A Phase-Synchronization Control of Bidirectional Wireless Power Transfer System for G2V and V2G Operation Modes

Synchronization control of the Bidirectional Wireless Power Transfer (BD-WPT) system maintains and locks the required phase difference between the primary and pickup converters. Communication is widely considered for synchronization; however, a delay in signal data transmission may influence efficiency or interrupt power transfer. The switching between grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes can also be impacted by synchronization delays. This paper proposes a new control integrating a lock-in amplifier to achieve precise phase synchronization between the two sides without employing communication techniques. Integrating a lock-in amplifier enables the controller to convert the received voltage into a distortion-free fundamental signal. In addition to the lock-in amplifier, the BD-WPT system utilizes a compensation method to mitigate the phase delay caused by high-frequency signal processing through Digital Signal Processors (DSPs). This compensation method addresses both voltage and current delays in the system. Orthogonal signals from the pickup voltage vector, processed through the lock-in amplifier, are subsequently utilized in the phase-locked loop (PLL). Current regulation through <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> current control is applied to both converters on the primary and pickup sides. The performance of the proposed control has been evaluated through experimental investigation on a 2 kW BD-WPT system prototype. Moreover, the overall system efficiency of the BD-WPT system, measured at a receiving DC power of 1.9 kW, reaches 94.634%.