Dual-Source Wireless Charging System Paves Way for Smarter EV Infrastructure
In a significant leap toward sustainable urban mobility, researchers from Nanjing University of Aeronautics and Astronautics have unveiled an innovative dual-source wireless charging system designed to transform how electric vehicles (EVs) are powered. The breakthrough, detailed in the Transactions of Nanjing University of Aeronautics and Astronautics, introduces a hybrid energy model that seamlessly integrates solar and grid power to deliver efficient, intelligent, and environmentally conscious charging solutions for next-generation transportation networks.
As global concerns over climate change intensify and fossil fuel dependency continues to strain environmental systems, the automotive industry stands at a pivotal crossroads. The shift toward electrification is no longer a distant aspiration but an urgent necessity. However, despite growing adoption of EVs, one persistent challenge remains: the limitations of current charging infrastructure. Most existing systems rely on single-source power inputs, often tied directly to the conventional grid, which not only limits flexibility but also undermines the full potential of renewable integration. Moreover, long charging times and the lack of dynamic charging capabilities during vehicle motion hinder widespread user acceptance.
The research team, led by Mr. Syed Zohair Raza under the guidance of Professor Xiao Lan and Dr. Menghan Jiang, has addressed these challenges head-on with a novel architecture that combines photovoltaic energy and alternating current (AC) power into a unified, intelligent charging platform. Their work presents a micro-scale model of an EV wireless charging booth capable of automatic source switching, real-time energy storage, and motion-responsive operation—features that could redefine the future of urban EV ecosystems.
At the heart of this innovation lies a dual-power supply framework that intelligently toggles between a 12-volt solar input and a standard 220-volt AC source. This design ensures continuous power delivery regardless of sunlight availability, making the system resilient to weather fluctuations and grid instability. Unlike traditional solar-powered charging stations that operate independently or require manual intervention during low-generation periods, this system employs an automated changeover circuit that detects power availability and switches sources without user input. This level of autonomy enhances reliability and makes the technology suitable for deployment in diverse environments—from city streets to remote highways.
The integration of renewable energy is not merely an add-on feature but a core component of the system’s design philosophy. By incorporating a 5-watt solar module, the prototype captures and stores solar energy in a lithium-ion battery bank, which then feeds into a buck-boost converter to regulate voltage output. This stored energy powers both the wireless transmission unit and auxiliary systems such as smart street lighting. In doing so, the model exemplifies a holistic approach to urban energy management, where transportation and public infrastructure are no longer siloed but interconnected through shared power networks.
Wireless inductive charging forms the second pillar of this technological advancement. Utilizing the principle of electromagnetic induction, the system transmits power from a transmitter coil embedded beneath the road surface to a receiver coil mounted on the underside of the EV. When the vehicle passes over the charging zone, magnetic flux generated by the primary coil induces a current in the secondary coil, which is then rectified, regulated, and used to charge the onboard battery. This process eliminates the need for physical connectors, reducing wear and tear, minimizing electrical hazards, and enabling seamless charging experiences—especially in dynamic scenarios where vehicles are in motion.
One of the most compelling aspects of the proposed system is its ability to support mobile charging. While most wireless EV chargers today are limited to static applications—such as parking spots or garages—this model demonstrates functionality under movement. The transmitter and receiver coils are engineered with precision: the former consisting of five turns of 20 SWG (Standard Wire Gauge) copper wire with a 6 cm diameter, and the latter featuring fifteen turns of the same gauge and diameter. This configuration optimizes coupling efficiency and ensures stable power transfer even when alignment varies slightly due to vehicle movement.
The researchers report that the system can charge a 4-volt battery from 20% to 100% in just five minutes, highlighting its potential for rapid energy replenishment. Such performance metrics suggest applicability in high-traffic zones where dwell time is minimal, such as toll plazas, bus stops, or traffic signals. If scaled, this capability could drastically reduce range anxiety and make EV ownership more practical for urban commuters.
Beyond the charging mechanism itself, the team has embedded intelligence into the surrounding environment. The system includes an automatic street lighting network controlled by an Atmega328 microcontroller—an open-source platform known for its adaptability and robustness. This controller interfaces with two types of sensors: light-dependent resistors (LDRs) and infrared (IR) sensors. The LDRs detect ambient light levels, ensuring that streetlights activate only during nighttime or low-visibility conditions. Meanwhile, the IR sensors monitor vehicular presence, switching lights on only when a car approaches and turning them off once it departs.
This dual-sensor approach results in substantial energy savings. Traditional street lighting systems operate on fixed schedules or dusk-to-dawn timers, often illuminating empty roads for hours. In contrast, the proposed model activates lighting only when needed, aligning energy use with actual demand. Furthermore, the same IR sensors can trigger the wireless charging sequence, ensuring that power transmission begins only when a vehicle is properly positioned above the transmitter coil. This selective activation minimizes energy waste and reduces unnecessary electromagnetic exposure.
