Wireless power transfer (WPT) technology, leveraging the unique advantage of contactless power supply, has been recognized as a core power supply solution for mobile devices such as automated guided vehicles (AGVs) and electric vehicles (EVs). However, its transmission performance is highly susceptible to lateral offset, longitudinal misalignment, and angular deflection of the coils, resulting in a sharp decline in efficiency and unstable output. This has become a key bottleneck restricting the engineering application of the technology. This paper presents a comprehensive review focusing on the misalignment tolerance technologies for WPT systems. First, taking the LCC-S/LCC topology as an example, the influence of coil misalignment on the system output performance is analyzed, and various misalignment tolerance methods are enumerated. Subsequently, the basic principles and main research achievements of four categories of misalignment tolerance technologies, namely coupling structure optimization, compensation topology optimization, control strategies, and alignment guidance technology, are systematically summarized, with their limitations identified. Finally, the future research directions of misalignment tolerance technologies are discussed.

Contactless slip rings often require relative rotation between primary and secondary coils due to operational demands in industrial applications. Theoretical and experimental studies reveal that rotational misalignment induces mutual inductance fluctuations, consequently degrading system output characteristics. This paper proposes a rotation-tolerant contactless slip ring system based on simultaneous wireless power and data transfer (SWPDT) technology. An optimized coupling mechanism featuring a rotation-insensitive coil design is developed to maintain stable mutual inductance during rotation, while orthogonal magnetic field decoupling between power and data transfer channels is achieved through directional current configuration in respective coil branches. For circuit topology, the power transfer loop employs an LCC-S compensated network, whereas the data loop adopts an S-S topology, with parameter optimization ensuring robust output performance under rotational misalignment. A 360-W experimental prototype is constructed for validation. Test results demonstrate stable 60-V constant voltage output with less than 2.33% fluctuation throughout 360° rotation, peak transfer efficiency of 88.9% maintained within 2.5% variation, and reliable 19.2-kbps data transfer, confirming the system’s stable operation under continuous rotation conditions.

In response to reliability issues such as mechanical abrasion, seal failures, and operational complexity associated with traditional downhole wired power supply systems. This paper proposes a coaxial nested magnetic coupling structure based on magnetic resonance coupling wireless power transfer (MRC-WPT). By implementing a segmented nested layout of toroidal and axial coils, a three-dimensional directional magnetic field with efficient energy transmission is established. The coil geometry and resonant compensation network are optimized specifically for harsh downhole conditions. Finite element analysis (FEA) demonstrates that the structure achieves a mutual inductance fluctuation ratio (MFR) of $\text{9 0. 1 \%}$, self-inductance fluctuation ratios (SFR) of 99.6 % for both primary and secondary coils. And it maintains stable mutual inductance within $30-32 \mu \mathrm{H}$ across an axial misalignment range of [$-150 ~\text{mm}$, 150 mm. The proposed structure effectively reduces magnetic leakage and core material usage, significantly enhancing both static and dynamic system performance. It provides theoretical support and technical guidance for reliable wireless power supply in intelligent downhole zonal production systems.

This letter proposes a single capacitive coupled wireless power transfer (SCC-WPT) system for unmanned aerial vehicle (UAV) wireless charging applications. By using the inherent UAV helipad as the relay plate, a constant voltage output is achieved. Furthermore, the SCC-WPT system circuits are well presented and analyzed in this letter, and strong misalignment tolerance performance in horizontal as well as rotational situations can be effectively achieved. An experimental prototype was developed, and the experimental results verify that the system can not only maintain stable output voltage under extremely strong misalignment conditions (when the receiver of the system is placed at any position in the xOy plane on the relay plate or rotates 360 degrees) but also achieve constant output voltage when the load changes. The experimental results greatly agree with the theoretical analysis.

This paper presents a wireless power transfer (WPT) system for Unmanned Aerial Vehicle (UAV). Employing a dual-coupled double-inductor-capacitor-capacitor (LCCLCC) compensation topology, the system aims to address the prevalent challenge of misalignment tolerance improvements. It reveals that the system's output is only influenced by M-1, which is the Mutual inductance between transmitting coil L-p and receiving coil L-s. Specifically, the Mutual inductance M-2 has no effect on the output current. The transmitting coil is formed by connecting an inner coil and an outer circular coil in series, with two rectangular coils positioned on the landing gears. As a result, the mutual inductance increases or decreases on the two receiving coils cancel each other out when moving along the y axis. Besides, the output current of this topology is higher than that of traditional LCC-LCC topology and zero voltage switching (ZVS) can be realized. With the help of above system proposed, the output current is stable regardless of load variations, and it can also remain stable within the misalignment range of 100 to 100 mm in x-axis and -70 to 70 mm in y-axis.

