel multiload capacitive power transfer (CPT) system with an SP-CL isolation compensation topology. Unlike the traditional multiload CPT system, where receivers function solely as power consumers, in the proposed system, each receiver not only supplies power to the connected load but transfers power wirelessly to the next receivers. The coupler model with the cross-coupling of metal containers is established for reefer container application. Then, the SP-CL isolation compensation topology analysis based on the single circuit is carried out to achieve the load-independent characteristics with constant output voltage. The output characteristics and efficiency of the proposed CPT system are analyzed, considering the impact of the parasitic resistance. Besides, the voltage stress of passive components is optimized to design the experiment system. A 1.8-kW prototype with three loads is built to validate the effectiveness of the proposed CPT system. The equal power distribution (600 W and 600 W and 600 W) is achieved, and the system efficiency can reach 83.7%.