Guangyao Li

Constant-current/constant-voltage (CC/CV) charging requires an inductive power transfer (IPT) converter to maintain the desired output characteristic and high efficiency over a wide range of operating-point load conditions. To address this challenge, this paper proposes a multimode reconfigurable IPT topology for high-power wireless charging of automated guided vehicles (AGVs). The topology coordinates reconfiguration between LCC–LCC and LCC–S compensation networks with full-bridge/half-bridge operation on both the inverter and rectifier sides, establishing three operating modes for low-load CC, higher-load CC, and high-load CV charging without a cascaded output DC–DC converter. A hybrid mode-switching strategy is further developed: the Mode 1/2 boundary is selected at the equal-efficiency point to preserve wide-range efficiency, whereas the Mode 2/3 boundary is selected at the equal-power point to reduce the CC-to-CV transition-power discontinuity. Experimental results obtained with resistive load banks over 3–144 Ω show that the hybrid strategy maintains a measured power-stage DC–DC efficiency of 91.72–94.95%. Compared with fixed single-mode operation over the same range, the hybrid strategy increases the minimum measured efficiency from 85.70% to 91.72%, an improvement of 6.02 percentage points. The prototype achieves a maximum output power of 15.26 kW at 94.71% efficiency, demonstrating the feasibility of the proposed reconfigurable approach for high-power, wide-load-range AGV wireless charging.

Compared with conventional two-coil wireless power transfer (WPT) systems, three-coil WPT systems with an intermediate relay coil offer superior performance in terms of transmission distance and tuning flexibility, making them suitable for a wider range of applications. To address the CC/CV hybrid charging challenge in practical three-coil wireless power transfer (WPT) systems, based on the dual-frequency compensation network (DFCN), this paper proposes a dual-frequency switchable LCC-S-S and S-S-S compensated three-coil topology along with a systematic parameter tuning methodology. Furthermore, the proposed system exhibits zero-phase angle (ZPA) input impedance characteristics at both resonant frequencies, and the ZPA condition remains invariant under coupling coefficient variations. Unlike conventional approaches requiring additional active components, such as relays or AC switches, the proposed compensation topology realizes simple and efficient CC/CV hybrid charging by only switching between two resonant frequencies. An experimental prototype rated at 400 W is constructed to assess the efficacy of the presented framework. The system has a simple structure, is easy to control, and has stable output. The peak DC-DC efficiency reaches 92.15% and 92.75% in both the CC and CV charging modes, respectively.

To address receiver-side weight constraints, resonance detuning, and output-current variations caused by coil misalignment in unmanned aerial vehicle (UAV) wireless charging, this paper proposes an inductive power transfer system employing an inductor-series/none (L-S/N) compensation topology and primary-side-sensing-based constant-current control. The topology eliminates the secondary compensation network, while its tuning conditions and constant-current characteristics are derived using a T-network immittance-inverter model. The mutual inductance is identified from two primary-current magnitude measurements without secondary-side sensing or wireless communication. A switched capacitor controlled by pulse-width modulation (PWM) is then used to restore resonance, and inverter phase-shift control compensates for the output-gain variation caused by changes in mutual inductance. In addition, a three-layer stacked magnetic coupler is designed to improve mutual-inductance stability under horizontal misalignment. Experimental results demonstrate stable operation at different misalignment positions, achieving a DC-to-DC efficiency of 84.3% at an output power of approximately 98 W.

In segmented dynamic wireless power transfer (DWPT) systems, the presence of cross-coupling mutual inductance leads to the generation of induced circulating current (ICC) in the inactive rails, resulting in power loss, magnetic field leakage, increased inverter capacity, and reduced efficiency. To address this problem, a parameter configuration method based on resonance tuning coefficient λ is proposed. This method effectively suppresses ICC, reduces inverter capacity, and improves system efficiency. In addition, it is found that the abnormal drop in inverter current during λ tuning is caused by multiple resonance points at the inverter input impedance. For scenarios involving multiple power supply rails (PSRs), it is revealed that under conventional parameter configuration method, the ICC exhibits hyperbolic-sine-type damped diffusion behavior. Building on this, a general circuit analysis model is proposed for different operating modes of PSR, with circuit parameters summarized and a design flowchart provided. Finally, a 12-meter DWPT platform is built to validate the proposed method, achieving maximum output power of 63.39 kW and system efficiency of 94.15%.