This article proposes an advanced framework for wireless charging systems in remote aerial vehicles (RAVs) that integrates magnetic coupling structures with multicoupling LCC-LCC compensation topologies. Unlike existing systems that focus on limited axis misalignment, the proposed system accommodates full 360 degrees rotational misalignment, allowing the UAV to land freely and charge in any orientation thanks to the carefully optimized turn numbers and spacings. As a result, the system supports a broad charging zone with lateral misalignments of Delta x is an element of[-100 mm, 100 mm], Delta y is an element of[-70 mm, 70 mm], and full 360 degrees rotational freedom. Under such a large charging area, the proposed coupler consistently delivers key benefits such as quasi-load-independent output and zero-voltage switching (ZVS). The proposed optimized magnetic coupler, by exploiting the inherent cross-coupling capabilities within the multicoupling LCC-LCC compensation network, effectively expands the ZVS region in the designed charging area.

In this article, a misalignment-adaptive wireless charging system for inspection robots (IRs) is proposed, which has autoalignment capability in the x-axis and high coupling tolerance in the y-axis. A reconfigurable secondary compensation circuit is designed to work initially in the inductor-capacitor-capacitor series (LCC-S) mode for magnetic field autoalignment, and it is then switched to LCC-LCC topology for wireless charging. The Q-coil is used in a reconfigurable coupling structure to adjust the IRs position for autoalignment, and it is also used as the compensation inductor for wireless power transfer (WPT). The DD coil in the secondary side is used to achieve high coupling tolerance capability in the y-axis. A laboratory prototype with an output current of 22 A and output voltage of 52 V is built, and practical results show that the system can achieve an alignment accuracy of +/- 5 mm in the x-axis, and the output current fluctuation of the system is +/- 3.2% when the misalignment ratio along the y-axis is 40%.

This article presents a wireless power transfer system for substation inspection robots. Employing a dual-coupled double inductor-capacitor-capacitor (LCC-LCC) compensation topology, the system aims to address the prevalent challenge of misalignment tolerance improvements. It reveals that the system's output is predominantly influenced by the denominator parameter (i.e., lambda), which is the sum of two dominant factors (i.e., lambda(1) and lambda(2)). Specifically, with larger misalignment, the changing trends of lambda(1) and lambda(2) are opposite. As a result, their sum (lambda) can remain constant by balancing the decrement (increment) in lambda(1) with the increment (decrement) in lambda(2), thereby achieving a relatively stable power transfer during a certain misalignment range. An experimental prototype is built to verify the effectiveness of the proposed system. The experimental results show that the output current is stable regardless of load variations, and it can also remain stable within the misalignment range of -100 to 100 mm in y-axis and 50 to 90 mm in z-axis.

This paper proposes a new method for simultaneous dynamic wireless power and data transfer (SDWPDT). When the receiver is moving, both power and data transfer channels are dynamically switched ON/OFF according to the receiver’s position. In essence, data is transmitted through the high-frequency electric field (EF) generated by the parasitic capacitances of the coupling coils and the metal shield plates, while power is transmitted through the relatively low-frequency magnetic field (MF) generated by coupling coils. By doing this, mutual interference between two transfer channels (i.e., power and data transfer channels) is relatively small. Firstly, the interference from power to data can be greatly reduced due to the absence of a direct electrical wire-based connection. Secondly, the power loss caused by the data transfer channel in the power link is very small so it can be ignored. In addition, the implementation of real-time communication facilitates the establishment of a closed-loop control within the system. This mechanism guarantees consistent power output during dynamic movement, even in the presence of fluctuations in load or input voltage. Laboratory prototype-based experimental findings substantiate the feasibility of the proposed approach.

In this paper, a wireless power transfer (WPT) system is proposed with the ability of parameter estimation for charging inspection robots without the need for an additional communication channel. A novel magnetic coupling and circuit tuning structure is proposed to achieve parameter estimation and closed-loop control using a sensing coil on the primary side. The design process is according to the industrial need of the application, i.e., substation inspection robots. One key procedure is the magnetic coupling design, utilizing the DD and Q coils to eliminate the undesired cross-coupling between them. Two practical series (S) and inductor-capacitor-capacitor (LCC) compensating topologies are adopted to tune with coils for improving energy transferability. Especially, the coupling parameters are identified by reconfiguring the LCC-LCC and SS topologies and detecting the two induced DC voltages of the primary detection circuit, providing the basis for the closed-loop control. Then the induced DC voltage of the primary detection circuit is used as a control feedback for realizing constant current (CC) charging, thereby obviating the need for complex pairing procedures and elimination of additional communication channels. A 480W experimental laboratory setup is constructed, and the feasibility of the proposed method has been validated through laboratory testing.

