基于反向串联耦合线圈的水下航行器抗偏移充电系统研究

Autonomous underwater vehicles (AUVs) have demonstrated significant application value in fields such as underwater resource exploration and ocean development. The challenges of underwater environments, including the limitations of wired power transmission, necessitate the adoption of wireless power transfer (WPT) technology, which eliminates the risk of short circuits associated with physical electrical contacts. However, WPT systems often face axial and rotational misalignment between the transmitting and receiving coils, reducing power transmission efficiency. This paper focuses on three key aspects: compensation network design, coupling mechanism design, and system control. Firstly, a novel circuit topology based on an LCC/S/S hybrid compensation network and a dual-path parallel rectifier bridge is proposed, as shown in Fig.A1. The LCC/S/S hybrid compensation network exhibits a load-independent, constant-voltage output characteristic under resonant conditions. Combined with the output-voltage-clamping behavior of the dual-path parallel-diode full-bridge rectifier, the system topology transitions through six distinct operating modes as axial misalignment varies. Although the power transfer path may differ across these modes, the rectified output voltage depends solely on the equivalent mutual inductance of the coupling mechanism. The rectified output voltage expressions for each operating mode can be summarized based on the relative magnitudes of M_ps1 and M_ps2, as shown in Equation (A1). Secondly, a new coupling mechanism utilizing reverse-series coaxial solenoid coils is designed. The coupling mechanism, based on reverse-series coaxial solenoid coils, exhibits full 360° rotational misalignment tolerance and radial misalignment tolerance within the structural constraints of the AUV and charging dock. With optimized design, the axial misalignment tolerance reaches ±132 mm, which is 75% of the total coupling structure length and represents a 2.3-fold improvement over a control configuration using a single solenoid receiver coil, which achieves only approximately ±57 mm of axial tolerance. Furthermore, a synchronous Buck converter employing a voltage-current dual-loop competitive control strategy is implemented to achieve constant-current and constant-voltage outputs. Each control loop generates its own error signal, V_e1 (voltage error) and V_e2 (current error). The channel selector chooses the one with the smaller magnitude as the final input to the PWM controller, eliminating the need for external state-switching logic. The dual-loop competitive control enables a seamless, automatic transition from constant-current (CC) to constant-voltage (CV) charging modes, offering superior dynamic adaptability that aligns well with the charging requirements of lithium-ion batteries. Finally, experimental results show that the rectifier output voltage fluctuates by only 9.7% over an axial misalignment range of ±132 mm. Within the axial misalignment range, the system transitions internally through six distinct operating modes while maintaining a stable constant-current/constant-voltage output of 25.2 V/5 A at the external terminals. When operating in Mode 3, where the currents in the two receiver coils are equal, the system achieves a peak DC-to-DC transmission efficiency of 95.1% and an overall system efficiency of 90.3%. The proposed system demonstrates significant advantages in both anti-misalignment capability and efficiency, highlighting its strong potential for practical engineering applications.