Identification and Control of LCC-S WPT Systems Using a Linear Parameter Varying Model

In this article, the problem of modeling and control of an LCC-S wireless power transfer (WPT) system in the presence of rectifier discontinuous conduction and load variation is considered. The diode bridge in an LCC-S WPT system often enters the discontinuous conduction mode (DCM), due to its unidirectional conductivity property. To better handle this type of nonlinearity, a linear parameter varying (LPV) model, which allows the model parameters to change with respect to a set of chosen dependence variables, is suggested to describe the dynamic behavior of the system. Based on this LPV model, a modified two degrees of freedom internal model control structure is proposed. The proposed control structure can switch between open loop and closed loop: when the system is in DCM, the system is configured as open loop because the load voltage or current is uncontrollable from the primary side, where any control action may impair the control system performance; otherwise, the system is operated in closed loop. Experimental results are provided to validate the effectiveness of the proposed modeling and control method.