Electric vehicles (EVs) have gained significant adoption due to their advantages over conventional vehicles. The Photovoltaic Inductive Wireless Power Transfer (PV-IWPT) system combines wireless charging technology with photovoltaic panels to provide clean, solar-powered EV charging. However, varying distances between the ground and EV chassis create inconsistent coupling coefficients, causing fluctuating optimal load conditions for the IWPT converter and making it challenging to maintain peak efficiency without manual recalibration. This paper introduces a Ground-to-Chassis distance adaptive control approach for PV-IWPT systems that simultaneously achieve Maximum Power Point Tracking (MPPT) for solar harvesting and Maximum Efficiency Point Tracking (MEPT) for power transfer across different ground-to-chassis distances. The system automatically adapts to positional variations without requiring hardware adjustments. We validate our approach through theoretical analysis and experimental verification using a 500-W test platform under multiple distance configurations and solar shading conditions, demonstrating its practical viability for real-world applications.

Conventional wireless power transfer (WPT) systems struggle to maintain constant voltage output under wide input voltage variations, such as battery-powered devices and renewable energy systems where voltages fluctuate due to load changes and environmental conditions. This paper addresses the challenge of maintaining constant voltage output under a tenfold input voltage range. The proposed adaptive full-bridge/half-bridge (FB/HB) dynamic modulation switching topology with asymmetric PWM (APWM). Comparing dynamic table lookup control (LUC) with the proposed method shows superior output voltage stability with reduced overshoot. The system achieves constant voltage regulation through single-stage modulation across the entire ten-fold input range that enables robust wireless power delivery.

In electric vehicle wireless power transfer systems, misalignment between primary and secondary coils commonly occurs, resulting in mutual inductance fluctuations that decrease transfer efficiency. To overcome this problem, this paper proposed a novel misalignment-tolerant coil design combining quadrupolar trapezoidal coils with unipolar square coils on the secondary side. These two sets of coils are connected in series through a diode rectifier, making the equivalent mutual inductance equal to the sum of their absolute mutual inductance values. When perfectly aligned, the unipolar square coils maintain good coupling with the transmitter coil while the quadrupolar trapezoidal coils remain decoupled. During misalignment, as the mutual inductance between unipolar coils and the transmitter decreases, the mutual inductance between quadrupolar coils and the transmitter increases. This complementary relationship maintains a nearly constant total equivalent mutual inductance, providing exceptional misalignment tolerance and stable system output. Simulation results show mutual inductance fluctuation of only 2.60%, with experimental verification demonstrating 3.11%. The output voltage fluctuation in simulation is just 2.51%, while the system achieves a peak efficiency of 95.52%.

Currently, electric vehicle (EV) battery platforms typically vary in standard, commonly rated at either 800V or 400V. Conventional wireless charging system (WCS) are limited to single voltage level charging, necessitating wireless communication or additional complex circuits for achieving multi-voltage level charging, which can compromise operational stability and overall efficiency. This article proposes a WCS based on the concept of bipolar partial power conversion. By incorporating reversing series switches on the secondary of the DC/DC converter, regulation voltage control enables switching between positive and negative polarity to supply power to either 800V or 400V battery for EV. This approach ensures high power transmission efficiency, without relying on wireless communication, thereby ensuring stable charging process. Furthermore, this article also presents various combinations of bipolar topologies that can be selectively employed based on application requirements. Finally, simulation results validate the feasibility of the proposed 3.2KW WCS.

For inductive power transfer (IPT) systems, the loosely coupled transformer (LCT) is a crucial component. Variations in the air gap can lead to fluctuations in the parameters of the LCT, such as self-inductance and mutual inductance, caused by positional deviations of the ferrite cores on both sides. However, such variable LCT parameters can damage the resonant tank, thus impacting transmission efficiency and output stability. To address this issue, this paper proposes a self-tuning S/S IPT system based on switch-controlled capacitors (SCCs). The system utilizes gradient descent methods independently on double-side to achieve decoupled tuning control. This approach effectively mitigates the impact of LCT parameter fluctuations without requiring wireless communication. Furthermore, all switches in the system operate at fixed frequencies and implement soft switching. Finally, a prototype is constructed to validate the effectiveness of the proposed system.

The use of unmanned surface vehicles (USVs) in oceanography research is widespread due to their ability to provide real-time data. Due to the limited battery size, recharging operations including plugging and unplugging decrease the overall utilization of the USV. To address this issue, wireless power transfer (WPT) can be implemented by installing coils at the dock and inside the USV. In this paper, a three-coil WPT system is designed for offshore USV wireless charging applications. The proposed three-coil structure is designed to ensure adequate coupling and achieve high transfer efficiency. Aiming to meet practical battery charging specifications, LCC-S-S compensation topology is analyzed with detailed parameter design to provide constant current output. Finally, simulations are conducted to verify the coupling and output characteristics of the system.

