Load and Mutual Inductance Identification of WPT System Based on Transmitter Information
Zhang Yan1, Du Yibin1, Zang Chaohui1, Zhang Yuwang1, Zhang Xian2
1. School of Electrical Engineering Hebei University of Science and Technology Shijiazhuang 050018 China; 2. State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin 300130 China
Abstract：In wireless power transfer systems, transmission efficiency and power capacity are primarily influenced by load and mutual inductance parameters. However, in practical applications, these parameters are often highly uncertain. For example, in the wireless charging system of electric vehicles, variations in vehicle chassis height and relative coil offsets alter the system's mutual inductance parameters. In addition, the equivalent battery load varies across vehicle models and changes dynamically during charging, directly affecting the system's transmission performance. Therefore, introducing parameter identification technology for real-time estimation of mutual inductance and load parameters not only enables accurate detection of system state but also supports optimization of control algorithms, thereby improving the overall performance of WPT systems. This paper takes a WPT system with the DLCC compensation topology as an example. A method for real-time joint identification of mutual inductance and load parameters is proposed by only collecting the voltage signals of the parallel compensation capacitor at the transmitting side. First, based on the system's steady-state equivalent-circuit model, multiple impedance expressions related to its transmission characteristics are derived, and a coupled-relationship equation system is established among the mutual inductance parameter, the load parameter, and the collected voltage information. By constructing auxiliary functions and introducing the intermediate variable γ, the original coupled equation is reconstructed and simplified, thereby decoupling the mutual inductance and load parameters. The originally complex joint-solution problem is transformed into a cubic equation. A unique real-number solution always exists under any practical operating condition, thereby verifying the theoretical effectiveness of the parameter identification method. By analyzing the relationship between the trigger signal phase and the required sampling information in inverter phase-shift control, it is possible to solve the cubic equation using only one voltage measurement. Then, a quantitative relationship expression between the sampled voltage and mutual inductance is derived to estimate the mutual inductance. Finally, a brief explanation of the overall identification process is given. A WPT system platform with a rated power of 1 kW is constructed. In the experiment, the fixed relationship between the capacitor-voltage phase and the trigger-signal phase across different phase-shift angles is verified by measuring the inverter trigger signal, inverter output-voltage waveform, and parallel-capacitor voltage waveform on the primary side. At the same time, tests under different load, mutual inductance, and phase-shift angle conditions show that the maximum identification errors of this method under variable inductance and variable load conditions are 5.3% and 6.9%, respectively. Compared with other methods, this method can maintain high identification accuracy without requiring communication between the primary and secondary sides, additional circuit topology, or uninterrupted power output.
张岩, 都义彬, 臧朝辉, 张玉旺, 张献. 基于发射端信息的无线电能传输系统负载与互感辨识方法[J]. 电工技术学报, 2026, 41(6): 1860-1871.
Zhang Yan, Du Yibin, Zang Chaohui, Zhang Yuwang, Zhang Xian. Load and Mutual Inductance Identification of WPT System Based on Transmitter Information. Transactions of China Electrotechnical Society, 2026, 41(6): 1860-1871.
[1] 窦润田, 张献, 李永建, 等. 磁耦合谐振无线电能传输系统电磁屏蔽应用发展与研究综述[J]. 中国电机工程学报, 2023, 43(15): 6020-6040. Dou Runtian, Zhang Xian, Li Yongjian, et al.Review of application development and research of electromagnetic shielding in magnetic coupling resonant wireless power transmission system[J]. Proceedings of the CSEE, 2023, 43(15): 6020-6040. [2] Sagar A, Kashyap A, Nasab M A, et al.A comprehensive review of the recent development of wireless power transfer technologies for electric vehicle charging systems[J]. IEEE Access, 2023, 11: 83703-83751. [3] 孙跃, 马皓, 赵雷. 无线电能传输技术及应用专辑主编述评[J]. 电源学报, 2023, 21(6): 1-6. Sun Yue, Ma Hao, Zhao Lei.Editorial for the special issue on wireless power transfer technology and its applications[J]. Journal of Power Supply, 2023, 21(6): 1-6. [4] 陈伟华, 宋宇航, 闫孝姮, 等. 心脏起搏器无线电能传输LCC-LCC磁集成印刷螺旋线圈研究[J]. 电工技术学报, 2024, 39(17): 5289-5299. Chen Weihua, Song Yuhang, Yan Xiaoheng, et al.Research on wireless power transmission for cardiac pacemakers using LCC-LCC magnetic integrated printed spiral coil[J]. Transactions of China Electrotechnical Society, 2024, 39(17): 5289-5299. [5] 陈伟华, 刘宗旺, 李政兴, 等. 谐振式无线供能心脏起搏器多线圈无功屏蔽研究[J]. 电工技术学报, 2022, 37(11): 2673-2685. Chen Weihua, Liu Zongwang, Li Zhengxing, et al.Research on multi coil reactive shielding of resonant wireless energy supply cardiac pacemaker[J]. Transactions of China Electrotechnical Society, 2022, 37(11): 2673-2685. [6] 陈浩, 丘东元, 张波, 等. 