Stable power transmission is one of the key factors in the inductive power transfer (IPT) system. However, misalignment between the primary and secondary sides is almost inevitable in practice, affecting the system performance due to the coupling variation. With the widespread use of IPT technology, it is desired to transfer power from the primary side to the secondary side with a wide misalignment range as large as possible. To address this issue, the design method of the detuned circuit is widely applied in the IPT system. This article analyzes the characteristics of the transfer power of the detuned series–series (S-S) topology with frequency variations and proposes a maintaining stable power transfer method versus wide coupling variation by adopting two discrete frequencies. Further, a design step is given to obtain the system parameters. Theoretical and experimental results are provided to demonstrate the misalignment performance of the proposed method. The results show that the coupling range is extended from (0.115–0.2) to (0.115–0.27) with a 5.6% fluctuation of the output power, and the corresponding efficiency varies from 91.46% to 95.52%.

For automatic guided vehicles with dynamic wireless power transfer (DWPT), the vertical variation in the height of the pickup coil is inescapable due to load variations. It can cause changes in the system coil parameters (self-inductances and mutual inductance), further affecting the stability of the system output power. To realize a stable output of the DWPT system when the height of the pickup coil is variable, a parameter design method is proposed in this paper. A mathematical model of output power is established considering the vibrations of coil parameters. The influences of the compensation circuit on the output power and the input impedance are analyzed. The fluctuation of the output power is limited with the circuit parameter optimization. Finally, a 1-kW prototype is built to verily the effectiveness of the proposed approach. Experimental results indicate that within the gap range (20mm~40mm), the maximum fluctuation of the designed system output power is only 4.39% even if the self-inductances vary by 12.33uH and 27.9uH, respectively, and the mutual inductance changes by 1.45 times. Furthermore, the lowest efficiency of the system can reach 91.73%

感应电能传输（inductive power transfer， IPT）系统的线圈偏移难以避免，这将导致系统输出电压平稳性下降。由于全桥逆变器所产生的方波电压，谐波难以完全消除。为利用谐波提升系统抗偏移能力，本文设计一种基于基波-谐波并行传输的复合式双频IPT系统，耦合机构接收端选取bipolar pad （BP）结构线圈以消除副边线圈间的交叉耦合，结合系统参数设计方法使系统在耦合机构发生偏移的情况下实现自适应恒定电压输出，该系统耦合机构采用单发射双接收结构，相较于传统基波-谐波并行IPT系统采用的双发射双接收结构所用线材更少，且无需复杂的反馈控制。最后搭建一个200W的原理样机验证所提方法的正确性和有效性，耦合机构横向偏移33%同时负载在24Ω-40Ω范围变化时，系统输出电压波动始终保持在5%以内。

Wireless power transfer (WPT) is widely exerted in the application with battery charging. Considering the safety and effectiveness, WPT system with the constant current (CC) output and constant voltage (CV) output is demanded to provide power for battery. In this paper, a cost-effective reconfigurable circuit based on CLC-S topology is proposed. With the reform of the proposed reconfigurable circuit, there is no need for extra passive component, and only one ac switch module is added. With the assistance of the extra ac switch module, the CC and CV output can be implemented in the proposed reconfigurable circuit. Finally, an experimental setup is established. The results show that the system can obtain the current output current with 2% fluctuation and the current output voltage with 5% fluctuation in CC or CV mode with the 1000% variation of the load, respectively.

在高压杆塔在线监测设备的电池充电过程中，为了兼顾充电速度与安全，常采用恒流/恒压充电方式。文中基于多中继线圈的无线电能传输系统，提出一种仅切换一次系统工作频率便能实现恒流/恒压输出的方法，该方法无需复杂的控制和额外的元件。首先，分析得到恒流、恒压与系统系数矩阵之间的定量关系；然后,采用迭代算法，确定各个补偿参数的数值，使得系统在两个不同的频率点上可以分别实现恒流或恒压输出；最后，切换系统的工作频率，即可从恒流输出模式切换到恒压输出模式。实验结果表明，在负载大范围变化时，电流增益和电压增益仅略微变化，且在整个充电过程中，几乎没有无功功率。