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 article proposes a new control integrating a lock-in amplifier (LA) to achieve precise phase synchronization between the two sides without employing communication techniques. Integrating an LA enables the controller to convert the received voltage into a distortion-free fundamental signal. In addition to the LA, the BD-WPT system uses a compensation method to mitigate the phase delay caused by high-frequency (HF) 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 LA, are subsequently used in the phase-locked loop (PLL). Current regulation through dq 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%.