Efficiency Enhancement in BiWPT Systems: A Novel Control Approach for Mitigating Impact of Misalignment and Load Variation

Misalignment can significantly affect the mutual inductance of a wireless power transfer (WPT) system, there by impacting the system’s power transfer capabilities and efficiency. Traditionally, to achieve optimal efficiency with constant output power under misalignment, individual closed loop feedback control needs to be used on both the transmitter and receiver sides. The receiver side phase shift (β) is controlled to maintain the constant output power, and the transmitter side phase shift (α) is controlled to achieve unity power factor for optimal efficiency. However, this necessitates additional high-bandwidth sensing circuitry, thereby increasing system complexity. This paper proposes a novel control approach for mitigating the impact of misalignment and load variation by employing a single receiver-side controller. A closed form analytical relationship between α and β has been established in this paper to maintain optimal efficiency while regulating output power. The proposed method obtains β from the receiver side controller and α from the derived relation. The proposed control method is validated using an experimental setup of a 1 kW bidirectional wireless power transfer (BiWPT) system. The simulation and experimental results of the BiWPT system under various loading and misalignment conditions are presented.