Characterizing an Autonomous WPT System with Either Constant Current or Constant Voltage Output Independency to Wide Multiple-Parameter Variations

This paper characterizes the performance of an autonomous WPT system under wide-multiple-parameter variations. The autonomous converter can maintain soft switching over the entire operating region, leading the system to present either constant current (CC) or constant voltage (CV) characteristics independent of wide changes in magnetic coupling, self-inductance, and loading conditions. The system has no other operating modes except CC and CV, and these two modes can transition adaptively. The transitional point between CC to CV is determined by theoretical analyzed. A prototype system is built to verify the system performance, and the experimental results show the output voltage is maintained between 9.2 to 12.7V as the coupling coefficient varies from 0.21 to 0.93, with the simultaneously load varies from 10Ω to 1000Ω. By contrast, the output current is able to maintained approximately constant when the coupling coefficient and the load changes from 0.05 to 0.21, with the simultaneously load from 0.5Ω to 10Ω, respectively. The experiment verifies the CC-CV transitional at a typical coupling 0.45. Apart from the coupling and load variations, the system shows excellent component tolerances as demonstrated by allowance of over 83% changes in the self-inductance and more than 100% of the tuning parameters.