Another critical feature of the system is the auto-cutoff charging circuit, which prevents overcharging and prolongs battery lifespan. Overcharging remains a common issue in consumer electronics and EVs alike, leading to thermal runaway, reduced cycle life, and safety risks. The inclusion of a relay-based cutoff mechanism ensures that once the battery reaches full capacity, the charging process halts automatically. This protective function is monitored via a three-segment LCD voltage indicator, providing real-time feedback on both input and output voltages. For end users, this translates into greater confidence in system safety and reliability.
From an engineering standpoint, the project demonstrates meticulous attention to component selection and circuit design. The AC power pathway begins with a step-down transformer that converts 220 V AC to 12 V DC, followed by a bridge rectifier and filtering capacitor to smooth the output. A 7809 voltage regulator further stabilizes the supply to 9 volts before it is distributed to the transmitter and control modules. On the solar side, a dedicated 5 V charger manages the battery input, while a buck-boost converter adjusts the output to match the transmitter’s requirements. Every element serves a defined purpose, contributing to overall system efficiency and stability.
The implications of this research extend far beyond the laboratory. If implemented at scale, such a system could be integrated into smart highways, urban transit corridors, and commercial parking facilities. Imagine a future where EVs recharge incrementally as they drive, drawing power from solar-embedded roadways and grid-backed charging strips. Such infrastructure would enable smaller, lighter batteries—reducing manufacturing costs and material consumption—while maintaining or even extending driving range.
Moreover, the decentralized nature of the system supports grid resilience. During peak demand periods, local solar generation can offset reliance on centralized power plants, reducing strain on the distribution network. In off-grid or disaster-prone areas, standalone versions of this charging booth could provide emergency power for essential transport services.
Despite its promise, the technology is not without limitations. The paper acknowledges that magnetic fields generated during wireless power transfer may pose health concerns, particularly with prolonged exposure. While current safety standards regulate electromagnetic emissions, the authors suggest that future iterations could incorporate additional sensors or shielding mechanisms to mitigate risks. Additionally, the efficiency of inductive coupling decreases with distance and misalignment, meaning precise installation and road design will be crucial for optimal performance.
Nevertheless, the study represents a meaningful step forward in the evolution of EV infrastructure. It bridges the gap between renewable energy harvesting, intelligent control systems, and wireless power delivery—three domains that have traditionally developed in parallel rather than in concert. By unifying them into a single, functional prototype, the researchers have demonstrated the feasibility of a truly integrated mobility ecosystem.
The work also reflects broader trends in engineering research: a move toward multidisciplinary solutions that address complex societal challenges. Climate change, urbanization, energy security, and digital transformation are no longer isolated issues—they intersect in the design of everyday technologies. This project embodies that convergence, showing how innovations in power electronics, embedded systems, and sustainable materials can collectively advance the cause of clean transportation.
For policymakers and city planners, the findings offer actionable insights. Investing in dual-source wireless charging infrastructure could yield multiple benefits: reduced greenhouse gas emissions, lower operational costs for public transit, enhanced energy independence, and improved quality of life through smarter urban design. Pilot programs in select cities could help refine the technology, assess public acceptance, and develop regulatory frameworks for large-scale deployment.
Automotive manufacturers, too, stand to gain from this development. As original equipment makers (OEMs) explore ways to differentiate their EV offerings, partnerships with universities and research institutions could accelerate the integration of advanced charging technologies. Features like motion-based charging and solar-assisted power supply could become key selling points in competitive markets.
Looking ahead, the research team has identified several avenues for improvement. These include increasing transmission efficiency through resonant tuning, expanding the power delivery range, and exploring bidirectional charging capabilities that allow vehicles to feed energy back into the grid. Future models may also incorporate machine learning algorithms to predict traffic patterns and optimize energy allocation dynamically.
In conclusion, the dual-source wireless charging system developed at Nanjing University of Aeronautics and Astronautics is more than a technical achievement—it is a vision of what sustainable mobility can become. It challenges the status quo of EV charging by introducing intelligence, adaptability, and environmental stewardship into the very fabric of transportation infrastructure. As cities around the world seek to decarbonize their fleets and modernize their streets, this innovation offers a compelling blueprint for the road ahead.
The success of this project underscores the importance of academic research in driving technological progress. With support from the National Natural Science Foundation of China and the Aviation Science Foundation, the team has transformed theoretical concepts into a working prototype with real-world relevance. Their collaborative effort—combining expertise in power electronics, control systems, and simulation analysis—exemplifies the kind of interdisciplinary teamwork needed to solve today’s most pressing engineering challenges.
As the global transition to electric mobility accelerates, solutions like this will play a defining role in shaping the cities of tomorrow. No longer will drivers need to plan their routes around charging stations or worry about battery depletion. Instead, energy will flow seamlessly from the environment into the vehicle, powered by the sun, managed by smart systems, and delivered without wires. The future of transportation is not just electric—it is intelligent, integrated, and inherently sustainable.
Syed Zohair Raza, Xiao Lan, Menghan Jiang, Nanjing University of Aeronautics and Astronautics, Transactions of Nanjing University of Aeronautics and Astronautics, http://dx.doi.org/10.16356/j.1005-1120.2024.S.005