Steady-State Multiple Parameters Estimation of the Inductive Power Transfer System

In this paper, we proposed a novel steady-state multiple parameters estimation method of the two-coil inductive power transfer (IPT) system based on the measurement of the primary-side voltage and current fundamentals. The method is used to estimate key parameters, such as mutual inductance and equivalent load resistance, as well as receiver self-inductance and compensation capacitance values, and the total parasitic resistance of the secondary side. The method also allows the identification of the secondary-side resonant frequency. The parameters estimation procedure involves three operating modes of the IPT system: 1) open-circuit of the secondary side, 2) short-circuit of the secondary side, and 3) load connection. Each of these modes allows the identification of different parameters. To make the system operate in predefined modes, two switches are added to the receiver circuit. These switches are controlled from the secondary side, while the parameters estimation process, including load voltage and/or current control, is fully conducted on the primary side. The experimental tests on the prototype have validated the proposed method and demonstrated its effectiveness. The method can be applied to a new generation of high-performance wireless battery charging systems, where the single transmitter unit can be used to charge the battery pack in different devices.