This paper presents a passive control method utilizing an auxiliary protection circuit for LCC-S compensated converters. The proposed method effectively addresses the challenges of over-load and over-aligned conditions, which can cause excessive inverter output current and higher-than-required system output voltage. By incorporating the auxiliary protection circuit, complex compensated circuits and wireless communication are eliminated, providing a simple and reliable solution. Experimental validation was performed in a 48 V wireless charging prototype to demonstrate the efficacy of the protection strategy in promptly safeguarding the primary circuit against device damage.

Compared with the conventional constant current-constant voltage (CC-CV) charging profile of Li-ion battery, multi-stage constant current (MSCC) charging profile that composed of different constant current stages can improve the charging rate. This paper proposes a MSCC charging profile for an inductive power transfer (IPT) converter with LCC-S compensation topology. However, the wide load range variation during charging process impacts the transfer efficiency of the IPT converter. Thus, aiming to improve the transfer efficiency throughout the whole MSCC charging process, a bivariate operation approach is proposed with a variable inductance to achieve different constant current stages, while the voltage-controlled semi-active rectifier (VCSAR) is controlled to ensure the converter’s efficiency optimization. Finally, simulation study is conducted based on PSIM software simulation to verify the validity and effectiveness of the bivariate control strategy and MSCC charging for the LCC-S compensated IPT converter.

In lithium-ion (li-ion) battery charging process, multistage constant-current (MSCC) charging can effectively increase the charging capacity with less charging time compared with the conventional constant current-to-constant voltage (CC-to-CV) charging in wired charging. This paper proposes and designs a MSCC charging strategy for the wireless power transfer system. By using the LCC-S compensation topology for the inductive power transfer (IPT) converter, the current gain is designed with mathematical derivation to achieve load-independent current output with zero phase angle (ZPA) according to the MSCC charging pattern. Phase-shift modulation (PSM) is adopted to control the input DC-link of the WPT system to achieve different current outputs according to different CC stages. Finally, the charging system is simulated to verify the correctness of the design and the feasibility of the proposed WPT system with MSCC charging. The maximum efficiency of the system is 92.4% and the time-averaged efficiency is 91.3%.

The market share of renewable energy grows rapidly with the rising issues like global warming and environment pollution. As a kind of flexible and mature way to collect solar energy, photovoltaic (PV) panels have been widely installed on lands. To save precious land resources, PV panels can be installed on water to form floating-PV farm. In this paper, an inductive power transfer (IPT) converter for wireless power transmission is proposed for the floating-PV system, which can avoid of possible electrical hazard and reduce the exposure of the components, thus enhance the performance of anti-humidity and anti-salinity of the floating-PV system. However, the varying irradiance conditions caused by changeable weather of lake or seashore scenario gives challenge to the trackable range of MPPT control strategy for the IPT converter. To address this problem, an irradiance-adaptive hybrid maximum power point tracking (MPPT) control strategy for the floating-PV system is also proposed, which can achieve the maximum power point (MPP) of the PV panels even under a wide range of irradiance conditions. In addition, the IPT converter with the proposed MPPT control strategy does not require a DC-DC converter to achieve the MPPT in a wide irradiance range, thus saving the system cost. Finally, the IPT converter with irradiance-adaptive hybrid MPPT control strategy is theoretically analyzed, and its feasibility is verified on an experiment platform.1

For the coils design of the inductive power transfer (IPT) system, the coils for the received-side and the transmitter-side are usually designed symmetrical in order to obtain better coupling coefficient and for simplicity. Along with a growing number of space-constrained devices, such as drones and small automated guided vehicles (AGV), much more flexible designs of receiver coil, such as asymmetrical coil designs are of great interest. Nevertheless, since power transfer efficiency of the IPT system is highly correlated with the parameters of coils, it is challenging to convert symmetrical coils into asymmetrical coils while maintaining the power transfer efficiency and the load independent output. This paper proposes a design methodology of converting symmetrical coils into asymmetrical coils for series-series inductive power transfer (SSIPT) that keeps similar transfer efficiency and maintain the load independent current (LIC) output. The analysis of coils’ parameters including the size and transfer distance is also taken into consideration, and the asymmetrical coil design flowchart is also introduced in this paper. Finally, a 30W experimental platform of the SSIPT system is built, and the experimental results verify the theoretical analysis and the practical feasibility of the proposed asymmetrical coil design.

Nowadays, automated guided vehicle (AGV) has been a key role of manufacturing and logistics, required to work with high automation. It is essential to guarantee the charging reliability of AGV for all-day work. However, in wireless battery charging applications, to utilize load-independent-current and load-independent-voltage transfer characteristics for constant current (CC) and constant voltage (CV) outputs respectively, existing inductive power transfer (IPT) converters either hopping the operating frequencies or switching the hybrid compensation topologies, resulting in necessity of state-of-charge detection and feedback control for the operating frequency hopping or the compensation topology switching. To improve the charging reliability of AGV by eliminating these active controls, this paper proposes an IPT converter with inherent CC-to-CV transition ability that can comply with the required charging profile of the batteries. Unity-power-factor design is also considered to minimize the voltage-ampere rating. This solution is passive, and control is unnecessary, so donating great reliability in automated guided vehicle. Experimental results are presented to verify the methodology and the performance.