This study introduces a design of the magnetic coupler tailored for unmanned aerial vehicles (UAVs), distinguished by its robust capability to counteract misalignments, ensuring consistent and reliable charging. This resilience extends beyond mere angular misalignment, also encompassing x-and y-deviations, a testament to the efficacy of the presented magnetic coupling design. The transmitter (TX) incorporates eight solenoid coils, establishing a magnetic field that spans from the core to the periphery. To capitalize on this magnetic field, two rectangular coils have been strategically mounted on the landing gears, aligning with the inherent geometry and space constraints of standard commercial UAV landing apparatus. The employment of air-core receivers also serves to mitigate on-board weight. This meticulously crafted coupling mechanism empowers the system with an impressive capacity to accommodate a full 360∘ of angular misalignments, in addition to a considerable horizontal offset range of (-50 mm, -50 mm) ≤ O=(x, y) ≤ (50 mm, 50 mm). Both finite element analysis (FEA) and an experimental prototype have been employed in this research. The outcomes align congruently with theoretical projections, showcasing output voltage variations of ±0.3 %, ±1.8 %, and ±1.4 % for angular, x-axis, and y-axis misalignments, respectively.

This paper introduces a simultaneous wireless power and data transfer (SWPDT) method by using a halfcylinder-stator and quarter-cylinder-rotator coupling mechanism for rotary steerable systems (RSSs). Through this configuration, stability and synchronization of both power and data transfers are ensured, notably under comprehensive 360° rotational conditions. Moreover, based on the decoupling characteristics, the interference between power and data transfer is also greatly reduced. A prototype is built, which illustrates that the proposed structure possesses the constant voltage (CV) output and stable data transfer capability. Furthermore, observations indicate that the output voltage can be maintained as stable at 48 V with a deviation of ±2.7%. And there is no detectable significant change in data transfer voltage amplitude. During the full 360° rotation, the system DC-DC efficiency range is from 86.7% to 88.9%

This paper proposes a design of a novel magnetic coupling structure, which is featured a strong anti-misalignment ability for reliable charging to unmanned aerial vehicles (UAVs). The strong tolerance is not only limited to rotational misalignment but also to diagonal, lateral, and longitudinal offsets, thanks to the presented magnetic coupling structure. Specifically, the transmitter (Tx) consists of eight solenoid coils and one regular octagon coil, forming a magnetic field between the center and the periphery. To make use of this field, two rectangular coils are mounted on the landing gears with the consideration of the intrinsic shape and space of the landing gears of commercial UAVs. The air-core receivers also save valuable on-board weight. With the help of such a well-designed coupling mechanism, the presented system can tolerate all 360° rotational misalignments and large-distance horizontal offset, i.e., $(-50\ \text{mm}.-50\ \text{mm})\leq(x, y)\leq(50\ \text{mm},50\ \text{mm})$ .

In this article, a robust wireless power transfer system is proposed with self-alignment capability and controllable output current characteristics for static charging of automatic-guided vehicles (AGVs). A reconfigurable circuitry is designed to work initially in an inductor–capacitor–capacitor-series compensation mode for achieving magnetic field self-alignment, then switched to the LCC – LCC configuration for wireless charging. Apart from the passive components used for wireless power transfer, no additional components, such as cameras, sensors, or dedicated sensing coils, are needed for self-alignment. The induced voltage of a series-tuned Q-coil on the load side is used for the AGV to automatically adjust its position. The vehicle will be self-aligned when the induced voltage becomes null, then the system is switched to a controllable constant current charging mode. A prototype is built, which demonstrates that the output charging current is controllable and can be kept constant against load variations. The experimental results show the proposed system can realize an 89.1% dc–dc power transfer efficiency at an output current of 30 A and an output voltage of 48 V.