Automated guided vehicles (AGVs) operating in uneven environments are typically designed with an elevated chassis to enhance obstacle-crossing. In inductive power transfer (IPT) systems for such AGVs, a long transmission distance along with limited installation space for coils leads to a medium distance-to-diameter ratio (DDR) (1 < DDR ≤ 2), which reduces coupling efficiency and degrades misalignment tolerance. To address this issue, this paper proposes a compact dual-receiver IPT system for medium DDR conditions. The system adopts a flat U-shaped solenoid (FUS) coil as both the transmitter and the primary receiver, and a square solenoid (SS) coil as the secondary receiver, forming the FUSS dual-receiver structure. The FUS coil is optimized through finite element analysis to improve coupling, while the SS coil captures vertical flux to compensate for misalignment losses, thereby enhancing misalignment tolerance. A hybrid rectifier integrating a full-bridge and voltage doubler topology is used to suppress output voltage fluctuation, reduce the number of receiver coil turns, and minimize system volume. A 300 W/100 kHz prototype with a coupler size of 183 × 126 × 838 mm³ achieves 83.51% efficiency under medium DDR and a 185 mm air gap. Voltage fluctuation remains within 5% under ±51.4% X-axis and ±51.7% Y-axis misalignment, confirming the stable power delivery and improved misalignment tolerance of the system.

Bidirectional inductive power transfer (BIPT) systems provide efficient and contactless power transfer for electric vehicles and other applications. However, practical challenges such as parking misalignment, battery state of charge (SoC) variations, and constraints imposed by the SAE J2954 standard limit their reliability, especially during vehicle-to-grid operation. Existing methods focus mainly on unidirectional charging and often assume ideal alignment, overlooking their applicability to practical operation. This paper proposes a novel BIPT system combining switching-controlled capacitors (SCC) and dualphase-shift (DPS) control to address these challenges. SCC compensates for reactance variations via resonant parameter tuning, while DPS achieves wide input-output gain control to accommodate SoC variations. The integrated approach ensures output characteristics and reliable performance under varying clearance distances and load conditions. A 6.6-kW prototype system was developed and experimentally validated, demonstrating its feasibility and robustness for practical applications.

The development of osteogenic biomaterials relies on updates in research methodologies. Establishing reasonable modes is the basis for obtaining reliable experimental conclusions. With the advancement in bone immunology, osteoimmunomodulatory properties have become one of the crucial indexes for evaluating osteogenic biomaterials. Summarizing the current models of bone immunomodulation is beneficial for optimizing experimental protocols and promoting the clinical application of osteogenic biomaterials. In this review, we introduced the crosstalk between the skeletal system and the immune system, in particular, the roles of different immune cells in the process of bone regeneration. Moreover, the mechanisms of osteogenic biomaterials in regulating the osteoimmune microenvironment were analyzed, followed by summarizing the benefits and limitations of current osteoimmunomodulation models in evaluating osteogenic biomaterials. Finally, we discussed the expected future directions of the applications of osteoimmunomodulation models.

The inevitable misalignment tolerance (MT) between the transmitter and receiver of a loosely coupled transformer (LCT) poses a significant challenge to the stability and efficiency of inductive power transfer (IPT) systems. This article proposes an IPT system featuring an integrated coupled complementary dual-receiver (ICCDR) structure to address this issue. The proposed ICCDR comprises two orthogonally arranged solenoid coils (SCs) designed to produce complementary mutual inductances, enabling the system to achieve an MT range of 172% (175%) of the transmitter length. Utilizing a synthesized equivalent mutual inductance, a single-switch reconfigurable topology is developed to achieve constant current (CC) and constant voltage (CV) outputs. The system maintains output current (voltage) fluctuations within 5.82% (5.96%) while ensuring system efficiency between 88.42% and 90.67% (86.08%–90.32%) across the MT range. These results are validated through a 535-W/85-kHz experimental prototype, confirming the system’s ability to improve MT, output stability, and efficiency effectively.

The inevitable misalignment of magnetic couplers presents a substantial challenge to the power transmission and efficiency of inductive power transfer (IPT) systems. In this study, an integrated mutually compensated dual receiver (IMCDR) IPT system for automated guided vehicles with high-efficiency constant current (CC) charging over a large misalignment tolerance (MT) range is proposed. The dual-channel receiver comprises two solenoid coils perpendicularly wound to each other to capture the magnetic flux along the y-and z-axes generated by the transmitter. In this way, two mutual inductances with opposite changing trends are utilized to synthesize an equivalent mutual inductance (Meq) over an MT range. Further, the proposed IMCDR structure was optimized using the finite element method to obtain the optimal receiver length and Meq fluctuation rate. Finally, a 535-W/85-kHz experimental prototype was conducted. Experimental results showed that the proposed IPT system can maintain the output current fluctuation rate within 5.82% with fixed duty/frequency condition when operating over a 172% MT range, and the system efficiency ranges from 88.42% to 90.67%.