A Monotonic Output Regulation Method for Series-Series Compensated Inductive Power Transfer Systems with Improved Efficiency and Communication-Less Control

To achieve output voltage regulation in a wireless power transfer (WPT) system, a conventional approach is to apply closed-loop output control to the load side DC-DC converter. However, for series-series compensated inductive power transfer (SS-IPT) systems, the system output has a nonmonotonic relationship with the control input of the load side converter, which could complicate the system controller design and may even cause instabilities. This paper proposes a monotonic load side output regulation method based on phase-shift control (PSC). Concurrently, a primary side pulse density modulation (PDM) control is applied to compensate the system efficiency drop brought by PSC. The overall control scheme requires no communication devices and can achieve high stability, reliability and efficiency.