Unilateral Compensation for Compact and Lightweight IPT Converters With Near Unity Power Factor and Load-Independent Constant Output

In many application scenarios, inductive power transfer (IPT) converters are expected to be compact and lightweight, especially in the charging device side. The unilateral compensation is an effective solution to eliminate the bulky passive inductors and capacitors. However, most existing unilateral compensation topologies in IPT converters cannot achieve multiple design objectives simultaneously, such as unity power factor (UPF), load-independent constant output, soft switching, and so on. This article starts from a generalized transformer model and proposes the design principle for unilateral compensation networks in terms of flexible constant-voltage or constant-current output while combating the parameter constraint of the given loosely coupled transformer. In addition, the near UPF and soft switching can be simultaneously achieved to improve the transfer efficiency. Based on the design principle, a family of unilateral compensation topologies is proposed and the design process is detailed. Finally, a 100-W prototype of CLC-N(none) compensated IPT converter is built to verify the design.