Multi-Inverter Phase-Shifted Control for Inductive Power Transfer with Overlapped Transmitters

A high-power inductive power transfer system with overlapped transmitters driven by a multi-inverter topology is proposed in this article. Each inverter drives an independent primary coil to transfer energy to the common secondary coil. A phase-shifted control strategy at inverter-level is proposed to regulate the output of the system. A dynamic model based on virtual resonant loop is proposed to describe the system with the phase-shift angle and the output voltage as the input and output variables, respectively. With the introduction of virtual resonant loop, n practical resonant loops at the primary side can be expressed by two equations, which greatly reduce the scale and order of the model. A PI controller is developed to evaluate the system regulating performance. A laboratory prototype driven by three inverters connected in parallel was built to verify the theoretical analysis. Experiments have shown that the setting times were within 13 ms under load resistance and reference disturbances, which verified the validity of the model and the controller.