植入式医疗设备无线供电技术综述[J]. 电源学报, 2025, 23(1): 188-199. Chen Hao, Qiu Dongyuan, Zhang Bo, et al.Overview of wireless power transfer technology for implantable medical devices[J]. Journal of Power Supply, 2025, 23(1): 188-199. [7] 张献, 邢子瑶, 薛明, 等. 无线电能传输系统异物检测技术研究综述[J]. 电工技术学报, 2022, 37(4): 793-807. Zhang Xian, Xing Ziyao, Xue Ming, et al.Overview of foreign object detection in wireless power transfer system[J]. Transactions of China Electrotechnical Society, 2022, 37(4): 793-807. [8] 孙瀛, 周天, 宋凯, 等. 提升无线充电异物检测系统灵敏度的高阶复合谐振拓扑[J]. 电工技术学报, 2023, 38(6): 1541-1552. Sun Ying, Zhou Tian, Song Kai, et al.Design of highorder composite resonant topology for improving the sensitivity of foreign object detection system[J]. Transactions of China Electrotechnical Society, 2023, 38(6): 1541-1552. [9] 赵航, 张杰, 许知博, 等. 水下磁耦合式无线电能传输系统建模与分析[J]. 电源学报, 2023, 21(6): 195-203. Zhao Hang, Zhang Jie, Xu Zhibo, et al.Modeling and analysis of underwater magnetically-coupled resonant wireless power transfer system[J]. Journal of Power Supply, 2023, 21(6): 195-203. [10] Dai Xin, Jiang Jincheng, Xu Zhou, et al.Cooperative control for multi-excitation units WPT system with multiple coupling parameter identification and area adaptation[J]. IEEE Access, 2020, 8: 38728-38741. [11] 黄文聪, 饶天彪, 蒋煊焱, 等. 无线电能传输系统最大效率追踪及恒压输出复合控制方法[J]. 电工技术学报, 2024, 39(12): 3589-3601, 3615. Huang Wencong, Rao Tianbiao, Jiang Xuanyan, et al.Maximum efficiency tracking and constant voltage output compound control method for wireless power transfer system[J]. Transactions of China Electrotechnical Society, 2024, 39(12): 3589-3601, 3615. [12] 王懿杰, 陆凯兴, 姚友素, 等. 具有强抗偏移性能的电动汽车用无线电能传输系统[J]. 中国电机工程学报, 2019, 39(13): 3907-3917. Wang Yijie, Lu Kaixing, Yao Yousu, et al.An electric vehicle (EV)-oriented wireless power transfer system featuring high misalignment tolerance[J]. Proceedings of the CSEE, 2019, 39(13): 3907-3917. [13] Li Weihan, Wei Guo, Cui Chao, et al.A double-side self-tuning LCC/S system using a variable switched capacitor based on parameter recognition[J]. IEEE Transactions on Industrial Electronics, 2021, 68(4): 3069-3078. [14] 张玉旺, 都义彬, 张岩, 等. 无线电能传输系统参数辨识技术研究综述[J/OL]. 电源学报, 2024: 1-12. (2024-06-13). https://kns.cnki.net/kcms/detail/12.1420.tm.20240613.0933.002.html. Zhang Yuwang, Du Yibin, Zhang Yan, et al. A review of the research on parameter identification technology of wireless power transmission system[J/OL]. Journal of Power Supply, 2024: 1-12. (2024-06-13). https://kns.cnki.net/kcms/detail/12.1420.tm.20240613.0933.002.html. [15] Jiwariyavej V, Imura T, Hori Y.Coupling coefficients estimation of wireless power transfer system via magnetic resonance coupling using information from either side of the system[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2015, 3(1): 191-200. [16] Chow J P, Chung H S, Cheng C S.Use of transmitterside electrical information to estimate mutual inductance and regulate receiver-side power in wireless inductive link[J]. IEEE Transactions on Power Electronics, 2016, 31(9): 6079-6091. [17] Wang Lei, Sun Pan, Wu Xusheng, et al.Mutual inductance identification of IPT system based on soft-start process[J]. IEEE Transactions on Power Electronics, 2022, 37(6): 7504-7517. [18] Hu Jianghao, Zhao Jiankang, Cui Chao.A wide charging range wireless power transfer control system with harmonic current to estimate the coupling coefficient[J]. IEEE Transactions on Power Electronics, 2021, 36(5): 5082-5094. [19] Dai Ruimin, Zhou Wei, Chen Yonghong, et al.Pulse density modulation based mutual inductance and load resistance identification method for wireless power transfer system[J]. IEEE Transactions on Power Electronics, 2022, 37(8): 9933-9943. [20] Su Yugang, Zhang Hongyan, Wang Zhihui, et al.Steady-state load identification method of inductive power transfer system based on switching capacitors[J]. IEEE Transactions on Power Electronics, 2015, 30(11): 6349-6355. [21] Sheng Xuerui, Shi Liming.Mutual inductance and load identification method for inductively coupled power transfer system based on auxiliary inverter[J]. IEEE Transactions on Vehicular Technology, 2020, 69(2): 1533-1541. [22] 苏玉刚, 陈龙, 吴学颖, 等. 基于遗传算法的SS型磁耦合WPT系统负载与互感识别方法[J]. 电工技术学报, 2018, 33(18): 4199-4206. Su Yugang, Chen Long, Wu Xueying, et al.Load and mutual inductance identification method of SS-type magnetically-coupled WPT system based on genetic algorithm[J]. Transactions of China Electrotechnical Society, 2018, 33(18): 4199-4206. [23] 苏玉刚, 阳剑, 戴欣, 等. 基于TensorFlow神经网络的MCR-WPT系统负载与互感识别方法[J]. 电力系统自动化, 2021, 45(18): 162-169. Su Yugang, Yang Jian, Dai Xin, et al.TensorFlow neural network based load and mutual inductance identification method for magnetic coupling resonant wireless power transfer system[J]. Automation of Electric Power Systems, 2021, 45(18): 162-169. [24] Guo Yanjie, Zhang Yuwang, Li Shufan, et al.Load parameter joint identification of wireless power transfer system based on the DC input current and phase-shift angle[J]. IEEE Transactions on Power Electronics, 2020, 35(10): 10542-10553.
2026, Vol. 41 