In this letter, a single-input and regulatable multioutput wireless power transfer system is presented. In particular, the system uses positive and negative half-wave rectifiers and a synchronous rectifier to realize multiple output channels. Each output channel is controllable, providing a flexible wireless charger to meet various charging requirements. Moreover, this system utilizes the inherent half-wave-rectifier channels (#B and #C) to detect synchronous signals for the rectifiers rather than using additional synchronous detection circuits, thereby leading to a cost-effective system. Finally, a 300 W laboratory prototype is contrasted with three voltage levels, i.e., 48, 30, and 24 V. With the help of the control logic, this system shows excellent robustness against different occasions, such as load variations, input disturbance, and misalignment. The overall efficiency ranges from 86.7% to 90.6%.

The magnetic coupling wireless power transfer (MC-WPT) system for automatic guided vehicles is characterized by a small and unfixed air gap, which leads to significant changes in self- and mutual inductance of the magnetic coupler. In this article, an efficiency improvement method is proposed for the MC-WPT system with variable self- and mutual inductance parameters. By optimizing the design of magnetic couplers and compensation parameters, a wide range of zero-voltage switching (ZVS) operation and minimization of the reactive current are achieved. The self-inductance variation is utilized to provide a variable system input impedance, which expands the ZVS operation range with phase-shift modulation. Meanwhile, the reactive current of the resonant tank in the entire air gap range can be reduced to the minimum when the tuning parameters are designed properly. Compared with the traditional hybrid control strategies, the proposed method offers a simpler control scheme and eliminates the adverse effects caused by the self-inductance variation. A laboratory prototype is built to verify the theoretical analysis. The experimental results show that the system achieves ZVS operation and minimum reactive current within an air gap range of 20–50 mm, and efficiency reaches 91.2%.

This paper proposes a method for parallel transmission of power and signals suitable for electric vehicle (EV) dynamic wireless charging. In essence, data is transmitted through the high-frequency electric field of the parasitic capacitance between the transmitting coil, the receiving coil and the shielding plate of the receiving end, and power is transmitted through the magnetic field of relative frequency generated by the coupling coil. In this paper, the coupling mechanism and working principle are expounded and explained, and the parameter design method of the system is given. In addition., the interference between the power wave and the data carrier is also analyzed. Finally, the simulation of the system is carried out, and the parallel transmission of power and signal in the dynamic charging of electric vehicles is realized.

In this paper, a parallel transmission method of power and signal in CPT system is proposed. Based on the typical double-sided LC compensated CPT system structure, on the one hand, power transmission is realized through capacitive coupling channel, and on the other hand, signal transmission is realized through an additional inductive coupling channel formed by compensation inductance. On the basis of establishing the mathematical model of the system, the power transmission, the interference of power to the signal channel and the process of signal transmission are analyzed. Because the frequency difference between the power carrier and the signal carrier is large, the influence between the power channel and the signal channel is relatively small. In order to achieve a compact structure, the signal coupler is used together with the capacitive coupler, which reduces the volume of the device and improves the power density of the system. Finally, a 100w circuit simulation model is established to verify the proposed method. The simulation results show that the system can realize the parallel transmission of power and signal.

This article proposes a magnetic integrated method for the coupler of the electric vehicle dynamic wireless charging system to suppress power fluctuation by transforming the problem into designing a stable equivalent mutual inductance between the receiving coil and transmitting coils on the road. Both primary-side and secondary-side couplers adopt a magnetic integrated design. The primary-side coupler integrates a reverse coil inside the transmitting coil, and the secondary-side coupler integrates a coil in the LCC resonance compensation inside the receiving coil. Two advantages are unveiled through theoretical analysis of system characteristics: the original single mutual inductance is replaced by the mutual inductance difference between the two reverse series transmitting coils and the receiving coil to determine the power transmission, which suppresses output power fluctuation; the secondary-side integrated inductor coil replaces the external bulky compensation inductor in the LCC resonance compensation network and additionally realizes better zero-voltage switching conditions. The optimized design process considering the additional couplings is given based on circuit analysis. A prototype is implemented to validate the proposed design. Experimental results show that the output power fluctuation is within ±4% during dynamic charging at a power level of 4.5 kW, and the efficiency reaches 91.6%.

Due to the diversity of the compensation circuit topology of the DWPT system, when the transmitter and the pickup end adopt different matching schemes for power transmission, the operating characteristics are quite different. In order to solve this interoperability problem, this paper assumes that the primary side adopts the LCC topology, analyzed the output power, efficiency and other parameters of the three matching schemes of LCC-S, LCC-P and LCC-LCC, and proposed a pick-up terminal topology identification method based on the dynamic detection of the primary DC side current. To improve the working condition of the system, the original topology is switched to the obtained topology, and finally the simulation model of the system is established to verify the effectiveness of the proposed method.